[PATCH v4 0/6]

[PATCH v4 0/6]

[Bill Roberts]

This is a continuation of:
  - https://lore.kernel.org/all/20260818225428.1983328-1-bill.roberts@arm.com/

FWIW X86 Maintaners and Rick, I structured this so you can just pull the bug fixes only
(up to but not including commit "x86/shstk: support via prctl") if you have concerns
on the other patches for me to address, this will allow you to take the bug fixes
and additional test now if desired.

History:
  - v1: Initial Patches
  - v2: Nacked by author
    - Refactors the test suite
  - v3:
    - Fixes an existing fork bug pointed out by Shashiko
    - Fixes a state rollback issue in the patch itself
    - Fixes Makefile dependencies
    - Add's a test for shadow stack state locking
    - Refactors the arch_prctl and prctl tests into two different files using
      a shared testing suite file
  - v4:
    - fix rollback state logic


Bill Roberts (6):
  selftests/x86: fix Makefile dependencies
  selftests/x86: fix fork bug
  selftests/x86: add shadow stack lock test
  x86/shstk: support via prctl
  selftests/x86: support header files in extra-files
  selftests/x86: add generic prctl shadow stack test

 arch/x86/kernel/shstk.c                       |   83 ++
 tools/testing/selftests/x86/Makefile          |   13 +-
 tools/testing/selftests/x86/shadow_stack.c    | 1287 +++++++++++++++++
 tools/testing/selftests/x86/shadow_stack.h    |   14 +
 .../testing/selftests/x86/test_shadow_stack.c | 1168 +--------------
 .../selftests/x86/test_shadow_stack_prctl.c   |   12 +
 6 files changed, 1411 insertions(+), 1166 deletions(-)
 create mode 100644 tools/testing/selftests/x86/shadow_stack.c
 create mode 100644 tools/testing/selftests/x86/shadow_stack.h
 create mode 100644 tools/testing/selftests/x86/test_shadow_stack_prctl.c

-- 
2.55.0

[PATCH v4 1/6] selftests/x86: fix Makefile dependencies

[Bill Roberts]

The Makefile has a macro called "extra-files" that sets up the
dependency on the target. Right now, for some targets that need
EXTRA_FILES added to the compilation, the dependency is left untracked.
Thus, to fix this, use the aforementioned macro.

Signed-off-by: Bill Roberts <bill.roberts@arm.com>
---
 tools/testing/selftests/x86/Makefile | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index 434065215d12..75315f1190d6 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -124,6 +124,9 @@ $(eval $(call extra-files,test_syscall_vdso_32,thunks_32.S))
 $(eval $(call extra-files,fsgsbase_restore_64,clang_helpers_64.S))
 $(eval $(call extra-files,fsgsbase_restore_32,clang_helpers_32.S))
 $(eval $(call extra-files,sysret_rip_64,clang_helpers_64.S))
+$(eval $(call extra-files,amx_64,xstate.c))
+$(eval $(call extra-files,avx_64,xstate.c))
+$(eval $(call extra-files,apx_64,xstate.c))
 
 # check_initial_reg_state is special: it needs a custom entry, and it
 # needs to be static so that its interpreter doesn't destroy its initial
@@ -135,6 +138,3 @@ $(OUTPUT)/nx_stack_32: CFLAGS += -Wl,-z,noexecstack
 $(OUTPUT)/nx_stack_64: CFLAGS += -Wl,-z,noexecstack
 
 $(OUTPUT)/avx_64: CFLAGS += -mno-avx -mno-avx512f
-$(OUTPUT)/amx_64: EXTRA_FILES += xstate.c
-$(OUTPUT)/avx_64: EXTRA_FILES += xstate.c
-$(OUTPUT)/apx_64: EXTRA_FILES += xstate.c
-- 
2.55.0

[PATCH v4 2/6] selftests/x86: fix fork bug

[Bill Roberts]

Shashiko correctly pointed out this fork bug, the report is below. This
patch fixes it by checking for the child and error conditions
explicitly.

[ ... ]
> +int test_ptrace(void)
> +{
> +     unsigned long saved_ssp, ssp = 0;
> +     struct sigaction sa = {};
> +     struct iovec iov;
> +     int status;
> +     int pid;
> +
> +     iov.iov_base = &ssp;
> +     iov.iov_len = sizeof(ssp);
> +
> +     pid = fork();
> +     if (!pid) {

[Severity: High]
This is a pre-existing issue, but could this code broadcast SIGKILL to
all user processes if fork() fails?

If fork() returns -1 due to resource limits, execution will proceed with
pid = -1. When ptrace() subsequently fails, the error path is triggered:

out_kill:
        kill(pid, SIGKILL);
        return 1;

Since pid is -1, POSIX specifies that this will kill all processes the
current user has permission to terminate, potentially crashing the host
environment.

Signed-off-by: Bill Roberts <bill.roberts@arm.com>
---
 tools/testing/selftests/x86/test_shadow_stack.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tools/testing/selftests/x86/test_shadow_stack.c b/tools/testing/selftests/x86/test_shadow_stack.c
index 3d6ca33edba4..b52c5420c137 100644
--- a/tools/testing/selftests/x86/test_shadow_stack.c
+++ b/tools/testing/selftests/x86/test_shadow_stack.c
@@ -971,6 +971,11 @@ int test_ptrace(void)
 	iov.iov_len = sizeof(ssp);
 
 	pid = fork();
+	if (pid < 0) {
+		printf("[FAIL]\tFork failed for %s\n", __func__);
+		return 1;
+	}
+
 	if (!pid) {
 		ssp = get_ssp();
 
-- 
2.55.0

[PATCH v4 3/6] selftests/x86: add shadow stack lock test

[Bill Roberts]

Add a test that locks the shadow stack write bit and then attempts to
disable write. The disable should fail with EPERM since it's in a locked
state. This also preserves the write bit being set for the whole test
suite as well as preserving the ability to unlock at the end.

Signed-off-by: Bill Roberts <bill.roberts@arm.com>
---
 .../testing/selftests/x86/test_shadow_stack.c | 39 +++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/tools/testing/selftests/x86/test_shadow_stack.c b/tools/testing/selftests/x86/test_shadow_stack.c
index b52c5420c137..72e7329d89d7 100644
--- a/tools/testing/selftests/x86/test_shadow_stack.c
+++ b/tools/testing/selftests/x86/test_shadow_stack.c
@@ -1060,6 +1060,24 @@ int test_ptrace(void)
 	return 1;
 }
 
+static int test_locking(void)
+{
+
+	if (ARCH_PRCTL(ARCH_SHSTK_LOCK, ARCH_SHSTK_WRSS)) {
+		printf("[FAIL]\tCould not lock Shadow stack write\n");
+		return 1;
+	}
+
+	if (ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_WRSS) != -EPERM) {
+		printf("[FAIL]\tCould change Shadow stack write after lock\n");
+		return 1;
+	}
+
+	printf("[OK]\tShadow stack locking\n");
+
+	return 0;
+}
+
 int main(int argc, char *argv[])
 {
 	int ret = 0;
@@ -1079,12 +1097,33 @@ int main(int argc, char *argv[])
 		return 1;
 	}
 
+	/* Note: test_shadow_stack_lock() needs write enabled */
 	if (ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_WRSS)) {
 		printf("[SKIP]\tCould not enable WRSS\n");
 		ret = 1;
 		goto out;
 	}
 
+	unsigned long status = 0;
+
+	if (ARCH_PRCTL(ARCH_SHSTK_STATUS, &status)) {
+		printf("[FAIL]\tCould not get Shadow stack status\n");
+		ret = 1;
+		goto out;
+	}
+
+	if (status != (ARCH_SHSTK_WRSS|ARCH_SHSTK_SHSTK)) {
+		printf("[FAIL]\tStatus not as expected, got 0x%lx status, wanted: 0x%llx\n",
+			status, (ARCH_SHSTK_WRSS|ARCH_SHSTK_SHSTK));
+		ret = 1;
+		goto out;
+	}
+
+	if (test_locking()) {
+		ret = 1;
+		goto out;
+	}
+
 	/* Should have succeeded if here, but this is a test, so double check. */
 	if (!get_ssp()) {
 		printf("[FAIL]\tShadow stack disabled\n");
-- 
2.55.0

[PATCH v4 4/6] x86/shstk: support via prctl

[Bill Roberts]

Historically, managing the user-space shadow stack state on x86 has
been handled exclusively through the arch_prctl() interface via the
ARCH_SHSTK_* operations. However, other architectures (such as arm64 and
riscv) do not implement arch_prctl() and instead utilize the newer,
arch-agnostic, prctl() interface (i.e. PR_GET_SHADOW_STACK_STATUS and
PR_SET_SHADOW_STACK_STATUS).

To provide language runtimes, toolchains, and libc implementations with a
consistent, cross-architecture interface for managing control-flow
integrity, wire up the generic shadow stack prctl handlers for x86.

Map the generic PR_SHADOW_STACK_ENABLE, PR_SHADOW_STACK_DISABLE, and
PR_SHADOW_STACK_LOCK operations onto the underlying x86 internal CET helper
routines. This allows portable userspace applications to toggle or query
shadow stack states without relying on architecture-specific system calls,
while maintaining backward compatibility with existing arch_prctl() calls.

Signed-off-by: Bill Roberts <bill.roberts@arm.com>
---
 arch/x86/kernel/shstk.c | 83 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)

diff --git a/arch/x86/kernel/shstk.c b/arch/x86/kernel/shstk.c
index 0ca64900192f..249c4998732a 100644
--- a/arch/x86/kernel/shstk.c
+++ b/arch/x86/kernel/shstk.c
@@ -18,6 +18,7 @@
 #include <linux/sizes.h>
 #include <linux/user.h>
 #include <linux/syscalls.h>
+#include <linux/prctl.h>
 #include <asm/msr.h>
 #include <asm/fpu/xstate.h>
 #include <asm/fpu/types.h>
@@ -630,3 +631,85 @@ bool shstk_is_enabled(void)
 {
 	return features_enabled(ARCH_SHSTK_SHSTK);
 }
+
+/* Handles the generic prctl interface for PR_SET_SHADOW_STACK_STATUS and its feature bits */
+int arch_set_shadow_stack_status(struct task_struct *t, unsigned long status)
+{
+	int rc;
+	bool shstk_was_enabled = features_enabled(ARCH_SHSTK_SHSTK);
+
+	/*
+	 * One must explicitly perform enable/disable calls for the whole feature set so
+	 * that the locked bits are checked. It is also important to capture entry state
+	 * for roll-back if needed. However, we must NOT try to enable or disable a feature
+	 * unless there is a change in feature status from old to new state. This is
+	 * because shstk_prctl(), correctly, checks locked bits before feature enabled/disabled
+	 * short circuit.
+	 */
+	switch (status) {
+	case 0:
+		/*
+		 * We do NOT explicitly disable WRSS here, disabling shadow stack will disable WRSS,
+		 * and we don't want a locked WRSS to prevent disable.
+		 */
+		return shstk_was_enabled ?
+			shstk_prctl(t, ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK) : 0;
+
+	case PR_SHADOW_STACK_ENABLE:
+		if (!shstk_was_enabled) {
+			rc = shstk_prctl(t, ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK);
+			if (rc)
+				return rc;
+		}
+
+		if (features_enabled(ARCH_SHSTK_WRSS)) {
+			rc = shstk_prctl(t, ARCH_SHSTK_DISABLE, ARCH_SHSTK_WRSS);
+			if (rc && !shstk_was_enabled)
+				shstk_prctl(t, ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK);
+			return rc;
+		}
+
+		return 0;
+
+	case PR_SHADOW_STACK_ENABLE|PR_SHADOW_STACK_WRITE:
+		if (!shstk_was_enabled) {
+			rc = shstk_prctl(t, ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK);
+			if (rc)
+				return rc;
+		}
+
+		if (!features_enabled(ARCH_SHSTK_WRSS)) {
+			rc = shstk_prctl(t, ARCH_SHSTK_ENABLE, ARCH_SHSTK_WRSS);
+			if (rc && !shstk_was_enabled)
+				shstk_prctl(t, ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK);
+
+			return rc;
+		}
+
+		return 0;
+
+	/*
+	 * Unknown bit mapping, unsupported PR_SHADOW_STACK_PUSH or *only*
+	 * PR_SHADOW_STACK_WRITE.
+	 */
+	default:
+		return -EINVAL;
+	}
+}
+
+/* Handles the generic prctl interface for PR_LOCK_SHADOW_STACK_STATUS and its feature bits */
+int arch_lock_shadow_stack_status(struct task_struct *t, unsigned long status)
+{
+	return shstk_prctl(t, ARCH_SHSTK_LOCK, status);
+}
+
+/*
+ * We assume the prctl() feature bits line up with the arch_prctl() specific ones. If not,
+ * the flags returned via arch_get_shadow_stack_status will be mapped wrong.
+ */
+static_assert(PR_SHADOW_STACK_ENABLE == ARCH_SHSTK_SHSTK);
+static_assert(PR_SHADOW_STACK_WRITE  == ARCH_SHSTK_WRSS);
+int arch_get_shadow_stack_status(struct task_struct *t, unsigned long __user *status)
+{
+	return shstk_prctl(t, ARCH_SHSTK_STATUS, (unsigned long)status);
+}
-- 
2.55.0

[PATCH v4 5/6] selftests/x86: support header files in extra-files

[Bill Roberts]

The Makefile dependencies do not include header files, and adding header
files to extra-files calls will cause the header to be passed to the
compiler to compile, which is not what we want. So filter out .h files
from EXTRA_FILES but keep them for the target's prerequisites.

Signed-off-by: Bill Roberts <bill.roberts@arm.com>
---
 tools/testing/selftests/x86/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index 75315f1190d6..ac181b065f37 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -114,7 +114,7 @@ endif
 # the dependencies ("header3.h"), because clang, unlike gcc, will not accept
 # header files as an input to the compiler invocation.
 define extra-files
-$(OUTPUT)/$(1): EXTRA_FILES := $(2)
+$(OUTPUT)/$(1): EXTRA_FILES := $(filter-out %.h,$(2))
 $(OUTPUT)/$(1): $(2)
 endef
 
-- 
2.55.0

[PATCH v4 6/6] selftests/x86: add generic prctl shadow stack test

[Bill Roberts]

Run the same test suite for arch_prctl, against prctl, to ensure
consistency and correctness between the interfaces.

Signed-off-by: Bill Roberts <bill.roberts@arm.com>
---
 tools/testing/selftests/x86/Makefile          |    5 +-
 tools/testing/selftests/x86/shadow_stack.c    | 1287 +++++++++++++++++
 tools/testing/selftests/x86/shadow_stack.h    |   14 +
 .../testing/selftests/x86/test_shadow_stack.c | 1212 +---------------
 .../selftests/x86/test_shadow_stack_prctl.c   |   12 +
 5 files changed, 1324 insertions(+), 1206 deletions(-)
 create mode 100644 tools/testing/selftests/x86/shadow_stack.c
 create mode 100644 tools/testing/selftests/x86/shadow_stack.h
 create mode 100644 tools/testing/selftests/x86/test_shadow_stack_prctl.c

diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index ac181b065f37..64d9057297ef 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -19,7 +19,8 @@ TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \
 			test_FCMOV test_FCOMI test_FISTTP \
 			vdso_restorer
 TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip syscall_numbering \
-			corrupt_xstate_header amx lam test_shadow_stack avx apx
+			corrupt_xstate_header amx lam test_shadow_stack avx apx \
+			test_shadow_stack_prctl
 # Some selftests require 32bit support enabled also on 64bit systems
 TARGETS_C_32BIT_NEEDED := ldt_gdt ptrace_syscall
 
@@ -127,6 +128,8 @@ $(eval $(call extra-files,sysret_rip_64,clang_helpers_64.S))
 $(eval $(call extra-files,amx_64,xstate.c))
 $(eval $(call extra-files,avx_64,xstate.c))
 $(eval $(call extra-files,apx_64,xstate.c))
+$(eval $(call extra-files,test_shadow_stack_64,shadow_stack.c shadow_stack.h))
+$(eval $(call extra-files,test_shadow_stack_prctl_64,shadow_stack.c shadow_stack.h))
 
 # check_initial_reg_state is special: it needs a custom entry, and it
 # needs to be static so that its interpreter doesn't destroy its initial
diff --git a/tools/testing/selftests/x86/shadow_stack.c b/tools/testing/selftests/x86/shadow_stack.c
new file mode 100644
index 000000000000..c29dde59b61f
--- /dev/null
+++ b/tools/testing/selftests/x86/shadow_stack.c
@@ -0,0 +1,1287 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+
+#include <sys/syscall.h>
+#include <asm/mman.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <x86intrin.h>
+#include <asm/prctl.h>
+#include <sys/prctl.h>
+#include <stdint.h>
+#include <signal.h>
+#include <pthread.h>
+#include <sys/ioctl.h>
+#include <linux/userfaultfd.h>
+#include <setjmp.h>
+#include <sys/ptrace.h>
+#include <sys/signal.h>
+#include <linux/elf.h>
+#include <linux/perf_event.h>
+
+#include "shadow_stack.h"
+
+/*
+ * Define the ABI defines if needed, so people can run the tests
+ * without building the headers.
+ */
+#ifndef __NR_map_shadow_stack
+#define __NR_map_shadow_stack	453
+
+#define SHADOW_STACK_SET_TOKEN	(1ULL << 0)
+
+#define ARCH_SHSTK_ENABLE	0x5001
+#define ARCH_SHSTK_DISABLE	0x5002
+#define ARCH_SHSTK_LOCK		0x5003
+#define ARCH_SHSTK_UNLOCK	0x5004
+#define ARCH_SHSTK_STATUS	0x5005
+
+#define ARCH_SHSTK_SHSTK	(1ULL <<  0)
+#define ARCH_SHSTK_WRSS		(1ULL <<  1)
+
+#define NT_X86_SHSTK	0x204
+#endif
+
+#ifndef PR_GET_SHADOW_STACK_STATUS
+#define PR_GET_SHADOW_STACK_STATUS      74
+#define PR_LOCK_SHADOW_STACK_STATUS     76
+#define PR_SET_SHADOW_STACK_STATUS      75
+#define PR_SHADOW_STACK_ENABLE          (1UL << 0)
+#define PR_SHADOW_STACK_WRITE		(1UL << 1)
+#define PR_SHADOW_STACK_PUSH		(1UL << 2)
+#endif
+
+#define SS_SIZE 0x200000
+#define PAGE_SIZE 0x1000
+
+#if (__GNUC__ > 8) || (__GNUC__ == 8 && __GNUC_MINOR__ >= 5)
+
+void write_shstk(unsigned long *addr, unsigned long val)
+{
+	asm volatile("wrssq %[val], (%[addr])\n"
+		     : "=m" (addr)
+		     : [addr] "r" (addr), [val] "r" (val));
+}
+
+static inline unsigned long __attribute__((always_inline)) get_ssp(void)
+{
+	unsigned long ret = 0;
+
+	asm volatile("xor %0, %0; rdsspq %0" : "=r" (ret));
+	return ret;
+}
+
+/*
+ * For use in inline enablement of shadow stack.
+ *
+ * The program can't return from the point where shadow stack gets enabled
+ * because there will be no address on the shadow stack. So it can't use
+ * syscall() for enablement, since it is a function.
+ *
+ * Based on code from nolibc.h. Keep a copy here because this can't pull in all
+ * of nolibc.h.
+ */
+#define ARCH_PRCTL(arg1, arg2)\
+({\
+	long _ret;\
+	register long _num  asm("eax") = __NR_arch_prctl; \
+	register long _arg1 asm("rdi") = (long)(arg1);    \
+	register long _arg2 asm("rsi") = (long)(arg2);    \
+							  \
+	asm volatile (                                    \
+		"syscall\n"                               \
+		: "=a"(_ret)                              \
+		: "r"(_arg1), "r"(_arg2),                 \
+		  "0"(_num)                               \
+		: "rcx", "r11", "memory", "cc"            \
+	);                                                \
+	_ret;                                             \
+})
+
+#define PRCTL(option, arg2, arg3, arg4, arg5)             \
+({                                                        \
+	long _ret;                                        \
+	register long _num  asm("rax") = __NR_prctl;      \
+	register long _arg1 asm("rdi") = (long)(option);  \
+	register long _arg2 asm("rsi") = (long)(arg2);    \
+	register long _arg3 asm("rdx") = (long)(arg3);    \
+	register long _arg4 asm("r10") = (long)(arg4);    \
+	register long _arg5 asm("r8")  = (long)(arg5);    \
+							  \
+	asm volatile (                                    \
+		"syscall"                                 \
+		: "=a"(_ret)                              \
+		: "0"(_num),                              \
+		  "r"(_arg1), "r"(_arg2), "r"(_arg3),     \
+		  "r"(_arg4), "r"(_arg5)                  \
+		: "rcx", "r11", "memory", "cc"            \
+	);                                                \
+	_ret;                                             \
+})
+
+#define SHADOW_STACK_DISABLE(which_test)                           \
+	((which_test) == SHADOW_STACK_TEST_ARCH_PRCTL ?            \
+		ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK) : \
+		PRCTL(PR_SET_SHADOW_STACK_STATUS, 0, 0, 0, 0))
+
+#define SHADOW_STACK_ENABLE(which_test)                                             \
+	((which_test) == SHADOW_STACK_TEST_ARCH_PRCTL ?                             \
+		ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK) :                   \
+		PRCTL(PR_SET_SHADOW_STACK_STATUS, PR_SHADOW_STACK_ENABLE, 0, 0, 0))
+
+#define SHADOW_STACK_ENABLE_WRITE(which_test)                                  \
+	((which_test) == SHADOW_STACK_TEST_ARCH_PRCTL ?                        \
+		ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_WRSS) :               \
+		PRCTL(PR_SET_SHADOW_STACK_STATUS,                              \
+			PR_SHADOW_STACK_ENABLE|PR_SHADOW_STACK_WRITE, 0, 0, 0))
+
+#define SHADOW_STACK_DISABLE_WRITE(which_test)                    \
+	((which_test) == SHADOW_STACK_TEST_ARCH_PRCTL ?           \
+		ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_WRSS) : \
+		PRCTL(PR_SET_SHADOW_STACK_STATUS,                 \
+			PR_SHADOW_STACK_ENABLE, 0, 0, 0))
+
+#define SHADOW_STACK_LOCK(which_test, features)                       \
+	((which_test) == SHADOW_STACK_TEST_ARCH_PRCTL ?               \
+		ARCH_PRCTL(ARCH_SHSTK_LOCK, features) :               \
+		PRCTL(PR_LOCK_SHADOW_STACK_STATUS, features, 0, 0, 0))
+
+#define SHADOW_STACK_GET_STATUS(which_test, status)        \
+	((which_test) == SHADOW_STACK_TEST_ARCH_PRCTL ?    \
+		ARCH_PRCTL(ARCH_SHSTK_STATUS, status) :    \
+		PRCTL(PR_GET_SHADOW_STACK_STATUS, status, 0, 0, 0))
+
+void *create_shstk(void *addr)
+{
+	return (void *)syscall(__NR_map_shadow_stack, addr, SS_SIZE, SHADOW_STACK_SET_TOKEN);
+}
+
+void *create_normal_mem(void *addr)
+{
+	return mmap(addr, SS_SIZE, PROT_READ | PROT_WRITE,
+		    MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+}
+
+void free_shstk(void *shstk)
+{
+	munmap(shstk, SS_SIZE);
+}
+
+int reset_shstk(void *shstk)
+{
+	return madvise(shstk, SS_SIZE, MADV_DONTNEED);
+}
+
+void try_shstk(unsigned long new_ssp)
+{
+	unsigned long ssp;
+
+	printf("[INFO]\tnew_ssp = %lx, *new_ssp = %lx\n",
+	       new_ssp, *((unsigned long *)new_ssp));
+
+	ssp = get_ssp();
+	printf("[INFO]\tchanging ssp from %lx to %lx\n", ssp, new_ssp);
+
+	asm volatile("rstorssp (%0)\n":: "r" (new_ssp));
+	asm volatile("saveprevssp");
+	printf("[INFO]\tssp is now %lx\n", get_ssp());
+
+	/* Switch back to original shadow stack */
+	ssp -= 8;
+	asm volatile("rstorssp (%0)\n":: "r" (ssp));
+	asm volatile("saveprevssp");
+}
+
+int test_shstk_pivot(void)
+{
+	void *shstk = create_shstk(0);
+
+	if (shstk == MAP_FAILED) {
+		printf("[FAIL]\tError creating shadow stack: %d\n", errno);
+		return 1;
+	}
+	try_shstk((unsigned long)shstk + SS_SIZE - 8);
+	free_shstk(shstk);
+
+	printf("[OK]\tShadow stack pivot\n");
+	return 0;
+}
+
+int test_shstk_faults(void)
+{
+	unsigned long *shstk = create_shstk(0);
+
+	/* Read shadow stack, test if it's zero to not get read optimized out */
+	if (*shstk != 0)
+		goto err;
+
+	/* Wrss memory that was already read. */
+	write_shstk(shstk, 1);
+	if (*shstk != 1)
+		goto err;
+
+	/* Page out memory, so we can wrss it again. */
+	if (reset_shstk((void *)shstk))
+		goto err;
+
+	write_shstk(shstk, 1);
+	if (*shstk != 1)
+		goto err;
+
+	printf("[OK]\tShadow stack faults\n");
+	return 0;
+
+err:
+	return 1;
+}
+
+unsigned long saved_ssp;
+unsigned long saved_ssp_val;
+volatile bool segv_triggered;
+
+void __attribute__((noinline)) violate_ss(void)
+{
+	saved_ssp = get_ssp();
+	saved_ssp_val = *(unsigned long *)saved_ssp;
+
+	/* Corrupt shadow stack */
+	printf("[INFO]\tCorrupting shadow stack\n");
+	write_shstk((void *)saved_ssp, 0);
+}
+
+void segv_handler(int signum, siginfo_t *si, void *uc)
+{
+	printf("[INFO]\tGenerated shadow stack violation successfully\n");
+
+	segv_triggered = true;
+
+	/* Fix shadow stack */
+	write_shstk((void *)saved_ssp, saved_ssp_val);
+}
+
+int test_shstk_violation(void)
+{
+	struct sigaction sa = {};
+
+	sa.sa_sigaction = segv_handler;
+	sa.sa_flags = SA_SIGINFO;
+	if (sigaction(SIGSEGV, &sa, NULL))
+		return 1;
+
+	segv_triggered = false;
+
+	/* Make sure segv_triggered is set before violate_ss() */
+	asm volatile("" : : : "memory");
+
+	violate_ss();
+
+	signal(SIGSEGV, SIG_DFL);
+
+	printf("[OK]\tShadow stack violation test\n");
+
+	return !segv_triggered;
+}
+
+/* Gup test state */
+#define MAGIC_VAL 0x12345678
+bool is_shstk_access;
+void *shstk_ptr;
+int fd;
+
+void reset_test_shstk(void *addr)
+{
+	if (shstk_ptr)
+		free_shstk(shstk_ptr);
+	shstk_ptr = create_shstk(addr);
+}
+
+void test_access_fix_handler(int signum, siginfo_t *si, void *uc)
+{
+	printf("[INFO]\tViolation from %s\n", is_shstk_access ? "shstk access" : "normal write");
+
+	segv_triggered = true;
+
+	/* Fix shadow stack */
+	if (is_shstk_access) {
+		reset_test_shstk(shstk_ptr);
+		return;
+	}
+
+	free_shstk(shstk_ptr);
+	create_normal_mem(shstk_ptr);
+}
+
+bool test_shstk_access(void *ptr)
+{
+	is_shstk_access = true;
+	segv_triggered = false;
+	write_shstk(ptr, MAGIC_VAL);
+
+	asm volatile("" : : : "memory");
+
+	return segv_triggered;
+}
+
+bool test_write_access(void *ptr)
+{
+	is_shstk_access = false;
+	segv_triggered = false;
+	*(unsigned long *)ptr = MAGIC_VAL;
+
+	asm volatile("" : : : "memory");
+
+	return segv_triggered;
+}
+
+bool gup_write(void *ptr)
+{
+	unsigned long val;
+
+	lseek(fd, (unsigned long)ptr, SEEK_SET);
+	if (write(fd, &val, sizeof(val)) < 0)
+		return 1;
+
+	return 0;
+}
+
+bool gup_read(void *ptr)
+{
+	unsigned long val;
+
+	lseek(fd, (unsigned long)ptr, SEEK_SET);
+	if (read(fd, &val, sizeof(val)) < 0)
+		return 1;
+
+	return 0;
+}
+
+int test_gup(void)
+{
+	struct sigaction sa = {};
+	int status;
+	pid_t pid;
+
+	sa.sa_sigaction = test_access_fix_handler;
+	sa.sa_flags = SA_SIGINFO;
+	if (sigaction(SIGSEGV, &sa, NULL))
+		return 1;
+
+	segv_triggered = false;
+
+	fd = open("/proc/self/mem", O_RDWR);
+	if (fd == -1)
+		return 1;
+
+	reset_test_shstk(0);
+	if (gup_read(shstk_ptr))
+		return 1;
+	if (test_shstk_access(shstk_ptr))
+		return 1;
+	printf("[INFO]\tGup read -> shstk access success\n");
+
+	reset_test_shstk(0);
+	if (gup_write(shstk_ptr))
+		return 1;
+	if (test_shstk_access(shstk_ptr))
+		return 1;
+	printf("[INFO]\tGup write -> shstk access success\n");
+
+	reset_test_shstk(0);
+	if (gup_read(shstk_ptr))
+		return 1;
+	if (!test_write_access(shstk_ptr))
+		return 1;
+	printf("[INFO]\tGup read -> write access success\n");
+
+	reset_test_shstk(0);
+	if (gup_write(shstk_ptr))
+		return 1;
+	if (!test_write_access(shstk_ptr))
+		return 1;
+	printf("[INFO]\tGup write -> write access success\n");
+
+	close(fd);
+
+	/* COW/gup test */
+	reset_test_shstk(0);
+	pid = fork();
+	if (!pid) {
+		fd = open("/proc/self/mem", O_RDWR);
+		if (fd == -1)
+			exit(1);
+
+		if (gup_write(shstk_ptr)) {
+			close(fd);
+			exit(1);
+		}
+		close(fd);
+		exit(0);
+	}
+	waitpid(pid, &status, 0);
+	if (WEXITSTATUS(status)) {
+		printf("[FAIL]\tWrite in child failed\n");
+		return 1;
+	}
+	if (*(unsigned long *)shstk_ptr == MAGIC_VAL) {
+		printf("[FAIL]\tWrite in child wrote through to shared memory\n");
+		return 1;
+	}
+
+	printf("[INFO]\tCow gup write -> write access success\n");
+
+	free_shstk(shstk_ptr);
+
+	signal(SIGSEGV, SIG_DFL);
+
+	printf("[OK]\tShadow gup test\n");
+
+	return 0;
+}
+
+int test_mprotect(void)
+{
+	struct sigaction sa = {};
+
+	sa.sa_sigaction = test_access_fix_handler;
+	sa.sa_flags = SA_SIGINFO;
+	if (sigaction(SIGSEGV, &sa, NULL))
+		return 1;
+
+	segv_triggered = false;
+
+	/* mprotect a shadow stack as read only */
+	reset_test_shstk(0);
+	if (mprotect(shstk_ptr, SS_SIZE, PROT_READ) < 0) {
+		printf("[FAIL]\tmprotect(PROT_READ) failed\n");
+		return 1;
+	}
+
+	/* try to wrss it and fail */
+	if (!test_shstk_access(shstk_ptr)) {
+		printf("[FAIL]\tShadow stack access to read-only memory succeeded\n");
+		return 1;
+	}
+
+	/*
+	 * The shadow stack was reset above to resolve the fault, make the new one
+	 * read-only.
+	 */
+	if (mprotect(shstk_ptr, SS_SIZE, PROT_READ) < 0) {
+		printf("[FAIL]\tmprotect(PROT_READ) failed\n");
+		return 1;
+	}
+
+	/* then back to writable */
+	if (mprotect(shstk_ptr, SS_SIZE, PROT_WRITE | PROT_READ) < 0) {
+		printf("[FAIL]\tmprotect(PROT_WRITE) failed\n");
+		return 1;
+	}
+
+	/* then wrss to it and succeed */
+	if (test_shstk_access(shstk_ptr)) {
+		printf("[FAIL]\tShadow stack access to mprotect() writable memory failed\n");
+		return 1;
+	}
+
+	free_shstk(shstk_ptr);
+
+	signal(SIGSEGV, SIG_DFL);
+
+	printf("[OK]\tmprotect() test\n");
+
+	return 0;
+}
+
+char zero[4096];
+
+static void *uffd_thread(void *arg)
+{
+	struct uffdio_copy req;
+	int uffd = *(int *)arg;
+	struct uffd_msg msg;
+	int ret;
+
+	while (1) {
+		ret = read(uffd, &msg, sizeof(msg));
+		if (ret > 0)
+			break;
+		else if (errno == EAGAIN)
+			continue;
+		return (void *)1;
+	}
+
+	req.dst = msg.arg.pagefault.address;
+	req.src = (__u64)zero;
+	req.len = 4096;
+	req.mode = 0;
+
+	if (ioctl(uffd, UFFDIO_COPY, &req))
+		return (void *)1;
+
+	return (void *)0;
+}
+
+int test_userfaultfd(void)
+{
+	struct uffdio_register uffdio_register;
+	struct uffdio_api uffdio_api;
+	struct sigaction sa = {};
+	pthread_t thread;
+	void *res;
+	int uffd;
+
+	sa.sa_sigaction = test_access_fix_handler;
+	sa.sa_flags = SA_SIGINFO;
+	if (sigaction(SIGSEGV, &sa, NULL))
+		return 1;
+
+	uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
+	if (uffd < 0) {
+		printf("[SKIP]\tUserfaultfd unavailable.\n");
+		return 0;
+	}
+
+	reset_test_shstk(0);
+
+	uffdio_api.api = UFFD_API;
+	uffdio_api.features = 0;
+	if (ioctl(uffd, UFFDIO_API, &uffdio_api))
+		goto err;
+
+	uffdio_register.range.start = (__u64)shstk_ptr;
+	uffdio_register.range.len = 4096;
+	uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
+	if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+		goto err;
+
+	if (pthread_create(&thread, NULL, &uffd_thread, &uffd))
+		goto err;
+
+	reset_shstk(shstk_ptr);
+	test_shstk_access(shstk_ptr);
+
+	if (pthread_join(thread, &res))
+		goto err;
+
+	if (test_shstk_access(shstk_ptr))
+		goto err;
+
+	free_shstk(shstk_ptr);
+
+	signal(SIGSEGV, SIG_DFL);
+
+	if (!res)
+		printf("[OK]\tUserfaultfd test\n");
+	return !!res;
+err:
+	free_shstk(shstk_ptr);
+	close(uffd);
+	signal(SIGSEGV, SIG_DFL);
+	return 1;
+}
+
+/* Simple linked list for keeping track of mappings in test_guard_gap() */
+struct node {
+	struct node *next;
+	void *mapping;
+};
+
+/*
+ * This tests whether mmap will place other mappings in a shadow stack's guard
+ * gap. The steps are:
+ *   1. Finds an empty place by mapping and unmapping something.
+ *   2. Map a shadow stack in the middle of the known empty area.
+ *   3. Map a bunch of PAGE_SIZE mappings. These will use the search down
+ *      direction, filling any gaps until it encounters the shadow stack's
+ *      guard gap.
+ *   4. When a mapping lands below the shadow stack from step 2, then all
+ *      of the above gaps are filled. The search down algorithm will have
+ *      looked at the shadow stack gaps.
+ *   5. See if it landed in the gap.
+ */
+int test_guard_gap_other_gaps(void)
+{
+	void *free_area, *shstk, *test_map = (void *)0xFFFFFFFFFFFFFFFF;
+	struct node *head = NULL, *cur;
+
+	free_area = mmap(0, SS_SIZE * 3, PROT_READ | PROT_WRITE,
+			 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	munmap(free_area, SS_SIZE * 3);
+
+	shstk = create_shstk(free_area + SS_SIZE);
+	if (shstk == MAP_FAILED)
+		return 1;
+
+	while (test_map > shstk) {
+		test_map = mmap(0, PAGE_SIZE, PROT_READ | PROT_WRITE,
+				MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+		if (test_map == MAP_FAILED)
+			return 1;
+		cur = malloc(sizeof(*cur));
+		cur->mapping = test_map;
+
+		cur->next = head;
+		head = cur;
+	}
+
+	while (head) {
+		cur = head;
+		head = cur->next;
+		munmap(cur->mapping, PAGE_SIZE);
+		free(cur);
+	}
+
+	free_shstk(shstk);
+
+	if (shstk - test_map - PAGE_SIZE != PAGE_SIZE)
+		return 1;
+
+	printf("[OK]\tGuard gap test, other mapping's gaps\n");
+
+	return 0;
+}
+
+/* Tests respecting the guard gap of the mapping getting placed */
+int test_guard_gap_new_mappings_gaps(void)
+{
+	void *free_area, *shstk_start, *test_map = (void *)0xFFFFFFFFFFFFFFFF;
+	struct node *head = NULL, *cur;
+	int ret = 0;
+
+	free_area = mmap(0, PAGE_SIZE * 4, PROT_READ | PROT_WRITE,
+			 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	munmap(free_area, PAGE_SIZE * 4);
+
+	/* Test letting map_shadow_stack find a free space */
+	shstk_start = mmap(free_area, PAGE_SIZE, PROT_READ | PROT_WRITE,
+			   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	if (shstk_start == MAP_FAILED || shstk_start != free_area)
+		return 1;
+
+	while (test_map > shstk_start) {
+		test_map = (void *)syscall(__NR_map_shadow_stack, 0, PAGE_SIZE, 0);
+		if (test_map == MAP_FAILED) {
+			printf("[INFO]\tmap_shadow_stack MAP_FAILED\n");
+			ret = 1;
+			break;
+		}
+
+		cur = malloc(sizeof(*cur));
+		cur->mapping = test_map;
+
+		cur->next = head;
+		head = cur;
+
+		if (test_map == free_area + PAGE_SIZE) {
+			printf("[INFO]\tNew mapping has other mapping in guard gap!\n");
+			ret = 1;
+			break;
+		}
+	}
+
+	while (head) {
+		cur = head;
+		head = cur->next;
+		munmap(cur->mapping, PAGE_SIZE);
+		free(cur);
+	}
+
+	munmap(shstk_start, PAGE_SIZE);
+
+	if (!ret)
+		printf("[OK]\tGuard gap test, placement mapping's gaps\n");
+
+	return ret;
+}
+
+/*
+ * Too complicated to pull it out of the 32 bit header, but also get the
+ * 64 bit one needed above. Just define a copy here.
+ */
+#define __NR_compat_sigaction 67
+
+/*
+ * Call 32 bit signal handler to get 32 bit signals ABI. Make sure
+ * to push the registers that will get clobbered.
+ */
+int sigaction32(int signum, const struct sigaction *restrict act,
+		struct sigaction *restrict oldact)
+{
+	register long syscall_reg asm("eax") = __NR_compat_sigaction;
+	register long signum_reg asm("ebx") = signum;
+	register long act_reg asm("ecx") = (long)act;
+	register long oldact_reg asm("edx") = (long)oldact;
+	int ret = 0;
+
+	asm volatile ("int $0x80;"
+		      : "=a"(ret), "=m"(oldact)
+		      : "r"(syscall_reg), "r"(signum_reg), "r"(act_reg),
+			"r"(oldact_reg)
+		      : "r8", "r9", "r10", "r11"
+		     );
+
+	return ret;
+}
+
+sigjmp_buf jmp_buffer;
+enum shadow_stack_test _which_test;
+void segv_gp_handler(int signum, siginfo_t *si, void *uc)
+{
+	segv_triggered = true;
+
+	/*
+	 * To work with old glibc, this can't rely on siglongjmp working with
+	 * shadow stack enabled, so disable shadow stack before siglongjmp().
+	 */
+	SHADOW_STACK_DISABLE(_which_test);
+	siglongjmp(jmp_buffer, -1);
+}
+
+/*
+ * Transition to 32 bit mode and check that a #GP triggers a segfault.
+ */
+int test_32bit(enum shadow_stack_test which_test)
+{
+	struct sigaction sa = {};
+	struct sigaction *sa32;
+
+	_which_test = which_test;
+
+	/* Create sigaction in 32 bit address range */
+	sa32 = mmap(0, 4096, PROT_READ | PROT_WRITE,
+		    MAP_32BIT | MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+	sa32->sa_flags = SA_SIGINFO;
+
+	sa.sa_sigaction = segv_gp_handler;
+	sa.sa_flags = SA_SIGINFO;
+	if (sigaction(SIGSEGV, &sa, NULL))
+		return 1;
+
+
+	segv_triggered = false;
+
+	/* Make sure segv_triggered is set before triggering the #GP */
+	asm volatile("" : : : "memory");
+
+	/*
+	 * Set handler to somewhere in 32 bit address space
+	 */
+	sa32->sa_handler = (void *)sa32;
+	if (sigaction32(SIGUSR1, sa32, NULL))
+		return 1;
+
+	if (!sigsetjmp(jmp_buffer, 1))
+		raise(SIGUSR1);
+
+	if (segv_triggered)
+		printf("[OK]\t32 bit test\n");
+
+	return !segv_triggered;
+}
+
+static int parse_uint_from_file(const char *file, const char *fmt)
+{
+	int err, ret;
+	FILE *f;
+
+	f = fopen(file, "re");
+	if (!f) {
+		err = -errno;
+		printf("failed to open '%s': %d\n", file, err);
+		return err;
+	}
+	err = fscanf(f, fmt, &ret);
+	if (err != 1) {
+		err = err == EOF ? -EIO : -errno;
+		printf("failed to parse '%s': %d\n", file, err);
+		fclose(f);
+		return err;
+	}
+	fclose(f);
+	return ret;
+}
+
+static int determine_uprobe_perf_type(void)
+{
+	const char *file = "/sys/bus/event_source/devices/uprobe/type";
+
+	return parse_uint_from_file(file, "%d\n");
+}
+
+static int determine_uprobe_retprobe_bit(void)
+{
+	const char *file = "/sys/bus/event_source/devices/uprobe/format/retprobe";
+
+	return parse_uint_from_file(file, "config:%d\n");
+}
+
+static ssize_t get_uprobe_offset(const void *addr)
+{
+	size_t start, end, base;
+	char buf[256];
+	bool found = false;
+	FILE *f;
+
+	f = fopen("/proc/self/maps", "r");
+	if (!f)
+		return -errno;
+
+	while (fscanf(f, "%zx-%zx %s %zx %*[^\n]\n", &start, &end, buf, &base) == 4) {
+		if (buf[2] == 'x' && (uintptr_t)addr >= start && (uintptr_t)addr < end) {
+			found = true;
+			break;
+		}
+	}
+
+	fclose(f);
+
+	if (!found)
+		return -ESRCH;
+
+	return (uintptr_t)addr - start + base;
+}
+
+static __attribute__((noinline)) void uretprobe_trigger(void)
+{
+	asm volatile ("");
+}
+
+/*
+ * This test setups return uprobe, which is sensitive to shadow stack
+ * (crashes without extra fix). After executing the uretprobe we fail
+ * the test if we receive SIGSEGV, no crash means we're good.
+ *
+ * Helper functions above borrowed from bpf selftests.
+ */
+static int test_uretprobe(enum shadow_stack_test which_test)
+{
+	const size_t attr_sz = sizeof(struct perf_event_attr);
+	const char *file = "/proc/self/exe";
+	int bit, fd = 0, type, err = 1;
+	struct perf_event_attr attr;
+	struct sigaction sa = {};
+	ssize_t offset;
+
+	type = determine_uprobe_perf_type();
+	if (type < 0) {
+		if (type == -ENOENT)
+			printf("[SKIP]\tUretprobe test, uprobes are not available\n");
+		return 0;
+	}
+
+	offset = get_uprobe_offset(uretprobe_trigger);
+	if (offset < 0)
+		return 1;
+
+	bit = determine_uprobe_retprobe_bit();
+	if (bit < 0)
+		return 1;
+
+	sa.sa_sigaction = segv_gp_handler;
+	sa.sa_flags = SA_SIGINFO;
+	if (sigaction(SIGSEGV, &sa, NULL))
+		return 1;
+
+	/* Setup return uprobe through perf event interface. */
+	memset(&attr, 0, attr_sz);
+	attr.size = attr_sz;
+	attr.type = type;
+	attr.config = 1 << bit;
+	attr.config1 = (__u64) (unsigned long) file;
+	attr.config2 = offset;
+
+	fd = syscall(__NR_perf_event_open, &attr, 0 /* pid */, -1 /* cpu */,
+		     -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
+	if (fd < 0)
+		goto out;
+
+	if (sigsetjmp(jmp_buffer, 1))
+		goto out;
+
+	SHADOW_STACK_ENABLE(which_test);
+
+	/*
+	 * This either segfaults and goes through sigsetjmp above
+	 * or succeeds and we're good.
+	 */
+	uretprobe_trigger();
+
+	printf("[OK]\tUretprobe test\n");
+	err = 0;
+
+out:
+	SHADOW_STACK_DISABLE(which_test);
+	signal(SIGSEGV, SIG_DFL);
+	if (fd)
+		close(fd);
+	return err;
+}
+
+/* Keep the CALL first so the function address is exactly the probed CALL. */
+extern void uprobe_call_trigger(void);
+asm (".pushsection .text\n"
+	".global uprobe_call_target\n"
+	".type uprobe_call_target, @function\n"
+	"uprobe_call_target:\n"
+	"	ret\n"
+	".size uprobe_call_target, .-uprobe_call_target\n"
+
+	".global uprobe_call_trigger\n"
+	".type uprobe_call_trigger, @function\n"
+	"uprobe_call_trigger:\n"
+	"	call uprobe_call_target\n"
+	"	ret\n"
+	".size uprobe_call_trigger, .-uprobe_call_trigger\n"
+	".popsection\n"
+);
+
+/* If CALL emulation misses the shadow stack update, this exits via SIGSEGV. */
+static int test_uprobe_call(enum shadow_stack_test which_test)
+{
+	const size_t attr_sz = sizeof(struct perf_event_attr);
+	const char *file = "/proc/self/exe";
+	int fd = -1, type, err = 1;
+	struct perf_event_attr attr;
+	struct sigaction sa = {};
+	ssize_t offset;
+
+	type = determine_uprobe_perf_type();
+	if (type < 0) {
+		if (type == -ENOENT)
+			printf("[SKIP]\tUprobe on CALL test, uprobes are not available\n");
+		return 0;
+	}
+
+	offset = get_uprobe_offset(uprobe_call_trigger);
+	if (offset < 0)
+		return 1;
+
+	sa.sa_sigaction = segv_gp_handler;
+	sa.sa_flags = SA_SIGINFO;
+	if (sigaction(SIGSEGV, &sa, NULL))
+		return 1;
+
+	/* Setup entry uprobe through perf event interface. */
+	memset(&attr, 0, attr_sz);
+	attr.size = attr_sz;
+	attr.type = type;
+	attr.config = 0;
+	attr.config1 = (__u64)(unsigned long)file;
+	attr.config2 = offset;
+
+	fd = syscall(__NR_perf_event_open, &attr, 0 /* pid */, -1 /* cpu */,
+		     -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
+	if (fd < 0)
+		goto out;
+
+	if (sigsetjmp(jmp_buffer, 1))
+		goto out;
+
+	if (SHADOW_STACK_ENABLE(which_test))
+		goto out;
+
+	/*
+	 * This either segfaults and goes through sigsetjmp above
+	 * or succeeds and we're good.
+	 */
+	uprobe_call_trigger();
+
+	printf("[OK]\tUprobe on CALL test\n");
+	err = 0;
+
+out:
+	SHADOW_STACK_DISABLE(which_test);
+	signal(SIGSEGV, SIG_DFL);
+	if (fd >= 0)
+		close(fd);
+	return err;
+}
+
+void segv_handler_ptrace(int signum, siginfo_t *si, void *uc)
+{
+	/* The SSP adjustment caused a segfault. */
+	exit(0);
+}
+
+int test_ptrace(void)
+{
+	unsigned long saved_ssp, ssp = 0;
+	struct sigaction sa = {};
+	struct iovec iov;
+	int status;
+	int pid;
+
+	iov.iov_base = &ssp;
+	iov.iov_len = sizeof(ssp);
+
+	pid = fork();
+	if (pid < 0) {
+		printf("[FAIL]\tFork failed for %s\n", __func__);
+		return 1;
+	}
+
+	if (!pid) {
+		ssp = get_ssp();
+
+		sa.sa_sigaction = segv_handler_ptrace;
+		sa.sa_flags = SA_SIGINFO;
+		if (sigaction(SIGSEGV, &sa, NULL))
+			return 1;
+
+		ptrace(PTRACE_TRACEME, NULL, NULL, NULL);
+		/*
+		 * The parent will tweak the SSP and return from this function
+		 * will #CP.
+		 */
+		raise(SIGTRAP);
+
+		exit(1);
+	}
+
+	while (waitpid(pid, &status, 0) != -1 && WSTOPSIG(status) != SIGTRAP);
+
+	if (ptrace(PTRACE_GETREGSET, pid, NT_X86_SHSTK, &iov)) {
+		printf("[INFO]\tFailed to PTRACE_GETREGS\n");
+		goto out_kill;
+	}
+
+	if (!ssp) {
+		printf("[INFO]\tPtrace child SSP was 0\n");
+		goto out_kill;
+	}
+
+	saved_ssp = ssp;
+
+	iov.iov_len = 0;
+	if (!ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
+		printf("[INFO]\tToo small size accepted via PTRACE_SETREGS\n");
+		goto out_kill;
+	}
+
+	iov.iov_len = sizeof(ssp) + 1;
+	if (!ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
+		printf("[INFO]\tToo large size accepted via PTRACE_SETREGS\n");
+		goto out_kill;
+	}
+
+	ssp += 1;
+	if (!ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
+		printf("[INFO]\tUnaligned SSP written via PTRACE_SETREGS\n");
+		goto out_kill;
+	}
+
+	ssp = 0xFFFFFFFFFFFF0000;
+	if (!ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
+		printf("[INFO]\tKernel range SSP written via PTRACE_SETREGS\n");
+		goto out_kill;
+	}
+
+	/*
+	 * Tweak the SSP so the child with #CP when it resumes and returns
+	 * from raise()
+	 */
+	ssp = saved_ssp + 8;
+	iov.iov_len = sizeof(ssp);
+	if (ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
+		printf("[INFO]\tFailed to PTRACE_SETREGS\n");
+		goto out_kill;
+	}
+
+	if (ptrace(PTRACE_DETACH, pid, NULL, NULL)) {
+		printf("[INFO]\tFailed to PTRACE_DETACH\n");
+		goto out_kill;
+	}
+
+	waitpid(pid, &status, 0);
+	if (WEXITSTATUS(status))
+		return 1;
+
+	printf("[OK]\tPtrace test\n");
+	return 0;
+
+out_kill:
+	kill(pid, SIGKILL);
+	return 1;
+}
+
+static int test_locking(enum shadow_stack_test which_test)
+{
+
+	if (SHADOW_STACK_LOCK(which_test, PR_SHADOW_STACK_WRITE)) {
+		printf("[FAIL]\tCould not lock Shadow stack write\n");
+		return 1;
+	}
+
+	if (SHADOW_STACK_DISABLE_WRITE(which_test) != -EPERM) {
+		printf("[FAIL]\tCould change Shadow stack write after lock\n");
+		return 1;
+	}
+
+	printf("[OK]\tShadow stack locking\n");
+
+	return 0;
+}
+
+/*
+ * These bits should never change since UAPI, but confirm with a static assert here and in the
+ * kernel code. These bits MUST line up for ARCH_SHSTK_STATUS and PR_GET_SHADOW_STACK_STATUS
+ * to work without remapping bits.
+ */
+_Static_assert(PR_SHADOW_STACK_ENABLE == ARCH_SHSTK_SHSTK,
+	"Expected PR_SHADOW_STACK_ENABLE == ARCH_SHSTK_SHSTK");
+_Static_assert(PR_SHADOW_STACK_WRITE == ARCH_SHSTK_WRSS,
+	 "Expected PR_SHADOW_STACK_WRITE == ARCH_SHSTK_WRSS");
+
+int shadow_stack_run_tests(enum shadow_stack_test which_test)
+{
+	int ret = 0;
+
+	if (SHADOW_STACK_ENABLE(which_test)) {
+		printf("[SKIP]\tCould not enable Shadow stack\n");
+		return 1;
+	}
+
+	if (SHADOW_STACK_DISABLE(which_test)) {
+		ret = 1;
+		printf("[FAIL]\tDisabling shadow stack failed\n");
+	}
+
+	if (SHADOW_STACK_ENABLE(which_test)) {
+		printf("[SKIP]\tCould not re-enable Shadow stack\n");
+		return 1;
+	}
+
+	/* Note: test_shadow_stack_lock() needs write enabled */
+	if (SHADOW_STACK_ENABLE_WRITE(which_test)) {
+		printf("[SKIP]\tCould not enable WRSS\n");
+		ret = 1;
+		goto out;
+	}
+
+	unsigned long status = 0;
+
+	if (SHADOW_STACK_GET_STATUS(which_test, &status)) {
+		printf("[FAIL]\tCould not get Shadow stack status\n");
+		ret = 1;
+		goto out;
+	}
+
+	if (status != ((PR_SHADOW_STACK_WRITE|PR_SHADOW_STACK_ENABLE))) {
+		printf("[FAIL]\tStatus not as expected, got 0x%lx status, wanted: 0x%llx\n",
+			status, (ARCH_SHSTK_WRSS|ARCH_SHSTK_SHSTK));
+		ret = 1;
+		goto out;
+	}
+
+	if (test_locking(which_test)) {
+		ret = 1;
+		goto out;
+	}
+
+	/* Should have succeeded if here, but this is a test, so double check. */
+	if (!get_ssp()) {
+		printf("[FAIL]\tShadow stack disabled\n");
+		return 1;
+	}
+
+	if (test_shstk_pivot()) {
+		ret = 1;
+		printf("[FAIL]\tShadow stack pivot\n");
+		goto out;
+	}
+
+	if (test_shstk_faults()) {
+		ret = 1;
+		printf("[FAIL]\tShadow stack fault test\n");
+		goto out;
+	}
+
+	if (test_shstk_violation()) {
+		ret = 1;
+		printf("[FAIL]\tShadow stack violation test\n");
+		goto out;
+	}
+
+	if (test_gup()) {
+		ret = 1;
+		printf("[FAIL]\tShadow shadow stack gup\n");
+		goto out;
+	}
+
+	if (test_mprotect()) {
+		ret = 1;
+		printf("[FAIL]\tShadow shadow mprotect test\n");
+		goto out;
+	}
+
+	if (test_userfaultfd()) {
+		ret = 1;
+		printf("[FAIL]\tUserfaultfd test\n");
+		goto out;
+	}
+
+	if (test_guard_gap_other_gaps()) {
+		ret = 1;
+		printf("[FAIL]\tGuard gap test, other mappings' gaps\n");
+		goto out;
+	}
+
+	if (test_guard_gap_new_mappings_gaps()) {
+		ret = 1;
+		printf("[FAIL]\tGuard gap test, placement mapping's gaps\n");
+		goto out;
+	}
+
+	if (test_ptrace()) {
+		ret = 1;
+		printf("[FAIL]\tptrace test\n");
+	}
+
+	if (test_32bit(which_test)) {
+		ret = 1;
+		printf("[FAIL]\t32 bit test\n");
+		goto out;
+	}
+
+	if (test_uretprobe(which_test)) {
+		ret = 1;
+		printf("[FAIL]\turetprobe test\n");
+		goto out;
+	}
+
+	if (test_uprobe_call(which_test)) {
+		ret = 1;
+		printf("[FAIL]\tuprobe on CALL test\n");
+		goto out;
+	}
+
+	return ret;
+
+out:
+	/*
+	 * Disable shadow stack before the function returns, or there will be a
+	 * shadow stack violation.
+	 */
+	if (SHADOW_STACK_DISABLE(which_test)) {
+		ret = 1;
+		printf("[FAIL]\tDisabling shadow stack failed\n");
+	}
+
+	return ret;
+}
+#else
+int shadow_stack_run_tests(enum shadow_stack_test unused)
+{
+	printf("[SKIP]\tCompiler does not support CET.\n");
+	return 0;
+}
+#endif
diff --git a/tools/testing/selftests/x86/shadow_stack.h b/tools/testing/selftests/x86/shadow_stack.h
new file mode 100644
index 000000000000..d36a44df7387
--- /dev/null
+++ b/tools/testing/selftests/x86/shadow_stack.h
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#ifndef TOOLS_TESTING_SELFTESTS_X86_SHADOW_STACK_H_
+#define TOOLS_TESTING_SELFTESTS_X86_SHADOW_STACK_H_
+
+enum shadow_stack_test {
+	SHADOW_STACK_TEST_ARCH_PRCTL,
+	SHADOW_STACK_TEST_PRCTL,
+	SHADOW_STACK_TEST_COUNT,
+};
+
+int shadow_stack_run_tests(enum shadow_stack_test which_test);
+
+#endif /* TOOLS_TESTING_SELFTESTS_X86_SHADOW_STACK_H_ */
diff --git a/tools/testing/selftests/x86/test_shadow_stack.c b/tools/testing/selftests/x86/test_shadow_stack.c
index 72e7329d89d7..41779c9161c8 100644
--- a/tools/testing/selftests/x86/test_shadow_stack.c
+++ b/tools/testing/selftests/x86/test_shadow_stack.c
@@ -1,1218 +1,20 @@
 // SPDX-License-Identifier: GPL-2.0
+
 /*
  * This program test's basic kernel shadow stack support. It enables shadow
  * stack manual via the arch_prctl(), instead of relying on glibc. It's
  * Makefile doesn't compile with shadow stack support, so it doesn't rely on
  * any particular glibc. As a result it can't do any operations that require
  * special glibc shadow stack support (longjmp(), swapcontext(), etc). Just
- * stick to the basics and hope the compiler doesn't do anything strange.
- */
-
-#define _GNU_SOURCE
-
-#include <sys/syscall.h>
-#include <asm/mman.h>
-#include <sys/mman.h>
-#include <sys/stat.h>
-#include <sys/wait.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <string.h>
-#include <errno.h>
-#include <stdbool.h>
-#include <x86intrin.h>
-#include <asm/prctl.h>
-#include <sys/prctl.h>
-#include <stdint.h>
-#include <signal.h>
-#include <pthread.h>
-#include <sys/ioctl.h>
-#include <linux/userfaultfd.h>
-#include <setjmp.h>
-#include <sys/ptrace.h>
-#include <sys/signal.h>
-#include <linux/elf.h>
-#include <linux/perf_event.h>
-
-/*
- * Define the ABI defines if needed, so people can run the tests
- * without building the headers.
- */
-#ifndef __NR_map_shadow_stack
-#define __NR_map_shadow_stack	453
-
-#define SHADOW_STACK_SET_TOKEN	(1ULL << 0)
-
-#define ARCH_SHSTK_ENABLE	0x5001
-#define ARCH_SHSTK_DISABLE	0x5002
-#define ARCH_SHSTK_LOCK		0x5003
-#define ARCH_SHSTK_UNLOCK	0x5004
-#define ARCH_SHSTK_STATUS	0x5005
-
-#define ARCH_SHSTK_SHSTK	(1ULL <<  0)
-#define ARCH_SHSTK_WRSS		(1ULL <<  1)
-
-#define NT_X86_SHSTK	0x204
-#endif
-
-#define SS_SIZE 0x200000
-#define PAGE_SIZE 0x1000
-
-#if (__GNUC__ < 8) || (__GNUC__ == 8 && __GNUC_MINOR__ < 5)
-int main(int argc, char *argv[])
-{
-	printf("[SKIP]\tCompiler does not support CET.\n");
-	return 0;
-}
-#else
-void write_shstk(unsigned long *addr, unsigned long val)
-{
-	asm volatile("wrssq %[val], (%[addr])\n"
-		     : "=m" (addr)
-		     : [addr] "r" (addr), [val] "r" (val));
-}
-
-static inline unsigned long __attribute__((always_inline)) get_ssp(void)
-{
-	unsigned long ret = 0;
-
-	asm volatile("xor %0, %0; rdsspq %0" : "=r" (ret));
-	return ret;
-}
-
-/*
- * For use in inline enablement of shadow stack.
- *
- * The program can't return from the point where shadow stack gets enabled
- * because there will be no address on the shadow stack. So it can't use
- * syscall() for enablement, since it is a function.
- *
- * Based on code from nolibc.h. Keep a copy here because this can't pull in all
- * of nolibc.h.
- */
-#define ARCH_PRCTL(arg1, arg2)					\
-({								\
-	long _ret;						\
-	register long _num  asm("eax") = __NR_arch_prctl;	\
-	register long _arg1 asm("rdi") = (long)(arg1);		\
-	register long _arg2 asm("rsi") = (long)(arg2);		\
-								\
-	asm volatile (						\
-		"syscall\n"					\
-		: "=a"(_ret)					\
-		: "r"(_arg1), "r"(_arg2),			\
-		  "0"(_num)					\
-		: "rcx", "r11", "memory", "cc"			\
-	);							\
-	_ret;							\
-})
-
-void *create_shstk(void *addr)
-{
-	return (void *)syscall(__NR_map_shadow_stack, addr, SS_SIZE, SHADOW_STACK_SET_TOKEN);
-}
-
-void *create_normal_mem(void *addr)
-{
-	return mmap(addr, SS_SIZE, PROT_READ | PROT_WRITE,
-		    MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
-}
-
-void free_shstk(void *shstk)
-{
-	munmap(shstk, SS_SIZE);
-}
-
-int reset_shstk(void *shstk)
-{
-	return madvise(shstk, SS_SIZE, MADV_DONTNEED);
-}
-
-void try_shstk(unsigned long new_ssp)
-{
-	unsigned long ssp;
-
-	printf("[INFO]\tnew_ssp = %lx, *new_ssp = %lx\n",
-	       new_ssp, *((unsigned long *)new_ssp));
-
-	ssp = get_ssp();
-	printf("[INFO]\tchanging ssp from %lx to %lx\n", ssp, new_ssp);
-
-	asm volatile("rstorssp (%0)\n":: "r" (new_ssp));
-	asm volatile("saveprevssp");
-	printf("[INFO]\tssp is now %lx\n", get_ssp());
-
-	/* Switch back to original shadow stack */
-	ssp -= 8;
-	asm volatile("rstorssp (%0)\n":: "r" (ssp));
-	asm volatile("saveprevssp");
-}
-
-int test_shstk_pivot(void)
-{
-	void *shstk = create_shstk(0);
-
-	if (shstk == MAP_FAILED) {
-		printf("[FAIL]\tError creating shadow stack: %d\n", errno);
-		return 1;
-	}
-	try_shstk((unsigned long)shstk + SS_SIZE - 8);
-	free_shstk(shstk);
-
-	printf("[OK]\tShadow stack pivot\n");
-	return 0;
-}
-
-int test_shstk_faults(void)
-{
-	unsigned long *shstk = create_shstk(0);
-
-	/* Read shadow stack, test if it's zero to not get read optimized out */
-	if (*shstk != 0)
-		goto err;
-
-	/* Wrss memory that was already read. */
-	write_shstk(shstk, 1);
-	if (*shstk != 1)
-		goto err;
-
-	/* Page out memory, so we can wrss it again. */
-	if (reset_shstk((void *)shstk))
-		goto err;
-
-	write_shstk(shstk, 1);
-	if (*shstk != 1)
-		goto err;
-
-	printf("[OK]\tShadow stack faults\n");
-	return 0;
-
-err:
-	return 1;
-}
-
-unsigned long saved_ssp;
-unsigned long saved_ssp_val;
-volatile bool segv_triggered;
-
-void __attribute__((noinline)) violate_ss(void)
-{
-	saved_ssp = get_ssp();
-	saved_ssp_val = *(unsigned long *)saved_ssp;
-
-	/* Corrupt shadow stack */
-	printf("[INFO]\tCorrupting shadow stack\n");
-	write_shstk((void *)saved_ssp, 0);
-}
-
-void segv_handler(int signum, siginfo_t *si, void *uc)
-{
-	printf("[INFO]\tGenerated shadow stack violation successfully\n");
-
-	segv_triggered = true;
-
-	/* Fix shadow stack */
-	write_shstk((void *)saved_ssp, saved_ssp_val);
-}
-
-int test_shstk_violation(void)
-{
-	struct sigaction sa = {};
-
-	sa.sa_sigaction = segv_handler;
-	sa.sa_flags = SA_SIGINFO;
-	if (sigaction(SIGSEGV, &sa, NULL))
-		return 1;
-
-	segv_triggered = false;
-
-	/* Make sure segv_triggered is set before violate_ss() */
-	asm volatile("" : : : "memory");
-
-	violate_ss();
-
-	signal(SIGSEGV, SIG_DFL);
-
-	printf("[OK]\tShadow stack violation test\n");
-
-	return !segv_triggered;
-}
-
-/* Gup test state */
-#define MAGIC_VAL 0x12345678
-bool is_shstk_access;
-void *shstk_ptr;
-int fd;
-
-void reset_test_shstk(void *addr)
-{
-	if (shstk_ptr)
-		free_shstk(shstk_ptr);
-	shstk_ptr = create_shstk(addr);
-}
-
-void test_access_fix_handler(int signum, siginfo_t *si, void *uc)
-{
-	printf("[INFO]\tViolation from %s\n", is_shstk_access ? "shstk access" : "normal write");
-
-	segv_triggered = true;
-
-	/* Fix shadow stack */
-	if (is_shstk_access) {
-		reset_test_shstk(shstk_ptr);
-		return;
-	}
-
-	free_shstk(shstk_ptr);
-	create_normal_mem(shstk_ptr);
-}
-
-bool test_shstk_access(void *ptr)
-{
-	is_shstk_access = true;
-	segv_triggered = false;
-	write_shstk(ptr, MAGIC_VAL);
-
-	asm volatile("" : : : "memory");
-
-	return segv_triggered;
-}
-
-bool test_write_access(void *ptr)
-{
-	is_shstk_access = false;
-	segv_triggered = false;
-	*(unsigned long *)ptr = MAGIC_VAL;
-
-	asm volatile("" : : : "memory");
-
-	return segv_triggered;
-}
-
-bool gup_write(void *ptr)
-{
-	unsigned long val;
-
-	lseek(fd, (unsigned long)ptr, SEEK_SET);
-	if (write(fd, &val, sizeof(val)) < 0)
-		return 1;
-
-	return 0;
-}
-
-bool gup_read(void *ptr)
-{
-	unsigned long val;
-
-	lseek(fd, (unsigned long)ptr, SEEK_SET);
-	if (read(fd, &val, sizeof(val)) < 0)
-		return 1;
-
-	return 0;
-}
-
-int test_gup(void)
-{
-	struct sigaction sa = {};
-	int status;
-	pid_t pid;
-
-	sa.sa_sigaction = test_access_fix_handler;
-	sa.sa_flags = SA_SIGINFO;
-	if (sigaction(SIGSEGV, &sa, NULL))
-		return 1;
-
-	segv_triggered = false;
-
-	fd = open("/proc/self/mem", O_RDWR);
-	if (fd == -1)
-		return 1;
-
-	reset_test_shstk(0);
-	if (gup_read(shstk_ptr))
-		return 1;
-	if (test_shstk_access(shstk_ptr))
-		return 1;
-	printf("[INFO]\tGup read -> shstk access success\n");
-
-	reset_test_shstk(0);
-	if (gup_write(shstk_ptr))
-		return 1;
-	if (test_shstk_access(shstk_ptr))
-		return 1;
-	printf("[INFO]\tGup write -> shstk access success\n");
-
-	reset_test_shstk(0);
-	if (gup_read(shstk_ptr))
-		return 1;
-	if (!test_write_access(shstk_ptr))
-		return 1;
-	printf("[INFO]\tGup read -> write access success\n");
-
-	reset_test_shstk(0);
-	if (gup_write(shstk_ptr))
-		return 1;
-	if (!test_write_access(shstk_ptr))
-		return 1;
-	printf("[INFO]\tGup write -> write access success\n");
-
-	close(fd);
-
-	/* COW/gup test */
-	reset_test_shstk(0);
-	pid = fork();
-	if (!pid) {
-		fd = open("/proc/self/mem", O_RDWR);
-		if (fd == -1)
-			exit(1);
-
-		if (gup_write(shstk_ptr)) {
-			close(fd);
-			exit(1);
-		}
-		close(fd);
-		exit(0);
-	}
-	waitpid(pid, &status, 0);
-	if (WEXITSTATUS(status)) {
-		printf("[FAIL]\tWrite in child failed\n");
-		return 1;
-	}
-	if (*(unsigned long *)shstk_ptr == MAGIC_VAL) {
-		printf("[FAIL]\tWrite in child wrote through to shared memory\n");
-		return 1;
-	}
-
-	printf("[INFO]\tCow gup write -> write access success\n");
-
-	free_shstk(shstk_ptr);
-
-	signal(SIGSEGV, SIG_DFL);
-
-	printf("[OK]\tShadow gup test\n");
-
-	return 0;
-}
-
-int test_mprotect(void)
-{
-	struct sigaction sa = {};
-
-	sa.sa_sigaction = test_access_fix_handler;
-	sa.sa_flags = SA_SIGINFO;
-	if (sigaction(SIGSEGV, &sa, NULL))
-		return 1;
-
-	segv_triggered = false;
-
-	/* mprotect a shadow stack as read only */
-	reset_test_shstk(0);
-	if (mprotect(shstk_ptr, SS_SIZE, PROT_READ) < 0) {
-		printf("[FAIL]\tmprotect(PROT_READ) failed\n");
-		return 1;
-	}
-
-	/* try to wrss it and fail */
-	if (!test_shstk_access(shstk_ptr)) {
-		printf("[FAIL]\tShadow stack access to read-only memory succeeded\n");
-		return 1;
-	}
-
-	/*
-	 * The shadow stack was reset above to resolve the fault, make the new one
-	 * read-only.
-	 */
-	if (mprotect(shstk_ptr, SS_SIZE, PROT_READ) < 0) {
-		printf("[FAIL]\tmprotect(PROT_READ) failed\n");
-		return 1;
-	}
-
-	/* then back to writable */
-	if (mprotect(shstk_ptr, SS_SIZE, PROT_WRITE | PROT_READ) < 0) {
-		printf("[FAIL]\tmprotect(PROT_WRITE) failed\n");
-		return 1;
-	}
-
-	/* then wrss to it and succeed */
-	if (test_shstk_access(shstk_ptr)) {
-		printf("[FAIL]\tShadow stack access to mprotect() writable memory failed\n");
-		return 1;
-	}
-
-	free_shstk(shstk_ptr);
-
-	signal(SIGSEGV, SIG_DFL);
-
-	printf("[OK]\tmprotect() test\n");
-
-	return 0;
-}
-
-char zero[4096];
-
-static void *uffd_thread(void *arg)
-{
-	struct uffdio_copy req;
-	int uffd = *(int *)arg;
-	struct uffd_msg msg;
-	int ret;
-
-	while (1) {
-		ret = read(uffd, &msg, sizeof(msg));
-		if (ret > 0)
-			break;
-		else if (errno == EAGAIN)
-			continue;
-		return (void *)1;
-	}
-
-	req.dst = msg.arg.pagefault.address;
-	req.src = (__u64)zero;
-	req.len = 4096;
-	req.mode = 0;
-
-	if (ioctl(uffd, UFFDIO_COPY, &req))
-		return (void *)1;
-
-	return (void *)0;
-}
-
-int test_userfaultfd(void)
-{
-	struct uffdio_register uffdio_register;
-	struct uffdio_api uffdio_api;
-	struct sigaction sa = {};
-	pthread_t thread;
-	void *res;
-	int uffd;
-
-	sa.sa_sigaction = test_access_fix_handler;
-	sa.sa_flags = SA_SIGINFO;
-	if (sigaction(SIGSEGV, &sa, NULL))
-		return 1;
-
-	uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
-	if (uffd < 0) {
-		printf("[SKIP]\tUserfaultfd unavailable.\n");
-		return 0;
-	}
-
-	reset_test_shstk(0);
-
-	uffdio_api.api = UFFD_API;
-	uffdio_api.features = 0;
-	if (ioctl(uffd, UFFDIO_API, &uffdio_api))
-		goto err;
-
-	uffdio_register.range.start = (__u64)shstk_ptr;
-	uffdio_register.range.len = 4096;
-	uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
-	if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
-		goto err;
-
-	if (pthread_create(&thread, NULL, &uffd_thread, &uffd))
-		goto err;
-
-	reset_shstk(shstk_ptr);
-	test_shstk_access(shstk_ptr);
-
-	if (pthread_join(thread, &res))
-		goto err;
-
-	if (test_shstk_access(shstk_ptr))
-		goto err;
-
-	free_shstk(shstk_ptr);
-
-	signal(SIGSEGV, SIG_DFL);
-
-	if (!res)
-		printf("[OK]\tUserfaultfd test\n");
-	return !!res;
-err:
-	free_shstk(shstk_ptr);
-	close(uffd);
-	signal(SIGSEGV, SIG_DFL);
-	return 1;
-}
-
-/* Simple linked list for keeping track of mappings in test_guard_gap() */
-struct node {
-	struct node *next;
-	void *mapping;
-};
-
-/*
- * This tests whether mmap will place other mappings in a shadow stack's guard
- * gap. The steps are:
- *   1. Finds an empty place by mapping and unmapping something.
- *   2. Map a shadow stack in the middle of the known empty area.
- *   3. Map a bunch of PAGE_SIZE mappings. These will use the search down
- *      direction, filling any gaps until it encounters the shadow stack's
- *      guard gap.
- *   4. When a mapping lands below the shadow stack from step 2, then all
- *      of the above gaps are filled. The search down algorithm will have
- *      looked at the shadow stack gaps.
- *   5. See if it landed in the gap.
- */
-int test_guard_gap_other_gaps(void)
-{
-	void *free_area, *shstk, *test_map = (void *)0xFFFFFFFFFFFFFFFF;
-	struct node *head = NULL, *cur;
-
-	free_area = mmap(0, SS_SIZE * 3, PROT_READ | PROT_WRITE,
-			 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-	munmap(free_area, SS_SIZE * 3);
-
-	shstk = create_shstk(free_area + SS_SIZE);
-	if (shstk == MAP_FAILED)
-		return 1;
-
-	while (test_map > shstk) {
-		test_map = mmap(0, PAGE_SIZE, PROT_READ | PROT_WRITE,
-				MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-		if (test_map == MAP_FAILED)
-			return 1;
-		cur = malloc(sizeof(*cur));
-		cur->mapping = test_map;
-
-		cur->next = head;
-		head = cur;
-	}
-
-	while (head) {
-		cur = head;
-		head = cur->next;
-		munmap(cur->mapping, PAGE_SIZE);
-		free(cur);
-	}
-
-	free_shstk(shstk);
-
-	if (shstk - test_map - PAGE_SIZE != PAGE_SIZE)
-		return 1;
-
-	printf("[OK]\tGuard gap test, other mapping's gaps\n");
-
-	return 0;
-}
-
-/* Tests respecting the guard gap of the mapping getting placed */
-int test_guard_gap_new_mappings_gaps(void)
-{
-	void *free_area, *shstk_start, *test_map = (void *)0xFFFFFFFFFFFFFFFF;
-	struct node *head = NULL, *cur;
-	int ret = 0;
-
-	free_area = mmap(0, PAGE_SIZE * 4, PROT_READ | PROT_WRITE,
-			 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-	munmap(free_area, PAGE_SIZE * 4);
-
-	/* Test letting map_shadow_stack find a free space */
-	shstk_start = mmap(free_area, PAGE_SIZE, PROT_READ | PROT_WRITE,
-			   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-	if (shstk_start == MAP_FAILED || shstk_start != free_area)
-		return 1;
-
-	while (test_map > shstk_start) {
-		test_map = (void *)syscall(__NR_map_shadow_stack, 0, PAGE_SIZE, 0);
-		if (test_map == MAP_FAILED) {
-			printf("[INFO]\tmap_shadow_stack MAP_FAILED\n");
-			ret = 1;
-			break;
-		}
-
-		cur = malloc(sizeof(*cur));
-		cur->mapping = test_map;
-
-		cur->next = head;
-		head = cur;
-
-		if (test_map == free_area + PAGE_SIZE) {
-			printf("[INFO]\tNew mapping has other mapping in guard gap!\n");
-			ret = 1;
-			break;
-		}
-	}
-
-	while (head) {
-		cur = head;
-		head = cur->next;
-		munmap(cur->mapping, PAGE_SIZE);
-		free(cur);
-	}
-
-	munmap(shstk_start, PAGE_SIZE);
-
-	if (!ret)
-		printf("[OK]\tGuard gap test, placement mapping's gaps\n");
-
-	return ret;
-}
-
-/*
- * Too complicated to pull it out of the 32 bit header, but also get the
- * 64 bit one needed above. Just define a copy here.
- */
-#define __NR_compat_sigaction 67
-
-/*
- * Call 32 bit signal handler to get 32 bit signals ABI. Make sure
- * to push the registers that will get clobbered.
- */
-int sigaction32(int signum, const struct sigaction *restrict act,
-		struct sigaction *restrict oldact)
-{
-	register long syscall_reg asm("eax") = __NR_compat_sigaction;
-	register long signum_reg asm("ebx") = signum;
-	register long act_reg asm("ecx") = (long)act;
-	register long oldact_reg asm("edx") = (long)oldact;
-	int ret = 0;
-
-	asm volatile ("int $0x80;"
-		      : "=a"(ret), "=m"(oldact)
-		      : "r"(syscall_reg), "r"(signum_reg), "r"(act_reg),
-			"r"(oldact_reg)
-		      : "r8", "r9", "r10", "r11"
-		     );
-
-	return ret;
-}
-
-sigjmp_buf jmp_buffer;
-
-void segv_gp_handler(int signum, siginfo_t *si, void *uc)
-{
-	segv_triggered = true;
-
-	/*
-	 * To work with old glibc, this can't rely on siglongjmp working with
-	 * shadow stack enabled, so disable shadow stack before siglongjmp().
-	 */
-	ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK);
-	siglongjmp(jmp_buffer, -1);
-}
-
-/*
- * Transition to 32 bit mode and check that a #GP triggers a segfault.
+ * stick to the basics and hope the compiler doesn't do anything strange. It
+ * uses the x86 specific interface for ARCH_PCTL, whereas
+ * test_shadow_stack_prctl.c uses the generic PRCTL interface mixed with x86
+ * specific code.
  */
-int test_32bit(void)
-{
-	struct sigaction sa = {};
-	struct sigaction *sa32;
-
-	/* Create sigaction in 32 bit address range */
-	sa32 = mmap(0, 4096, PROT_READ | PROT_WRITE,
-		    MAP_32BIT | MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
-	sa32->sa_flags = SA_SIGINFO;
-
-	sa.sa_sigaction = segv_gp_handler;
-	sa.sa_flags = SA_SIGINFO;
-	if (sigaction(SIGSEGV, &sa, NULL))
-		return 1;
-
-
-	segv_triggered = false;
-
-	/* Make sure segv_triggered is set before triggering the #GP */
-	asm volatile("" : : : "memory");
-
-	/*
-	 * Set handler to somewhere in 32 bit address space
-	 */
-	sa32->sa_handler = (void *)sa32;
-	if (sigaction32(SIGUSR1, sa32, NULL))
-		return 1;
-
-	if (!sigsetjmp(jmp_buffer, 1))
-		raise(SIGUSR1);
-
-	if (segv_triggered)
-		printf("[OK]\t32 bit test\n");
-
-	return !segv_triggered;
-}
-
-static int parse_uint_from_file(const char *file, const char *fmt)
-{
-	int err, ret;
-	FILE *f;
-
-	f = fopen(file, "re");
-	if (!f) {
-		err = -errno;
-		printf("failed to open '%s': %d\n", file, err);
-		return err;
-	}
-	err = fscanf(f, fmt, &ret);
-	if (err != 1) {
-		err = err == EOF ? -EIO : -errno;
-		printf("failed to parse '%s': %d\n", file, err);
-		fclose(f);
-		return err;
-	}
-	fclose(f);
-	return ret;
-}
-
-static int determine_uprobe_perf_type(void)
-{
-	const char *file = "/sys/bus/event_source/devices/uprobe/type";
-
-	return parse_uint_from_file(file, "%d\n");
-}
-
-static int determine_uprobe_retprobe_bit(void)
-{
-	const char *file = "/sys/bus/event_source/devices/uprobe/format/retprobe";
-
-	return parse_uint_from_file(file, "config:%d\n");
-}
-
-static ssize_t get_uprobe_offset(const void *addr)
-{
-	size_t start, end, base;
-	char buf[256];
-	bool found = false;
-	FILE *f;
-
-	f = fopen("/proc/self/maps", "r");
-	if (!f)
-		return -errno;
-
-	while (fscanf(f, "%zx-%zx %s %zx %*[^\n]\n", &start, &end, buf, &base) == 4) {
-		if (buf[2] == 'x' && (uintptr_t)addr >= start && (uintptr_t)addr < end) {
-			found = true;
-			break;
-		}
-	}
-
-	fclose(f);
-
-	if (!found)
-		return -ESRCH;
-
-	return (uintptr_t)addr - start + base;
-}
-
-static __attribute__((noinline)) void uretprobe_trigger(void)
-{
-	asm volatile ("");
-}
-
-/*
- * This test setups return uprobe, which is sensitive to shadow stack
- * (crashes without extra fix). After executing the uretprobe we fail
- * the test if we receive SIGSEGV, no crash means we're good.
- *
- * Helper functions above borrowed from bpf selftests.
- */
-static int test_uretprobe(void)
-{
-	const size_t attr_sz = sizeof(struct perf_event_attr);
-	const char *file = "/proc/self/exe";
-	int bit, fd = 0, type, err = 1;
-	struct perf_event_attr attr;
-	struct sigaction sa = {};
-	ssize_t offset;
 
-	type = determine_uprobe_perf_type();
-	if (type < 0) {
-		if (type == -ENOENT)
-			printf("[SKIP]\tUretprobe test, uprobes are not available\n");
-		return 0;
-	}
-
-	offset = get_uprobe_offset(uretprobe_trigger);
-	if (offset < 0)
-		return 1;
-
-	bit = determine_uprobe_retprobe_bit();
-	if (bit < 0)
-		return 1;
-
-	sa.sa_sigaction = segv_gp_handler;
-	sa.sa_flags = SA_SIGINFO;
-	if (sigaction(SIGSEGV, &sa, NULL))
-		return 1;
-
-	/* Setup return uprobe through perf event interface. */
-	memset(&attr, 0, attr_sz);
-	attr.size = attr_sz;
-	attr.type = type;
-	attr.config = 1 << bit;
-	attr.config1 = (__u64) (unsigned long) file;
-	attr.config2 = offset;
-
-	fd = syscall(__NR_perf_event_open, &attr, 0 /* pid */, -1 /* cpu */,
-		     -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
-	if (fd < 0)
-		goto out;
-
-	if (sigsetjmp(jmp_buffer, 1))
-		goto out;
-
-	ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK);
-
-	/*
-	 * This either segfaults and goes through sigsetjmp above
-	 * or succeeds and we're good.
-	 */
-	uretprobe_trigger();
-
-	printf("[OK]\tUretprobe test\n");
-	err = 0;
-
-out:
-	ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK);
-	signal(SIGSEGV, SIG_DFL);
-	if (fd)
-		close(fd);
-	return err;
-}
-
-/* Keep the CALL first so the function address is exactly the probed CALL. */
-extern void uprobe_call_trigger(void);
-asm (".pushsection .text\n"
-	".global uprobe_call_target\n"
-	".type uprobe_call_target, @function\n"
-	"uprobe_call_target:\n"
-	"	ret\n"
-	".size uprobe_call_target, .-uprobe_call_target\n"
-
-	".global uprobe_call_trigger\n"
-	".type uprobe_call_trigger, @function\n"
-	"uprobe_call_trigger:\n"
-	"	call uprobe_call_target\n"
-	"	ret\n"
-	".size uprobe_call_trigger, .-uprobe_call_trigger\n"
-	".popsection\n"
-);
-
-/* If CALL emulation misses the shadow stack update, this exits via SIGSEGV. */
-static int test_uprobe_call(void)
-{
-	const size_t attr_sz = sizeof(struct perf_event_attr);
-	const char *file = "/proc/self/exe";
-	int fd = -1, type, err = 1;
-	struct perf_event_attr attr;
-	struct sigaction sa = {};
-	ssize_t offset;
-
-	type = determine_uprobe_perf_type();
-	if (type < 0) {
-		if (type == -ENOENT)
-			printf("[SKIP]\tUprobe on CALL test, uprobes are not available\n");
-		return 0;
-	}
-
-	offset = get_uprobe_offset(uprobe_call_trigger);
-	if (offset < 0)
-		return 1;
-
-	sa.sa_sigaction = segv_gp_handler;
-	sa.sa_flags = SA_SIGINFO;
-	if (sigaction(SIGSEGV, &sa, NULL))
-		return 1;
-
-	/* Setup entry uprobe through perf event interface. */
-	memset(&attr, 0, attr_sz);
-	attr.size = attr_sz;
-	attr.type = type;
-	attr.config = 0;
-	attr.config1 = (__u64)(unsigned long)file;
-	attr.config2 = offset;
-
-	fd = syscall(__NR_perf_event_open, &attr, 0 /* pid */, -1 /* cpu */,
-		     -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
-	if (fd < 0)
-		goto out;
-
-	if (sigsetjmp(jmp_buffer, 1))
-		goto out;
-
-	if (ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK))
-		goto out;
-
-	/*
-	 * This either segfaults and goes through sigsetjmp above
-	 * or succeeds and we're good.
-	 */
-	uprobe_call_trigger();
-
-	printf("[OK]\tUprobe on CALL test\n");
-	err = 0;
-
-out:
-	ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK);
-	signal(SIGSEGV, SIG_DFL);
-	if (fd >= 0)
-		close(fd);
-	return err;
-}
-
-void segv_handler_ptrace(int signum, siginfo_t *si, void *uc)
-{
-	/* The SSP adjustment caused a segfault. */
-	exit(0);
-}
-
-int test_ptrace(void)
-{
-	unsigned long saved_ssp, ssp = 0;
-	struct sigaction sa= {};
-	struct iovec iov;
-	int status;
-	int pid;
-
-	iov.iov_base = &ssp;
-	iov.iov_len = sizeof(ssp);
-
-	pid = fork();
-	if (pid < 0) {
-		printf("[FAIL]\tFork failed for %s\n", __func__);
-		return 1;
-	}
-
-	if (!pid) {
-		ssp = get_ssp();
-
-		sa.sa_sigaction = segv_handler_ptrace;
-		sa.sa_flags = SA_SIGINFO;
-		if (sigaction(SIGSEGV, &sa, NULL))
-			return 1;
-
-		ptrace(PTRACE_TRACEME, NULL, NULL, NULL);
-		/*
-		 * The parent will tweak the SSP and return from this function
-		 * will #CP.
-		 */
-		raise(SIGTRAP);
-
-		exit(1);
-	}
-
-	while (waitpid(pid, &status, 0) != -1 && WSTOPSIG(status) != SIGTRAP);
-
-	if (ptrace(PTRACE_GETREGSET, pid, NT_X86_SHSTK, &iov)) {
-		printf("[INFO]\tFailed to PTRACE_GETREGS\n");
-		goto out_kill;
-	}
-
-	if (!ssp) {
-		printf("[INFO]\tPtrace child SSP was 0\n");
-		goto out_kill;
-	}
-
-	saved_ssp = ssp;
-
-	iov.iov_len = 0;
-	if (!ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
-		printf("[INFO]\tToo small size accepted via PTRACE_SETREGS\n");
-		goto out_kill;
-	}
-
-	iov.iov_len = sizeof(ssp) + 1;
-	if (!ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
-		printf("[INFO]\tToo large size accepted via PTRACE_SETREGS\n");
-		goto out_kill;
-	}
-
-	ssp += 1;
-	if (!ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
-		printf("[INFO]\tUnaligned SSP written via PTRACE_SETREGS\n");
-		goto out_kill;
-	}
-
-	ssp = 0xFFFFFFFFFFFF0000;
-	if (!ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
-		printf("[INFO]\tKernel range SSP written via PTRACE_SETREGS\n");
-		goto out_kill;
-	}
-
-	/*
-	 * Tweak the SSP so the child with #CP when it resumes and returns
-	 * from raise()
-	 */
-	ssp = saved_ssp + 8;
-	iov.iov_len = sizeof(ssp);
-	if (ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
-		printf("[INFO]\tFailed to PTRACE_SETREGS\n");
-		goto out_kill;
-	}
-
-	if (ptrace(PTRACE_DETACH, pid, NULL, NULL)) {
-		printf("[INFO]\tFailed to PTRACE_DETACH\n");
-		goto out_kill;
-	}
-
-	waitpid(pid, &status, 0);
-	if (WEXITSTATUS(status))
-		return 1;
-
-	printf("[OK]\tPtrace test\n");
-	return 0;
-
-out_kill:
-	kill(pid, SIGKILL);
-	return 1;
-}
-
-static int test_locking(void)
-{
-
-	if (ARCH_PRCTL(ARCH_SHSTK_LOCK, ARCH_SHSTK_WRSS)) {
-		printf("[FAIL]\tCould not lock Shadow stack write\n");
-		return 1;
-	}
-
-	if (ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_WRSS) != -EPERM) {
-		printf("[FAIL]\tCould change Shadow stack write after lock\n");
-		return 1;
-	}
-
-	printf("[OK]\tShadow stack locking\n");
-
-	return 0;
-}
+#include "shadow_stack.h"
 
 int main(int argc, char *argv[])
 {
-	int ret = 0;
-
-	if (ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK)) {
-		printf("[SKIP]\tCould not enable Shadow stack\n");
-		return 1;
-	}
-
-	if (ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK)) {
-		ret = 1;
-		printf("[FAIL]\tDisabling shadow stack failed\n");
-	}
-
-	if (ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK)) {
-		printf("[SKIP]\tCould not re-enable Shadow stack\n");
-		return 1;
-	}
-
-	/* Note: test_shadow_stack_lock() needs write enabled */
-	if (ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_WRSS)) {
-		printf("[SKIP]\tCould not enable WRSS\n");
-		ret = 1;
-		goto out;
-	}
-
-	unsigned long status = 0;
-
-	if (ARCH_PRCTL(ARCH_SHSTK_STATUS, &status)) {
-		printf("[FAIL]\tCould not get Shadow stack status\n");
-		ret = 1;
-		goto out;
-	}
-
-	if (status != (ARCH_SHSTK_WRSS|ARCH_SHSTK_SHSTK)) {
-		printf("[FAIL]\tStatus not as expected, got 0x%lx status, wanted: 0x%llx\n",
-			status, (ARCH_SHSTK_WRSS|ARCH_SHSTK_SHSTK));
-		ret = 1;
-		goto out;
-	}
-
-	if (test_locking()) {
-		ret = 1;
-		goto out;
-	}
-
-	/* Should have succeeded if here, but this is a test, so double check. */
-	if (!get_ssp()) {
-		printf("[FAIL]\tShadow stack disabled\n");
-		return 1;
-	}
-
-	if (test_shstk_pivot()) {
-		ret = 1;
-		printf("[FAIL]\tShadow stack pivot\n");
-		goto out;
-	}
-
-	if (test_shstk_faults()) {
-		ret = 1;
-		printf("[FAIL]\tShadow stack fault test\n");
-		goto out;
-	}
-
-	if (test_shstk_violation()) {
-		ret = 1;
-		printf("[FAIL]\tShadow stack violation test\n");
-		goto out;
-	}
-
-	if (test_gup()) {
-		ret = 1;
-		printf("[FAIL]\tShadow shadow stack gup\n");
-		goto out;
-	}
-
-	if (test_mprotect()) {
-		ret = 1;
-		printf("[FAIL]\tShadow shadow mprotect test\n");
-		goto out;
-	}
-
-	if (test_userfaultfd()) {
-		ret = 1;
-		printf("[FAIL]\tUserfaultfd test\n");
-		goto out;
-	}
-
-	if (test_guard_gap_other_gaps()) {
-		ret = 1;
-		printf("[FAIL]\tGuard gap test, other mappings' gaps\n");
-		goto out;
-	}
-
-	if (test_guard_gap_new_mappings_gaps()) {
-		ret = 1;
-		printf("[FAIL]\tGuard gap test, placement mapping's gaps\n");
-		goto out;
-	}
-
-	if (test_ptrace()) {
-		ret = 1;
-		printf("[FAIL]\tptrace test\n");
-	}
-
-	if (test_32bit()) {
-		ret = 1;
-		printf("[FAIL]\t32 bit test\n");
-		goto out;
-	}
-
-	if (test_uretprobe()) {
-		ret = 1;
-		printf("[FAIL]\turetprobe test\n");
-		goto out;
-	}
-
-	if (test_uprobe_call()) {
-		ret = 1;
-		printf("[FAIL]\tuprobe on CALL test\n");
-		goto out;
-	}
-
-	return ret;
-
-out:
-	/*
-	 * Disable shadow stack before the function returns, or there will be a
-	 * shadow stack violation.
-	 */
-	if (ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK)) {
-		ret = 1;
-		printf("[FAIL]\tDisabling shadow stack failed\n");
-	}
-
-	return ret;
+	return shadow_stack_run_tests(SHADOW_STACK_TEST_ARCH_PRCTL);
 }
-#endif
diff --git a/tools/testing/selftests/x86/test_shadow_stack_prctl.c b/tools/testing/selftests/x86/test_shadow_stack_prctl.c
new file mode 100644
index 000000000000..4641a3b1ca03
--- /dev/null
+++ b/tools/testing/selftests/x86/test_shadow_stack_prctl.c
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Same as test_shadow_stack.c but uses the PRCTL interface
+ * instead of ARCH_PRCTL.
+ */
+#include "shadow_stack.h"
+
+int main(int argc, char *argv[])
+{
+	return shadow_stack_run_tests(SHADOW_STACK_TEST_PRCTL);
+}
-- 
2.55.0

[PATCH v4 0/6]

[Geert Uytterhoeven]

	Hi all,

This patch series adds support for SPI slave controllers to the Linux
SPI subsystem, including:
  - DT binding updates for SPI slave support,
  - Core support for SPI slave controllers,
  - SPI slave support for the Renesas MSIOF device driver (thanks to
    Nakamura-san for the initial implementation in the R-Car BSP!),
  - Sample SPI slave handlers.

Due to the nature of SPI slave (simultaneous transmit and receive, while
everything runs at the pace of the master), it has hard real-time
requirements: once an SPI transfer is started by the SPI master, a
software SPI slave must have prepared all data to be sent back to the
SPI master.  Hence without additional hardware support, an SPI slave
response can never be a reply to a command being simultaneously
transmitted, and SPI slave replies must be received by the SPI master in
a subsequent SPI transfer.

Examples of possible use cases:
  - Receiving streams of data in fixed-size messages (e.g. from a
    tuner),
  - Receiving and transmitting fixed-size messages of data (e.g. network
    frames),
  - Sending commands, and querying for responses,
  - ...

Binding an SPI slave handler to the SPI slave device represented by an
SPI slave controller can either be done from DT, or through sysfs.
The latter, which also allows unregistering, is done through a sysfs
virtual file named "slave", cfr. Documentation/spi/spi-summary.

Originally I wanted to implement a simple SPI slave handler that could
interface with an existing Linux SPI slave driver, cfr. Wolfram Sang's
I2C slave mode EEPROM simulator for the i2c subsystem.
Unfortunately I couldn't find any existing driver using an SPI slave
protocol that fulfills the above requirements. The Nordic Semiconductor
nRF8001 BLE controller seems to use a suitable protocol, but I couldn't
find a Linux driver for it.  Hence I created two sample SPI slave
protocols and drivers myself:
  1. "spi-slave-time" responds with the system uptime at the time of
     reception of the last SPI message, which can be used by an external
     microcontroller as a dead man's switch.
  2. "spi-slave-system-control" allows remote control of system reboot,
     power off, halt, and suspend.

For some use cases, using spidev from user space may be a more appropriate
solution than an in-kernel SPI protocol handler, and this is fully
supported.

>From the point of view of an SPI slave protocol handler, an SPI slave
controller looks almost like an ordinary SPI master controller. The only
exception is that a transfer request will block on the remote SPI
master, and may be cancelled using spi_slave_abort().
Hence "struct spi_master" has become a misnomer.  I'll send an RFC
follow-up patch to fix that.

For now, the MSIOF SPI slave driver only supports the transmission of
messages with a size that is known in advance (the hardware can provide
an interrupt when CS is deasserted before, though).
I.e. when the SPI master sends a shorter message, the slave won't
receive it.  When the SPI master sends a longer message, the slave will
receive the first part, and the rest will remain in the FIFO.

Handshaking (5-pin SPI, RDY-signal) is optional, and not yet
implemented.  An RDY-signal may be used for one or both of:
  1. The SPI slave asserts RDY when it has data available, and wants to
     be queried by the SPI master.
       -> This can be handled on top, in the SPI slave protocol handler,
	  using a GPIO.
  2. After the SPI master has asserted CS, the SPI slave asserts RDY
     when it is ready to accept the transfer.
       -> This may need hardware support in the SPI slave controller,
	  or dynamic GPIO vs. CS pinmuxing.

Changes compared to v3:
  - Add Reviewed-by, Acked-by,
  - Add missing kerneldoc for spi_master.slave,
  - Use slave_aborted flag and complete() instead of messing with
    internal completion and thread state,

Changes compared to v2 (highlights only, see individual patches for
more details):
  - In SPI slave mode, represent the (single) slave device again as a
    child of the controller node, which is now optional, and must be
    named "slave" if present,
  - Introduce a separate spi_alloc_slave() function,
  - Replace the SPI_CONTROLLER_IS_SLAVE flag in spi_master.flags by a
    bool in spi_master,
  - Fix cancellation in the spi-sh-msiof driver,
  - Drop "spi: core: Extract of_spi_parse_dt()", which was applied,

Changes compared to v1 (highlights only, see individual patches for
more details):
  - Do not create a child node in SPI slave mode. Instead, add an
    "spi-slave" property, and put the mode properties in the controller
    node.
  - Attach SPI slave controllers to a new "spi_slave" device class,
  - Use a "slave" virtual file in sysfs to (un)register the (single)
    slave device for an SPI slave controller, incl. specifying the slave
    protocol handler,
  - Add cancellation support using spi_master.slave_abort() and
    spi_slave_abort(),
  - Please see the individual patches for more detailed changelog
    information.

Dependencies:
  - Today's spi/for-next,

For your convenience, I've pushed this series and its dependencies to
the topic/spi-slave-v4 branch of the git repository at
https://git.kernel.org/cgit/linux/kernel/git/geert/renesas-drivers.git

Full test information is also available on the eLinux wiki
(http://elinux.org/Tests:MSIOF-SPI-Slave).

For testing, device tree overlays enabling SPI master and slave
controllers on an expansion I/O connector on r8a7791/koelsch are
available in the topic/renesas-overlays branch of my renesas-drivers git
repository.  Please see http://elinux.org/R-Car/DT-Overlays for more
information about using these overlays.

Test wiring on r8a7791/koelsch, between MSIOF1 and MSIOF2 on EXIO
connector A:
   - Connect pin 48 (MSIOF1 CS#) to pin 63 (MSIOF2 CS#),
   - Connect pin 46 (MSIOF1 SCK) to pin 61 (MSIOF2 SCK),
   - Connect pin 54 (MSIOF1 TX/MOSI) to pin 70 (MSIOF2 RX/MOSI),
   - Connect pin 56 (MSIOF1 RX/MISO) to pin 68 (MSIOF2 TX/MISO).

Preparation for all examples below:
    # overlay add a-msiof1-spidev # buggy DT: spidev listed directly in DT
    # overlay add a-msiof2-slave

Example 1:

    # echo spi-slave-time > /sys/class/spi_slave/spi3/slave 
    # spidev_test -D /dev/spidev2.0 -p dummy-8B
    spi mode: 0x0
    bits per word: 8
    max speed: 500000 Hz (500 KHz)
    RX | 00 00 04 6D 00 09 5B BB __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __  | ...m..[�
               ^^^^^    ^^^^^^^^
	       seconds  microseconds

Example 2:

    # echo spi-slave-system-control > /sys/class/spi_slave/spi3/slave 
    # reboot='\x7c\x50'
    # poweroff='\x71\x3f'
    # halt='\x38\x76'
    # suspend='\x1b\x1b'
    # spidev_test -D /dev/spidev2.0 -p $suspend # or $reboot, $poweroff, $halt

Example 3:

    # echo spidev > /sys/class/spi_slave/spi3/slave 
    # spidev_test -D /dev/spidev3.0 -p slave-hello-to-master &
    # spidev_test -D /dev/spidev2.0 -p master-hello-to-slave

Thanks!

Geert Uytterhoeven (5):
  spi: Document DT bindings for SPI controllers in slave mode
  spi: core: Add support for registering SPI slave controllers
  spi: Document SPI slave controller support
  spi: slave: Add SPI slave handler reporting uptime at previous message
  spi: slave: Add SPI slave handler controlling system state

Hisashi Nakamura (1):
  spi: sh-msiof: Add slave mode support

 Documentation/devicetree/bindings/spi/sh-msiof.txt |   2 +
 Documentation/devicetree/bindings/spi/spi-bus.txt  |  76 +++++----
 Documentation/spi/spi-summary                      |  27 +++-
 drivers/spi/Kconfig                                |  26 ++-
 drivers/spi/Makefile                               |   4 +
 drivers/spi/spi-sh-msiof.c                         | 111 +++++++++----
 drivers/spi/spi-slave-system-control.c             | 154 ++++++++++++++++++
 drivers/spi/spi-slave-time.c                       | 127 +++++++++++++++
 drivers/spi/spi.c                                  | 179 ++++++++++++++++++---
 include/linux/spi/sh_msiof.h                       |   6 +
 include/linux/spi/spi.h                            |  35 +++-
 11 files changed, 647 insertions(+), 100 deletions(-)
 create mode 100644 drivers/spi/spi-slave-system-control.c
 create mode 100644 drivers/spi/spi-slave-time.c

-- 
2.7.4

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds