From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Mathieu Desnoyers <compudj@krystal.dyndns.org>,
Andi Kleen <andi@firstfloor.org>, Jason Baron <jbaron@redhat.com>,
David Miller <davem@davemloft.net>
Subject: [PATCH 01/11] jump label: Make dynamic no-op selection available outside of ftrace
Date: Wed, 22 Sep 2010 23:49:11 -0400 [thread overview]
Message-ID: <20100923035607.740674188@goodmis.org> (raw)
In-Reply-To: <20100923034910.867858597@goodmis.org>
[-- Attachment #1: 0001-jump-label-Make-dynamic-no-op-selection-available-ou.patch --]
[-- Type: text/plain, Size: 6638 bytes --]
From: Jason Baron <jbaron@redhat.com>
Move Steve's code for finding the best 5-byte no-op from ftrace.c to
alternative.c. The idea is that other consumers (in this case jump label)
want to make use of that code.
Signed-off-by: Jason Baron <jbaron@redhat.com>
LKML-Reference: <96259ae74172dcac99c0020c249743c523a92e18.1284733808.git.jbaron@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
arch/x86/include/asm/alternative.h | 8 ++++
arch/x86/kernel/alternative.c | 64 ++++++++++++++++++++++++++++++++++++
arch/x86/kernel/ftrace.c | 63 +----------------------------------
arch/x86/kernel/setup.c | 6 +++
4 files changed, 79 insertions(+), 62 deletions(-)
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index bc6abb7..27a35b6 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -180,4 +180,12 @@ static inline void apply_paravirt(struct paravirt_patch_site *start,
extern void *text_poke(void *addr, const void *opcode, size_t len);
extern void *text_poke_smp(void *addr, const void *opcode, size_t len);
+#if defined(CONFIG_DYNAMIC_FTRACE)
+#define IDEAL_NOP_SIZE_5 5
+extern unsigned char ideal_nop5[IDEAL_NOP_SIZE_5];
+extern void arch_init_ideal_nop5(void);
+#else
+static inline void arch_init_ideal_nop5(void) {}
+#endif
+
#endif /* _ASM_X86_ALTERNATIVE_H */
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index f65ab8b..1849d80 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -641,3 +641,67 @@ void *__kprobes text_poke_smp(void *addr, const void *opcode, size_t len)
return addr;
}
+#if defined(CONFIG_DYNAMIC_FTRACE)
+
+unsigned char ideal_nop5[IDEAL_NOP_SIZE_5];
+
+void __init arch_init_ideal_nop5(void)
+{
+ extern const unsigned char ftrace_test_p6nop[];
+ extern const unsigned char ftrace_test_nop5[];
+ extern const unsigned char ftrace_test_jmp[];
+ int faulted = 0;
+
+ /*
+ * There is no good nop for all x86 archs.
+ * We will default to using the P6_NOP5, but first we
+ * will test to make sure that the nop will actually
+ * work on this CPU. If it faults, we will then
+ * go to a lesser efficient 5 byte nop. If that fails
+ * we then just use a jmp as our nop. This isn't the most
+ * efficient nop, but we can not use a multi part nop
+ * since we would then risk being preempted in the middle
+ * of that nop, and if we enabled tracing then, it might
+ * cause a system crash.
+ *
+ * TODO: check the cpuid to determine the best nop.
+ */
+ asm volatile (
+ "ftrace_test_jmp:"
+ "jmp ftrace_test_p6nop\n"
+ "nop\n"
+ "nop\n"
+ "nop\n" /* 2 byte jmp + 3 bytes */
+ "ftrace_test_p6nop:"
+ P6_NOP5
+ "jmp 1f\n"
+ "ftrace_test_nop5:"
+ ".byte 0x66,0x66,0x66,0x66,0x90\n"
+ "1:"
+ ".section .fixup, \"ax\"\n"
+ "2: movl $1, %0\n"
+ " jmp ftrace_test_nop5\n"
+ "3: movl $2, %0\n"
+ " jmp 1b\n"
+ ".previous\n"
+ _ASM_EXTABLE(ftrace_test_p6nop, 2b)
+ _ASM_EXTABLE(ftrace_test_nop5, 3b)
+ : "=r"(faulted) : "0" (faulted));
+
+ switch (faulted) {
+ case 0:
+ pr_info("converting mcount calls to 0f 1f 44 00 00\n");
+ memcpy(ideal_nop5, ftrace_test_p6nop, IDEAL_NOP_SIZE_5);
+ break;
+ case 1:
+ pr_info("converting mcount calls to 66 66 66 66 90\n");
+ memcpy(ideal_nop5, ftrace_test_nop5, IDEAL_NOP_SIZE_5);
+ break;
+ case 2:
+ pr_info("converting mcount calls to jmp . + 5\n");
+ memcpy(ideal_nop5, ftrace_test_jmp, IDEAL_NOP_SIZE_5);
+ break;
+ }
+
+}
+#endif
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index cd37469..3afb33f 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -257,14 +257,9 @@ do_ftrace_mod_code(unsigned long ip, void *new_code)
return mod_code_status;
}
-
-
-
-static unsigned char ftrace_nop[MCOUNT_INSN_SIZE];
-
static unsigned char *ftrace_nop_replace(void)
{
- return ftrace_nop;
+ return ideal_nop5;
}
static int
@@ -338,62 +333,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
int __init ftrace_dyn_arch_init(void *data)
{
- extern const unsigned char ftrace_test_p6nop[];
- extern const unsigned char ftrace_test_nop5[];
- extern const unsigned char ftrace_test_jmp[];
- int faulted = 0;
-
- /*
- * There is no good nop for all x86 archs.
- * We will default to using the P6_NOP5, but first we
- * will test to make sure that the nop will actually
- * work on this CPU. If it faults, we will then
- * go to a lesser efficient 5 byte nop. If that fails
- * we then just use a jmp as our nop. This isn't the most
- * efficient nop, but we can not use a multi part nop
- * since we would then risk being preempted in the middle
- * of that nop, and if we enabled tracing then, it might
- * cause a system crash.
- *
- * TODO: check the cpuid to determine the best nop.
- */
- asm volatile (
- "ftrace_test_jmp:"
- "jmp ftrace_test_p6nop\n"
- "nop\n"
- "nop\n"
- "nop\n" /* 2 byte jmp + 3 bytes */
- "ftrace_test_p6nop:"
- P6_NOP5
- "jmp 1f\n"
- "ftrace_test_nop5:"
- ".byte 0x66,0x66,0x66,0x66,0x90\n"
- "1:"
- ".section .fixup, \"ax\"\n"
- "2: movl $1, %0\n"
- " jmp ftrace_test_nop5\n"
- "3: movl $2, %0\n"
- " jmp 1b\n"
- ".previous\n"
- _ASM_EXTABLE(ftrace_test_p6nop, 2b)
- _ASM_EXTABLE(ftrace_test_nop5, 3b)
- : "=r"(faulted) : "0" (faulted));
-
- switch (faulted) {
- case 0:
- pr_info("converting mcount calls to 0f 1f 44 00 00\n");
- memcpy(ftrace_nop, ftrace_test_p6nop, MCOUNT_INSN_SIZE);
- break;
- case 1:
- pr_info("converting mcount calls to 66 66 66 66 90\n");
- memcpy(ftrace_nop, ftrace_test_nop5, MCOUNT_INSN_SIZE);
- break;
- case 2:
- pr_info("converting mcount calls to jmp . + 5\n");
- memcpy(ftrace_nop, ftrace_test_jmp, MCOUNT_INSN_SIZE);
- break;
- }
-
/* The return code is retured via data */
*(unsigned long *)data = 0;
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index c3a4fbb..00e1678 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -112,6 +112,7 @@
#include <asm/numa_64.h>
#endif
#include <asm/mce.h>
+#include <asm/alternative.h>
/*
* end_pfn only includes RAM, while max_pfn_mapped includes all e820 entries.
@@ -726,6 +727,7 @@ void __init setup_arch(char **cmdline_p)
{
int acpi = 0;
int k8 = 0;
+ unsigned long flags;
#ifdef CONFIG_X86_32
memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));
@@ -1071,6 +1073,10 @@ void __init setup_arch(char **cmdline_p)
x86_init.oem.banner();
mcheck_init();
+
+ local_irq_save(flags);
+ arch_init_ideal_nop5();
+ local_irq_restore(flags);
}
#ifdef CONFIG_X86_32
--
1.7.1
next prev parent reply other threads:[~2010-09-23 3:57 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-23 3:49 [GIT PULL] jump label: add jump label code Steven Rostedt
2010-09-23 3:49 ` Steven Rostedt [this message]
2010-09-23 3:49 ` [PATCH 02/11] jump label: Make text_poke_early() globally visible Steven Rostedt
2010-09-23 3:49 ` [PATCH 03/11] jump label: Base patch for jump label Steven Rostedt
2010-09-23 14:37 ` Mathieu Desnoyers
2010-09-23 15:39 ` Jason Baron
2010-09-23 15:48 ` Mathieu Desnoyers
2010-09-23 18:40 ` Jason Baron
2010-09-23 18:55 ` Mathieu Desnoyers
2010-09-23 19:08 ` Mathieu Desnoyers
2010-09-23 19:11 ` Jason Baron
2010-09-24 0:44 ` Rusty Russell
2010-09-24 13:54 ` Steven Rostedt
2010-09-24 20:54 ` Mathieu Desnoyers
2010-09-24 21:45 ` Jason Baron
2010-09-23 16:52 ` Steven Rostedt
2010-09-23 17:09 ` Mathieu Desnoyers
2010-09-23 3:49 ` [PATCH 04/11] jump label: Initialize workqueue tracepoints *before* they are registered Steven Rostedt
2010-09-23 3:49 ` [PATCH 05/11] jump label: Add jump_label_text_reserved() to reserve jump points Steven Rostedt
2010-09-23 3:49 ` [PATCH 06/11] jump label: Tracepoint support for jump labels Steven Rostedt
2010-09-23 3:49 ` [PATCH 07/11] jump label: Convert dynamic debug to use " Steven Rostedt
2010-09-23 3:49 ` [PATCH 08/11] jump label: x86 support Steven Rostedt
2010-09-23 3:49 ` [PATCH 09/11] jump label: Add sparc64 support Steven Rostedt
2010-09-23 3:49 ` [PATCH 10/11] jump label: Remove duplicate structure for x86 Steven Rostedt
2010-09-23 3:49 ` [PATCH 11/11] jump label/x86/sparc64: Remove !CC_OPTIMIZE_FOR_SIZE config conditions Steven Rostedt
2010-09-23 4:06 ` [GIT PULL] jump label: add jump label code Steven Rostedt
2010-09-23 6:32 ` Ingo Molnar
2010-09-23 12:42 ` Steven Rostedt
2010-09-24 9:02 ` [tip:perf/core] jump label: Fix GCC feature check when distcc is used tip-bot for Ingo Molnar
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