[PATCH v2 0/6] um: Minor fixes and cleanups

[PATCH v2 0/6] um: Minor fixes and cleanups

[Tiwei Bie]

A series of minor fixes and cleanups for UML.

Changes since v1:
https://lore.kernel.org/lkml/20240123110347.1274217-1-tiwei.btw@antgroup.com/
- Add "um: Stop tracking host PID in cpu_tasks";
- Add missing headers for i386;

Tiwei Bie (6):
  um: Make local functions and variables static
  um: Fix the declaration of vfree
  um: Remove unused functions
  um: Fix the return type of __switch_to
  um: Add missing headers
  um: Stop tracking host PID in cpu_tasks

 arch/um/drivers/pcap_kern.c              |  4 +--
 arch/um/drivers/ubd_user.c               |  2 +-
 arch/um/include/shared/as-layout.h       |  1 -
 arch/um/include/shared/um_malloc.h       |  2 +-
 arch/um/kernel/kmsg_dump.c               |  2 +-
 arch/um/kernel/mem.c                     |  2 ++
 arch/um/kernel/process.c                 | 46 ++++++------------------
 arch/um/kernel/reboot.c                  |  1 +
 arch/um/kernel/skas/mmu.c                |  1 +
 arch/um/kernel/skas/process.c            |  5 +--
 arch/um/kernel/time.c                    |  6 ++--
 arch/um/kernel/tlb.c                     |  7 +---
 arch/um/os-Linux/drivers/ethertap_kern.c |  2 +-
 arch/um/os-Linux/drivers/tuntap_kern.c   |  2 +-
 arch/um/os-Linux/signal.c                |  4 +--
 arch/x86/um/bugs_32.c                    |  1 +
 arch/x86/um/bugs_64.c                    |  1 +
 arch/x86/um/elfcore.c                    |  1 +
 arch/x86/um/fault.c                      |  1 +
 arch/x86/um/os-Linux/mcontext.c          |  1 +
 arch/x86/um/os-Linux/registers.c         |  2 +-
 arch/x86/um/os-Linux/tls.c               |  1 +
 22 files changed, 35 insertions(+), 60 deletions(-)

-- 
2.34.1

[PATCH v2 1/6] um: Make local functions and variables static

[Tiwei Bie]

This will also fix the warnings like:

warning: no previous prototype for ‘fork_handler’ [-Wmissing-prototypes]
  140 | void fork_handler(void)
      |      ^~~~~~~~~~~~

Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
---
 arch/um/drivers/pcap_kern.c              | 4 ++--
 arch/um/drivers/ubd_user.c               | 2 +-
 arch/um/kernel/kmsg_dump.c               | 2 +-
 arch/um/kernel/process.c                 | 8 ++++----
 arch/um/kernel/time.c                    | 6 +++---
 arch/um/os-Linux/drivers/ethertap_kern.c | 2 +-
 arch/um/os-Linux/drivers/tuntap_kern.c   | 2 +-
 arch/um/os-Linux/signal.c                | 4 ++--
 arch/x86/um/os-Linux/registers.c         | 2 +-
 9 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/arch/um/drivers/pcap_kern.c b/arch/um/drivers/pcap_kern.c
index 25ee2c97ca21..d9bf95d7867b 100644
--- a/arch/um/drivers/pcap_kern.c
+++ b/arch/um/drivers/pcap_kern.c
@@ -15,7 +15,7 @@ struct pcap_init {
 	char *filter;
 };
 
-void pcap_init_kern(struct net_device *dev, void *data)
+static void pcap_init_kern(struct net_device *dev, void *data)
 {
 	struct uml_net_private *pri;
 	struct pcap_data *ppri;
@@ -50,7 +50,7 @@ static const struct net_kern_info pcap_kern_info = {
 	.write			= pcap_write,
 };
 
-int pcap_setup(char *str, char **mac_out, void *data)
+static int pcap_setup(char *str, char **mac_out, void *data)
 {
 	struct pcap_init *init = data;
 	char *remain, *host_if = NULL, *options[2] = { NULL, NULL };
diff --git a/arch/um/drivers/ubd_user.c b/arch/um/drivers/ubd_user.c
index a1afe414ce48..b4f8b8e60564 100644
--- a/arch/um/drivers/ubd_user.c
+++ b/arch/um/drivers/ubd_user.c
@@ -23,7 +23,7 @@
 #include <os.h>
 #include <poll.h>
 
-struct pollfd kernel_pollfd;
+static struct pollfd kernel_pollfd;
 
 int start_io_thread(unsigned long sp, int *fd_out)
 {
diff --git a/arch/um/kernel/kmsg_dump.c b/arch/um/kernel/kmsg_dump.c
index 427dd5a61a38..4382cf02a6d1 100644
--- a/arch/um/kernel/kmsg_dump.c
+++ b/arch/um/kernel/kmsg_dump.c
@@ -57,7 +57,7 @@ static struct kmsg_dumper kmsg_dumper = {
 	.dump = kmsg_dumper_stdout
 };
 
-int __init kmsg_dumper_stdout_init(void)
+static int __init kmsg_dumper_stdout_init(void)
 {
 	return kmsg_dump_register(&kmsg_dumper);
 }
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index ab95648e93e1..20f3813143d8 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -137,7 +137,7 @@ void new_thread_handler(void)
 }
 
 /* Called magically, see new_thread_handler above */
-void fork_handler(void)
+static void fork_handler(void)
 {
 	force_flush_all();
 
@@ -268,14 +268,14 @@ int clear_user_proc(void __user *buf, int size)
 static atomic_t using_sysemu = ATOMIC_INIT(0);
 int sysemu_supported;
 
-void set_using_sysemu(int value)
+static void set_using_sysemu(int value)
 {
 	if (value > sysemu_supported)
 		return;
 	atomic_set(&using_sysemu, value);
 }
 
-int get_using_sysemu(void)
+static int get_using_sysemu(void)
 {
 	return atomic_read(&using_sysemu);
 }
@@ -313,7 +313,7 @@ static const struct proc_ops sysemu_proc_ops = {
 	.proc_write	= sysemu_proc_write,
 };
 
-int __init make_proc_sysemu(void)
+static int __init make_proc_sysemu(void)
 {
 	struct proc_dir_entry *ent;
 	if (!sysemu_supported)
diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c
index 3e270da6b6f6..efa5b9c97992 100644
--- a/arch/um/kernel/time.c
+++ b/arch/um/kernel/time.c
@@ -319,7 +319,7 @@ void time_travel_add_event_rel(struct time_travel_event *e,
 	time_travel_add_event(e, time_travel_time + delay_ns);
 }
 
-void time_travel_periodic_timer(struct time_travel_event *e)
+static void time_travel_periodic_timer(struct time_travel_event *e)
 {
 	time_travel_add_event(&time_travel_timer_event,
 			      time_travel_time + time_travel_timer_interval);
@@ -812,7 +812,7 @@ unsigned long calibrate_delay_is_known(void)
 	return 0;
 }
 
-int setup_time_travel(char *str)
+static int setup_time_travel(char *str)
 {
 	if (strcmp(str, "=inf-cpu") == 0) {
 		time_travel_mode = TT_MODE_INFCPU;
@@ -862,7 +862,7 @@ __uml_help(setup_time_travel,
 "devices using it, assuming the device has the right capabilities.\n"
 "The optional ID is a 64-bit integer that's sent to the central scheduler.\n");
 
-int setup_time_travel_start(char *str)
+static int setup_time_travel_start(char *str)
 {
 	int err;
 
diff --git a/arch/um/os-Linux/drivers/ethertap_kern.c b/arch/um/os-Linux/drivers/ethertap_kern.c
index 3182e759d8de..5e5ee40680ce 100644
--- a/arch/um/os-Linux/drivers/ethertap_kern.c
+++ b/arch/um/os-Linux/drivers/ethertap_kern.c
@@ -63,7 +63,7 @@ const struct net_kern_info ethertap_kern_info = {
 	.write 			= etap_write,
 };
 
-int ethertap_setup(char *str, char **mac_out, void *data)
+static int ethertap_setup(char *str, char **mac_out, void *data)
 {
 	struct ethertap_init *init = data;
 
diff --git a/arch/um/os-Linux/drivers/tuntap_kern.c b/arch/um/os-Linux/drivers/tuntap_kern.c
index adcb6717be6f..ff022d9cf0dd 100644
--- a/arch/um/os-Linux/drivers/tuntap_kern.c
+++ b/arch/um/os-Linux/drivers/tuntap_kern.c
@@ -53,7 +53,7 @@ const struct net_kern_info tuntap_kern_info = {
 	.write 			= tuntap_write,
 };
 
-int tuntap_setup(char *str, char **mac_out, void *data)
+static int tuntap_setup(char *str, char **mac_out, void *data)
 {
 	struct tuntap_init *init = data;
 
diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
index 24a403a70a02..787cfb9a0308 100644
--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -72,7 +72,7 @@ static int signals_blocked;
 static unsigned int signals_pending;
 static unsigned int signals_active = 0;
 
-void sig_handler(int sig, struct siginfo *si, mcontext_t *mc)
+static void sig_handler(int sig, struct siginfo *si, mcontext_t *mc)
 {
 	int enabled = signals_enabled;
 
@@ -108,7 +108,7 @@ static void timer_real_alarm_handler(mcontext_t *mc)
 	timer_handler(SIGALRM, NULL, &regs);
 }
 
-void timer_alarm_handler(int sig, struct siginfo *unused_si, mcontext_t *mc)
+static void timer_alarm_handler(int sig, struct siginfo *unused_si, mcontext_t *mc)
 {
 	int enabled;
 
diff --git a/arch/x86/um/os-Linux/registers.c b/arch/x86/um/os-Linux/registers.c
index df8f4b4bf98b..f3638dd09cec 100644
--- a/arch/x86/um/os-Linux/registers.c
+++ b/arch/x86/um/os-Linux/registers.c
@@ -17,7 +17,7 @@
 #include <linux/elf.h>
 #include <registers.h>
 
-int have_xstate_support;
+static int have_xstate_support;
 
 int save_i387_registers(int pid, unsigned long *fp_regs)
 {
-- 
2.34.1

[PATCH v2 2/6] um: Fix the declaration of vfree

[Tiwei Bie]

The definition of vfree has changed since commit b3bdda02aa54
("vmalloc: add const to void* parameters"). Update the declaration
of vfree in um_malloc.h to match the latest definition.

Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
---
 arch/um/include/shared/um_malloc.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/um/include/shared/um_malloc.h b/arch/um/include/shared/um_malloc.h
index 13da93284c2c..d25084447c69 100644
--- a/arch/um/include/shared/um_malloc.h
+++ b/arch/um/include/shared/um_malloc.h
@@ -12,7 +12,7 @@ extern void *uml_kmalloc(int size, int flags);
 extern void kfree(const void *ptr);
 
 extern void *vmalloc(unsigned long size);
-extern void vfree(void *ptr);
+extern void vfree(const void *ptr);
 
 #endif /* __UM_MALLOC_H__ */
 
-- 
2.34.1

[PATCH v2 3/6] um: Remove unused functions

[Tiwei Bie]

These functions are not used anymore. Removing them will also address
below -Wmissing-prototypes warnings:

arch/um/kernel/process.c:51:5: warning: no previous prototype for ‘pid_to_processor_id’ [-Wmissing-prototypes]
arch/um/kernel/process.c:253:5: warning: no previous prototype for ‘copy_to_user_proc’ [-Wmissing-prototypes]
arch/um/kernel/process.c:263:5: warning: no previous prototype for ‘clear_user_proc’ [-Wmissing-prototypes]
arch/um/kernel/tlb.c:579:6: warning: no previous prototype for ‘flush_tlb_mm_range’ [-Wmissing-prototypes]

Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
---
 arch/um/kernel/process.c | 21 ---------------------
 arch/um/kernel/tlb.c     |  6 ------
 2 files changed, 27 deletions(-)

diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 20f3813143d8..292c8014aaa6 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -48,17 +48,6 @@ static inline int external_pid(void)
 	return userspace_pid[0];
 }
 
-int pid_to_processor_id(int pid)
-{
-	int i;
-
-	for (i = 0; i < ncpus; i++) {
-		if (cpu_tasks[i].pid == pid)
-			return i;
-	}
-	return -1;
-}
-
 void free_stack(unsigned long stack, int order)
 {
 	free_pages(stack, order);
@@ -250,21 +239,11 @@ char *uml_strdup(const char *string)
 }
 EXPORT_SYMBOL(uml_strdup);
 
-int copy_to_user_proc(void __user *to, void *from, int size)
-{
-	return copy_to_user(to, from, size);
-}
-
 int copy_from_user_proc(void *to, void __user *from, int size)
 {
 	return copy_from_user(to, from, size);
 }
 
-int clear_user_proc(void __user *buf, int size)
-{
-	return clear_user(buf, size);
-}
-
 static atomic_t using_sysemu = ATOMIC_INIT(0);
 int sysemu_supported;
 
diff --git a/arch/um/kernel/tlb.c b/arch/um/kernel/tlb.c
index 7d050ab0f78a..70b5e47e9761 100644
--- a/arch/um/kernel/tlb.c
+++ b/arch/um/kernel/tlb.c
@@ -576,12 +576,6 @@ void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 }
 EXPORT_SYMBOL(flush_tlb_range);
 
-void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
-			unsigned long end)
-{
-	fix_range(mm, start, end, 0);
-}
-
 void flush_tlb_mm(struct mm_struct *mm)
 {
 	struct vm_area_struct *vma;
-- 
2.34.1

[PATCH v2 4/6] um: Fix the return type of __switch_to

[Tiwei Bie]

Make it match the declaration in asm-generic/switch_to.h. And
also include the header to allow the compiler to check it.

Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
---
 arch/um/kernel/process.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 292c8014aaa6..a7607ef1b02f 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -26,6 +26,7 @@
 #include <linux/resume_user_mode.h>
 #include <asm/current.h>
 #include <asm/mmu_context.h>
+#include <asm/switch_to.h>
 #include <linux/uaccess.h>
 #include <as-layout.h>
 #include <kern_util.h>
@@ -73,7 +74,7 @@ static inline void set_current(struct task_struct *task)
 
 extern void arch_switch_to(struct task_struct *to);
 
-void *__switch_to(struct task_struct *from, struct task_struct *to)
+struct task_struct *__switch_to(struct task_struct *from, struct task_struct *to)
 {
 	to->thread.prev_sched = from;
 	set_current(to);
-- 
2.34.1

[PATCH v2 5/6] um: Add missing headers

[Tiwei Bie]

This will address below -Wmissing-prototypes warnings:

arch/um/kernel/mem.c:202:8: warning: no previous prototype for ‘pgd_alloc’ [-Wmissing-prototypes]
arch/um/kernel/mem.c:215:7: warning: no previous prototype for ‘uml_kmalloc’ [-Wmissing-prototypes]
arch/um/kernel/process.c:207:6: warning: no previous prototype for ‘arch_cpu_idle’ [-Wmissing-prototypes]
arch/um/kernel/process.c:328:15: warning: no previous prototype for ‘arch_align_stack’ [-Wmissing-prototypes]
arch/um/kernel/reboot.c:45:6: warning: no previous prototype for ‘machine_restart’ [-Wmissing-prototypes]
arch/um/kernel/reboot.c:51:6: warning: no previous prototype for ‘machine_power_off’ [-Wmissing-prototypes]
arch/um/kernel/reboot.c:57:6: warning: no previous prototype for ‘machine_halt’ [-Wmissing-prototypes]
arch/um/kernel/skas/mmu.c:17:5: warning: no previous prototype for ‘init_new_context’ [-Wmissing-prototypes]
arch/um/kernel/skas/mmu.c:60:6: warning: no previous prototype for ‘destroy_context’ [-Wmissing-prototypes]
arch/um/kernel/skas/process.c:36:12: warning: no previous prototype for ‘start_uml’ [-Wmissing-prototypes]
arch/um/kernel/tlb.c:594:6: warning: no previous prototype for ‘force_flush_all’ [-Wmissing-prototypes]
arch/x86/um/bugs_32.c:22:6: warning: no previous prototype for ‘arch_check_bugs’ [-Wmissing-prototypes]
arch/x86/um/bugs_32.c:44:6: warning: no previous prototype for ‘arch_examine_signal’ [-Wmissing-prototypes]
arch/x86/um/bugs_64.c:9:6: warning: no previous prototype for ‘arch_check_bugs’ [-Wmissing-prototypes]
arch/x86/um/bugs_64.c:13:6: warning: no previous prototype for ‘arch_examine_signal’ [-Wmissing-prototypes]
arch/x86/um/elfcore.c:10:12: warning: no previous prototype for ‘elf_core_extra_phdrs’ [-Wmissing-prototypes]
arch/x86/um/elfcore.c:15:5: warning: no previous prototype for ‘elf_core_write_extra_phdrs’ [-Wmissing-prototypes]
arch/x86/um/elfcore.c:42:5: warning: no previous prototype for ‘elf_core_write_extra_data’ [-Wmissing-prototypes]
arch/x86/um/elfcore.c:63:8: warning: no previous prototype for ‘elf_core_extra_data_size’ [-Wmissing-prototypes]
arch/x86/um/fault.c:18:5: warning: no previous prototype for ‘arch_fixup’ [-Wmissing-prototypes]
arch/x86/um/os-Linux/mcontext.c:7:6: warning: no previous prototype for ‘get_regs_from_mc’ [-Wmissing-prototypes]
arch/x86/um/os-Linux/tls.c:22:6: warning: no previous prototype for ‘check_host_supports_tls’ [-Wmissing-prototypes]

Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
---
 arch/um/kernel/mem.c            | 2 ++
 arch/um/kernel/process.c        | 2 ++
 arch/um/kernel/reboot.c         | 1 +
 arch/um/kernel/skas/mmu.c       | 1 +
 arch/um/kernel/skas/process.c   | 1 +
 arch/um/kernel/tlb.c            | 1 +
 arch/x86/um/bugs_32.c           | 1 +
 arch/x86/um/bugs_64.c           | 1 +
 arch/x86/um/elfcore.c           | 1 +
 arch/x86/um/fault.c             | 1 +
 arch/x86/um/os-Linux/mcontext.c | 1 +
 arch/x86/um/os-Linux/tls.c      | 1 +
 12 files changed, 14 insertions(+)

diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index 38d5a71a579b..ca91accd64fc 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -12,12 +12,14 @@
 #include <linux/slab.h>
 #include <asm/fixmap.h>
 #include <asm/page.h>
+#include <asm/pgalloc.h>
 #include <as-layout.h>
 #include <init.h>
 #include <kern.h>
 #include <kern_util.h>
 #include <mem_user.h>
 #include <os.h>
+#include <um_malloc.h>
 #include <linux/sched/task.h>
 
 #ifdef CONFIG_KASAN
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index a7607ef1b02f..4235e2ca2664 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -15,6 +15,7 @@
 #include <linux/proc_fs.h>
 #include <linux/ptrace.h>
 #include <linux/random.h>
+#include <linux/cpu.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
@@ -27,6 +28,7 @@
 #include <asm/current.h>
 #include <asm/mmu_context.h>
 #include <asm/switch_to.h>
+#include <asm/exec.h>
 #include <linux/uaccess.h>
 #include <as-layout.h>
 #include <kern_util.h>
diff --git a/arch/um/kernel/reboot.c b/arch/um/kernel/reboot.c
index 48c0610d506e..25840eee1068 100644
--- a/arch/um/kernel/reboot.c
+++ b/arch/um/kernel/reboot.c
@@ -9,6 +9,7 @@
 #include <linux/spinlock.h>
 #include <linux/slab.h>
 #include <linux/oom.h>
+#include <linux/reboot.h>
 #include <kern_util.h>
 #include <os.h>
 #include <skas.h>
diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c
index 656fe16c9b63..aeed1c2aaf3c 100644
--- a/arch/um/kernel/skas/mmu.c
+++ b/arch/um/kernel/skas/mmu.c
@@ -10,6 +10,7 @@
 
 #include <asm/pgalloc.h>
 #include <asm/sections.h>
+#include <asm/mmu_context.h>
 #include <as-layout.h>
 #include <os.h>
 #include <skas.h>
diff --git a/arch/um/kernel/skas/process.c b/arch/um/kernel/skas/process.c
index f2ac134c9752..fdd5922f9222 100644
--- a/arch/um/kernel/skas/process.c
+++ b/arch/um/kernel/skas/process.c
@@ -12,6 +12,7 @@
 #include <kern.h>
 #include <os.h>
 #include <skas.h>
+#include <kern_util.h>
 
 extern void start_kernel(void);
 
diff --git a/arch/um/kernel/tlb.c b/arch/um/kernel/tlb.c
index 70b5e47e9761..8784f03fa4a6 100644
--- a/arch/um/kernel/tlb.c
+++ b/arch/um/kernel/tlb.c
@@ -8,6 +8,7 @@
 #include <linux/sched/signal.h>
 
 #include <asm/tlbflush.h>
+#include <asm/mmu_context.h>
 #include <as-layout.h>
 #include <mem_user.h>
 #include <os.h>
diff --git a/arch/x86/um/bugs_32.c b/arch/x86/um/bugs_32.c
index 33daff4dade4..d29929efcc07 100644
--- a/arch/x86/um/bugs_32.c
+++ b/arch/x86/um/bugs_32.c
@@ -3,6 +3,7 @@
  * Licensed under the GPL
  */
 
+#include <arch.h>
 #include <signal.h>
 #include <kern_util.h>
 #include <longjmp.h>
diff --git a/arch/x86/um/bugs_64.c b/arch/x86/um/bugs_64.c
index 8cc8256c698d..b01295e8a676 100644
--- a/arch/x86/um/bugs_64.c
+++ b/arch/x86/um/bugs_64.c
@@ -4,6 +4,7 @@
  * Licensed under the GPL
  */
 
+#include <arch.h>
 #include <sysdep/ptrace.h>
 
 void arch_check_bugs(void)
diff --git a/arch/x86/um/elfcore.c b/arch/x86/um/elfcore.c
index 650cdbbdaf45..ef50662fc40d 100644
--- a/arch/x86/um/elfcore.c
+++ b/arch/x86/um/elfcore.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/elf.h>
+#include <linux/elfcore.h>
 #include <linux/coredump.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
diff --git a/arch/x86/um/fault.c b/arch/x86/um/fault.c
index 84ac7f7b0257..0dde4d613a87 100644
--- a/arch/x86/um/fault.c
+++ b/arch/x86/um/fault.c
@@ -3,6 +3,7 @@
  * Licensed under the GPL
  */
 
+#include <arch.h>
 #include <sysdep/ptrace.h>
 
 /* These two are from asm-um/uaccess.h and linux/module.h, check them. */
diff --git a/arch/x86/um/os-Linux/mcontext.c b/arch/x86/um/os-Linux/mcontext.c
index 49c3744cac37..e80ab7d28117 100644
--- a/arch/x86/um/os-Linux/mcontext.c
+++ b/arch/x86/um/os-Linux/mcontext.c
@@ -3,6 +3,7 @@
 #define __FRAME_OFFSETS
 #include <asm/ptrace.h>
 #include <sysdep/ptrace.h>
+#include <sysdep/mcontext.h>
 
 void get_regs_from_mc(struct uml_pt_regs *regs, mcontext_t *mc)
 {
diff --git a/arch/x86/um/os-Linux/tls.c b/arch/x86/um/os-Linux/tls.c
index 3e1b1bf6acbc..eed9efe29ade 100644
--- a/arch/x86/um/os-Linux/tls.c
+++ b/arch/x86/um/os-Linux/tls.c
@@ -6,6 +6,7 @@
 #include <sys/syscall.h>
 #include <unistd.h>
 
+#include <os.h>
 #include <sysdep/tls.h>
 
 #ifndef PTRACE_GET_THREAD_AREA
-- 
2.34.1

[PATCH v2 6/6] um: Stop tracking host PID in cpu_tasks

[Tiwei Bie]

The host PID tracked in 'cpu_tasks' is no longer used. Stopping
tracking it will also save some cycles.

Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
---
 arch/um/include/shared/as-layout.h |  1 -
 arch/um/kernel/process.c           | 12 ++----------
 arch/um/kernel/skas/process.c      |  4 ----
 3 files changed, 2 insertions(+), 15 deletions(-)

diff --git a/arch/um/include/shared/as-layout.h b/arch/um/include/shared/as-layout.h
index 9ec3015bc5e2..c22f46a757dc 100644
--- a/arch/um/include/shared/as-layout.h
+++ b/arch/um/include/shared/as-layout.h
@@ -31,7 +31,6 @@
 #include <sysdep/ptrace.h>
 
 struct cpu_task {
-	int pid;
 	void *task;
 };
 
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 4235e2ca2664..1201c1a79b23 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -43,13 +43,7 @@
  * cares about its entry, so it's OK if another processor is modifying its
  * entry.
  */
-struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };
-
-static inline int external_pid(void)
-{
-	/* FIXME: Need to look up userspace_pid by cpu */
-	return userspace_pid[0];
-}
+struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { NULL } };
 
 void free_stack(unsigned long stack, int order)
 {
@@ -70,8 +64,7 @@ unsigned long alloc_stack(int order, int atomic)
 
 static inline void set_current(struct task_struct *task)
 {
-	cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
-		{ external_pid(), task });
+	cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task) { task });
 }
 
 extern void arch_switch_to(struct task_struct *to);
@@ -208,7 +201,6 @@ void um_idle_sleep(void)
 
 void arch_cpu_idle(void)
 {
-	cpu_tasks[current_thread_info()->cpu].pid = os_getpid();
 	um_idle_sleep();
 }
 
diff --git a/arch/um/kernel/skas/process.c b/arch/um/kernel/skas/process.c
index fdd5922f9222..99a5cbb36083 100644
--- a/arch/um/kernel/skas/process.c
+++ b/arch/um/kernel/skas/process.c
@@ -18,12 +18,8 @@ extern void start_kernel(void);
 
 static int __init start_kernel_proc(void *unused)
 {
-	int pid;
-
 	block_signals_trace();
-	pid = os_getpid();
 
-	cpu_tasks[0].pid = pid;
 	cpu_tasks[0].task = current;
 
 	start_kernel();
-- 
2.34.1