Commit-ID: 46f5a10a721ce8dce8cc8fe55279b49e1c6b3288
Gitweb: https://git.kernel.org/tip/46f5a10a721ce8dce8cc8fe55279b49e1c6b3288
Author: Andy Lutomirski <luto@xxxxxxxxxx>
AuthorDate: Thu, 2 Nov 2017 00:59:14 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 2 Nov 2017 11:04:47 +0100
x86/entry/64: Remove all remaining direct thread_struct::sp0 reads
The only remaining readers in context switch code or vm86(), and
they all just want to update TSS.sp0 to match the current task.
Replace them all with a new helper update_sp0().
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Cc: Borislav Petkov <bpetkov@xxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/2d231687f4ff288c9d9e98d7861b7df374246ac3.1509609304.git.luto@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/switch_to.h | 6 ++++++
arch/x86/kernel/process_32.c | 2 +-
arch/x86/kernel/process_64.c | 2 +-
arch/x86/kernel/vm86_32.c | 4 ++--
4 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h
index 7ae8caf..54e64d9 100644
--- a/arch/x86/include/asm/switch_to.h
+++ b/arch/x86/include/asm/switch_to.h
@@ -84,4 +84,10 @@ static inline void refresh_sysenter_cs(struct thread_struct *thread)
}
#endif
+/* This is used when switching tasks or entering/exiting vm86 mode. */
+static inline void update_sp0(struct task_struct *task)
+{
+ load_sp0(task->thread.sp0);
+}
+
#endif /* _ASM_X86_SWITCH_TO_H */
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 40b8587..45bf0c5 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -287,7 +287,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
* current_thread_info(). Refresh the SYSENTER configuration in
* case prev or next is vm86.
*/
- load_sp0(next->sp0);
+ update_sp0(next_p);
refresh_sysenter_cs(next);
this_cpu_write(cpu_current_top_of_stack,
(unsigned long)task_stack_page(next_p) +
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 2124304..45e3809 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -465,7 +465,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
this_cpu_write(current_task, next_p);
/* Reload sp0. */
- load_sp0(next->sp0);
+ update_sp0(next_p);
/*
* Now maybe reload the debug registers and handle I/O bitmaps
diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index 0f1d92c..a7b44c7 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -148,7 +148,7 @@ void save_v86_state(struct kernel_vm86_regs *regs, int retval)
preempt_disable();
tsk->thread.sp0 = vm86->saved_sp0;
tsk->thread.sysenter_cs = __KERNEL_CS;
- load_sp0(tsk->thread.sp0);
+ update_sp0(tsk);
refresh_sysenter_cs(&tsk->thread);
vm86->saved_sp0 = 0;
preempt_enable();
@@ -373,7 +373,7 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus)
refresh_sysenter_cs(&tsk->thread);
}
- load_sp0(tsk->thread.sp0);
+ update_sp0(tsk);
preempt_enable();
if (vm86->flags & VM86_SCREEN_BITMAP)
--
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