diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2019-03-19 13:35:46 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2019-04-03 12:02:24 +0300 |
| commit | 64604d54d3115fee89598bfb6d8d2252f8a2d114 (patch) | |
| tree | 8f2dd9b37fb0011a9814d57150307872db6f294e | |
| parent | 2f0f9e9ad7b3459c5c54ef2c03145a98e65dd158 (diff) | |
| download | linux-64604d54d3115fee89598bfb6d8d2252f8a2d114.tar.xz | |
sched/x86_64: Don't save flags on context switch
Now that we have objtool validating AC=1 state for all x86_64 code,
we can once again guarantee clean flags on schedule.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/entry/entry_64.S | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/switch_to.h | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/process_64.c | 7 |
3 files changed, 1 insertions, 10 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 4fe27b67d7e2..1f0efdb7b629 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -291,7 +291,6 @@ ENTRY(__switch_to_asm) pushq %r13 pushq %r14 pushq %r15 - pushfq /* switch stack */ movq %rsp, TASK_threadsp(%rdi) @@ -314,7 +313,6 @@ ENTRY(__switch_to_asm) #endif /* restore callee-saved registers */ - popfq popq %r15 popq %r14 popq %r13 diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h index 157149d4129c..18a4b6890fa8 100644 --- a/arch/x86/include/asm/switch_to.h +++ b/arch/x86/include/asm/switch_to.h @@ -40,13 +40,13 @@ asmlinkage void ret_from_fork(void); * order of the fields must match the code in __switch_to_asm(). */ struct inactive_task_frame { - unsigned long flags; #ifdef CONFIG_X86_64 unsigned long r15; unsigned long r14; unsigned long r13; unsigned long r12; #else + unsigned long flags; unsigned long si; unsigned long di; #endif diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 026a43be9bd1..844a28b29967 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -393,13 +393,6 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp, fork_frame = container_of(childregs, struct fork_frame, regs); frame = &fork_frame->frame; - /* - * For a new task use the RESET flags value since there is no before. - * All the status flags are zero; DF and all the system flags must also - * be 0, specifically IF must be 0 because we context switch to the new - * task with interrupts disabled. - */ - frame->flags = X86_EFLAGS_FIXED; frame->bp = 0; frame->ret_addr = (unsigned long) ret_from_fork; p->thread.sp = (unsigned long) fork_frame; |