diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2020-03-25 19:53:38 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-06-11 15:14:41 +0200 |
| commit | d73a332936a6d33be3aa3fa4bee959efab09e431 (patch) | |
| tree | f4889da78bf15d6213dc64e7e0a971e8f8fe7340 | |
| parent | 1c3e5d3f60e26415d4227aa1193cf9e2db4df834 (diff) | |
x86/traps: Mark fixup_bad_iret() noinstr
This is called from deep entry ASM in a situation where instrumentation
will cause more harm than providing useful information.
Switch from memmove() to memcpy() because memmove() can't be called
from noinstr code.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505134903.346741553@linutronix.de
| -rw-r--r-- | arch/x86/kernel/traps.c | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 48468f61202c..b2b36561a569 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -578,7 +578,7 @@ struct bad_iret_stack { struct pt_regs regs; }; -asmlinkage __visible notrace +asmlinkage __visible noinstr struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s) { /* @@ -589,19 +589,21 @@ struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s) * just below the IRET frame) and we want to pretend that the * exception came from the IRET target. */ - struct bad_iret_stack *new_stack = - (struct bad_iret_stack *)this_cpu_read(cpu_tss_rw.x86_tss.sp0) - 1; + struct bad_iret_stack tmp, *new_stack = + (struct bad_iret_stack *)__this_cpu_read(cpu_tss_rw.x86_tss.sp0) - 1; - /* Copy the IRET target to the new stack. */ - memmove(&new_stack->regs.ip, (void *)s->regs.sp, 5*8); + /* Copy the IRET target to the temporary storage. */ + memcpy(&tmp.regs.ip, (void *)s->regs.sp, 5*8); /* Copy the remainder of the stack from the current stack. */ - memmove(new_stack, s, offsetof(struct bad_iret_stack, regs.ip)); + memcpy(&tmp, s, offsetof(struct bad_iret_stack, regs.ip)); + + /* Update the entry stack */ + memcpy(new_stack, &tmp, sizeof(tmp)); BUG_ON(!user_mode(&new_stack->regs)); return new_stack; } -NOKPROBE_SYMBOL(fixup_bad_iret); #endif static bool is_sysenter_singlestep(struct pt_regs *regs) |