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x86/mm/kmmio: Use this_cpu_ptr() instead get_cpu_var() for kmmio_ctx 

Both call sites that access kmmio_ctx, access kmmio_ctx with interrupts
disabled. There is no need to use get_cpu_var() which additionally
disables preemption.

Use this_cpu_ptr() to access the kmmio_ctx variable of the current CPU.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200205143426.2592512-1-bigeasy@linutronix.de
This commit is contained in:
Sebastian Andrzej Siewior 2020-02-05 15:34:26 +01:00 committed by Borislav Petkov
parent 681ff0181b
commit 6a9feaa877
1 changed files with 3 additions and 7 deletions
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10
arch/x86/mm/kmmio.c
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@ -260,7 +260,7 @@ int kmmio_handler(struct pt_regs *regs, unsigned long addr)
goto no_kmmio;
}
ctx = &get_cpu_var(kmmio_ctx);
ctx = this_cpu_ptr(&kmmio_ctx);
if (ctx->active) {
if (page_base == ctx->addr) {
/*
@ -285,7 +285,7 @@ int kmmio_handler(struct pt_regs *regs, unsigned long addr)
pr_emerg("previous hit was at 0x%08lx.\n", ctx->addr);
disarm_kmmio_fault_page(faultpage);
}
goto no_kmmio_ctx;
goto no_kmmio;
}
ctx->active++;
@ -314,11 +314,8 @@ int kmmio_handler(struct pt_regs *regs, unsigned long addr)
* the user should drop to single cpu before tracing.
*/
put_cpu_var(kmmio_ctx);
return 1; /* fault handled */
no_kmmio_ctx:
put_cpu_var(kmmio_ctx);
no_kmmio:
rcu_read_unlock();
preempt_enable_no_resched();
@ -333,7 +330,7 @@ int kmmio_handler(struct pt_regs *regs, unsigned long addr)
static int post_kmmio_handler(unsigned long condition, struct pt_regs *regs)
{
int ret = 0;
struct kmmio_context *ctx = &get_cpu_var(kmmio_ctx);
struct kmmio_context *ctx = this_cpu_ptr(&kmmio_ctx);
if (!ctx->active) {
/*
@ -371,7 +368,6 @@ static int post_kmmio_handler(unsigned long condition, struct pt_regs *regs)
if (!(regs->flags & X86_EFLAGS_TF))
ret = 1;
out:
put_cpu_var(kmmio_ctx);
return ret;
}