Commit e1007770 authored by Borislav Petkov's avatar Borislav Petkov
Browse files

x86/mce: Annotate mce_rd/wrmsrl() with noinstr 



They do get called from the #MC handler which is already marked
"noinstr".

Commit

  e2def7d4 ("x86/mce: Make mce_rdmsrl() panic on an inaccessible MSR")

already got rid of the instrumentation in the MSR accessors, fix the
annotation now too, in order to get rid of:

  vmlinux.o: warning: objtool: do_machine_check()+0x4a: call to mce_rdmsrl() leaves .noinstr.text section

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200915194020.28807-1-bp@alien8.de
parent dc0592b7

arch/x86/kernel/cpu/mce/core.c

+21 −6
Original line number Diff line number Diff line
@@ -392,16 +392,25 @@ __visible bool ex_handler_rdmsr_fault(const struct exception_table_entry *fixup, 
}



/* MSR access wrappers used for error injection */

static u64 mce_rdmsrl(u32 msr)

static noinstr u64 mce_rdmsrl(u32 msr)

{

	DECLARE_ARGS(val, low, high);



	if (__this_cpu_read(injectm.finished)) {

		int offset = msr_to_offset(msr);

		int offset;

		u64 ret;



		instrumentation_begin();



		offset = msr_to_offset(msr);

		if (offset < 0)

			return 0;

		return *(u64 *)((char *)this_cpu_ptr(&injectm) + offset);

			ret = 0;

		else

			ret = *(u64 *)((char *)this_cpu_ptr(&injectm) + offset);



		instrumentation_end();



		return ret;

	}



	/*
@@ -437,15 +446,21 @@ __visible bool ex_handler_wrmsr_fault(const struct exception_table_entry *fixup, 
	return true;

}



static void mce_wrmsrl(u32 msr, u64 v)

static noinstr void mce_wrmsrl(u32 msr, u64 v)

{

	u32 low, high;



	if (__this_cpu_read(injectm.finished)) {

		int offset = msr_to_offset(msr);

		int offset;



		instrumentation_begin();



		offset = msr_to_offset(msr);

		if (offset >= 0)

			*(u64 *)((char *)this_cpu_ptr(&injectm) + offset) = v;



		instrumentation_end();



		return;

	}

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