From e100777016fdf6ec3a9d7c1773b15a2b5eca6c55 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Mon, 14 Sep 2020 19:21:28 +0200 Subject: [PATCH] x86/mce: Annotate mce_rd/wrmsrl() with noinstr They do get called from the #MC handler which is already marked "noinstr". Commit e2def7d49d08 ("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: Borislav Petkov Link: https://lkml.kernel.org/r/20200915194020.28807-1-bp@alien8.de --- arch/x86/kernel/cpu/mce/core.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 5b1d5f3..11b6697 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -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; } -- 2.7.4