Re: [PATCH] x86/nospec: Unwreck the RSB stuffing

On August 16, 2022 6:04:36 PM UTC, Daniel Sneddon daniel.sneddon@linux.intel.com wrote:

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 62f6b8b7c4a5..5c476b37b3bc 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -284,6 +284,9 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start, /* Mask away "NOT" flag bit for feature to test. */ u16 feature = a->cpuid & ~ALTINSTR_FLAG_INV;

I guess it is time for struct altinstr.flags. I never liked this INV mask bit...

•           if (feature == X86_FEATURE_NEVER)
  

•                   goto next;
  

•          instr = (u8 *)&a->instr_offset + a->instr_offset;
           replacement = (u8 *)&a->repl_offset + a->repl_offset;
           BUG_ON(a->instrlen > sizeof(insn_buff));