]> git.ipfire.org Git - thirdparty/kernel/linux.git/commit
objtool/x86: Fix NOP decode
authorPeter Zijlstra <peterz@infradead.org>
Wed, 24 Sep 2025 13:27:03 +0000 (15:27 +0200)
committerPeter Zijlstra <peterz@infradead.org>
Tue, 14 Oct 2025 11:43:11 +0000 (13:43 +0200)
commit044f721ccd33103349eebbb960825584bc6d8e23
tree3e9c6be0aa5d332a7e50798611fafdd60b7a7a1e
parent76e1851a1bc28e760d6acc7a54ec9dce05717028
objtool/x86: Fix NOP decode

For x86_64 the kernel consistently uses 2 instructions for all NOPs:

  90       - NOP
  0f 1f /0 - NOPL

Notably:

 - REP NOP is PAUSE, not a NOP instruction.

 - 0f {0c...0f} is reserved space,
   except for 0f 0d /1, which is PREFETCHW, not a NOP.

 - 0f {19,1c...1f} is reserved space,
   except for 0f 1f /0, which is NOPL.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
tools/objtool/arch/x86/decode.c