[PATCH 0/4] x86/srso: Reduce overhead of the mitigation

[Andrew Cooper]

The main point of this series is patch 4 to remove one taken branch from every
function return.  Everything else is cleanup.

Patch 3 has an issue that sadly may invalidate this as a technique.  Patch 4
needs some objtool whispering to fix.

Based on x86/urgent but I suspect this may want rebasing around other fixes in
flight.

Andrew Cooper (4):
  x86/srso: Rename srso_alias_*() to srso_fam19_*()
  x86/srso: Rename fam17 SRSO infrastructure to srso_fam17_*()
  x86/ret-thunk: Support CALL-ing to the ret-thunk
  x86/srso: Use CALL-based return thunks to reduce overhead

 arch/x86/include/asm/nospec-branch.h |  9 ++--
 arch/x86/kernel/alternative.c        |  4 +-
 arch/x86/kernel/cpu/bugs.c           |  9 ++--
 arch/x86/kernel/ftrace.c             |  8 +--
 arch/x86/kernel/static_call.c        | 10 ++--
 arch/x86/kernel/vmlinux.lds.S        | 10 ++--
 arch/x86/lib/retpoline.S             | 75 ++++++++++++----------------
 arch/x86/net/bpf_jit_comp.c          |  5 +-
 8 files changed, 67 insertions(+), 63 deletions(-)


base-commit: 6405b72e8d17bd1875a56ae52d23ec3cd51b9d66
-- 
2.30.2