linux/arch
Borislav Petkov (AMD) 0e11073247 x86/retpoline: Do the necessary fixup to the Zen3/4 srso return thunk for !SRSO
The srso_alias_untrain_ret() dummy thunk in the !CONFIG_MITIGATION_SRSO
case is there only for the altenative in CALL_UNTRAIN_RET to have
a symbol to resolve.

However, testing with kernels which don't have CONFIG_MITIGATION_SRSO
enabled, leads to the warning in patch_return() to fire:

  missing return thunk: srso_alias_untrain_ret+0x0/0x10-0x0: eb 0e 66 66 2e
  WARNING: CPU: 0 PID: 0 at arch/x86/kernel/alternative.c:826 apply_returns (arch/x86/kernel/alternative.c:826

Put in a plain "ret" there so that gcc doesn't put a return thunk in
in its place which special and gets checked.

In addition:

  ERROR: modpost: "srso_alias_untrain_ret" [arch/x86/kvm/kvm-amd.ko] undefined!
  make[2]: *** [scripts/Makefile.modpost:145: Module.symvers] Chyba 1
  make[1]: *** [/usr/src/linux-6.8.3/Makefile:1873: modpost] Chyba 2
  make: *** [Makefile:240: __sub-make] Chyba 2

since !SRSO builds would use the dummy return thunk as reported by
petr.pisar@atlas.cz, https://bugzilla.kernel.org/show_bug.cgi?id=218679.

Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202404020901.da75a60f-oliver.sang@intel.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/all/202404020901.da75a60f-oliver.sang@intel.com/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-04-03 10:12:38 -07:00
..
alpha Kbuild updates for v6.9 2024-03-21 14:41:00 -07:00
arc - Sumanth Korikkar has taught s390 to allocate hotplug-time page frames 2024-03-14 17:43:30 -07:00
arm ARM: prctl: reject PR_SET_MDWE on pre-ARMv6 2024-03-26 11:07:22 -07:00
arm64 Including fixes from bpf, WiFi and netfilter. 2024-03-28 13:09:37 -07:00
csky - Sumanth Korikkar has taught s390 to allocate hotplug-time page frames 2024-03-14 17:43:30 -07:00
hexagon hexagon: vmlinux.lds.S: handle attributes section 2024-03-26 11:07:23 -07:00
loongarch LoongArch changes for v6.9 2024-03-22 10:22:45 -07:00
m68k TTY/Serial driver update for 6.9-rc1 2024-03-21 12:44:10 -07:00
microblaze arch: define CONFIG_PAGE_SIZE_*KB on all architectures 2024-03-06 19:29:09 +01:00
mips MIPS: move unselectable FIT_IMAGE_FDT_EPM5 out of the "System type" choice 2024-03-27 01:58:34 +09:00
nios2 - Sumanth Korikkar has taught s390 to allocate hotplug-time page frames 2024-03-14 17:43:30 -07:00
openrisc OpenRISC updates for 6.9 2024-03-14 15:53:10 -07:00
parisc prctl: generalize PR_SET_MDWE support check to be per-arch 2024-03-26 11:07:22 -07:00
powerpc powerpc updates for 6.9 #2 2024-03-23 09:21:26 -07:00
riscv Including fixes from bpf, WiFi and netfilter. 2024-03-28 13:09:37 -07:00
s390 bpf-for-netdev 2024-03-26 12:55:18 +01:00
sh sh updates for v6.9 2024-03-21 10:13:47 -07:00
sparc This includes the following changes related to sparc for v6.9: 2024-03-15 12:47:21 -07:00
um Devicetree updates for v6.9: 2024-03-15 12:37:59 -07:00
x86 x86/retpoline: Do the necessary fixup to the Zen3/4 srso return thunk for !SRSO 2024-04-03 10:12:38 -07:00
xtensa - Sumanth Korikkar has taught s390 to allocate hotplug-time page frames 2024-03-14 17:43:30 -07:00
.gitignore
Kconfig hardening fixes for v6.9-rc1 2024-03-23 08:43:21 -07:00