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author | Borislav Petkov (AMD) <bp@alien8.de> | 2024-04-02 17:05:49 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-04-10 17:35:51 +0300 |
commit | 3ec21104c8815c1787b2b4e5eb88adfc13c685cb (patch) | |
tree | 65363c0f211ebb63668aeda987c31b0546e52062 /arch/arm64/kvm/hyp/pgtable.c | |
parent | 668b3074aa14829e2ac2759799537a93b60fef86 (diff) | |
download | linux-3ec21104c8815c1787b2b4e5eb88adfc13c685cb.tar.xz |
x86/retpoline: Do the necessary fixup to the Zen3/4 srso return thunk for !SRSO
commit 0e110732473e14d6520e49d75d2c88ef7d46fe67 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arm64/kvm/hyp/pgtable.c')
0 files changed, 0 insertions, 0 deletions