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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-07-14 20:11:20 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-07-14 20:11:20 +0300 |
| commit | 35ce46324556ba2dbc66a88013870d8bec8a99ef (patch) | |
| tree | 85cf3a89c545c290205a927160627d4de588a781 | |
| parent | 4d145e3f830ba2c2745b42bfba5c2f8fcb8d078a (diff) | |
| parent | ac8b270b61d48fcc61f052097777e3b5e11591e0 (diff) | |
| download | linux-35ce46324556ba2dbc66a88013870d8bec8a99ef.tar.xz | |
Merge tag 'x86_urgent_for_v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fix from Borislav Petkov:
- Make sure TF is cleared before calling other functions (BHI
mitigation in this case) in the SYSENTER compat handler, as
otherwise it will warn about being in single-step mode
* tag 'x86_urgent_for_v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/bhi: Avoid warning in #DB handler due to BHI mitigation
| -rw-r--r-- | arch/x86/entry/entry_64_compat.S | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index 11c9b8efdc4c..ed0a5f2dc129 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -89,10 +89,6 @@ SYM_INNER_LABEL(entry_SYSENTER_compat_after_hwframe, SYM_L_GLOBAL) cld - IBRS_ENTER - UNTRAIN_RET - CLEAR_BRANCH_HISTORY - /* * SYSENTER doesn't filter flags, so we need to clear NT and AC * ourselves. To save a few cycles, we can check whether @@ -116,6 +112,16 @@ SYM_INNER_LABEL(entry_SYSENTER_compat_after_hwframe, SYM_L_GLOBAL) jnz .Lsysenter_fix_flags .Lsysenter_flags_fixed: + /* + * CPU bugs mitigations mechanisms can call other functions. They + * should be invoked after making sure TF is cleared because + * single-step is ignored only for instructions inside the + * entry_SYSENTER_compat function. + */ + IBRS_ENTER + UNTRAIN_RET + CLEAR_BRANCH_HISTORY + movq %rsp, %rdi call do_SYSENTER_32 jmp sysret32_from_system_call |