Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
+10
-4
+10
-4
arch/x86/entry/entry_64_compat.S
+10
-4
arch/x86/entry/entry_64_compat.S
···
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cld
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92
-
IBRS_ENTER
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-
UNTRAIN_RET
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-
CLEAR_BRANCH_HISTORY
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-
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/*
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* SYSENTER doesn't filter flags, so we need to clear NT and AC
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* ourselves. To save a few cycles, we can check whether
···
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testl $X86_EFLAGS_NT|X86_EFLAGS_AC|X86_EFLAGS_TF, EFLAGS(%rsp)
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jnz .Lsysenter_fix_flags
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.Lsysenter_flags_fixed:
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+
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+
/*
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* CPU bugs mitigations mechanisms can call other functions. They
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+
* should be invoked after making sure TF is cleared because
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+
* single-step is ignored only for instructions inside the
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+
* entry_SYSENTER_compat function.
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+
*/
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+
IBRS_ENTER
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+
UNTRAIN_RET
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+
CLEAR_BRANCH_HISTORY
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movq %rsp, %rdi
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call do_SYSENTER_32