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Merge tag 'x86_fsgsbase_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull x86 fsgsbase updates from Borislav Petkov:
 "Misc minor cleanups and corrections to the fsgsbase code and
  respective selftests"

* tag 'x86_fsgsbase_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  selftests/x86/fsgsbase: Test PTRACE_PEEKUSER for GSBASE with invalid LDT GS
  selftests/x86/fsgsbase: Reap a forgotten child
  x86/fsgsbase: Replace static_cpu_has() with boot_cpu_has()
  x86/entry/64: Correct the comment over SAVE_AND_SET_GSBASE
This commit is contained in:
Linus Torvalds
2020-10-12 10:44:24 -07:00
parent 9e536c8179 1b9abd1755
commit 87194efe7e
4 changed files with 77 additions and 8 deletions
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5
arch/x86/entry/entry_64.S
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@@ -842,8 +842,9 @@ SYM_CODE_START_LOCAL(paranoid_entry)
* retrieve and set the current CPUs kernel GSBASE. The stored value
* has to be restored in paranoid_exit unconditionally.
*
* The MSR write ensures that no subsequent load is based on a
* mispredicted GSBASE. No extra FENCE required.
* The unconditional write to GS base below ensures that no subsequent
* loads based on a mispredicted GS base can happen, therefore no LFENCE
* is needed here.
*/
SAVE_AND_SET_GSBASE scratch_reg=%rax save_reg=%rbx
ret