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| author | Nikolay Borisov <nik.borisov@suse.com> | 2024-05-29 18:28:50 +0300 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2024-06-17 17:45:19 +0200 |
| commit | 54183d103d38e5efefce8500ec41dfbfaba9c19d (patch) | |
| tree | a6c855cc5c0ce9f54c4c8cfe8a1abd933a87849c | |
| parent | f385f024639431bec3e70c33cdbc9563894b3ee5 (diff) | |
| download | linux-54183d103d38e5efefce8500ec41dfbfaba9c19d.tar.gz linux-54183d103d38e5efefce8500ec41dfbfaba9c19d.tar.bz2 linux-54183d103d38e5efefce8500ec41dfbfaba9c19d.zip | |
x86/kexec: Remove spurious unconditional JMP from from identity_mapped()
This seemingly straightforward JMP was introduced in the initial version
of the the 64bit kexec code without any explanation.
It turns out (check accompanying Link) it's likely a copy/paste artefact
from 32-bit code, where such a JMP could be used as a serializing
instruction for the 486's prefetch queue. On x86_64 that's not needed
because there's already a preceding write to cr4 which itself is
a serializing operation.
[ bp: Typos. Let's try this and see what cries out. If it does,
reverting it is trivial. ]
Signed-off-by: Nikolay Borisov <nik.borisov@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/all/55bc0649-c017-49ab-905d-212f140a403f@citrix.com/
| -rw-r--r-- | arch/x86/kernel/relocate_kernel_64.S | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S index 56cab1bb25f5..54e620021c7e 100644 --- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -153,9 +153,6 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped) 1: movq %rax, %cr4 - jmp 1f -1: - /* Flush the TLB (needed?) */ movq %r9, %cr3 |