Commit-ID: 2238246ff8d533a5f2327d1f953375876d8a013c Gitweb: https://git.kernel.org/tip/2238246ff8d533a5f2327d1f953375876d8a013c Author: Xiaoyao Li <xiaoyao.li@xxxxxxxxxxxxxxx> AuthorDate: Thu, 27 Jun 2019 12:55:25 +0800 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Thu, 27 Jun 2019 10:56:11 +0200 x86/boot: Make the GDT 8-byte aligned The segment descriptors are loaded with an implicitly LOCK-ed instruction, which could trigger the split lock #AC exception if the variable is not properly aligned and crosses a cache line. Align the GDT properly so the descriptors are all 8 byte aligned. Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx> Link: https://lkml.kernel.org/r/20190627045525.105266-1-xiaoyao.li@xxxxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/boot/compressed/head_64.S | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index fafb75c6c592..6233ae35d0d9 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -659,6 +659,7 @@ no_longmode: gdt64: .word gdt_end - gdt .quad 0 + .balign 8 gdt: .word gdt_end - gdt .long gdt
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