From: Ard Biesheuvel <ardb@xxxxxxxxxx> The x86 purgatory switches to a new GDT twice, and the first time, it doesn't even bother to switch to the new code segment. Given that data segment selectors are ignored in long mode, and the fact that the GDT is reprogrammed again after returning from purgatory(), the first switch is entirely pointless and can just be dropped altogether. Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> --- arch/x86/purgatory/setup-x86_64.S | 29 -------------------- 1 file changed, 29 deletions(-) diff --git a/arch/x86/purgatory/setup-x86_64.S b/arch/x86/purgatory/setup-x86_64.S index 2d10ff88851d..f160fc729cbe 100644 --- a/arch/x86/purgatory/setup-x86_64.S +++ b/arch/x86/purgatory/setup-x86_64.S @@ -15,17 +15,6 @@ .code64 SYM_CODE_START(purgatory_start) - /* Load a gdt so I know what the segment registers are */ - lgdt gdt(%rip) - - /* load the data segments */ - movl $0x18, %eax /* data segment */ - movl %eax, %ds - movl %eax, %es - movl %eax, %ss - movl %eax, %fs - movl %eax, %gs - /* Setup a stack */ leaq lstack_end(%rip), %rsp @@ -34,24 +23,6 @@ SYM_CODE_START(purgatory_start) jmp entry64 SYM_CODE_END(purgatory_start) - .section ".rodata" - .balign 16 -SYM_DATA_START_LOCAL(gdt) - /* 0x00 unusable segment - * 0x08 unused - * so use them as the gdt ptr - */ - .word gdt_end - gdt - 1 - .quad gdt - .word 0, 0, 0 - - /* 0x10 4GB flat code segment */ - .word 0xFFFF, 0x0000, 0x9A00, 0x00AF - - /* 0x18 4GB flat data segment */ - .word 0xFFFF, 0x0000, 0x9200, 0x00CF -SYM_DATA_END_LABEL(gdt, SYM_L_LOCAL, gdt_end) - .bss .balign 16 SYM_DATA_START_LOCAL(lstack) -- 2.44.0.769.g3c40516874-goog _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
