Commit-ID: 8ec6993d9f7d961014af970ded57542961fe9ad9 Gitweb: http://git.kernel.org/tip/8ec6993d9f7d961014af970ded57542961fe9ad9 Author: Brian Gerst <brgerst@xxxxxxxxx> AuthorDate: Wed, 25 Nov 2009 11:17:36 -0500 Committer: Ingo Molnar <mingo@xxxxxxx> CommitDate: Thu, 26 Nov 2009 10:44:30 +0100 x86, 64-bit: Set data segments to null after switching to 64-bit mode This prevents kernel threads from inheriting non-null segment selectors, and causing optimizations in __switch_to() to be ineffective. Signed-off-by: Brian Gerst <brgerst@xxxxxxxxx> Cc: Tim Blechmann <tim@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx> Cc: Jan Beulich <JBeulich@xxxxxxxxxx> LKML-Reference: <1259165856-3512-1-git-send-email-brgerst@xxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxx> --- arch/x86/kernel/head_64.S | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 2640660..17ba9ec 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -212,8 +212,8 @@ ENTRY(secondary_startup_64) */ lgdt early_gdt_descr(%rip) - /* set up data segments. actually 0 would do too */ - movl $__KERNEL_DS,%eax + /* set up data segments */ + xorl %eax,%eax movl %eax,%ds movl %eax,%ss movl %eax,%es -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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