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x86/entry: Remove outdated comment about SYSCALL targets

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The comment probably meant some old AMD64 incarnation which most likely
never saw the light of day. STAR and LSTAR are two different registers
and STAR sets CS/SS(DS) selectors for *all* modes, not only 32-bit.

So simply remove that comment.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160823172356.15879-1-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Borislav Petkov 2016-08-23 19:23:56 +02:00 committed by Ingo Molnar
parent 4950d6d48a
commit 556b672368
1 changed files with 0 additions and 5 deletions
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5
arch/x86/kernel/cpu/common.c
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@ -1305,11 +1305,6 @@ static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
/* May not be marked __init: used by software suspend */
void syscall_init(void)
{
/*
* LSTAR and STAR live in a bit strange symbiosis.
* They both write to the same internal register. STAR allows to
* set CS/DS but only a 32bit target. LSTAR sets the 64bit rip.
*/
wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS);
wrmsrl(MSR_LSTAR, (unsigned long)entry_SYSCALL_64);