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x86/entry/64: Don't compile ignore_sysret if 32-bit emulation is enabled

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It's only used if !CONFIG_IA32_EMULATION, so disable it in normal
configs.  This will save a few bytes of text and reduce confusion.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc:  "BaeChang Seok" <chang.seok.bae@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Bae, Chang Seok" <chang.seok.bae@intel.com>
Link: https://lkml.kernel.org/r/0f7dafa72fe7194689de5ee8cfe5d83509fabcf5.1562035429.git.luto@kernel.org
This commit is contained in:
Andy Lutomirski 2019-07-01 20:43:20 -07:00 committed by Thomas Gleixner
parent 9402eaf4c1
commit dffb3f9db6
1 changed files with 6 additions and 0 deletions
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6
arch/x86/entry/entry_64.S
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@ -1743,11 +1743,17 @@ nmi_restore:
iretq
END(nmi)
#ifndef CONFIG_IA32_EMULATION
/*
* This handles SYSCALL from 32-bit code. There is no way to program
* MSRs to fully disable 32-bit SYSCALL.
*/
ENTRY(ignore_sysret)
UNWIND_HINT_EMPTY
mov $-ENOSYS, %eax
sysret
END(ignore_sysret)
#endif
ENTRY(rewind_stack_do_exit)
UNWIND_HINT_FUNC