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x86/entry/64: Use PUSH_AND_CLEAN_REGS in more cases

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entry_SYSCALL_64_after_hwframe() and nmi() can be converted to use
PUSH_AND_CLEAN_REGS instead of opencoded variants thereof. Due to
the interleaving, the additional XOR-based clearing of R8 and R9
in entry_SYSCALL_64_after_hwframe() should not have any noticeable
negative implications.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
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: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dan.j.williams@intel.com
Link: http://lkml.kernel.org/r/20180211104949.12992-6-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Dominik Brodowski
2018-02-11 11:49:46 +01:00
committed by Ingo Molnar
parent 3f01daecd5
commit 30907fd13b
2 changed files with 6 additions and 65 deletions
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6
arch/x86/entry/calling.h
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@@ -137,7 +137,7 @@ For 32-bit we have the following conventions - kernel is built with
UNWIND_HINT_REGS offset=\offset
.endm
.macro PUSH_AND_CLEAR_REGS
.macro PUSH_AND_CLEAR_REGS rdx=%rdx rax=%rax
/*
* Push registers and sanitize registers of values that a
* speculation attack might otherwise want to exploit. The
@@ -147,9 +147,9 @@ For 32-bit we have the following conventions - kernel is built with
*/
pushq %rdi /* pt_regs->di */
pushq %rsi /* pt_regs->si */
pushq %rdx /* pt_regs->dx */
pushq \rdx /* pt_regs->dx */
pushq %rcx /* pt_regs->cx */
pushq %rax /* pt_regs->ax */
pushq \rax /* pt_regs->ax */
pushq %r8 /* pt_regs->r8 */
xorq %r8, %r8 /* nospec r8 */
pushq %r9 /* pt_regs->r9 */