Commit a586f98e authored Jul 03, 2015 by Andy Lutomirski Committed by Ingo Molnar Jul 07, 2015

x86/asm/entry/64: Simplify IRQ stack pt_regs handling

There's no need for both RSI and RDI to point to the original stack.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/3a0481f809dd340c7d3f54ce3fd6d66ef2a578cd.1435952415.git.luto@kernel.org

Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent ff467594

arch/x86/entry/entry_64.S

+3 −5

Original line number	Diff line number	Diff line
		@@ -506,8 +506,6 @@ END(irq_entries_start)
		SAVE_C_REGS
		SAVE_EXTRA_REGS

		movq %rsp,%rdi /* arg1 for \func (pointer to pt_regs) */

		testb $3, CS(%rsp)
		jz 1f
		SWAPGS
		@@ -519,14 +517,14 @@ END(irq_entries_start)
		* a little cheaper to use a separate counter in the PDA (short of
		* moving irq_enter into assembly, which would be too much work)
		*/
		movq %rsp, %rsi
		movq %rsp, %rdi
		incl PER_CPU_VAR(irq_count)
		cmovzq PER_CPU_VAR(irq_stack_ptr), %rsp
		pushq %rsi
		pushq %rdi
		/* We entered an interrupt context - irqs are off: */
		TRACE_IRQS_OFF

		call \func
		call \func /* rdi points to pt_regs */
		.endm

		/*