From a7bea8308933aaeea76dad7d42a6e51000417626 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Mon, 2 Jul 2018 04:31:54 -0600 Subject: x86/asm/64: Use 32-bit XOR to zero registers Some Intel CPUs don't recognize 64-bit XORs as zeroing idioms. Zeroing idioms don't require execution bandwidth, as they're being taken care of in the frontend (through register renaming). Use 32-bit XORs instead. Signed-off-by: Jan Beulich Cc: Alok Kataria Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: davem@davemloft.net Cc: herbert@gondor.apana.org.au Cc: pavel@ucw.cz Cc: rjw@rjwysocki.net Link: http://lkml.kernel.org/r/5B39FF1A02000078001CFB54@prv1-mh.provo.novell.com Signed-off-by: Ingo Molnar --- arch/x86/power/hibernate_asm_64.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/power') diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S index ce8da3a0412c..fd369a6e9ff8 100644 --- a/arch/x86/power/hibernate_asm_64.S +++ b/arch/x86/power/hibernate_asm_64.S @@ -137,7 +137,7 @@ ENTRY(restore_registers) /* Saved in save_processor_state. */ lgdt saved_context_gdt_desc(%rax) - xorq %rax, %rax + xorl %eax, %eax /* tell the hibernation core that we've just restored the memory */ movq %rax, in_suspend(%rip) -- cgit v1.2.3