Commit a534b679 authored Sep 06, 2007 by Andi Kleen Committed by Linus Torvalds Sep 10, 2007

x86_64: Remove CLFLUSH in text_poke()



The CLFLUSH for the modified code line in text_poke was supposed
to speed up CPU recovery. Unfortunately it seems to cause hangs
on some VIA C3s (at least on VIA Esther Model 10 Stepping 9)
Remove it.

Thanks to Stefan Becker for reporting/testing.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 23d5ea5d

arch/i386/kernel/alternative.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -445,8 +445,6 @@ void __kprobes text_poke(void addr, unsigned char opcode, int len)
		{
		memcpy(addr, opcode, len);
		sync_core();
		/* Not strictly needed, but can speed CPU recovery up. Ignore cross cacheline
		case. */
		if (cpu_has_clflush)
		asm("clflush (%0) " :: "r" (addr) : "memory");
		/* Could also do a CLFLUSH here to speed up CPU recovery; but
		that causes hangs on some VIA CPUs. */
		}