Commit-ID: 3796366614598e48edf0561b86f18c230a7debc8 Gitweb: http://git.kernel.org/tip/3796366614598e48edf0561b86f18c230a7debc8 Author: Andy Lutomirski <luto@xxxxxxxxxx> AuthorDate: Thu, 25 Jun 2015 18:44:01 +0200 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Mon, 6 Jul 2015 15:23:27 +0200 x86/asm/tsc, x86/cpu/amd: Use the full 64-bit TSC to detect the 2.6.2 bug This code is timing 100k indirect calls, so the added overhead of counting the number of cycles elapsed as a 64-bit number should be insignificant. Drop the optimization of using a 32-bit count. Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Brian Gerst <brgerst@xxxxxxxxx> Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Huang Rui <ray.huang@xxxxxxx> Cc: John Stultz <john.stultz@xxxxxxxxxx> Cc: Len Brown <lenb@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: kvm ML <kvm@xxxxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/d58f339a9c0dd8352b50d2f7a216f67ec2844f20.1434501121.git.luto@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/kernel/cpu/amd.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index dd3a4ba..a69710d 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -114,7 +114,7 @@ static void init_amd_k6(struct cpuinfo_x86 *c) const int K6_BUG_LOOP = 1000000; int n; void (*f_vide)(void); - unsigned long d, d2; + u64 d, d2; printk(KERN_INFO "AMD K6 stepping B detected - "); @@ -125,10 +125,10 @@ static void init_amd_k6(struct cpuinfo_x86 *c) n = K6_BUG_LOOP; f_vide = vide; - rdtscl(d); + d = native_read_tsc(); while (n--) f_vide(); - rdtscl(d2); + d2 = native_read_tsc(); d = d2-d; if (d > 20*K6_BUG_LOOP) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
