[PATCH] x86_64: Support constantly ticking TSCs

On Intel Noconas the TSC ticks with a constant frequency.  Don't scale the
factor used by udelay when cpufreq changes the frequency.

This generalizes an earlier patch by Intel for this. 

Cc: <venkatesh.pallipadi@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c
index a191d4831789..b06221e31952 100644
--- a/arch/x86_64/kernel/setup.c
+++ b/arch/x86_64/kernel/setup.c
@@ -855,6 +855,8 @@ static void __init init_intel(struct cpuinfo_x86 *c)
 
         if (c->x86 == 15)
                 c->x86_cache_alignment = c->x86_clflush_size * 2;
+        if (c->x86 >= 15)
+                set_bit(X86_FEATURE_CONSTANT_TSC, &c->x86_capability);
 }
 
 void __init get_cpu_vendor(struct cpuinfo_x86 *c)
@@ -1055,7 +1057,8 @@ static int show_cpuinfo(struct seq_file *m, void *v)
                 NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
 
                 /* Other (Linux-defined) */
-                "cxmmx", "k6_mtrr", "cyrix_arr", "centaur_mcr", NULL, NULL, NULL, NULL,
+                "cxmmx", NULL, "cyrix_arr", "centaur_mcr", "k8c+",
+                "constant_tsc", NULL, NULL,
                 NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
                 NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
                 NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,