Previously the apicid<->coreid split was computed based on the max
number of cores. Now use a new CPUID AMD defined for that. On most
systems right now it should be 0 and the old method will be used.
Signed-off-by: Andi Kleen <[email protected]>
---
arch/i386/kernel/cpu/amd.c | 14 ++++++++------
arch/x86_64/kernel/setup.c | 20 +++++++++++++-------
2 files changed, 21 insertions(+), 13 deletions(-)
Index: linux/arch/x86_64/kernel/setup.c
===================================================================
--- linux.orig/arch/x86_64/kernel/setup.c
+++ linux/arch/x86_64/kernel/setup.c
@@ -968,10 +968,18 @@ static void __init amd_detect_cmp(struct
int node = 0;
unsigned apicid = hard_smp_processor_id();
#endif
+ unsigned ecx = cpuid_ecx(0x80000008);
- bits = 0;
- while ((1 << bits) < c->x86_max_cores)
- bits++;
+ c->x86_max_cores = (ecx & 0xff) + 1;
+
+ /* CPU telling us the core id bits shift? */
+ bits = (ecx >> 12) & 0xF;
+
+ /* Otherwise recompute */
+ if (bits == 0) {
+ while ((1 << bits) < c->x86_max_cores)
+ bits++;
+ }
/* Low order bits define the core id (index of core in socket) */
cpu_core_id[cpu] = phys_proc_id[cpu] & ((1 << bits)-1);
@@ -1059,11 +1067,9 @@ static int __init init_amd(struct cpuinf
if (c->x86_power & (1<<8))
set_bit(X86_FEATURE_CONSTANT_TSC, &c->x86_capability);
- if (c->extended_cpuid_level >= 0x80000008) {
- c->x86_max_cores = (cpuid_ecx(0x80000008) & 0xff) + 1;
-
+ /* Multi core CPU? */
+ if (c->extended_cpuid_level >= 0x80000008)
amd_detect_cmp(c);
- }
return r;
}
Index: linux/arch/i386/kernel/cpu/amd.c
===================================================================
--- linux.orig/arch/i386/kernel/cpu/amd.c
+++ linux/arch/i386/kernel/cpu/amd.c
@@ -224,15 +224,17 @@ static void __init init_amd(struct cpuin
#ifdef CONFIG_X86_HT
/*
- * On a AMD dual core setup the lower bits of the APIC id
- * distingush the cores. Assumes number of cores is a power
- * of two.
+ * On a AMD multi core setup the lower bits of the APIC id
+ * distingush the cores.
*/
if (c->x86_max_cores > 1) {
int cpu = smp_processor_id();
- unsigned bits = 0;
- while ((1 << bits) < c->x86_max_cores)
- bits++;
+ unsigned bits = (cpuid_ecx(0x80000008) >> 12) & 0xf;
+
+ if (bits == 0) {
+ while ((1 << bits) < c->x86_max_cores)
+ bits++;
+ }
cpu_core_id[cpu] = phys_proc_id[cpu] & ((1<<bits)-1);
phys_proc_id[cpu] >>= bits;
printk(KERN_INFO "CPU %d(%d) -> Core %d\n",
-
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