[PATCH] x86_64: Final support for AMD dual core

Clean up the code greatly.  Now uses the infrastructure from the Intel dual
core patch Should fix a final bug noticed by Tyan of not detecting the nodes
correctly in some corner cases.

Patch for x86-64 and i386

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 15 insertions, 11 deletions

diff --git a/arch/i386/kernel/cpu/amd.c b/arch/i386/kernel/cpu/amd.c
index fa10d0a509c7..8d182e875cd7 100644
--- a/arch/i386/kernel/cpu/amd.c
+++ b/arch/i386/kernel/cpu/amd.c
@@ -24,6 +24,9 @@ __asm__(".align 4\nvide: ret");
 
 static void __init init_amd(struct cpuinfo_x86 *c)
 {
+#ifdef CONFIG_SMP
+        int cpu = c == &boot_cpu_data ? 0 : c - cpu_data;
+#endif
         u32 l, h;
         int mbytes = num_physpages >> (20-PAGE_SHIFT);
         int r;
@@ -195,16 +198,17 @@ static void __init init_amd(struct cpuinfo_x86 *c)
                         c->x86_num_cores = 1;
         }
 
-        detect_ht(c);
-
-#ifdef CONFIG_X86_HT
-        /* AMD dual core looks like HT but isn't really. Hide it from the
-           scheduler. This works around problems with the domain scheduler.
-           Also probably gives slightly better scheduling and disables
-           SMT nice which is harmful on dual core.
-           TBD tune the domain scheduler for dual core. */
-        if (cpu_has(c, X86_FEATURE_CMP_LEGACY))
-                smp_num_siblings = 1;
+#ifdef CONFIG_SMP
+        /*
+         * 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.
+         */
+        if (c->x86_num_cores > 1) {
+                cpu_core_id[cpu] = cpu >> hweight32(c->x86_num_cores - 1);
+                printk(KERN_INFO "CPU %d(%d) -> Core %d\n",
+                       cpu, c->x86_num_cores, cpu_core_id[cpu]);
+        }
 #endif
 }
 
diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c
index ed4c9c3fe667..6be0310e3cd3 100644
--- a/arch/i386/kernel/cpu/common.c
+++ b/arch/i386/kernel/cpu/common.c
@@ -437,7 +437,7 @@ void __init detect_ht(struct cpuinfo_x86 *c)
         int     index_msb, tmp;
         int     cpu = smp_processor_id();
 
-        if (!cpu_has(c, X86_FEATURE_HT))
+        if (!cpu_has(c, X86_FEATURE_HT) || cpu_has(c, X86_FEATURE_CMP_LEGACY))
                 return;
 
         cpuid(1, &eax, &ebx, &ecx, &edx);