Merge commit 'v2.6.27-rc7' into x86/debug
[linux-2.6.git] / arch / x86 / kernel / cpu / common_64.c
index bca2d6980e829ddda3b5b798b9d8cd27c58386dc..305b465889b096a5205556ca02accf1466abe780 100644 (file)
@@ -18,6 +18,7 @@
 #include <asm/mtrr.h>
 #include <asm/mce.h>
 #include <asm/pat.h>
+#include <asm/asm.h>
 #include <asm/numa.h>
 #ifdef CONFIG_X86_LOCAL_APIC
 #include <asm/mpspec.h>
@@ -215,6 +216,39 @@ static void __init early_cpu_support_print(void)
        }
 }
 
+/*
+ * The NOPL instruction is supposed to exist on all CPUs with
+ * family >= 6, unfortunately, that's not true in practice because
+ * of early VIA chips and (more importantly) broken virtualizers that
+ * are not easy to detect.  Hence, probe for it based on first
+ * principles.
+ *
+ * Note: no 64-bit chip is known to lack these, but put the code here
+ * for consistency with 32 bits, and to make it utterly trivial to
+ * diagnose the problem should it ever surface.
+ */
+static void __cpuinit detect_nopl(struct cpuinfo_x86 *c)
+{
+       const u32 nopl_signature = 0x888c53b1; /* Random number */
+       u32 has_nopl = nopl_signature;
+
+       clear_cpu_cap(c, X86_FEATURE_NOPL);
+       if (c->x86 >= 6) {
+               asm volatile("\n"
+                            "1:      .byte 0x0f,0x1f,0xc0\n" /* nopl %eax */
+                            "2:\n"
+                            "        .section .fixup,\"ax\"\n"
+                            "3:      xor %0,%0\n"
+                            "        jmp 2b\n"
+                            "        .previous\n"
+                            _ASM_EXTABLE(1b,3b)
+                            : "+a" (has_nopl));
+
+               if (has_nopl == nopl_signature)
+                       set_cpu_cap(c, X86_FEATURE_NOPL);
+       }
+}
+
 static void __cpuinit early_identify_cpu(struct cpuinfo_x86 *c);
 
 void __init early_cpu_init(void)
@@ -313,6 +347,8 @@ static void __cpuinit early_identify_cpu(struct cpuinfo_x86 *c)
                c->x86_phys_bits = eax & 0xff;
        }
 
+       detect_nopl(c);
+
        if (c->x86_vendor != X86_VENDOR_UNKNOWN &&
            cpu_devs[c->x86_vendor]->c_early_init)
                cpu_devs[c->x86_vendor]->c_early_init(c);
@@ -544,17 +580,20 @@ void pda_init(int cpu)
                /* others are initialized in smpboot.c */
                pda->pcurrent = &init_task;
                pda->irqstackptr = boot_cpu_stack;
+               pda->irqstackptr += IRQSTACKSIZE - 64;
        } else {
-               pda->irqstackptr = (char *)
-                       __get_free_pages(GFP_ATOMIC, IRQSTACK_ORDER);
-               if (!pda->irqstackptr)
-                       panic("cannot allocate irqstack for cpu %d", cpu);
+               if (!pda->irqstackptr) {
+                       pda->irqstackptr = (char *)
+                               __get_free_pages(GFP_ATOMIC, IRQSTACK_ORDER);
+                       if (!pda->irqstackptr)
+                               panic("cannot allocate irqstack for cpu %d",
+                                     cpu);
+                       pda->irqstackptr += IRQSTACKSIZE - 64;
+               }
 
                if (pda->nodenumber == 0 && cpu_to_node(cpu) != NUMA_NO_NODE)
                        pda->nodenumber = cpu_to_node(cpu);
        }
-
-       pda->irqstackptr += IRQSTACKSIZE-64;
 }
 
 char boot_exception_stacks[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ +
@@ -652,19 +691,22 @@ void __cpuinit cpu_init(void)
        /*
         * set up and load the per-CPU TSS
         */
-       for (v = 0; v < N_EXCEPTION_STACKS; v++) {
+       if (!orig_ist->ist[0]) {
                static const unsigned int order[N_EXCEPTION_STACKS] = {
-                       [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STACK_ORDER,
-                       [DEBUG_STACK - 1] = DEBUG_STACK_ORDER
+                 [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STACK_ORDER,
+                 [DEBUG_STACK - 1] = DEBUG_STACK_ORDER
                };
-               if (cpu) {
-                       estacks = (char *)__get_free_pages(GFP_ATOMIC, order[v]);
-                       if (!estacks)
-                               panic("Cannot allocate exception stack %ld %d\n",
-                                     v, cpu);
+               for (v = 0; v < N_EXCEPTION_STACKS; v++) {
+                       if (cpu) {
+                               estacks = (char *)__get_free_pages(GFP_ATOMIC, order[v]);
+                               if (!estacks)
+                                       panic("Cannot allocate exception "
+                                             "stack %ld %d\n", v, cpu);
+                       }
+                       estacks += PAGE_SIZE << order[v];
+                       orig_ist->ist[v] = t->x86_tss.ist[v] =
+                                       (unsigned long)estacks;
                }
-               estacks += PAGE_SIZE << order[v];
-               orig_ist->ist[v] = t->x86_tss.ist[v] = (unsigned long)estacks;
        }
 
        t->x86_tss.io_bitmap_base = offsetof(struct tss_struct, io_bitmap);