x86: begin fault_{32|64}.c unification
Move X86_32 only get_segment_eip to X86_64
Move X86_64 only is_errata93 to X86_32
Change X86_32 loop in is_prefetch to highlight the differences
between them. Fold the logic from __is_prefetch in as well on
X86_32.
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/mm/fault_32.c b/arch/x86/mm/fault_32.c
index 870b561..300c9d8 100644
--- a/arch/x86/mm/fault_32.c
+++ b/arch/x86/mm/fault_32.c
@@ -61,6 +61,7 @@
#endif
}
+#ifdef CONFIG_X86_32
/*
* Return EIP plus the CS segment base. The segment limit is also
* adjusted, clamped to the kernel/user address space (whichever is
@@ -135,26 +136,61 @@
*eip_limit = seg_limit;
return ip + base;
}
+#endif
/*
+ * X86_32
* Sometimes AMD Athlon/Opteron CPUs report invalid exceptions on prefetch.
* Check that here and ignore it.
+ *
+ * X86_64
+ * Sometimes the CPU reports invalid exceptions on prefetch.
+ * Check that here and ignore it.
+ *
+ * Opcode checker based on code by Richard Brunner
*/
-static int __is_prefetch(struct pt_regs *regs, unsigned long addr)
+static int is_prefetch(struct pt_regs *regs, unsigned long addr,
+ unsigned long error_code)
{
- unsigned long limit;
- unsigned char *instr = (unsigned char *)get_segment_eip(regs, &limit);
+ unsigned char *instr;
int scan_more = 1;
int prefetch = 0;
- int i;
+ unsigned char *max_instr;
- for (i = 0; scan_more && i < 15; i++) {
+#ifdef CONFIG_X86_32
+ unsigned long limit;
+ if (unlikely(boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
+ boot_cpu_data.x86 >= 6)) {
+ /* Catch an obscure case of prefetch inside an NX page. */
+ if (nx_enabled && (error_code & PF_INSTR))
+ return 0;
+ } else {
+ return 0;
+ }
+ instr = (unsigned char *)get_segment_eip(regs, &limit);
+#else
+ /* If it was a exec fault ignore */
+ if (error_code & PF_INSTR)
+ return 0;
+ instr = (unsigned char __user *)convert_rip_to_linear(current, regs);
+#endif
+
+ max_instr = instr + 15;
+
+#ifdef CONFIG_X86_64
+ if (user_mode(regs) && instr >= (unsigned char *)TASK_SIZE)
+ return 0;
+#endif
+
+ while (scan_more && instr < max_instr) {
unsigned char opcode;
unsigned char instr_hi;
unsigned char instr_lo;
+#ifdef CONFIG_X86_32
if (instr > (unsigned char *)limit)
break;
+#endif
if (probe_kernel_address(instr, opcode))
break;
@@ -196,8 +232,10 @@
case 0x00:
/* Prefetch instruction is 0x0F0D or 0x0F18 */
scan_more = 0;
+#ifdef CONFIG_X86_32
if (instr > (unsigned char *)limit)
break;
+#endif
if (probe_kernel_address(instr, opcode))
break;
prefetch = (instr_lo == 0xF) &&
@@ -211,19 +249,6 @@
return prefetch;
}
-static inline int is_prefetch(struct pt_regs *regs, unsigned long addr,
- unsigned long error_code)
-{
- if (unlikely(boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
- boot_cpu_data.x86 >= 6)) {
- /* Catch an obscure case of prefetch inside an NX page. */
- if (nx_enabled && (error_code & 16))
- return 0;
- return __is_prefetch(regs, addr);
- }
- return 0;
-}
-
static noinline void force_sig_info_fault(int si_signo, int si_code,
unsigned long address, struct task_struct *tsk)
{
@@ -274,6 +299,42 @@
return pmd_k;
}
+#ifdef CONFIG_X86_64
+static const char errata93_warning[] =
+KERN_ERR "******* Your BIOS seems to not contain a fix for K8 errata #93\n"
+KERN_ERR "******* Working around it, but it may cause SEGVs or burn power.\n"
+KERN_ERR "******* Please consider a BIOS update.\n"
+KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n";
+
+/* Workaround for K8 erratum #93 & buggy BIOS.
+ BIOS SMM functions are required to use a specific workaround
+ to avoid corruption of the 64bit RIP register on C stepping K8.
+ A lot of BIOS that didn't get tested properly miss this.
+ The OS sees this as a page fault with the upper 32bits of RIP cleared.
+ Try to work around it here.
+ Note we only handle faults in kernel here. */
+
+static int is_errata93(struct pt_regs *regs, unsigned long address)
+{
+ static int warned;
+ if (address != regs->ip)
+ return 0;
+ if ((address >> 32) != 0)
+ return 0;
+ address |= 0xffffffffUL << 32;
+ if ((address >= (u64)_stext && address <= (u64)_etext) ||
+ (address >= MODULES_VADDR && address <= MODULES_END)) {
+ if (!warned) {
+ printk(errata93_warning);
+ warned = 1;
+ }
+ regs->ip = address;
+ return 1;
+ }
+ return 0;
+}
+#endif
+
/*
* Handle a fault on the vmalloc or module mapping area
*