x86: function ifdefs in fault_32|64.c

Add caller of is_errata93() to X86_32, ifdef'd to do
nothing.

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>

2 files changed, 83 insertions, 6 deletions

diff --git a/arch/x86/mm/fault_32.c b/arch/x86/mm/fault_32.c
index 31113deeb7c0..eba90198b15a 100644
--- a/arch/x86/mm/fault_32.c
+++ b/arch/x86/mm/fault_32.c
@@ -217,6 +217,7 @@ 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";
+#endif
 
 /* Workaround for K8 erratum #93 & buggy BIOS.
    BIOS SMM functions are required to use a specific workaround
@@ -224,10 +225,12 @@ KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n";
    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. */
-
+   Note we only handle faults in kernel here.
+   Does nothing for X86_32
+ */
 static int is_errata93(struct pt_regs *regs, unsigned long address)
 {
+#ifdef CONFIG_X86_64
         static int warned;
         if (address != regs->ip)
                 return 0;
@@ -243,9 +246,10 @@ static int is_errata93(struct pt_regs *regs, unsigned long address)
                 regs->ip = address;
                 return 1;
         }
+#endif
         return 0;
 }
-#endif
+
 
 /*
  * Handle a fault on the vmalloc or module mapping area
@@ -254,6 +258,7 @@ static int is_errata93(struct pt_regs *regs, unsigned long address)
  */
 static inline int vmalloc_fault(unsigned long address)
 {
+#ifdef CONFIG_X86_32
         unsigned long pgd_paddr;
         pmd_t *pmd_k;
         pte_t *pte_k;
@@ -272,6 +277,51 @@ static inline int vmalloc_fault(unsigned long address)
         if (!pte_present(*pte_k))
                 return -1;
         return 0;
+#else
+        pgd_t *pgd, *pgd_ref;
+        pud_t *pud, *pud_ref;
+        pmd_t *pmd, *pmd_ref;
+        pte_t *pte, *pte_ref;
+
+        /* Copy kernel mappings over when needed. This can also
+           happen within a race in page table update. In the later
+           case just flush. */
+
+        pgd = pgd_offset(current->mm ?: &init_mm, address);
+        pgd_ref = pgd_offset_k(address);
+        if (pgd_none(*pgd_ref))
+                return -1;
+        if (pgd_none(*pgd))
+                set_pgd(pgd, *pgd_ref);
+        else
+                BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
+
+        /* Below here mismatches are bugs because these lower tables
+           are shared */
+
+        pud = pud_offset(pgd, address);
+        pud_ref = pud_offset(pgd_ref, address);
+        if (pud_none(*pud_ref))
+                return -1;
+        if (pud_none(*pud) || pud_page_vaddr(*pud) != pud_page_vaddr(*pud_ref))
+                BUG();
+        pmd = pmd_offset(pud, address);
+        pmd_ref = pmd_offset(pud_ref, address);
+        if (pmd_none(*pmd_ref))
+                return -1;
+        if (pmd_none(*pmd) || pmd_page(*pmd) != pmd_page(*pmd_ref))
+                BUG();
+        pte_ref = pte_offset_kernel(pmd_ref, address);
+        if (!pte_present(*pte_ref))
+                return -1;
+        pte = pte_offset_kernel(pmd, address);
+        /* Don't use pte_page here, because the mappings can point
+           outside mem_map, and the NUMA hash lookup cannot handle
+           that. */
+        if (!pte_present(*pte) || pte_pfn(*pte) != pte_pfn(*pte_ref))
+                BUG();
+        return 0;
+#endif
 }
 
 int show_unhandled_signals = 1;
@@ -507,6 +557,9 @@ no_context:
         if (is_prefetch(regs, address, error_code))
                 return;
 
+        if (is_errata93(regs, address))
+                return;
+
 /*
  * Oops. The kernel tried to access some bad page. We'll have to
  * terminate things with extreme prejudice.
diff --git a/arch/x86/mm/fault_64.c b/arch/x86/mm/fault_64.c
index c48d95c306df..75b7b165bdf3 100644
--- a/arch/x86/mm/fault_64.c
+++ b/arch/x86/mm/fault_64.c
@@ -223,6 +223,7 @@ 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";
+#endif
 
 /* Workaround for K8 erratum #93 & buggy BIOS.
    BIOS SMM functions are required to use a specific workaround
@@ -230,10 +231,12 @@ KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n";
    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. */
-
+   Note we only handle faults in kernel here.
+   Does nothing for X86_32
+ */
 static int is_errata93(struct pt_regs *regs, unsigned long address)
 {
+#ifdef CONFIG_X86_64
         static int warned;
         if (address != regs->ip)
                 return 0;
@@ -249,9 +252,9 @@ static int is_errata93(struct pt_regs *regs, unsigned long address)
                 regs->ip = address;
                 return 1;
         }
+#endif
         return 0;
 }
-#endif
 
 static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
                                  unsigned long error_code)
@@ -278,6 +281,26 @@ static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
  */
 static int vmalloc_fault(unsigned long address)
 {
+#ifdef CONFIG_X86_32
+        unsigned long pgd_paddr;
+        pmd_t *pmd_k;
+        pte_t *pte_k;
+        /*
+         * Synchronize this task's top level page-table
+         * with the 'reference' page table.
+         *
+         * Do _not_ use "current" here. We might be inside
+         * an interrupt in the middle of a task switch..
+         */
+        pgd_paddr = read_cr3();
+        pmd_k = vmalloc_sync_one(__va(pgd_paddr), address);
+        if (!pmd_k)
+                return -1;
+        pte_k = pte_offset_kernel(pmd_k, address);
+        if (!pte_present(*pte_k))
+                return -1;
+        return 0;
+#else
         pgd_t *pgd, *pgd_ref;
         pud_t *pud, *pud_ref;
         pmd_t *pmd, *pmd_ref;
@@ -321,6 +344,7 @@ static int vmalloc_fault(unsigned long address)
         if (!pte_present(*pte) || pte_pfn(*pte) != pte_pfn(*pte_ref))
                 BUG();
         return 0;
+#endif
 }
 
 int show_unhandled_signals = 1;