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Date: Sat, 12 Jan 2008 14:10:19 -0800
From: Harvey Harrison <harvey.harrison@...il.com>
To: Ingo Molnar <mingo@...e.hu>
Cc: "H. Peter Anvin" <hpa@...or.com>,
LKML <linux-kernel@...r.kernel.org>,
Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 2/2] 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@...il.com>
---
arch/x86/mm/fault_32.c | 59 +++++++++++++++++++++++++++++++++++++++++++++--
arch/x86/mm/fault_64.c | 30 ++++++++++++++++++++++--
2 files changed, 83 insertions(+), 6 deletions(-)
diff --git a/arch/x86/mm/fault_32.c b/arch/x86/mm/fault_32.c
index 5a52489..7361f96 100644
--- a/arch/x86/mm/fault_32.c
+++ b/arch/x86/mm/fault_32.c
@@ -228,6 +228,7 @@ 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
@@ -235,10 +236,12 @@ 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;
@@ -254,9 +257,10 @@ 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
@@ -265,6 +269,7 @@ 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;
@@ -283,6 +288,51 @@ 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;
@@ -524,6 +574,9 @@ 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 befe9da..481e045 100644
--- a/arch/x86/mm/fault_64.c
+++ b/arch/x86/mm/fault_64.c
@@ -234,6 +234,7 @@ 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
@@ -241,10 +242,12 @@ 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;
@@ -260,9 +263,9 @@ 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)
@@ -289,6 +292,26 @@ 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;
@@ -332,6 +355,7 @@ 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;
--
1.5.4.rc2.1164.g6451
--
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