From 8c938f9fae887f6e180bf802aa1c33cf74712aff Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Fri, 20 Feb 2009 22:12:18 +0100
Subject: [PATCH] x86, mm: fault.c, factor out the vm86 fault check
Impact: cleanup
Instead of an ugly, open-coded, #ifdef-ed vm86 related legacy check
in do_page_fault(), put it into the check_v8086_mode() helper
function and merge it with an existing #ifdef.
Also, simplify the code flow a tiny bit in the helper.
No code changed:
arch/x86/mm/fault.o:
text data bss dec hex filename
2711 12 12 2735 aaf fault.o.before
2711 12 12 2735 aaf fault.o.after
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/mm/fault.c | 43 +++++++++++++++++++++++++++++++------------
1 file changed, 31 insertions(+), 12 deletions(-)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 72973c7682ba..7dc0615c3cfe 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -328,14 +328,41 @@ static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
return pmd_k;
}
-#endif
-#ifdef CONFIG_X86_64
+/*
+ * Did it hit the DOS screen memory VA from vm86 mode?
+ */
+static inline void
+check_v8086_mode(struct pt_regs *regs, unsigned long address,
+ struct task_struct *tsk)
+{
+ unsigned long bit;
+
+ if (!v8086_mode(regs))
+ return;
+
+ bit = (address - 0xA0000) >> PAGE_SHIFT;
+ if (bit < 32)
+ tsk->thread.screen_bitmap |= 1 << bit;
+}
+
+#else /* 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";
+
+/*
+ * No vm86 mode in 64-bit mode:
+ */
+static inline void
+check_v8086_mode(struct pt_regs *regs, unsigned long address,
+ struct task_struct *tsk)
+{
+}
+
#endif
/*
@@ -1091,16 +1118,8 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
else
tsk->min_flt++;
-#ifdef CONFIG_X86_32
- /*
- * Did it hit the DOS screen memory VA from vm86 mode?
- */
- if (v8086_mode(regs)) {
- unsigned long bit = (address - 0xA0000) >> PAGE_SHIFT;
- if (bit < 32)
- tsk->thread.screen_bitmap |= 1 << bit;
- }
-#endif
+ check_v8086_mode(regs, address, tsk);
+
up_read(&mm->mmap_sem);
}
--
2.30.9