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authorZachary Amsden <zach@vmware.com>2007-02-13 13:26:21 +0100
committerAndi Kleen <andi@basil.nowhere.org>2007-02-13 13:26:21 +0100
commit7b3552024380f306a6c50d5105d18d9d4258fa4e (patch)
tree904a408768b216be7f759b4a190809f851a914d5 /include/asm-i386
parentbbab4f3bb7f528d2b8ccb5de9ae5f6ff3fb29684 (diff)
downloadop-kernel-dev-7b3552024380f306a6c50d5105d18d9d4258fa4e.zip
op-kernel-dev-7b3552024380f306a6c50d5105d18d9d4258fa4e.tar.gz
[PATCH] i386: Profile pc badness
Profile_pc was broken when using paravirtualization because the assumption the kernel was running at CPL 0 was violated, causing bad logic to read a random value off the stack. The only way to be in kernel lock functions is to be in kernel code, so validate that assumption explicitly by checking the CS value. We don't want to be fooled by BIOS / APM segments and try to read those stacks, so only match KERNEL_CS. I moved some stuff in segment.h to make it prettier. Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'include/asm-i386')
-rw-r--r--include/asm-i386/ptrace.h4
-rw-r--r--include/asm-i386/segment.h19
2 files changed, 17 insertions, 6 deletions
diff --git a/include/asm-i386/ptrace.h b/include/asm-i386/ptrace.h
index 1646996..6002597 100644
--- a/include/asm-i386/ptrace.h
+++ b/include/asm-i386/ptrace.h
@@ -49,6 +49,10 @@ static inline int user_mode_vm(struct pt_regs *regs)
{
return ((regs->xcs & SEGMENT_RPL_MASK) | (regs->eflags & VM_MASK)) >= USER_RPL;
}
+static inline int v8086_mode(struct pt_regs *regs)
+{
+ return (regs->eflags & VM_MASK);
+}
#define instruction_pointer(regs) ((regs)->eip)
#define regs_return_value(regs) ((regs)->eax)
diff --git a/include/asm-i386/segment.h b/include/asm-i386/segment.h
index 3c796af..065f10b 100644
--- a/include/asm-i386/segment.h
+++ b/include/asm-i386/segment.h
@@ -83,14 +83,8 @@
* The GDT has 32 entries
*/
#define GDT_ENTRIES 32
-
#define GDT_SIZE (GDT_ENTRIES * 8)
-/* Matches __KERNEL_CS and __USER_CS (they must be 2 entries apart) */
-#define SEGMENT_IS_FLAT_CODE(x) (((x) & 0xec) == GDT_ENTRY_KERNEL_CS * 8)
-/* Matches PNP_CS32 and PNP_CS16 (they must be consecutive) */
-#define SEGMENT_IS_PNP_CODE(x) (((x) & 0xf4) == GDT_ENTRY_PNPBIOS_BASE * 8)
-
/* Simple and small GDT entries for booting only */
#define GDT_ENTRY_BOOT_CS 2
@@ -134,4 +128,17 @@
#ifndef CONFIG_PARAVIRT
#define get_kernel_rpl() 0
#endif
+/*
+ * Matching rules for certain types of segments.
+ */
+
+/* Matches only __KERNEL_CS, ignoring PnP / USER / APM segments */
+#define SEGMENT_IS_KERNEL_CODE(x) (((x) & 0xfc) == GDT_ENTRY_KERNEL_CS * 8)
+
+/* Matches __KERNEL_CS and __USER_CS (they must be 2 entries apart) */
+#define SEGMENT_IS_FLAT_CODE(x) (((x) & 0xec) == GDT_ENTRY_KERNEL_CS * 8)
+
+/* Matches PNP_CS32 and PNP_CS16 (they must be consecutive) */
+#define SEGMENT_IS_PNP_CODE(x) (((x) & 0xf4) == GDT_ENTRY_PNPBIOS_BASE * 8)
+
#endif
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