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Diffstat (limited to 'arch/x86/include/asm/ptrace.h')
-rw-r--r--arch/x86/include/asm/ptrace.h43
1 files changed, 37 insertions, 6 deletions
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index 2b5d686ea9f3..91c04c8e67fa 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -9,6 +9,20 @@
#ifdef __i386__
struct pt_regs {
+ /*
+ * NB: 32-bit x86 CPUs are inconsistent as what happens in the
+ * following cases (where %seg represents a segment register):
+ *
+ * - pushl %seg: some do a 16-bit write and leave the high
+ * bits alone
+ * - movl %seg, [mem]: some do a 16-bit write despite the movl
+ * - IDT entry: some (e.g. 486) will leave the high bits of CS
+ * and (if applicable) SS undefined.
+ *
+ * Fortunately, x86-32 doesn't read the high bits on POP or IRET,
+ * so we can just treat all of the segment registers as 16-bit
+ * values.
+ */
unsigned long bx;
unsigned long cx;
unsigned long dx;
@@ -16,16 +30,22 @@ struct pt_regs {
unsigned long di;
unsigned long bp;
unsigned long ax;
- unsigned long ds;
- unsigned long es;
- unsigned long fs;
- unsigned long gs;
+ unsigned short ds;
+ unsigned short __dsh;
+ unsigned short es;
+ unsigned short __esh;
+ unsigned short fs;
+ unsigned short __fsh;
+ unsigned short gs;
+ unsigned short __gsh;
unsigned long orig_ax;
unsigned long ip;
- unsigned long cs;
+ unsigned short cs;
+ unsigned short __csh;
unsigned long flags;
unsigned long sp;
- unsigned long ss;
+ unsigned short ss;
+ unsigned short __ssh;
};
#else /* __i386__ */
@@ -176,6 +196,17 @@ static inline unsigned long regs_get_register(struct pt_regs *regs,
if (offset == offsetof(struct pt_regs, sp) &&
regs->cs == __KERNEL_CS)
return kernel_stack_pointer(regs);
+
+ /* The selector fields are 16-bit. */
+ if (offset == offsetof(struct pt_regs, cs) ||
+ offset == offsetof(struct pt_regs, ss) ||
+ offset == offsetof(struct pt_regs, ds) ||
+ offset == offsetof(struct pt_regs, es) ||
+ offset == offsetof(struct pt_regs, fs) ||
+ offset == offsetof(struct pt_regs, gs)) {
+ return *(u16 *)((unsigned long)regs + offset);
+
+ }
#endif
return *(unsigned long *)((unsigned long)regs + offset);
}