[PATCH] i386: reliable stack trace support (i386)

These are the i386-specific pieces to enable reliable stack traces. This is
going to be even more useful once CFI annotations get added to he assembly
code, namely to entry.S.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 98 insertions, 0 deletions

diff --git a/include/asm-i386/unwind.h b/include/asm-i386/unwind.h
new file mode 100644
index 000000000000..1c076897ac21
--- /dev/null
+++ b/include/asm-i386/unwind.h
@@ -0,0 +1,98 @@
+#ifndef _ASM_I386_UNWIND_H
+#define _ASM_I386_UNWIND_H
+
+/*
+ * Copyright (C) 2002-2006 Novell, Inc.
+ *      Jan Beulich <jbeulich@novell.com>
+ * This code is released under version 2 of the GNU GPL.
+ */
+
+#ifdef CONFIG_STACK_UNWIND
+
+#include <linux/sched.h>
+#include <asm/fixmap.h>
+#include <asm/ptrace.h>
+#include <asm/uaccess.h>
+
+struct unwind_frame_info
+{
+        struct pt_regs regs;
+        struct task_struct *task;
+};
+
+#define UNW_PC(frame)        (frame)->regs.eip
+#define UNW_SP(frame)        (frame)->regs.esp
+#ifdef CONFIG_FRAME_POINTER
+#define UNW_FP(frame)        (frame)->regs.ebp
+#define FRAME_RETADDR_OFFSET 4
+#define FRAME_LINK_OFFSET    0
+#define STACK_BOTTOM(tsk)    STACK_LIMIT((tsk)->thread.esp0)
+#define STACK_TOP(tsk)       ((tsk)->thread.esp0)
+#endif
+#define STACK_LIMIT(ptr)     (((ptr) - 1) & ~(THREAD_SIZE - 1))
+
+#define UNW_REGISTER_INFO \
+        PTREGS_INFO(eax), \
+        PTREGS_INFO(ecx), \
+        PTREGS_INFO(edx), \
+        PTREGS_INFO(ebx), \
+        PTREGS_INFO(esp), \
+        PTREGS_INFO(ebp), \
+        PTREGS_INFO(esi), \
+        PTREGS_INFO(edi), \
+        PTREGS_INFO(eip)
+
+static inline void arch_unw_init_frame_info(struct unwind_frame_info *info,
+                                            /*const*/ struct pt_regs *regs)
+{
+        if (user_mode_vm(regs))
+                info->regs = *regs;
+        else {
+                memcpy(&info->regs, regs, offsetof(struct pt_regs, esp));
+                info->regs.esp = (unsigned long)&regs->esp;
+                info->regs.xss = __KERNEL_DS;
+        }
+}
+
+static inline void arch_unw_init_blocked(struct unwind_frame_info *info)
+{
+        memset(&info->regs, 0, sizeof(info->regs));
+        info->regs.eip = info->task->thread.eip;
+        info->regs.xcs = __KERNEL_CS;
+        __get_user(info->regs.ebp, (long *)info->task->thread.esp);
+        info->regs.esp = info->task->thread.esp;
+        info->regs.xss = __KERNEL_DS;
+        info->regs.xds = __USER_DS;
+        info->regs.xes = __USER_DS;
+}
+
+extern asmlinkage void arch_unwind_init_running(struct unwind_frame_info *,
+                                                asmlinkage void (*callback)(struct unwind_frame_info *,
+                                                                            void *arg),
+                                                void *arg);
+
+static inline int arch_unw_user_mode(const struct unwind_frame_info *info)
+{
+#if 0 /* This can only work when selector register and EFLAGS saves/restores
+         are properly annotated (and tracked in UNW_REGISTER_INFO). */
+        return user_mode_vm(&info->regs);
+#else
+        return info->regs.eip < PAGE_OFFSET
+               || (info->regs.eip >= __fix_to_virt(FIX_VSYSCALL)
+                    && info->regs.eip < __fix_to_virt(FIX_VSYSCALL) + PAGE_SIZE)
+               || info->regs.esp < PAGE_OFFSET;
+#endif
+}
+
+#else
+
+#define UNW_PC(frame) ((void)(frame), 0)
+
+static inline int arch_unw_user_mode(const void *info)
+{
+        return 0;
+}
+
+#endif
+
+#endif /* _ASM_I386_UNWIND_H */