From b538ed278b80641ee6d7b75497d5e14de1bb1137 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Mon, 26 Jun 2006 13:57:32 +0200 Subject: [PATCH] [PATCH] x86_64: reliable stack trace support (x86-64) These are the x86_64-specific pieces to enable reliable stack traces. The only restriction with this is that it currently cannot unwind across the interrupt->normal stack boundary, as that transition is lacking proper annotation. Signed-off-by: Jan Beulich Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- arch/x86_64/kernel/entry.S | 33 ++++++++++ arch/x86_64/kernel/process.c | 2 +- arch/x86_64/kernel/traps.c | 54 ++++++++++++++-- arch/x86_64/kernel/vmlinux.lds.S | 9 +++ include/asm-x86_64/proto.h | 2 +- include/asm-x86_64/unwind.h | 106 +++++++++++++++++++++++++++++++ lib/Kconfig.debug | 2 +- 7 files changed, 199 insertions(+), 9 deletions(-) create mode 100644 include/asm-x86_64/unwind.h diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S index 9999d703b6c..6c68beec51b 100644 --- a/arch/x86_64/kernel/entry.S +++ b/arch/x86_64/kernel/entry.S @@ -1089,3 +1089,36 @@ ENTRY(call_softirq) ret CFI_ENDPROC ENDPROC(call_softirq) + +#ifdef CONFIG_STACK_UNWIND +ENTRY(arch_unwind_init_running) + CFI_STARTPROC + movq %r15, R15(%rdi) + movq %r14, R14(%rdi) + xchgq %rsi, %rdx + movq %r13, R13(%rdi) + movq %r12, R12(%rdi) + xorl %eax, %eax + movq %rbp, RBP(%rdi) + movq %rbx, RBX(%rdi) + movq (%rsp), %rcx + movq %rax, R11(%rdi) + movq %rax, R10(%rdi) + movq %rax, R9(%rdi) + movq %rax, R8(%rdi) + movq %rax, RAX(%rdi) + movq %rax, RCX(%rdi) + movq %rax, RDX(%rdi) + movq %rax, RSI(%rdi) + movq %rax, RDI(%rdi) + movq %rax, ORIG_RAX(%rdi) + movq %rcx, RIP(%rdi) + leaq 8(%rsp), %rcx + movq $__KERNEL_CS, CS(%rdi) + movq %rax, EFLAGS(%rdi) + movq %rcx, RSP(%rdi) + movq $__KERNEL_DS, SS(%rdi) + jmpq *%rdx + CFI_ENDPROC +ENDPROC(arch_unwind_init_running) +#endif diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c index dcb77b46234..d6fa41459c8 100644 --- a/arch/x86_64/kernel/process.c +++ b/arch/x86_64/kernel/process.c @@ -334,7 +334,7 @@ void show_regs(struct pt_regs *regs) { printk("CPU %d:", smp_processor_id()); __show_regs(regs); - show_trace(®s->rsp); + show_trace(NULL, regs, (void *)(regs + 1)); } /* diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c index 9f8f1eff4a6..eb1534ff1f5 100644 --- a/arch/x86_64/kernel/traps.c +++ b/arch/x86_64/kernel/traps.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include @@ -39,7 +40,7 @@ #include #include #include - +#include #include #include #include @@ -189,6 +190,23 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack, return NULL; } +static void show_trace_unwind(struct unwind_frame_info *info, void *context) +{ + int i = 11; + + while (unwind(info) == 0 && UNW_PC(info)) { + if (i > 50) { + printk("\n "); + i = 7; + } else + i += printk(" "); + i += printk_address(UNW_PC(info)); + if (arch_unw_user_mode(info)) + break; + } + printk("\n"); +} + /* * x86-64 can have upto three kernel stacks: * process stack @@ -196,15 +214,34 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack, * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack */ -void show_trace(unsigned long *stack) +void show_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * stack) { const unsigned cpu = safe_smp_processor_id(); unsigned long *irqstack_end = (unsigned long *)cpu_pda(cpu)->irqstackptr; int i; unsigned used = 0; + struct unwind_frame_info info; printk("\nCall Trace:"); + if (!tsk) + tsk = current; + + if (regs) { + if (unwind_init_frame_info(&info, tsk, regs) == 0) { + show_trace_unwind(&info, NULL); + return; + } + } else if (tsk == current) { + if (unwind_init_running(&info, show_trace_unwind, NULL) == 0) + return; + } else { + if (unwind_init_blocked(&info, tsk) == 0) { + show_trace_unwind(&info, NULL); + return; + } + } + #define HANDLE_STACK(cond) \ do while (cond) { \ unsigned long addr = *stack++; \ @@ -262,7 +299,7 @@ void show_trace(unsigned long *stack) printk("\n"); } -void show_stack(struct task_struct *tsk, unsigned long * rsp) +static void _show_stack(struct task_struct *tsk, struct pt_regs *regs, unsigned long * rsp) { unsigned long *stack; int i; @@ -296,7 +333,12 @@ void show_stack(struct task_struct *tsk, unsigned long * rsp) printk("%016lx ", *stack++); touch_nmi_watchdog(); } - show_trace((unsigned long *)rsp); + show_trace(tsk, regs, rsp); +} + +void show_stack(struct task_struct *tsk, unsigned long * rsp) +{ + _show_stack(tsk, NULL, rsp); } /* @@ -305,7 +347,7 @@ void show_stack(struct task_struct *tsk, unsigned long * rsp) void dump_stack(void) { unsigned long dummy; - show_trace(&dummy); + show_trace(NULL, NULL, &dummy); } EXPORT_SYMBOL(dump_stack); @@ -332,7 +374,7 @@ void show_registers(struct pt_regs *regs) if (in_kernel) { printk("Stack: "); - show_stack(NULL, (unsigned long*)rsp); + _show_stack(NULL, regs, (unsigned long*)rsp); printk("\nCode: "); if (regs->rip < PAGE_OFFSET) diff --git a/arch/x86_64/kernel/vmlinux.lds.S b/arch/x86_64/kernel/vmlinux.lds.S index 5968c2415da..1c6a5f32291 100644 --- a/arch/x86_64/kernel/vmlinux.lds.S +++ b/arch/x86_64/kernel/vmlinux.lds.S @@ -45,6 +45,15 @@ SECTIONS RODATA +#ifdef CONFIG_STACK_UNWIND + . = ALIGN(8); + .eh_frame : AT(ADDR(.eh_frame) - LOAD_OFFSET) { + __start_unwind = .; + *(.eh_frame) + __end_unwind = .; + } +#endif + /* Data */ .data : AT(ADDR(.data) - LOAD_OFFSET) { *(.data) diff --git a/include/asm-x86_64/proto.h b/include/asm-x86_64/proto.h index 1064533e095..105476ff803 100644 --- a/include/asm-x86_64/proto.h +++ b/include/asm-x86_64/proto.h @@ -75,7 +75,7 @@ extern void main_timer_handler(struct pt_regs *regs); extern unsigned long end_pfn_map; -extern void show_trace(unsigned long * rsp); +extern void show_trace(struct task_struct *, struct pt_regs *, unsigned long * rsp); extern void show_registers(struct pt_regs *regs); extern void exception_table_check(void); diff --git a/include/asm-x86_64/unwind.h b/include/asm-x86_64/unwind.h new file mode 100644 index 00000000000..4f61de24617 --- /dev/null +++ b/include/asm-x86_64/unwind.h @@ -0,0 +1,106 @@ +#ifndef _ASM_X86_64_UNWIND_H +#define _ASM_X86_64_UNWIND_H + +/* + * Copyright (C) 2002-2006 Novell, Inc. + * Jan Beulich + * This code is released under version 2 of the GNU GPL. + */ + +#ifdef CONFIG_STACK_UNWIND + +#include +#include +#include +#include + +struct unwind_frame_info +{ + struct pt_regs regs; + struct task_struct *task; +}; + +#define UNW_PC(frame) (frame)->regs.rip +#define UNW_SP(frame) (frame)->regs.rsp +#ifdef CONFIG_FRAME_POINTER +#define UNW_FP(frame) (frame)->regs.rbp +#define FRAME_RETADDR_OFFSET 8 +#define FRAME_LINK_OFFSET 0 +#define STACK_BOTTOM(tsk) (((tsk)->thread.rsp0 - 1) & ~(THREAD_SIZE - 1)) +#define STACK_TOP(tsk) ((tsk)->thread.rsp0) +#endif +/* Might need to account for the special exception and interrupt handling + stacks here, since normally + EXCEPTION_STACK_ORDER < THREAD_ORDER < IRQSTACK_ORDER, + but the construct is needed only for getting across the stack switch to + the interrupt stack - thus considering the IRQ stack itself is unnecessary, + and the overhead of comparing against all exception handling stacks seems + not desirable. */ +#define STACK_LIMIT(ptr) (((ptr) - 1) & ~(THREAD_SIZE - 1)) + +#define UNW_REGISTER_INFO \ + PTREGS_INFO(rax), \ + PTREGS_INFO(rdx), \ + PTREGS_INFO(rcx), \ + PTREGS_INFO(rbx), \ + PTREGS_INFO(rsi), \ + PTREGS_INFO(rdi), \ + PTREGS_INFO(rbp), \ + PTREGS_INFO(rsp), \ + PTREGS_INFO(r8), \ + PTREGS_INFO(r9), \ + PTREGS_INFO(r10), \ + PTREGS_INFO(r11), \ + PTREGS_INFO(r12), \ + PTREGS_INFO(r13), \ + PTREGS_INFO(r14), \ + PTREGS_INFO(r15), \ + PTREGS_INFO(rip) + +static inline void arch_unw_init_frame_info(struct unwind_frame_info *info, + /*const*/ struct pt_regs *regs) +{ + info->regs = *regs; +} + +static inline void arch_unw_init_blocked(struct unwind_frame_info *info) +{ + extern const char thread_return[]; + + memset(&info->regs, 0, sizeof(info->regs)); + info->regs.rip = (unsigned long)thread_return; + info->regs.cs = __KERNEL_CS; + __get_user(info->regs.rbp, (unsigned long *)info->task->thread.rsp); + info->regs.rsp = info->task->thread.rsp; + info->regs.ss = __KERNEL_DS; +} + +extern void arch_unwind_init_running(struct unwind_frame_info *, + 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 saves/restores + are properly annotated (and tracked in UNW_REGISTER_INFO). */ + return user_mode(&info->regs); +#else + return (long)info->regs.rip >= 0 + || (info->regs.rip >= VSYSCALL_START && info->regs.rip < VSYSCALL_END) + || (long)info->regs.rsp >= 0; +#endif +} + +#else + +#define UNW_PC(frame) ((void)(frame), 0) + +static inline int arch_unw_user_mode(const void *info) +{ + return 0; +} + +#endif + +#endif /* _ASM_X86_64_UNWIND_H */ diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 256b3b805c5..bbaed84a686 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -199,7 +199,7 @@ config UNWIND_INFO config STACK_UNWIND bool "Stack unwind support" depends on UNWIND_INFO - depends on n + depends on X86_64 help This enables more precise stack traces, omitting all unrelated occurrences of pointers into kernel code from the dump. -- 2.41.1