From eecac38b0423a69715073ecbde581dafd1abb28b Mon Sep 17 00:00:00 2001 From: Stafford Horne Date: Mon, 24 Jul 2017 21:44:35 +0900 Subject: openrisc: support framepointers and STACKTRACE_SUPPORT For lockdep support a reliable stack trace mechanism is needed. This patch adds support in OpenRISC for the stacktrace framework, implemented by a simple unwinder api. The unwinder api supports both framepointer and basic stack tracing. The unwinder is now used to replace the stack_dump() implementation as well. The new traces are inline with other architectures trace format: Call trace: [] show_stack+0x3c/0x58 [] dump_stack+0xa8/0xe4 [] __cpu_up+0x64/0x130 [] bringup_cpu+0x3c/0x178 [] cpuhp_invoke_callback+0xa8/0x1fc [] cpuhp_up_callbacks+0x44/0x14c [] cpu_up+0x14c/0x1bc [] smp_init+0x104/0x15c [] ? kernel_init+0x0/0x140 [] kernel_init_freeable+0xbc/0x25c [] ? kernel_init+0x0/0x140 [] kernel_init+0x1c/0x140 [] ? schedule_tail+0x18/0xa0 [] ret_from_fork+0x1c/0x9c Signed-off-by: Stafford Horne --- arch/openrisc/Kconfig | 4 ++ arch/openrisc/include/asm/unwinder.h | 20 +++++++ arch/openrisc/kernel/Makefile | 3 +- arch/openrisc/kernel/stacktrace.c | 86 ++++++++++++++++++++++++++++ arch/openrisc/kernel/traps.c | 54 +++--------------- arch/openrisc/kernel/unwinder.c | 105 +++++++++++++++++++++++++++++++++++ 6 files changed, 224 insertions(+), 48 deletions(-) create mode 100644 arch/openrisc/include/asm/unwinder.h create mode 100644 arch/openrisc/kernel/stacktrace.c create mode 100644 arch/openrisc/kernel/unwinder.c (limited to 'arch/openrisc') diff --git a/arch/openrisc/Kconfig b/arch/openrisc/Kconfig index bfff04ae7f7d..399f55e82dcb 100644 --- a/arch/openrisc/Kconfig +++ b/arch/openrisc/Kconfig @@ -33,6 +33,7 @@ config OPENRISC select ARCH_USE_QUEUED_SPINLOCKS select ARCH_USE_QUEUED_RWLOCKS select OMPIC if SMP + select ARCH_WANT_FRAME_POINTERS config CPU_BIG_ENDIAN def_bool y @@ -60,6 +61,9 @@ config TRACE_IRQFLAGS_SUPPORT config GENERIC_CSUM def_bool y +config STACKTRACE_SUPPORT + def_bool y + source "init/Kconfig" source "kernel/Kconfig.freezer" diff --git a/arch/openrisc/include/asm/unwinder.h b/arch/openrisc/include/asm/unwinder.h new file mode 100644 index 000000000000..165ec6f02ab8 --- /dev/null +++ b/arch/openrisc/include/asm/unwinder.h @@ -0,0 +1,20 @@ +/* + * OpenRISC unwinder.h + * + * Architecture API for unwinding stacks. + * + * Copyright (C) 2017 Stafford Horne + * + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + */ + +#ifndef __ASM_OPENRISC_UNWINDER_H +#define __ASM_OPENRISC_UNWINDER_H + +void unwind_stack(void *data, unsigned long *stack, + void (*trace)(void *data, unsigned long addr, + int reliable)); + +#endif /* __ASM_OPENRISC_UNWINDER_H */ diff --git a/arch/openrisc/kernel/Makefile b/arch/openrisc/kernel/Makefile index 7d94643c878d..b4b51a07016a 100644 --- a/arch/openrisc/kernel/Makefile +++ b/arch/openrisc/kernel/Makefile @@ -6,9 +6,10 @@ extra-y := head.o vmlinux.lds obj-y := setup.o or32_ksyms.o process.o dma.o \ traps.o time.o irq.o entry.o ptrace.o signal.o \ - sys_call_table.o + sys_call_table.o unwinder.o obj-$(CONFIG_SMP) += smp.o +obj-$(CONFIG_STACKTRACE) += stacktrace.o obj-$(CONFIG_MODULES) += module.o obj-$(CONFIG_OF) += prom.o diff --git a/arch/openrisc/kernel/stacktrace.c b/arch/openrisc/kernel/stacktrace.c new file mode 100644 index 000000000000..43f140a28bc7 --- /dev/null +++ b/arch/openrisc/kernel/stacktrace.c @@ -0,0 +1,86 @@ +/* + * Stack trace utility for OpenRISC + * + * Copyright (C) 2017 Stafford Horne + * + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + * + * Losely based on work from sh and powerpc. + */ + +#include +#include +#include +#include + +#include +#include + +/* + * Save stack-backtrace addresses into a stack_trace buffer. + */ +static void +save_stack_address(void *data, unsigned long addr, int reliable) +{ + struct stack_trace *trace = data; + + if (!reliable) + return; + + if (trace->skip > 0) { + trace->skip--; + return; + } + + if (trace->nr_entries < trace->max_entries) + trace->entries[trace->nr_entries++] = addr; +} + +void save_stack_trace(struct stack_trace *trace) +{ + unwind_stack(trace, (unsigned long *) &trace, save_stack_address); +} +EXPORT_SYMBOL_GPL(save_stack_trace); + +static void +save_stack_address_nosched(void *data, unsigned long addr, int reliable) +{ + struct stack_trace *trace = (struct stack_trace *)data; + + if (!reliable) + return; + + if (in_sched_functions(addr)) + return; + + if (trace->skip > 0) { + trace->skip--; + return; + } + + if (trace->nr_entries < trace->max_entries) + trace->entries[trace->nr_entries++] = addr; +} + +void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +{ + unsigned long *sp = NULL; + + if (tsk == current) + sp = (unsigned long *) &sp; + else + sp = (unsigned long *) KSTK_ESP(tsk); + + unwind_stack(trace, sp, save_stack_address_nosched); +} +EXPORT_SYMBOL_GPL(save_stack_trace_tsk); + +void +save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace) +{ + unwind_stack(trace, (unsigned long *) regs->sp, + save_stack_address_nosched); +} +EXPORT_SYMBOL_GPL(save_stack_trace_regs); diff --git a/arch/openrisc/kernel/traps.c b/arch/openrisc/kernel/traps.c index 803e9e756f77..4085d72fa5ae 100644 --- a/arch/openrisc/kernel/traps.c +++ b/arch/openrisc/kernel/traps.c @@ -38,6 +38,7 @@ #include #include #include +#include extern char _etext, _stext; @@ -45,61 +46,20 @@ int kstack_depth_to_print = 0x180; int lwa_flag; unsigned long __user *lwa_addr; -static inline int valid_stack_ptr(struct thread_info *tinfo, void *p) +void print_trace(void *data, unsigned long addr, int reliable) { - return p > (void *)tinfo && p < (void *)tinfo + THREAD_SIZE - 3; -} - -void show_trace(struct task_struct *task, unsigned long *stack) -{ - struct thread_info *context; - unsigned long addr; - - context = (struct thread_info *) - ((unsigned long)stack & (~(THREAD_SIZE - 1))); - - while (valid_stack_ptr(context, stack)) { - addr = *stack++; - if (__kernel_text_address(addr)) { - printk(" [<%08lx>]", addr); - print_symbol(" %s", addr); - printk("\n"); - } - } - printk(" =======================\n"); + pr_emerg("[<%p>] %s%pS\n", (void *) addr, reliable ? "" : "? ", + (void *) addr); } /* displays a short stack trace */ void show_stack(struct task_struct *task, unsigned long *esp) { - unsigned long addr, *stack; - int i; - if (esp == NULL) esp = (unsigned long *)&esp; - stack = esp; - - printk("Stack dump [0x%08lx]:\n", (unsigned long)esp); - for (i = 0; i < kstack_depth_to_print; i++) { - if (kstack_end(stack)) - break; - if (__get_user(addr, stack)) { - /* This message matches "failing address" marked - s390 in ksymoops, so lines containing it will - not be filtered out by ksymoops. */ - printk("Failing address 0x%lx\n", (unsigned long)stack); - break; - } - stack++; - - printk("sp + %02d: 0x%08lx\n", i * 4, addr); - } - printk("\n"); - - show_trace(task, esp); - - return; + pr_emerg("Call trace:\n"); + unwind_stack(NULL, esp, print_trace); } void show_trace_task(struct task_struct *tsk) @@ -115,7 +75,7 @@ void show_registers(struct pt_regs *regs) int in_kernel = 1; unsigned long esp; - esp = (unsigned long)(®s->sp); + esp = (unsigned long)(regs->sp); if (user_mode(regs)) in_kernel = 0; diff --git a/arch/openrisc/kernel/unwinder.c b/arch/openrisc/kernel/unwinder.c new file mode 100644 index 000000000000..8ae15c2c1845 --- /dev/null +++ b/arch/openrisc/kernel/unwinder.c @@ -0,0 +1,105 @@ +/* + * OpenRISC unwinder.c + * + * Reusable arch specific api for unwinding stacks. + * + * Copyright (C) 2017 Stafford Horne + * + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + */ + +#include +#include + +#include + +#ifdef CONFIG_FRAME_POINTER +struct or1k_frameinfo { + unsigned long *fp; + unsigned long ra; + unsigned long top; +}; + +/* + * Verify a frameinfo structure. The return address should be a valid text + * address. The frame pointer may be null if its the last frame, otherwise + * the frame pointer should point to a location in the stack after the the + * top of the next frame up. + */ +static inline int or1k_frameinfo_valid(struct or1k_frameinfo *frameinfo) +{ + return (frameinfo->fp == NULL || + (!kstack_end(frameinfo->fp) && + frameinfo->fp > &frameinfo->top)) && + __kernel_text_address(frameinfo->ra); +} + +/* + * Create a stack trace doing scanning which is frame pointer aware. We can + * get reliable stack traces by matching the previously found frame + * pointer with the top of the stack address every time we find a valid + * or1k_frameinfo. + * + * Ideally the stack parameter will be passed as FP, but it can not be + * guaranteed. Therefore we scan each address looking for the first sign + * of a return address. + * + * The OpenRISC stack frame looks something like the following. The + * location SP is held in r1 and location FP is held in r2 when frame pointers + * enabled. + * + * SP -> (top of stack) + * - (callee saved registers) + * - (local variables) + * FP-8 -> previous FP \ + * FP-4 -> return address |- or1k_frameinfo + * FP -> (previous top of stack) / + */ +void unwind_stack(void *data, unsigned long *stack, + void (*trace)(void *data, unsigned long addr, int reliable)) +{ + unsigned long *next_fp = NULL; + struct or1k_frameinfo *frameinfo = NULL; + int reliable = 0; + + while (!kstack_end(stack)) { + frameinfo = container_of(stack, + struct or1k_frameinfo, + top); + + if (__kernel_text_address(frameinfo->ra)) { + if (or1k_frameinfo_valid(frameinfo) && + (next_fp == NULL || + next_fp == &frameinfo->top)) { + reliable = 1; + next_fp = frameinfo->fp; + } else + reliable = 0; + + trace(data, frameinfo->ra, reliable); + } + stack++; + } +} + +#else /* CONFIG_FRAME_POINTER */ + +/* + * Create a stack trace by doing a simple scan treating all text addresses + * as return addresses. + */ +void unwind_stack(void *data, unsigned long *stack, + void (*trace)(void *data, unsigned long addr, int reliable)) +{ + unsigned long addr; + + while (!kstack_end(stack)) { + addr = *stack++; + if (__kernel_text_address(addr)) + trace(data, addr, 0); + } +} +#endif /* CONFIG_FRAME_POINTER */ + -- cgit v1.2.3-70-g09d2