From 4bf1fa5a34aa2dd0d2cc58f0fc213a2e22d007a4 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Tue, 21 Jul 2009 09:56:27 +0100 Subject: [ARM] 5613/1: implement CALLER_ADDRESSx MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Uwe Kleine-König As __builtin_return_address(n) doesn't work for ARM with n > 0, the kernel needs its own implementation. This fixes many warnings saying: warning: unsupported argument to '__builtin_return_address' The new methods and walk_stackframe must not be instrumented because CALLER_ADDRESSx is used in the various tracers and tracing the tracer is a bad idea. What's currently missing is an implementation using unwind tables. This is not fatal though, it's just that the tracers don't get enough information to be really useful. Note that if both ARM_UNWIND and FRAME_POINTER are enabled, walk_stackframe uses unwind information. So in this case the same implementation is used as when FRAME_POINTER is disabled. Cc: Catalin Marinas Signed-off-by: Uwe Kleine-König Signed-off-by: Russell King --- arch/arm/include/asm/ftrace.h | 34 +++++++++++++++++++ arch/arm/kernel/Makefile | 4 ++- arch/arm/kernel/return_address.c | 71 ++++++++++++++++++++++++++++++++++++++++ arch/arm/kernel/stacktrace.c | 4 +-- 4 files changed, 110 insertions(+), 3 deletions(-) create mode 100644 arch/arm/kernel/return_address.c (limited to 'arch/arm') diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h index 39c8bc1a006..d74265cffd8 100644 --- a/arch/arm/include/asm/ftrace.h +++ b/arch/arm/include/asm/ftrace.h @@ -11,4 +11,38 @@ extern void mcount(void); #endif +#ifndef __ASSEMBLY__ + +#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) +/* + * return_address uses walk_stackframe to do it's work. If both + * CONFIG_FRAME_POINTER=y and CONFIG_ARM_UNWIND=y walk_stackframe uses unwind + * information. For this to work in the function tracer many functions would + * have to be marked with __notrace. So for now just depend on + * !CONFIG_ARM_UNWIND. + */ + +void *return_address(unsigned int); + +#else + +extern inline void *return_address(unsigned int level) +{ + return NULL; +} + +#endif + +#define HAVE_ARCH_CALLER_ADDR + +#define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0)) +#define CALLER_ADDR1 ((unsigned long)return_address(1)) +#define CALLER_ADDR2 ((unsigned long)return_address(2)) +#define CALLER_ADDR3 ((unsigned long)return_address(3)) +#define CALLER_ADDR4 ((unsigned long)return_address(4)) +#define CALLER_ADDR5 ((unsigned long)return_address(5)) +#define CALLER_ADDR6 ((unsigned long)return_address(6)) + +#endif /* ifndef __ASSEMBLY__ */ + #endif /* _ASM_ARM_FTRACE */ diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index ff89d0b3abc..3213c9382b1 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -8,10 +8,12 @@ ifdef CONFIG_DYNAMIC_FTRACE CFLAGS_REMOVE_ftrace.o = -pg endif +CFLAGS_REMOVE_return_address.o = -pg + # Object file lists. obj-y := compat.o elf.o entry-armv.o entry-common.o irq.o \ - process.o ptrace.o setup.o signal.o \ + process.o ptrace.o return_address.o setup.o signal.o \ sys_arm.o stacktrace.o time.o traps.o obj-$(CONFIG_ISA_DMA_API) += dma.o diff --git a/arch/arm/kernel/return_address.c b/arch/arm/kernel/return_address.c new file mode 100644 index 00000000000..df246da4cec --- /dev/null +++ b/arch/arm/kernel/return_address.c @@ -0,0 +1,71 @@ +/* + * arch/arm/kernel/return_address.c + * + * Copyright (C) 2009 Uwe Kleine-Koenig + * for Pengutronix + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + */ +#include + +#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) +#include + +#include + +struct return_address_data { + unsigned int level; + void *addr; +}; + +static int save_return_addr(struct stackframe *frame, void *d) +{ + struct return_address_data *data = d; + + if (!data->level) { + data->addr = (void *)frame->lr; + + return 1; + } else { + --data->level; + return 0; + } +} + +void *return_address(unsigned int level) +{ + struct return_address_data data; + struct stackframe frame; + register unsigned long current_sp asm ("sp"); + + data.level = level + 1; + + frame.fp = (unsigned long)__builtin_frame_address(0); + frame.sp = current_sp; + frame.lr = (unsigned long)__builtin_return_address(0); + frame.pc = (unsigned long)return_address; + + walk_stackframe(&frame, save_return_addr, &data); + + if (!data.level) + return data.addr; + else + return NULL; +} + +#else /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) */ + +#if defined(CONFIG_ARM_UNWIND) +#warning "TODO: return_address should use unwind tables" +#endif + +void *return_address(unsigned int level) +{ + return NULL; +} + +#endif /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) / else */ + +EXPORT_SYMBOL_GPL(return_address); diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c index 9f444e5cc16..20b7411e47f 100644 --- a/arch/arm/kernel/stacktrace.c +++ b/arch/arm/kernel/stacktrace.c @@ -21,7 +21,7 @@ * Note that with framepointer enabled, even the leaf functions have the same * prologue and epilogue, therefore we can ignore the LR value in this case. */ -int unwind_frame(struct stackframe *frame) +int notrace unwind_frame(struct stackframe *frame) { unsigned long high, low; unsigned long fp = frame->fp; @@ -43,7 +43,7 @@ int unwind_frame(struct stackframe *frame) } #endif -void walk_stackframe(struct stackframe *frame, +void notrace walk_stackframe(struct stackframe *frame, int (*fn)(struct stackframe *, void *), void *data) { while (1) { -- cgit v1.2.3