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| author | Max Filippov <jcmvbkbc@gmail.com> | 2013-04-08 01:29:19 +0400 |
|---|---|---|
| committer | Chris Zankel <chris@zankel.net> | 2013-05-09 01:07:10 -0700 |
| commit | 3ae908c99e944a7a5c4f4b2d8c603a6bc57b728b (patch) | |
| tree | 10159f1a9c02b862957d7d196cb1da6bb762ad39 /arch | |
| parent | 3e4196a5cc9cff50900f3dc8acc3d41e5963fd50 (diff) | |
| download | lwn-3ae908c99e944a7a5c4f4b2d8c603a6bc57b728b.tar.gz lwn-3ae908c99e944a7a5c4f4b2d8c603a6bc57b728b.zip | |
xtensa: provide custom CALLER_ADDR* implementations
Definition of CALLER_ADDR* through __builtin_return_address makes
compiler insert calls to __xtensa_libgcc_window_spill, which in turn
makes fast_syscall_spill_registers syscall that clobbers registers when
called from the kernel mode, leading to invalid opcode exceptions on
return to userspace.
Provide definition for CALLER_ADDR0 as MAKE_PC_FROM_RA(a0, a1) and in
case CONFIG_FRAME_POINTER is enabled extract CALLER_ADDR{1-3} from
stack.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/xtensa/include/asm/ftrace.h | 34 | ||||
| -rw-r--r-- | arch/xtensa/kernel/stacktrace.c | 33 |
2 files changed, 66 insertions, 1 deletions
diff --git a/arch/xtensa/include/asm/ftrace.h b/arch/xtensa/include/asm/ftrace.h index 40a8c178f10d..36dc7a684397 100644 --- a/arch/xtensa/include/asm/ftrace.h +++ b/arch/xtensa/include/asm/ftrace.h @@ -1 +1,33 @@ -/* empty */ +/* + * arch/xtensa/include/asm/ftrace.h + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2013 Tensilica Inc. + */ +#ifndef _XTENSA_FTRACE_H +#define _XTENSA_FTRACE_H + +#include <asm/processor.h> + +#define HAVE_ARCH_CALLER_ADDR +#define CALLER_ADDR0 ({ unsigned long a0, a1; \ + __asm__ __volatile__ ( \ + "mov %0, a0\n" \ + "mov %1, a1\n" \ + : "=r"(a0), "=r"(a1) : : ); \ + MAKE_PC_FROM_RA(a0, a1); }) +#ifdef CONFIG_FRAME_POINTER +extern unsigned long return_address(unsigned level); +#define CALLER_ADDR1 return_address(1) +#define CALLER_ADDR2 return_address(2) +#define CALLER_ADDR3 return_address(3) +#else +#define CALLER_ADDR1 (0) +#define CALLER_ADDR2 (0) +#define CALLER_ADDR3 (0) +#endif + +#endif /* _XTENSA_FTRACE_H */ diff --git a/arch/xtensa/kernel/stacktrace.c b/arch/xtensa/kernel/stacktrace.c index e3aff9575183..7d2c317bd98b 100644 --- a/arch/xtensa/kernel/stacktrace.c +++ b/arch/xtensa/kernel/stacktrace.c @@ -85,3 +85,36 @@ void save_stack_trace(struct stack_trace *trace) EXPORT_SYMBOL_GPL(save_stack_trace); #endif + +#ifdef CONFIG_FRAME_POINTER + +struct return_addr_data { + unsigned long addr; + unsigned skip; +}; + +static int return_address_cb(struct stackframe *frame, void *data) +{ + struct return_addr_data *r = data; + + if (r->skip) { + --r->skip; + return 0; + } + if (!kernel_text_address(frame->pc)) + return 0; + r->addr = frame->pc; + return 1; +} + +unsigned long return_address(unsigned level) +{ + struct return_addr_data r = { + .skip = level + 1, + }; + walk_stackframe(stack_pointer(NULL), return_address_cb, &r); + return r.addr; +} +EXPORT_SYMBOL(return_address); + +#endif |