From 3ae908c99e944a7a5c4f4b2d8c603a6bc57b728b Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Mon, 8 Apr 2013 01:29:19 +0400 Subject: 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 Signed-off-by: Chris Zankel --- arch/xtensa/kernel/stacktrace.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'arch/xtensa/kernel') 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 -- cgit v1.2.1