Commit-ID: 6bcdf9d51b9892dd5c6892d50cf5e9628efb8062 Gitweb: http://git.kernel.org/tip/6bcdf9d51b9892dd5c6892d50cf5e9628efb8062 Author: Josh Poimboeuf <jpoim...@redhat.com> AuthorDate: Wed, 12 Apr 2017 13:47:11 -0500 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Fri, 14 Apr 2017 10:19:59 +0200
x86/unwind: Read stack return address in update_stack_state() Instead of reading the return address when unwind_get_return_address() is called, read it from update_stack_state() and store it in the unwind state. This enables the next patch to check the return address from unwind_next_frame() so it can detect an entry code frame. Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com> Acked-by: Thomas Gleixner <t...@linutronix.de> Cc: Andy Lutomirski <l...@kernel.org> Cc: Borislav Petkov <b...@alien8.de> Cc: Brian Gerst <brge...@gmail.com> Cc: Daniel Borkmann <dan...@iogearbox.net> Cc: Dave Jones <da...@codemonkey.org.uk> Cc: Denys Vlasenko <dvlas...@redhat.com> Cc: H. Peter Anvin <h...@zytor.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Link: http://lkml.kernel.org/r/af0c5e4560c49c0343dca486ea26c4fa92bc4e35.1492020577.git.jpoim...@redhat.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/x86/include/asm/unwind.h | 1 + arch/x86/kernel/unwind_frame.c | 25 +++++++++++++------------ 2 files changed, 14 insertions(+), 12 deletions(-) diff --git a/arch/x86/include/asm/unwind.h b/arch/x86/include/asm/unwind.h index 6fa75b1..5663425 100644 --- a/arch/x86/include/asm/unwind.h +++ b/arch/x86/include/asm/unwind.h @@ -14,6 +14,7 @@ struct unwind_state { #ifdef CONFIG_FRAME_POINTER unsigned long *bp, *orig_sp; struct pt_regs *regs; + unsigned long ip; #else unsigned long *sp; #endif diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c index 9098ef1..c67a059 100644 --- a/arch/x86/kernel/unwind_frame.c +++ b/arch/x86/kernel/unwind_frame.c @@ -56,20 +56,10 @@ static void unwind_dump(struct unwind_state *state, unsigned long *sp) unsigned long unwind_get_return_address(struct unwind_state *state) { - unsigned long addr; - unsigned long *addr_p = unwind_get_return_address_ptr(state); - if (unwind_done(state)) return 0; - if (state->regs && user_mode(state->regs)) - return 0; - - addr = READ_ONCE_TASK_STACK(state->task, *addr_p); - addr = ftrace_graph_ret_addr(state->task, &state->graph_idx, addr, - addr_p); - - return __kernel_text_address(addr) ? addr : 0; + return __kernel_text_address(state->ip) ? state->ip : 0; } EXPORT_SYMBOL_GPL(unwind_get_return_address); @@ -141,7 +131,7 @@ static bool update_stack_state(struct unwind_state *state, struct stack_info *info = &state->stack_info; enum stack_type prev_type = info->type; struct pt_regs *regs; - unsigned long *frame, *prev_frame_end; + unsigned long *frame, *prev_frame_end, *addr_p, addr; size_t len; if (state->regs) @@ -185,6 +175,16 @@ static bool update_stack_state(struct unwind_state *state, state->regs = NULL; } + /* Save the return address: */ + if (state->regs && user_mode(state->regs)) + state->ip = 0; + else { + addr_p = unwind_get_return_address_ptr(state); + addr = READ_ONCE_TASK_STACK(state->task, *addr_p); + state->ip = ftrace_graph_ret_addr(state->task, &state->graph_idx, + addr, addr_p); + } + /* Save the original stack pointer for unwind_dump(): */ if (!state->orig_sp || info->type != prev_type) state->orig_sp = frame; @@ -228,6 +228,7 @@ bool unwind_next_frame(struct unwind_state *state) */ state->regs = regs; state->bp = NULL; + state->ip = 0; return true; }
