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x86/unwind: Read stack return address in update_stack_state()

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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 <jpoimboe@redhat.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/af0c5e4560c49c0343dca486ea26c4fa92bc4e35.1492020577.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Josh Poimboeuf 2017-04-12 13:47:11 -05:00 committed by Ingo Molnar
parent 5ed8d8bb38
commit 6bcdf9d51b
2 changed files with 14 additions and 12 deletions
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1
arch/x86/include/asm/unwind.h
View File

@ -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

25
arch/x86/kernel/unwind_frame.c
View File

@ -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;
}