diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2025-09-23 13:27:34 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2025-10-29 10:29:57 +0100 |
| commit | c79dd946e370af3537edb854f210cba3a94b4516 (patch) | |
| tree | eb10e80ca5238c82698adb1a8d49ce3030584d35 | |
| parent | 5578534e4b92350995a20068f2e6ea3186c62d7f (diff) | |
unwind: Implement compat fp unwind
It is important to be able to unwind compat tasks too.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20250924080119.613695709@infradead.org
| -rw-r--r-- | include/linux/unwind_user_types.h | 1 | ||||
| -rw-r--r-- | kernel/unwind/user.c | 40 |
2 files changed, 30 insertions, 11 deletions
diff --git a/include/linux/unwind_user_types.h b/include/linux/unwind_user_types.h index a449f15be890..938f7e623332 100644 --- a/include/linux/unwind_user_types.h +++ b/include/linux/unwind_user_types.h @@ -36,6 +36,7 @@ struct unwind_user_state { unsigned long ip; unsigned long sp; unsigned long fp; + unsigned int ws; enum unwind_user_type current_type; unsigned int available_types; bool done; diff --git a/kernel/unwind/user.c b/kernel/unwind/user.c index 9dcde797b5d9..642871527a13 100644 --- a/kernel/unwind/user.c +++ b/kernel/unwind/user.c @@ -8,19 +8,32 @@ #include <linux/unwind_user.h> #include <linux/uaccess.h> -static const struct unwind_user_frame fp_frame = { - ARCH_INIT_USER_FP_FRAME -}; - #define for_each_user_frame(state) \ for (unwind_user_start(state); !(state)->done; unwind_user_next(state)) +static inline int +get_user_word(unsigned long *word, unsigned long base, int off, unsigned int ws) +{ + unsigned long __user *addr = (void __user *)base + off; +#ifdef CONFIG_COMPAT + if (ws == sizeof(int)) { + unsigned int data; + int ret = get_user(data, (unsigned int __user *)addr); + *word = data; + return ret; + } +#endif + return get_user(*word, addr); +} + static int unwind_user_next_fp(struct unwind_user_state *state) { - const struct unwind_user_frame *frame = &fp_frame; + const struct unwind_user_frame frame = { + ARCH_INIT_USER_FP_FRAME(state->ws) + }; unsigned long cfa, fp, ra; - if (frame->use_fp) { + if (frame.use_fp) { if (state->fp < state->sp) return -EINVAL; cfa = state->fp; @@ -29,26 +42,26 @@ static int unwind_user_next_fp(struct unwind_user_state *state) } /* Get the Canonical Frame Address (CFA) */ - cfa += frame->cfa_off; + cfa += frame.cfa_off; /* stack going in wrong direction? */ if (cfa <= state->sp) return -EINVAL; /* Make sure that the address is word aligned */ - if (cfa & (sizeof(long) - 1)) + if (cfa & (state->ws - 1)) return -EINVAL; /* Find the Return Address (RA) */ - if (get_user(ra, (unsigned long *)(cfa + frame->ra_off))) + if (get_user_word(&ra, cfa, frame.ra_off, state->ws)) return -EINVAL; - if (frame->fp_off && get_user(fp, (unsigned long __user *)(cfa + frame->fp_off))) + if (frame.fp_off && get_user_word(&fp, cfa, frame.fp_off, state->ws)) return -EINVAL; state->ip = ra; state->sp = cfa; - if (frame->fp_off) + if (frame.fp_off) state->fp = fp; return 0; } @@ -100,6 +113,11 @@ static int unwind_user_start(struct unwind_user_state *state) state->ip = instruction_pointer(regs); state->sp = user_stack_pointer(regs); state->fp = frame_pointer(regs); + state->ws = unwind_user_word_size(regs); + if (!state->ws) { + state->done = true; + return -EINVAL; + } return 0; } |