Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
+30
-11
+1
include/linux/unwind_user_types.h
+1
include/linux/unwind_user_types.h
+29
-11
kernel/unwind/user.c
+29
-11
kernel/unwind/user.c
···
8
8
#include <linux/unwind_user.h>
9
9
#include <linux/uaccess.h>
10
10
11
-
static const struct unwind_user_frame fp_frame = {
12
-
ARCH_INIT_USER_FP_FRAME
13
-
};
14
-
15
11
#define for_each_user_frame(state) \
16
12
for (unwind_user_start(state); !(state)->done; unwind_user_next(state))
17
13
14
+
static inline int
15
+
get_user_word(unsigned long *word, unsigned long base, int off, unsigned int ws)
16
+
{
17
+
unsigned long __user *addr = (void __user *)base + off;
18
+
#ifdef CONFIG_COMPAT
19
+
if (ws == sizeof(int)) {
20
+
unsigned int data;
21
+
int ret = get_user(data, (unsigned int __user *)addr);
22
+
*word = data;
23
+
return ret;
24
+
}
25
+
#endif
26
+
return get_user(*word, addr);
27
+
}
28
+
18
29
static int unwind_user_next_fp(struct unwind_user_state *state)
19
30
{
20
-
const struct unwind_user_frame *frame = &fp_frame;
31
+
const struct unwind_user_frame frame = {
32
+
ARCH_INIT_USER_FP_FRAME(state->ws)
33
+
};
21
34
unsigned long cfa, fp, ra;
22
35
23
-
if (frame->use_fp) {
36
+
if (frame.use_fp) {
24
37
if (state->fp < state->sp)
25
38
return -EINVAL;
26
39
cfa = state->fp;
···
42
29
}
43
30
44
31
/* Get the Canonical Frame Address (CFA) */
45
-
cfa += frame->cfa_off;
32
+
cfa += frame.cfa_off;
46
33
47
34
/* stack going in wrong direction? */
48
35
if (cfa <= state->sp)
49
36
return -EINVAL;
50
37
51
38
/* Make sure that the address is word aligned */
52
-
if (cfa & (sizeof(long) - 1))
39
+
if (cfa & (state->ws - 1))
53
40
return -EINVAL;
54
41
55
42
/* Find the Return Address (RA) */
56
-
if (get_user(ra, (unsigned long *)(cfa + frame->ra_off)))
43
+
if (get_user_word(&ra, cfa, frame.ra_off, state->ws))
57
44
return -EINVAL;
58
45
59
-
if (frame->fp_off && get_user(fp, (unsigned long __user *)(cfa + frame->fp_off)))
46
+
if (frame.fp_off && get_user_word(&fp, cfa, frame.fp_off, state->ws))
60
47
return -EINVAL;
61
48
62
49
state->ip = ra;
63
50
state->sp = cfa;
64
-
if (frame->fp_off)
51
+
if (frame.fp_off)
65
52
state->fp = fp;
66
53
return 0;
67
54
}
···
113
100
state->ip = instruction_pointer(regs);
114
101
state->sp = user_stack_pointer(regs);
115
102
state->fp = frame_pointer(regs);
103
+
state->ws = unwind_user_word_size(regs);
104
+
if (!state->ws) {
105
+
state->done = true;
106
+
return -EINVAL;
107
+
}
116
108
117
109
return 0;
118
110
}