1 /*
2 * Helper routines to provide target memory access for semihosting
3 * syscalls in system emulation mode.
4 *
5 * Copyright (c) 2007 CodeSourcery.
6 *
7 * This code is licensed under the GPL
8 */
9
10 #include "qemu/osdep.h"
11 #include "exec/cpu-all.h"
12 #include "exec/exec-all.h"
13 #include "semihosting/uaccess.h"
14
uaccess_lock_user(CPUArchState * env,target_ulong addr,target_ulong len,bool copy)15 void *uaccess_lock_user(CPUArchState *env, target_ulong addr,
16 target_ulong len, bool copy)
17 {
18 void *p = malloc(len);
19 if (p && copy) {
20 if (cpu_memory_rw_debug(env_cpu(env), addr, p, len, 0)) {
21 free(p);
22 p = NULL;
23 }
24 }
25 return p;
26 }
27
uaccess_strlen_user(CPUArchState * env,target_ulong addr)28 ssize_t uaccess_strlen_user(CPUArchState *env, target_ulong addr)
29 {
30 int mmu_idx = cpu_mmu_index(env_cpu(env), false);
31 size_t len = 0;
32
33 while (1) {
34 size_t left_in_page;
35 int flags;
36 void *h;
37
38 /* Find the number of bytes remaining in the page. */
39 left_in_page = TARGET_PAGE_SIZE - (addr & ~TARGET_PAGE_MASK);
40
41 flags = probe_access_flags(env, addr, 0, MMU_DATA_LOAD,
42 mmu_idx, true, &h, 0);
43 if (flags & TLB_INVALID_MASK) {
44 return -1;
45 }
46 if (flags & TLB_MMIO) {
47 do {
48 uint8_t c;
49 if (cpu_memory_rw_debug(env_cpu(env), addr, &c, 1, 0)) {
50 return -1;
51 }
52 if (c == 0) {
53 return len;
54 }
55 addr++;
56 len++;
57 if (len > INT32_MAX) {
58 return -1;
59 }
60 } while (--left_in_page != 0);
61 } else {
62 char *p = memchr(h, 0, left_in_page);
63 if (p) {
64 len += p - (char *)h;
65 return len <= INT32_MAX ? (ssize_t)len : -1;
66 }
67 addr += left_in_page;
68 len += left_in_page;
69 if (len > INT32_MAX) {
70 return -1;
71 }
72 }
73 }
74 }
75
uaccess_lock_user_string(CPUArchState * env,target_ulong addr)76 char *uaccess_lock_user_string(CPUArchState *env, target_ulong addr)
77 {
78 ssize_t len = uaccess_strlen_user(env, addr);
79 if (len < 0) {
80 return NULL;
81 }
82 return uaccess_lock_user(env, addr, len + 1, true);
83 }
84
uaccess_unlock_user(CPUArchState * env,void * p,target_ulong addr,target_ulong len)85 void uaccess_unlock_user(CPUArchState *env, void *p,
86 target_ulong addr, target_ulong len)
87 {
88 if (len) {
89 cpu_memory_rw_debug(env_cpu(env), addr, p, len, 1);
90 }
91 free(p);
92 }
93