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 "accel/tcg/cpu-mmu-index.h"
12 #include "accel/tcg/probe.h"
13 #include "exec/target_page.h"
14 #include "exec/tlb-flags.h"
15 #include "semihosting/uaccess.h"
16
uaccess_lock_user(CPUArchState * env,target_ulong addr,target_ulong len,bool copy)17 void *uaccess_lock_user(CPUArchState *env, target_ulong addr,
18 target_ulong len, bool copy)
19 {
20 void *p = malloc(len);
21 if (p && copy) {
22 if (cpu_memory_rw_debug(env_cpu(env), addr, p, len, 0)) {
23 free(p);
24 p = NULL;
25 }
26 }
27 return p;
28 }
29
uaccess_strlen_user(CPUArchState * env,target_ulong addr)30 ssize_t uaccess_strlen_user(CPUArchState *env, target_ulong addr)
31 {
32 int mmu_idx = cpu_mmu_index(env_cpu(env), false);
33 size_t len = 0;
34
35 while (1) {
36 size_t left_in_page;
37 int flags;
38 void *h;
39
40 /* Find the number of bytes remaining in the page. */
41 left_in_page = TARGET_PAGE_SIZE - (addr & ~TARGET_PAGE_MASK);
42
43 flags = probe_access_flags(env, addr, 0, MMU_DATA_LOAD,
44 mmu_idx, true, &h, 0);
45 if (flags & TLB_INVALID_MASK) {
46 return -1;
47 }
48 if (flags & TLB_MMIO) {
49 do {
50 uint8_t c;
51 if (cpu_memory_rw_debug(env_cpu(env), addr, &c, 1, 0)) {
52 return -1;
53 }
54 if (c == 0) {
55 return len;
56 }
57 addr++;
58 len++;
59 if (len > INT32_MAX) {
60 return -1;
61 }
62 } while (--left_in_page != 0);
63 } else {
64 char *p = memchr(h, 0, left_in_page);
65 if (p) {
66 len += p - (char *)h;
67 return len <= INT32_MAX ? (ssize_t)len : -1;
68 }
69 addr += left_in_page;
70 len += left_in_page;
71 if (len > INT32_MAX) {
72 return -1;
73 }
74 }
75 }
76 }
77
uaccess_lock_user_string(CPUArchState * env,target_ulong addr)78 char *uaccess_lock_user_string(CPUArchState *env, target_ulong addr)
79 {
80 ssize_t len = uaccess_strlen_user(env, addr);
81 if (len < 0) {
82 return NULL;
83 }
84 return uaccess_lock_user(env, addr, len + 1, true);
85 }
86
uaccess_unlock_user(CPUArchState * env,void * p,target_ulong addr,target_ulong len)87 void uaccess_unlock_user(CPUArchState *env, void *p,
88 target_ulong addr, target_ulong len)
89 {
90 if (len) {
91 cpu_memory_rw_debug(env_cpu(env), addr, p, len, 1);
92 }
93 free(p);
94 }
95