| 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 | |
| 17 | void *uaccess_lock_user(CPUArchState *env, vaddr addr, |
| 18 | size_t 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 | |
| 30 | ssize_t uaccess_strlen_user(CPUArchState *env, vaddr 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 | |
| 78 | char *uaccess_lock_user_string(CPUArchState *env, vaddr 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 | |
| 87 | void uaccess_unlock_user(CPUArchState *env, void *p, |
| 88 | vaddr addr, size_t len) |
| 89 | { |
| 90 | if (len) { |
| 91 | cpu_memory_rw_debug(env_cpu(env), addr, p, len, 1); |
| 92 | } |
| 93 | free(p); |
| 94 | } |