/*************************************************************************** * Copyright (C) 2009 by Marvell Technology Group Ltd. * * Written by Nicolas Pitre * * * * This program is free software; you can redistribute it and/or modify * * it under the terms of the GNU General Public License as published by * * the Free Software Foundation; either version 2 of the License, or * * (at your option) any later version. * * * * This program is distributed in the hope that it will be useful, * * but WITHOUT ANY WARRANTY; without even the implied warranty of * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * * GNU General Public License for more details. * * * * You should have received a copy of the GNU General Public License * * along with this program; if not, write to the * * Free Software Foundation, Inc., * * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * ***************************************************************************/ /** * @file * Hold ARM semihosting support. * * Semihosting enables code running on an ARM target to use the I/O * facilities on the host computer. The target application must be linked * against a library that forwards operation requests by using the SVC * instruction trapped at the Supervisor Call vector by the debugger. * Details can be found in chapter 8 of DUI0203I_rvct_developer_guide.pdf * from ARM Ltd. */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include "armv4_5.h" #include "register.h" #include "arm_semihosting.h" #include #include /* TODO: this needs to be per target */ int semihosting_active; int semihosting_errno; static int do_semihosting(struct target *target) { struct arm *armv4_5 = target_to_armv4_5(target); uint32_t r0 = buf_get_u32(armv4_5->core_cache->reg_list[0].value, 0, 32); uint32_t r1 = buf_get_u32(armv4_5->core_cache->reg_list[1].value, 0, 32); uint32_t lr = buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, ARMV4_5_MODE_SVC, 14).value, 0, 32); uint32_t spsr = buf_get_u32(armv4_5->spsr->value, 0, 32);; uint8_t params[16]; int retval, result; /* * TODO: lots of security issues are not considered yet, such as: * - no validation on target provided file descriptors * - no safety checks on opened/deleted/renamed file paths * Beware the target app you use this support with. */ switch (r0) { case 0x01: /* SYS_OPEN */ retval = target_read_memory(target, r1, 4, 3, params); if (retval != ERROR_OK) return retval; else { uint32_t a = target_buffer_get_u32(target, params+0); uint32_t m = target_buffer_get_u32(target, params+4); uint32_t l = target_buffer_get_u32(target, params+8); if (l <= 255 && m <= 11) { uint8_t fn[256]; int mode; retval = target_read_memory(target, a, 1, l, fn); if (retval != ERROR_OK) return retval; fn[l] = 0; if (m & 0x2) mode = O_RDWR; else if (m & 0xc) mode = O_WRONLY; else mode = O_RDONLY; if (m >= 8) mode |= O_CREAT|O_APPEND; else if (m >= 4) mode |= O_CREAT|O_TRUNC; if (strcmp((char *)fn, ":tt") == 0) { if ((mode & 3) == 0) result = dup(0); else result = dup(1); } else result = open((char *)fn, mode); semihosting_errno = errno; } else { result = -1; semihosting_errno = EINVAL; } } break; case 0x02: /* SYS_CLOSE */ retval = target_read_memory(target, r1, 4, 1, params); if (retval != ERROR_OK) return retval; else { int fd = target_buffer_get_u32(target, params+0); result = close(fd); semihosting_errno = errno; } break; case 0x03: /* SYS_WRITEC */ { unsigned char c; retval = target_read_memory(target, r1, 1, 1, &c); if (retval != ERROR_OK) return retval; putchar(c); result = 0; } break; case 0x04: /* SYS_WRITE0 */ do { unsigned char c; retval = target_read_memory(target, r1, 1, 1, &c); if (retval != ERROR_OK) return retval; if (!c) break; putchar(c); } while (1); result = 0; break; case 0x05: /* SYS_WRITE */ retval = target_read_memory(target, r1, 4, 3, params); if (retval != ERROR_OK) return retval; else { int fd = target_buffer_get_u32(target, params+0); uint32_t a = target_buffer_get_u32(target, params+4); size_t l = target_buffer_get_u32(target, params+8); uint8_t *buf = malloc(l); if (!buf) { result = -1; semihosting_errno = ENOMEM; } else { retval = target_read_buffer(target, a, l, buf); if (retval != ERROR_OK) { free(buf); return retval; } result = write(fd, buf, l); semihosting_errno = errno; if (result >= 0) result = l - result; free(buf); } } break; case 0x06: /* SYS_READ */ retval = target_read_memory(target, r1, 4, 3, params); if (retval != ERROR_OK) return retval; else { int fd = target_buffer_get_u32(target, params+0); uint32_t a = target_buffer_get_u32(target, params+4); ssize_t l = target_buffer_get_u32(target, params+8); uint8_t *buf = malloc(l); if (!buf) { result = -1; semihosting_errno = ENOMEM; } else { result = read(fd, buf, l); semihosting_errno = errno; if (result > 0) { retval = target_write_buffer(target, a, result, buf); if (retval != ERROR_OK) { free(buf); return retval; } result = l - result; } free(buf); } } break; case 0x07: /* SYS_READC */ result = getchar(); break; case 0x08: /* SYS_ISERROR */ retval = target_read_memory(target, r1, 4, 1, params); if (retval != ERROR_OK) return retval; result = (target_buffer_get_u32(target, params+0) != 0); break; case 0x09: /* SYS_ISTTY */ retval = target_read_memory(target, r1, 4, 1, params); if (retval != ERROR_OK) return retval; result = isatty(target_buffer_get_u32(target, params+0)); break; case 0x0a: /* SYS_SEEK */ retval = target_read_memory(target, r1, 4, 2, params); if (retval != ERROR_OK) return retval; else { int fd = target_buffer_get_u32(target, params+0); off_t pos = target_buffer_get_u32(target, params+4); result = lseek(fd, pos, SEEK_SET); semihosting_errno = errno; if (result == pos) result = 0; } break; case 0x0c: /* SYS_FLEN */ retval = target_read_memory(target, r1, 4, 1, params); if (retval != ERROR_OK) return retval; else { int fd = target_buffer_get_u32(target, params+0); off_t cur = lseek(fd, 0, SEEK_CUR); if (cur == (off_t)-1) { semihosting_errno = errno; result = -1; break; } result = lseek(fd, 0, SEEK_END); semihosting_errno = errno; if (lseek(fd, cur, SEEK_SET) == (off_t)-1) { semihosting_errno = errno; result = -1; } } break; case 0x0e: /* SYS_REMOVE */ retval = target_read_memory(target, r1, 4, 2, params); if (retval != ERROR_OK) return retval; else { uint32_t a = target_buffer_get_u32(target, params+0); uint32_t l = target_buffer_get_u32(target, params+4); if (l <= 255) { uint8_t fn[256]; retval = target_read_memory(target, a, 1, l, fn); if (retval != ERROR_OK) return retval; fn[l] = 0; result = remove((char *)fn); semihosting_errno = errno; } else { result = -1; semihosting_errno = EINVAL; } } break; case 0x0f: /* SYS_RENAME */ retval = target_read_memory(target, r1, 4, 4, params); if (retval != ERROR_OK) return retval; else { uint32_t a1 = target_buffer_get_u32(target, params+0); uint32_t l1 = target_buffer_get_u32(target, params+4); uint32_t a2 = target_buffer_get_u32(target, params+8); uint32_t l2 = target_buffer_get_u32(target, params+12); if (l1 <= 255 && l2 <= 255) { uint8_t fn1[256], fn2[256]; retval = target_read_memory(target, a1, 1, l1, fn1); if (retval != ERROR_OK) return retval; retval = target_read_memory(target, a2, 1, l2, fn2); if (retval != ERROR_OK) return retval; fn1[l1] = 0; fn2[l2] = 0; result = rename((char *)fn1, (char *)fn2); semihosting_errno = errno; } else { result = -1; semihosting_errno = EINVAL; } } break; case 0x11: /* SYS_TIME */ result = time(NULL); break; case 0x13: /* SYS_ERRNO */ result = semihosting_errno; break; case 0x15: /* SYS_GET_CMDLINE */ retval = target_read_memory(target, r1, 4, 2, params); if (retval != ERROR_OK) return retval; else { uint32_t a = target_buffer_get_u32(target, params+0); uint32_t l = target_buffer_get_u32(target, params+4); char *arg = "foobar"; uint32_t s = strlen(arg) + 1; if (l < s) result = -1; else { retval = target_write_buffer(target, a, s, (void*)arg); if (retval != ERROR_OK) return retval; result = 0; } } break; case 0x16: /* SYS_HEAPINFO */ retval = target_read_memory(target, r1, 4, 1, params); if (retval != ERROR_OK) return retval; else { uint32_t a = target_buffer_get_u32(target, params+0); /* tell the remote we have no idea */ memset(params, 0, 4*4); retval = target_write_memory(target, a, 4, 4, params); if (retval != ERROR_OK) return retval; result = 0; } break; case 0x18: /* angel_SWIreason_ReportException */ switch (r1) { case 0x20026: /* ADP_Stopped_ApplicationExit */ fprintf(stderr, "semihosting: *** application exited ***\n"); break; case 0x20000: /* ADP_Stopped_BranchThroughZero */ case 0x20001: /* ADP_Stopped_UndefinedInstr */ case 0x20002: /* ADP_Stopped_SoftwareInterrupt */ case 0x20003: /* ADP_Stopped_PrefetchAbort */ case 0x20004: /* ADP_Stopped_DataAbort */ case 0x20005: /* ADP_Stopped_AddressException */ case 0x20006: /* ADP_Stopped_IRQ */ case 0x20007: /* ADP_Stopped_FIQ */ case 0x20020: /* ADP_Stopped_BreakPoint */ case 0x20021: /* ADP_Stopped_WatchPoint */ case 0x20022: /* ADP_Stopped_StepComplete */ case 0x20023: /* ADP_Stopped_RunTimeErrorUnknown */ case 0x20024: /* ADP_Stopped_InternalError */ case 0x20025: /* ADP_Stopped_UserInterruption */ case 0x20027: /* ADP_Stopped_StackOverflow */ case 0x20028: /* ADP_Stopped_DivisionByZero */ case 0x20029: /* ADP_Stopped_OSSpecific */ default: fprintf(stderr, "semihosting: exception %#x\n", (unsigned) r1); } return target_call_event_callbacks(target, TARGET_EVENT_HALTED); case 0x0d: /* SYS_TMPNAM */ case 0x10: /* SYS_CLOCK */ case 0x12: /* SYS_SYSTEM */ case 0x17: /* angel_SWIreason_EnterSVC */ case 0x30: /* SYS_ELAPSED */ case 0x31: /* SYS_TICKFREQ */ default: fprintf(stderr, "semihosting: unsupported call %#x\n", (unsigned) r0); result = -1; semihosting_errno = ENOTSUP; } /* resume execution to the original mode */ buf_set_u32(armv4_5->core_cache->reg_list[0].value, 0, 32, result); armv4_5->core_cache->reg_list[0].dirty = 1; buf_set_u32(armv4_5->core_cache->reg_list[15].value, 0, 32, lr); armv4_5->core_cache->reg_list[15].dirty = 1; buf_set_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 0, 32, spsr); armv4_5->core_cache->reg_list[ARMV4_5_CPSR].dirty = 1; armv4_5->core_mode = spsr & 0x1f; if (spsr & 0x20) armv4_5->core_state = ARMV4_5_STATE_THUMB; return target_resume(target, 1, 0, 0, 0); } /** * Checks for and processes an ARM semihosting request. This is meant * to be called when the target is stopped due to a debug mode entry. * If the value 0 is returned then there was nothing to process. A non-zero * return value signifies that a request was processed and the target resumed, * or an error was encountered, in which case the caller must return * immediately. * * @param target Pointer to the ARM target to process * @param retval Pointer to a location where the return code will be stored * @return non-zero value if a request was processed or an error encountered */ int arm_semihosting(struct target *target, int *retval) { struct arm *armv4_5 = target_to_armv4_5(target); uint32_t lr, spsr; if (!semihosting_active || armv4_5->core_mode != ARMV4_5_MODE_SVC || buf_get_u32(armv4_5->core_cache->reg_list[15].value, 0, 32) != 0x08) return 0; lr = buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, ARMV4_5_MODE_SVC, 14).value, 0, 32); spsr = buf_get_u32(armv4_5->spsr->value, 0, 32); /* check instruction that triggered this trap */ if (spsr & (1 << 5)) { /* was in Thumb mode */ uint8_t insn_buf[2]; uint16_t insn; *retval = target_read_memory(target, lr-2, 2, 1, insn_buf); if (*retval != ERROR_OK) return 1; insn = target_buffer_get_u16(target, insn_buf); if (insn != 0xDFAB) return 0; } else { /* was in ARM mode */ uint8_t insn_buf[4]; uint32_t insn; *retval = target_read_memory(target, lr-4, 4, 1, insn_buf); if (*retval != ERROR_OK) return 1; insn = target_buffer_get_u32(target, insn_buf); if (insn != 0xEF123456) return 0; } *retval = do_semihosting(target); return 1; }