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openocd/src/target/arm_semihosting.c

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/***************************************************************************
* Copyright (C) 2009 by Marvell Technology Group Ltd. *
* Written by Nicolas Pitre <nico@marvell.com> *
* *
* 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 <helper/binarybuffer.h>
#include <helper/log.h>
/* 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", 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", 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;
}
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