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qemu/target/arm/arm-semi.c
Alex Bennée 78e24848f6 semihosting: split console_out into string and char versions 
This is ostensibly to avoid the weirdness of len looking like it might
come from a guest and sometimes being used. While we are at it fix up
the error checking for the arm-linux-user implementation of the API
which got flagged up by Coverity (CID 1401700).

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
2019-06-12 17:53:22 +01:00

661 lines
20 KiB
C
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/*
* Arm "Angel" semihosting syscalls
*
* Copyright (c) 2005, 2007 CodeSourcery.
* Copyright (c) 2019 Linaro
* Written by Paul Brook.
*
* 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, see <http://www.gnu.org/licenses/>.
*
* ARM Semihosting is documented in:
* Semihosting for AArch32 and AArch64 Release 2.0
* https://static.docs.arm.com/100863/0200/semihosting.pdf
*/
#include "qemu/osdep.h"
#include "cpu.h"
#include "hw/semihosting/semihost.h"
#include "hw/semihosting/console.h"
#include "qemu/log.h"
#ifdef CONFIG_USER_ONLY
#include "qemu.h"
#define ARM_ANGEL_HEAP_SIZE (128 * 1024 * 1024)
#else
#include "exec/gdbstub.h"
#include "qemu/cutils.h"
#endif
#define TARGET_SYS_OPEN 0x01
#define TARGET_SYS_CLOSE 0x02
#define TARGET_SYS_WRITEC 0x03
#define TARGET_SYS_WRITE0 0x04
#define TARGET_SYS_WRITE 0x05
#define TARGET_SYS_READ 0x06
#define TARGET_SYS_READC 0x07
#define TARGET_SYS_ISTTY 0x09
#define TARGET_SYS_SEEK 0x0a
#define TARGET_SYS_FLEN 0x0c
#define TARGET_SYS_TMPNAM 0x0d
#define TARGET_SYS_REMOVE 0x0e
#define TARGET_SYS_RENAME 0x0f
#define TARGET_SYS_CLOCK 0x10
#define TARGET_SYS_TIME 0x11
#define TARGET_SYS_SYSTEM 0x12
#define TARGET_SYS_ERRNO 0x13
#define TARGET_SYS_GET_CMDLINE 0x15
#define TARGET_SYS_HEAPINFO 0x16
#define TARGET_SYS_EXIT 0x18
#define TARGET_SYS_SYNCCACHE 0x19
/* ADP_Stopped_ApplicationExit is used for exit(0),
* anything else is implemented as exit(1) */
#define ADP_Stopped_ApplicationExit (0x20026)
#ifndef O_BINARY
#define O_BINARY 0
#endif
#define GDB_O_RDONLY 0x000
#define GDB_O_WRONLY 0x001
#define GDB_O_RDWR 0x002
#define GDB_O_APPEND 0x008
#define GDB_O_CREAT 0x200
#define GDB_O_TRUNC 0x400
#define GDB_O_BINARY 0
static int gdb_open_modeflags[12] = {
GDB_O_RDONLY,
GDB_O_RDONLY | GDB_O_BINARY,
GDB_O_RDWR,
GDB_O_RDWR | GDB_O_BINARY,
GDB_O_WRONLY | GDB_O_CREAT | GDB_O_TRUNC,
GDB_O_WRONLY | GDB_O_CREAT | GDB_O_TRUNC | GDB_O_BINARY,
GDB_O_RDWR | GDB_O_CREAT | GDB_O_TRUNC,
GDB_O_RDWR | GDB_O_CREAT | GDB_O_TRUNC | GDB_O_BINARY,
GDB_O_WRONLY | GDB_O_CREAT | GDB_O_APPEND,
GDB_O_WRONLY | GDB_O_CREAT | GDB_O_APPEND | GDB_O_BINARY,
GDB_O_RDWR | GDB_O_CREAT | GDB_O_APPEND,
GDB_O_RDWR | GDB_O_CREAT | GDB_O_APPEND | GDB_O_BINARY
};
static int open_modeflags[12] = {
O_RDONLY,
O_RDONLY | O_BINARY,
O_RDWR,
O_RDWR | O_BINARY,
O_WRONLY | O_CREAT | O_TRUNC,
O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
O_RDWR | O_CREAT | O_TRUNC,
O_RDWR | O_CREAT | O_TRUNC | O_BINARY,
O_WRONLY | O_CREAT | O_APPEND,
O_WRONLY | O_CREAT | O_APPEND | O_BINARY,
O_RDWR | O_CREAT | O_APPEND,
O_RDWR | O_CREAT | O_APPEND | O_BINARY
};
#ifdef CONFIG_USER_ONLY
static inline uint32_t set_swi_errno(TaskState *ts, uint32_t code)
{
if (code == (uint32_t)-1)
ts->swi_errno = errno;
return code;
}
#else
static inline uint32_t set_swi_errno(CPUARMState *env, uint32_t code)
{
return code;
}
#include "exec/softmmu-semi.h"
#endif
static target_ulong arm_semi_syscall_len;
#if !defined(CONFIG_USER_ONLY)
static target_ulong syscall_err;
#endif
static void arm_semi_cb(CPUState *cs, target_ulong ret, target_ulong err)
{
ARMCPU *cpu = ARM_CPU(cs);
CPUARMState *env = &cpu->env;
#ifdef CONFIG_USER_ONLY
TaskState *ts = cs->opaque;
#endif
target_ulong reg0 = is_a64(env) ? env->xregs[0] : env->regs[0];
if (ret == (target_ulong)-1) {
#ifdef CONFIG_USER_ONLY
ts->swi_errno = err;
#else
syscall_err = err;
#endif
reg0 = ret;
} else {
/* Fixup syscalls that use nonstardard return conventions. */
switch (reg0) {
case TARGET_SYS_WRITE:
case TARGET_SYS_READ:
reg0 = arm_semi_syscall_len - ret;
break;
case TARGET_SYS_SEEK:
reg0 = 0;
break;
default:
reg0 = ret;
break;
}
}
if (is_a64(env)) {
env->xregs[0] = reg0;
} else {
env->regs[0] = reg0;
}
}
static target_ulong arm_flen_buf(ARMCPU *cpu)
{
/* Return an address in target memory of 64 bytes where the remote
* gdb should write its stat struct. (The format of this structure
* is defined by GDB's remote protocol and is not target-specific.)
* We put this on the guest's stack just below SP.
*/
CPUARMState *env = &cpu->env;
target_ulong sp;
if (is_a64(env)) {
sp = env->xregs[31];
} else {
sp = env->regs[13];
}
return sp - 64;
}
static void arm_semi_flen_cb(CPUState *cs, target_ulong ret, target_ulong err)
{
ARMCPU *cpu = ARM_CPU(cs);
CPUARMState *env = &cpu->env;
/* The size is always stored in big-endian order, extract
the value. We assume the size always fit in 32 bits. */
uint32_t size;
cpu_memory_rw_debug(cs, arm_flen_buf(cpu) + 32, (uint8_t *)&size, 4, 0);
size = be32_to_cpu(size);
if (is_a64(env)) {
env->xregs[0] = size;
} else {
env->regs[0] = size;
}
#ifdef CONFIG_USER_ONLY
((TaskState *)cs->opaque)->swi_errno = err;
#else
syscall_err = err;
#endif
}
static target_ulong arm_gdb_syscall(ARMCPU *cpu, gdb_syscall_complete_cb cb,
const char *fmt, ...)
{
va_list va;
CPUARMState *env = &cpu->env;
va_start(va, fmt);
gdb_do_syscallv(cb, fmt, va);
va_end(va);
/* FIXME: we are implicitly relying on the syscall completing
* before this point, which is not guaranteed. We should
* put in an explicit synchronization between this and
* the callback function.
*/
return is_a64(env) ? env->xregs[0] : env->regs[0];
}
/* Read the input value from the argument block; fail the semihosting
* call if the memory read fails.
*/
#define GET_ARG(n) do { \
if (is_a64(env)) { \
if (get_user_u64(arg ## n, args + (n) * 8)) { \
return -1; \
} \
} else { \
if (get_user_u32(arg ## n, args + (n) * 4)) { \
return -1; \
} \
} \
} while (0)
#define SET_ARG(n, val) \
(is_a64(env) ? \
put_user_u64(val, args + (n) * 8) : \
put_user_u32(val, args + (n) * 4))
/*
* Do a semihosting call.
*
* The specification always says that the "return register" either
* returns a specific value or is corrupted, so we don't need to
* report to our caller whether we are returning a value or trying to
* leave the register unchanged. We use 0xdeadbeef as the return value
* when there isn't a defined return value for the call.
*/
target_ulong do_arm_semihosting(CPUARMState *env)
{
ARMCPU *cpu = env_archcpu(env);
CPUState *cs = env_cpu(env);
target_ulong args;
target_ulong arg0, arg1, arg2, arg3;
char * s;
int nr;
uint32_t ret;
uint32_t len;
#ifdef CONFIG_USER_ONLY
TaskState *ts = cs->opaque;
#else
CPUARMState *ts = env;
#endif
if (is_a64(env)) {
/* Note that the syscall number is in W0, not X0 */
nr = env->xregs[0] & 0xffffffffU;
args = env->xregs[1];
} else {
nr = env->regs[0];
args = env->regs[1];
}
switch (nr) {
case TARGET_SYS_OPEN:
GET_ARG(0);
GET_ARG(1);
GET_ARG(2);
s = lock_user_string(arg0);
if (!s) {
/* FIXME - should this error code be -TARGET_EFAULT ? */
return (uint32_t)-1;
}
if (arg1 >= 12) {
unlock_user(s, arg0, 0);
return (uint32_t)-1;
}
if (strcmp(s, ":tt") == 0) {
int result_fileno = arg1 < 4 ? STDIN_FILENO : STDOUT_FILENO;
unlock_user(s, arg0, 0);
return result_fileno;
}
if (use_gdb_syscalls()) {
ret = arm_gdb_syscall(cpu, arm_semi_cb, "open,%s,%x,1a4", arg0,
(int)arg2+1, gdb_open_modeflags[arg1]);
} else {
ret = set_swi_errno(ts, open(s, open_modeflags[arg1], 0644));
}
unlock_user(s, arg0, 0);
return ret;
case TARGET_SYS_CLOSE:
GET_ARG(0);
if (use_gdb_syscalls()) {
return arm_gdb_syscall(cpu, arm_semi_cb, "close,%x", arg0);
} else {
return set_swi_errno(ts, close(arg0));
}
case TARGET_SYS_WRITEC:
qemu_semihosting_console_outc(env, args);
return 0xdeadbeef;
case TARGET_SYS_WRITE0:
return qemu_semihosting_console_outs(env, args);
case TARGET_SYS_WRITE:
GET_ARG(0);
GET_ARG(1);
GET_ARG(2);
len = arg2;
if (use_gdb_syscalls()) {
arm_semi_syscall_len = len;
return arm_gdb_syscall(cpu, arm_semi_cb, "write,%x,%x,%x",
arg0, arg1, len);
} else {
s = lock_user(VERIFY_READ, arg1, len, 1);
if (!s) {
/* Return bytes not written on error */
return len;
}
ret = set_swi_errno(ts, write(arg0, s, len));
unlock_user(s, arg1, 0);
if (ret == (uint32_t)-1) {
ret = 0;
}
/* Return bytes not written */
return len - ret;
}
case TARGET_SYS_READ:
GET_ARG(0);
GET_ARG(1);
GET_ARG(2);
len = arg2;
if (use_gdb_syscalls()) {
arm_semi_syscall_len = len;
return arm_gdb_syscall(cpu, arm_semi_cb, "read,%x,%x,%x",
arg0, arg1, len);
} else {
s = lock_user(VERIFY_WRITE, arg1, len, 0);
if (!s) {
/* return bytes not read */
return len;
}
do {
ret = set_swi_errno(ts, read(arg0, s, len));
} while (ret == -1 && errno == EINTR);
unlock_user(s, arg1, len);
if (ret == (uint32_t)-1) {
ret = 0;
}
/* Return bytes not read */
return len - ret;
}
case TARGET_SYS_READC:
qemu_log_mask(LOG_UNIMP, "%s: SYS_READC not implemented", __func__);
return 0;
case TARGET_SYS_ISTTY:
GET_ARG(0);
if (use_gdb_syscalls()) {
return arm_gdb_syscall(cpu, arm_semi_cb, "isatty,%x", arg0);
} else {
return isatty(arg0);
}
case TARGET_SYS_SEEK:
GET_ARG(0);
GET_ARG(1);
if (use_gdb_syscalls()) {
return arm_gdb_syscall(cpu, arm_semi_cb, "lseek,%x,%x,0",
arg0, arg1);
} else {
ret = set_swi_errno(ts, lseek(arg0, arg1, SEEK_SET));
if (ret == (uint32_t)-1)
return -1;
return 0;
}
case TARGET_SYS_FLEN:
GET_ARG(0);
if (use_gdb_syscalls()) {
return arm_gdb_syscall(cpu, arm_semi_flen_cb, "fstat,%x,%x",
arg0, arm_flen_buf(cpu));
} else {
struct stat buf;
ret = set_swi_errno(ts, fstat(arg0, &buf));
if (ret == (uint32_t)-1)
return -1;
return buf.st_size;
}
case TARGET_SYS_TMPNAM:
qemu_log_mask(LOG_UNIMP, "%s: SYS_TMPNAM not implemented", __func__);
return -1;
case TARGET_SYS_REMOVE:
GET_ARG(0);
GET_ARG(1);
if (use_gdb_syscalls()) {
ret = arm_gdb_syscall(cpu, arm_semi_cb, "unlink,%s",
arg0, (int)arg1+1);
} else {
s = lock_user_string(arg0);
if (!s) {
/* FIXME - should this error code be -TARGET_EFAULT ? */
return (uint32_t)-1;
}
ret = set_swi_errno(ts, remove(s));
unlock_user(s, arg0, 0);
}
return ret;
case TARGET_SYS_RENAME:
GET_ARG(0);
GET_ARG(1);
GET_ARG(2);
GET_ARG(3);
if (use_gdb_syscalls()) {
return arm_gdb_syscall(cpu, arm_semi_cb, "rename,%s,%s",
arg0, (int)arg1+1, arg2, (int)arg3+1);
} else {
char *s2;
s = lock_user_string(arg0);
s2 = lock_user_string(arg2);
if (!s || !s2)
/* FIXME - should this error code be -TARGET_EFAULT ? */
ret = (uint32_t)-1;
else
ret = set_swi_errno(ts, rename(s, s2));
if (s2)
unlock_user(s2, arg2, 0);
if (s)
unlock_user(s, arg0, 0);
return ret;
}
case TARGET_SYS_CLOCK:
return clock() / (CLOCKS_PER_SEC / 100);
case TARGET_SYS_TIME:
return set_swi_errno(ts, time(NULL));
case TARGET_SYS_SYSTEM:
GET_ARG(0);
GET_ARG(1);
if (use_gdb_syscalls()) {
return arm_gdb_syscall(cpu, arm_semi_cb, "system,%s",
arg0, (int)arg1+1);
} else {
s = lock_user_string(arg0);
if (!s) {
/* FIXME - should this error code be -TARGET_EFAULT ? */
return (uint32_t)-1;
}
ret = set_swi_errno(ts, system(s));
unlock_user(s, arg0, 0);
return ret;
}
case TARGET_SYS_ERRNO:
#ifdef CONFIG_USER_ONLY
return ts->swi_errno;
#else
return syscall_err;
#endif
case TARGET_SYS_GET_CMDLINE:
{
/* Build a command-line from the original argv.
*
* The inputs are:
* * arg0, pointer to a buffer of at least the size
* specified in arg1.
* * arg1, size of the buffer pointed to by arg0 in
* bytes.
*
* The outputs are:
* * arg0, pointer to null-terminated string of the
* command line.
* * arg1, length of the string pointed to by arg0.
*/
char *output_buffer;
size_t input_size;
size_t output_size;
int status = 0;
#if !defined(CONFIG_USER_ONLY)
const char *cmdline;
#endif
GET_ARG(0);
GET_ARG(1);
input_size = arg1;
/* Compute the size of the output string. */
#if !defined(CONFIG_USER_ONLY)
cmdline = semihosting_get_cmdline();
if (cmdline == NULL) {
cmdline = ""; /* Default to an empty line. */
}
output_size = strlen(cmdline) + 1; /* Count terminating 0. */
#else
unsigned int i;
output_size = ts->info->arg_end - ts->info->arg_start;
if (!output_size) {
/*
* We special-case the "empty command line" case (argc==0).
* Just provide the terminating 0.
*/
output_size = 1;
}
#endif
if (output_size > input_size) {
/* Not enough space to store command-line arguments. */
return -1;
}
/* Adjust the command-line length. */
if (SET_ARG(1, output_size - 1)) {
/* Couldn't write back to argument block */
return -1;
}
/* Lock the buffer on the ARM side. */
output_buffer = lock_user(VERIFY_WRITE, arg0, output_size, 0);
if (!output_buffer) {
return -1;
}
/* Copy the command-line arguments. */
#if !defined(CONFIG_USER_ONLY)
pstrcpy(output_buffer, output_size, cmdline);
#else
if (output_size == 1) {
/* Empty command-line. */
output_buffer[0] = '\0';
goto out;
}
if (copy_from_user(output_buffer, ts->info->arg_start,
output_size)) {
status = -1;
goto out;
}
/* Separate arguments by white spaces. */
for (i = 0; i < output_size - 1; i++) {
if (output_buffer[i] == 0) {
output_buffer[i] = ' ';
}
}
out:
#endif
/* Unlock the buffer on the ARM side. */
unlock_user(output_buffer, arg0, output_size);
return status;
}
case TARGET_SYS_HEAPINFO:
{
target_ulong retvals[4];
target_ulong limit;
int i;
GET_ARG(0);
#ifdef CONFIG_USER_ONLY
/*
* Some C libraries assume the heap immediately follows .bss, so
* allocate it using sbrk.
*/
if (!ts->heap_limit) {
abi_ulong ret;
ts->heap_base = do_brk(0);
limit = ts->heap_base + ARM_ANGEL_HEAP_SIZE;
/* Try a big heap, and reduce the size if that fails. */
for (;;) {
ret = do_brk(limit);
if (ret >= limit) {
break;
}
limit = (ts->heap_base >> 1) + (limit >> 1);
}
ts->heap_limit = limit;
}
retvals[0] = ts->heap_base;
retvals[1] = ts->heap_limit;
retvals[2] = ts->stack_base;
retvals[3] = 0; /* Stack limit. */
#else
limit = ram_size;
/* TODO: Make this use the limit of the loaded application. */
retvals[0] = limit / 2;
retvals[1] = limit;
retvals[2] = limit; /* Stack base */
retvals[3] = 0; /* Stack limit. */
#endif
for (i = 0; i < ARRAY_SIZE(retvals); i++) {
bool fail;
if (is_a64(env)) {
fail = put_user_u64(retvals[i], arg0 + i * 8);
} else {
fail = put_user_u32(retvals[i], arg0 + i * 4);
}
if (fail) {
/* Couldn't write back to argument block */
return -1;
}
}
return 0;
}
case TARGET_SYS_EXIT:
if (is_a64(env)) {
/*
* The A64 version of this call takes a parameter block,
* so the application-exit type can return a subcode which
* is the exit status code from the application.
*/
GET_ARG(0);
GET_ARG(1);
if (arg0 == ADP_Stopped_ApplicationExit) {
ret = arg1;
} else {
ret = 1;
}
} else {
/*
* ARM specifies only Stopped_ApplicationExit as normal
* exit, everything else is considered an error
*/
ret = (args == ADP_Stopped_ApplicationExit) ? 0 : 1;
}
gdb_exit(env, ret);
exit(ret);
case TARGET_SYS_SYNCCACHE:
/*
* Clean the D-cache and invalidate the I-cache for the specified
* virtual address range. This is a nop for us since we don't
* implement caches. This is only present on A64.
*/
if (is_a64(env)) {
return 0;
}
/* fall through -- invalid for A32/T32 */
default:
fprintf(stderr, "qemu: Unsupported SemiHosting SWI 0x%02x\n", nr);
cpu_dump_state(cs, stderr, 0);
abort();
}
}
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