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Add Nios II semihosting support.

Browse Source 
This patch adds support for libgloss semihosting to Nios II bare-metal
emulation.  The specification for the protocol can be found in the
libgloss sources.

Signed-off-by: Sandra Loosemore <sandra@codesourcery.com>
Signed-off-by: Julian Brown <julian@codesourcery.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1554321185-2825-3-git-send-email-sandra@codesourcery.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Sandra Loosemore 2019-04-03 13:53:05 -06:00 committed by Peter Maydell
parent ed960ba905
commit 413a99a92c
5 changed files with 476 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
qemu-options.hx
View File

@ -3968,21 +3968,21 @@ ETEXI
DEF("semihosting", 0, QEMU_OPTION_semihosting,
"-semihosting semihosting mode\n",
QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
QEMU_ARCH_MIPS)
QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2)
STEXI
@item -semihosting
@findex -semihosting
Enable semihosting mode (ARM, M68K, Xtensa, MIPS only).
Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II only).
ETEXI
DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config,
"-semihosting-config [enable=on|off][,target=native|gdb|auto][,arg=str[,...]]\n" \
" semihosting configuration\n",
QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
QEMU_ARCH_MIPS)
QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2)
STEXI
@item -semihosting-config [enable=on|off][,target=native|gdb|auto][,arg=str[,...]]
@findex -semihosting-config
Enable and configure semihosting (ARM, M68K, Xtensa, MIPS only).
Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II only).
@table @option
@item target=@code{native|gdb|auto}
Defines where the semihosting calls will be addressed, to QEMU (@code{native})

2
target/nios2/Makefile.objs
View File

@ -1,4 +1,4 @@
obj-y += translate.o op_helper.o helper.o cpu.o mmu.o
obj-y += translate.o op_helper.o helper.o cpu.o mmu.o nios2-semi.o
obj-$(CONFIG_SOFTMMU) += monitor.o
$(obj)/op_helper.o: QEMU_CFLAGS += $(HELPER_CFLAGS)

4
target/nios2/cpu.h
View File

@ -141,7 +141,7 @@ typedef struct Nios2CPUClass {
#define R_PC 64
/* Exceptions */
#define EXCP_BREAK -1
#define EXCP_BREAK 0x1000
#define EXCP_RESET 0
#define EXCP_PRESET 1
#define EXCP_IRQ 2
@ -222,6 +222,8 @@ void nios2_cpu_do_unaligned_access(CPUState *cpu, vaddr addr,
qemu_irq *nios2_cpu_pic_init(Nios2CPU *cpu);
void nios2_check_interrupts(CPUNios2State *env);
void do_nios2_semihosting(CPUNios2State *env);
#define TARGET_PHYS_ADDR_SPACE_BITS 32
#ifdef CONFIG_USER_ONLY
# define TARGET_VIRT_ADDR_SPACE_BITS 31

13
target/nios2/helper.c
View File

@ -23,8 +23,10 @@
#include "cpu.h"
#include "qemu/host-utils.h"
#include "exec/exec-all.h"
#include "exec/cpu_ldst.h"
#include "exec/log.h"
#include "exec/helper-proto.h"
#include "exec/semihost.h"
#if defined(CONFIG_USER_ONLY)
@ -169,6 +171,17 @@ void nios2_cpu_do_interrupt(CPUState *cs)
break;
case EXCP_BREAK:
qemu_log_mask(CPU_LOG_INT, "BREAK exception at pc=%x\n",
env->regs[R_PC]);
/* The semihosting instruction is "break 1". */
if (semihosting_enabled() &&
cpu_ldl_code(env, env->regs[R_PC]) == 0x003da07a) {
qemu_log_mask(CPU_LOG_INT, "Entering semihosting\n");
env->regs[R_PC] += 4;
do_nios2_semihosting(env);
break;
}
if ((env->regs[CR_STATUS] & CR_STATUS_EH) == 0) {
env->regs[CR_BSTATUS] = env->regs[CR_STATUS];
env->regs[R_BA] = env->regs[R_PC] + 4;

455
target/nios2/nios2-semi.c Normal file
View File

@ -0,0 +1,455 @@
/*
* Nios II Semihosting syscall interface.
* This code is derived from m68k-semi.c.
* The semihosting protocol implemented here is described in the
* libgloss sources:
* https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;a=blob;f=libgloss/nios2/nios2-semi.txt;hb=HEAD
*
* Copyright (c) 2017-2019 Mentor Graphics
*
* 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/>.
*/
#include "qemu/osdep.h"
#include "cpu.h"
#if defined(CONFIG_USER_ONLY)
#include "qemu.h"
#else
#include "qemu-common.h"
#include "exec/gdbstub.h"
#include "exec/softmmu-semi.h"
#endif
#include "qemu/log.h"
#include "sysemu/sysemu.h"
#define HOSTED_EXIT 0
#define HOSTED_INIT_SIM 1
#define HOSTED_OPEN 2
#define HOSTED_CLOSE 3
#define HOSTED_READ 4
#define HOSTED_WRITE 5
#define HOSTED_LSEEK 6
#define HOSTED_RENAME 7
#define HOSTED_UNLINK 8
#define HOSTED_STAT 9
#define HOSTED_FSTAT 10
#define HOSTED_GETTIMEOFDAY 11
#define HOSTED_ISATTY 12
#define HOSTED_SYSTEM 13
typedef uint32_t gdb_mode_t;
typedef uint32_t gdb_time_t;
struct nios2_gdb_stat {
uint32_t gdb_st_dev; /* device */
uint32_t gdb_st_ino; /* inode */
gdb_mode_t gdb_st_mode; /* protection */
uint32_t gdb_st_nlink; /* number of hard links */
uint32_t gdb_st_uid; /* user ID of owner */
uint32_t gdb_st_gid; /* group ID of owner */
uint32_t gdb_st_rdev; /* device type (if inode device) */
uint64_t gdb_st_size; /* total size, in bytes */
uint64_t gdb_st_blksize; /* blocksize for filesystem I/O */
uint64_t gdb_st_blocks; /* number of blocks allocated */
gdb_time_t gdb_st_atime; /* time of last access */
gdb_time_t gdb_st_mtime; /* time of last modification */
gdb_time_t gdb_st_ctime; /* time of last change */
} QEMU_PACKED;
struct gdb_timeval {
gdb_time_t tv_sec; /* second */
uint64_t tv_usec; /* microsecond */
} QEMU_PACKED;
#define GDB_O_RDONLY 0x0
#define GDB_O_WRONLY 0x1
#define GDB_O_RDWR 0x2
#define GDB_O_APPEND 0x8
#define GDB_O_CREAT 0x200
#define GDB_O_TRUNC 0x400
#define GDB_O_EXCL 0x800
static int translate_openflags(int flags)
{
int hf;
if (flags & GDB_O_WRONLY) {
hf = O_WRONLY;
} else if (flags & GDB_O_RDWR) {
hf = O_RDWR;
} else {
hf = O_RDONLY;
}
if (flags & GDB_O_APPEND) {
hf |= O_APPEND;
}
if (flags & GDB_O_CREAT) {
hf |= O_CREAT;
}
if (flags & GDB_O_TRUNC) {
hf |= O_TRUNC;
}
if (flags & GDB_O_EXCL) {
hf |= O_EXCL;
}
return hf;
}
static bool translate_stat(CPUNios2State *env, target_ulong addr,
struct stat *s)
{
struct nios2_gdb_stat *p;
p = lock_user(VERIFY_WRITE, addr, sizeof(struct nios2_gdb_stat), 0);
if (!p) {
return false;
}
p->gdb_st_dev = cpu_to_be32(s->st_dev);
p->gdb_st_ino = cpu_to_be32(s->st_ino);
p->gdb_st_mode = cpu_to_be32(s->st_mode);
p->gdb_st_nlink = cpu_to_be32(s->st_nlink);
p->gdb_st_uid = cpu_to_be32(s->st_uid);
p->gdb_st_gid = cpu_to_be32(s->st_gid);
p->gdb_st_rdev = cpu_to_be32(s->st_rdev);
p->gdb_st_size = cpu_to_be64(s->st_size);
#ifdef _WIN32
/* Windows stat is missing some fields. */
p->gdb_st_blksize = 0;
p->gdb_st_blocks = 0;
#else
p->gdb_st_blksize = cpu_to_be64(s->st_blksize);
p->gdb_st_blocks = cpu_to_be64(s->st_blocks);
#endif
p->gdb_st_atime = cpu_to_be32(s->st_atime);
p->gdb_st_mtime = cpu_to_be32(s->st_mtime);
p->gdb_st_ctime = cpu_to_be32(s->st_ctime);
unlock_user(p, addr, sizeof(struct nios2_gdb_stat));
return true;
}
static void nios2_semi_return_u32(CPUNios2State *env, uint32_t ret,
uint32_t err)
{
target_ulong args = env->regs[R_ARG1];
if (put_user_u32(ret, args) ||
put_user_u32(err, args + 4)) {
/*
* The nios2 semihosting ABI does not provide any way to report this
* error to the guest, so the best we can do is log it in qemu.
* It is always a guest error not to pass us a valid argument block.
*/
qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: return value "
"discarded because argument block not writable\n");
}
}
static void nios2_semi_return_u64(CPUNios2State *env, uint64_t ret,
uint32_t err)
{
target_ulong args = env->regs[R_ARG1];
if (put_user_u32(ret >> 32, args) ||
put_user_u32(ret, args + 4) ||
put_user_u32(err, args + 8)) {
/* No way to report this via nios2 semihosting ABI; just log it */
qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: return value "
"discarded because argument block not writable\n");
}
}
static int nios2_semi_is_lseek;
static void nios2_semi_cb(CPUState *cs, target_ulong ret, target_ulong err)
{
Nios2CPU *cpu = NIOS2_CPU(cs);
CPUNios2State *env = &cpu->env;
if (nios2_semi_is_lseek) {
/*
* FIXME: We've already lost the high bits of the lseek
* return value.
*/
nios2_semi_return_u64(env, ret, err);
nios2_semi_is_lseek = 0;
} else {
nios2_semi_return_u32(env, ret, err);
}
}
/*
* Read the input value from the argument block; fail the semihosting
* call if the memory read fails.
*/
#define GET_ARG(n) do { \
if (get_user_ual(arg ## n, args + (n) * 4)) { \
result = -1; \
errno = EFAULT; \
goto failed; \
} \
} while (0)
void do_nios2_semihosting(CPUNios2State *env)
{
int nr;
uint32_t args;
target_ulong arg0, arg1, arg2, arg3;
void *p;
void *q;
uint32_t len;
uint32_t result;
nr = env->regs[R_ARG0];
args = env->regs[R_ARG1];
switch (nr) {
case HOSTED_EXIT:
gdb_exit(env, env->regs[R_ARG0]);
exit(env->regs[R_ARG0]);
case HOSTED_OPEN:
GET_ARG(0);
GET_ARG(1);
GET_ARG(2);
GET_ARG(3);
if (use_gdb_syscalls()) {
gdb_do_syscall(nios2_semi_cb, "open,%s,%x,%x", arg0, (int)arg1,
arg2, arg3);
return;
} else {
p = lock_user_string(arg0);
if (!p) {
result = -1;
errno = EFAULT;
} else {
result = open(p, translate_openflags(arg2), arg3);
unlock_user(p, arg0, 0);
}
}
break;
case HOSTED_CLOSE:
{
/* Ignore attempts to close stdin/out/err. */
GET_ARG(0);
int fd = arg0;
if (fd > 2) {
if (use_gdb_syscalls()) {
gdb_do_syscall(nios2_semi_cb, "close,%x", arg0);
return;
} else {
result = close(fd);
}
} else {
result = 0;
}
break;
}
case HOSTED_READ:
GET_ARG(0);
GET_ARG(1);
GET_ARG(2);
len = arg2;
if (use_gdb_syscalls()) {
gdb_do_syscall(nios2_semi_cb, "read,%x,%x,%x",
arg0, arg1, len);
return;
} else {
p = lock_user(VERIFY_WRITE, arg1, len, 0);
if (!p) {
result = -1;
errno = EFAULT;
} else {
result = read(arg0, p, len);
unlock_user(p, arg1, len);
}
}
break;
case HOSTED_WRITE:
GET_ARG(0);
GET_ARG(1);
GET_ARG(2);
len = arg2;
if (use_gdb_syscalls()) {
gdb_do_syscall(nios2_semi_cb, "write,%x,%x,%x",
arg0, arg1, len);
return;
} else {
p = lock_user(VERIFY_READ, arg1, len, 1);
if (!p) {
result = -1;
errno = EFAULT;
} else {
result = write(arg0, p, len);
unlock_user(p, arg0, 0);
}
}
break;
case HOSTED_LSEEK:
{
uint64_t off;
GET_ARG(0);
GET_ARG(1);
GET_ARG(2);
GET_ARG(3);
off = (uint32_t)arg2 | ((uint64_t)arg1 << 32);
if (use_gdb_syscalls()) {
nios2_semi_is_lseek = 1;
gdb_do_syscall(nios2_semi_cb, "lseek,%x,%lx,%x",
arg0, off, arg3);
} else {
off = lseek(arg0, off, arg3);
nios2_semi_return_u64(env, off, errno);
}
return;
}
case HOSTED_RENAME:
GET_ARG(0);
GET_ARG(1);
GET_ARG(2);
GET_ARG(3);
if (use_gdb_syscalls()) {
gdb_do_syscall(nios2_semi_cb, "rename,%s,%s",
arg0, (int)arg1, arg2, (int)arg3);
return;
} else {
p = lock_user_string(arg0);
q = lock_user_string(arg2);
if (!p || !q) {
result = -1;
errno = EFAULT;
} else {
result = rename(p, q);
}
unlock_user(p, arg0, 0);
unlock_user(q, arg2, 0);
}
break;
case HOSTED_UNLINK:
GET_ARG(0);
GET_ARG(1);
if (use_gdb_syscalls()) {
gdb_do_syscall(nios2_semi_cb, "unlink,%s",
arg0, (int)arg1);
return;
} else {
p = lock_user_string(arg0);
if (!p) {
result = -1;
errno = EFAULT;
} else {
result = unlink(p);
unlock_user(p, arg0, 0);
}
}
break;
case HOSTED_STAT:
GET_ARG(0);
GET_ARG(1);
GET_ARG(2);
if (use_gdb_syscalls()) {
gdb_do_syscall(nios2_semi_cb, "stat,%s,%x",
arg0, (int)arg1, arg2);
return;
} else {
struct stat s;
p = lock_user_string(arg0);
if (!p) {
result = -1;
errno = EFAULT;
} else {
result = stat(p, &s);
unlock_user(p, arg0, 0);
}
if (result == 0 && !translate_stat(env, arg2, &s)) {
result = -1;
errno = EFAULT;
}
}
break;
case HOSTED_FSTAT:
GET_ARG(0);
GET_ARG(1);
if (use_gdb_syscalls()) {
gdb_do_syscall(nios2_semi_cb, "fstat,%x,%x",
arg0, arg1);
return;
} else {
struct stat s;
result = fstat(arg0, &s);
if (result == 0 && !translate_stat(env, arg1, &s)) {
result = -1;
errno = EFAULT;
}
}
break;
case HOSTED_GETTIMEOFDAY:
/* Only the tv parameter is used. tz is assumed NULL. */
GET_ARG(0);
if (use_gdb_syscalls()) {
gdb_do_syscall(nios2_semi_cb, "gettimeofday,%x,%x",
arg0, 0);
return;
} else {
qemu_timeval tv;
struct gdb_timeval *p;
result = qemu_gettimeofday(&tv);
if (result != 0) {
p = lock_user(VERIFY_WRITE, arg0, sizeof(struct gdb_timeval),
0);
if (!p) {
result = -1;
errno = EFAULT;
} else {
p->tv_sec = cpu_to_be32(tv.tv_sec);
p->tv_usec = cpu_to_be64(tv.tv_usec);
unlock_user(p, arg0, sizeof(struct gdb_timeval));
}
}
}
break;
case HOSTED_ISATTY:
GET_ARG(0);
if (use_gdb_syscalls()) {
gdb_do_syscall(nios2_semi_cb, "isatty,%x", arg0);
return;
} else {
result = isatty(arg0);
}
break;
case HOSTED_SYSTEM:
GET_ARG(0);
GET_ARG(1);
if (use_gdb_syscalls()) {
gdb_do_syscall(nios2_semi_cb, "system,%s",
arg0, (int)arg1);
return;
} else {
p = lock_user_string(arg0);
if (!p) {
result = -1;
errno = EFAULT;
} else {
result = system(p);
unlock_user(p, arg0, 0);
}
}
break;
default:
qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: unsupported "
"semihosting syscall %d\n", nr);
result = 0;
}
failed:
nios2_semi_return_u32(env, result, errno);
}