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[Qemu-devel] [PATCH v5 2/2] Add Nios II semihosting support.
|
From: |
Sandra Loosemore |
|
Subject: |
[Qemu-devel] [PATCH v5 2/2] Add Nios II semihosting support. |
|
Date: |
Tue, 12 Feb 2019 20:46:00 -0700 |
This patch adds support for libgloss semihosting to Nios II bare-metal
emulation.
Signed-off-by: Sandra Loosemore <address@hidden>
Signed-off-by: Julian Brown <address@hidden>
---
qemu-options.hx | 8 +-
target/nios2/Makefile.objs | 2 +-
target/nios2/cpu.h | 4 +-
target/nios2/helper.c | 11 ++
target/nios2/nios2-semi.c | 446 +++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 465 insertions(+), 6 deletions(-)
create mode 100644 target/nios2/nios2-semi.c
diff --git a/qemu-options.hx b/qemu-options.hx
index 06ef1a7..5019ede 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3712,21 +3712,21 @@ 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 address@hidden|gdb|auto}
Defines where the semihosting calls will be addressed, to QEMU (@code{native})
diff --git a/target/nios2/Makefile.objs b/target/nios2/Makefile.objs
index 2a11c5c..010de0e 100644
--- a/target/nios2/Makefile.objs
+++ b/target/nios2/Makefile.objs
@@ -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)
diff --git a/target/nios2/cpu.h b/target/nios2/cpu.h
index 047f376..afd30d5 100644
--- a/target/nios2/cpu.h
+++ b/target/nios2/cpu.h
@@ -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
@@ -223,6 +223,8 @@ 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
diff --git a/target/nios2/helper.c b/target/nios2/helper.c
index a8b8ec6..ca3b087 100644
--- a/target/nios2/helper.c
+++ b/target/nios2/helper.c
@@ -25,6 +25,7 @@
#include "exec/exec-all.h"
#include "exec/log.h"
#include "exec/helper-proto.h"
+#include "exec/semihost.h"
#if defined(CONFIG_USER_ONLY)
@@ -169,6 +170,16 @@ 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]);
+
+ if (semihosting_enabled()) {
+ 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;
diff --git a/target/nios2/nios2-semi.c b/target/nios2/nios2-semi.c
new file mode 100644
index 0000000..9db518a
--- /dev/null
+++ b/target/nios2/nios2-semi.c
@@ -0,0 +1,446 @@
+/*
+ * Nios II Semihosting syscall interface.
+ * This code is derived from m68k-semi.c.
+ *
+ * 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 void 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) {
+ /* FIXME - should this return an error code? */
+ return;
+ }
+ 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));
+}
+
+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_fseek;
+
+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_fseek) {
+ /* FIXME: We've already lost the high bits of the fseek
+ return value. */
+ nios2_semi_return_u64(env, ret, err);
+ nios2_semi_is_fseek = 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) {
+ /* FIXME - check error code? */
+ result = -1;
+ } 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) {
+ /* FIXME - check error code? */
+ result = -1;
+ } 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) {
+ /* FIXME - check error code? */
+ result = -1;
+ } 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_fseek = 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) {
+ /* FIXME - check error code? */
+ result = -1;
+ } 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) {
+ /* FIXME - check error code? */
+ result = -1;
+ } 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) {
+ /* FIXME - check error code? */
+ result = -1;
+ } else {
+ result = stat(p, &s);
+ unlock_user(p, arg0, 0);
+ }
+ if (result == 0) {
+ translate_stat(env, arg2, &s);
+ }
+ }
+ 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);
+ }
+ }
+ 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) {
+ /* FIXME - check error code? */
+ result = -1;
+ } 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) {
+ /* FIXME - check error code? */
+ result = -1;
+ } else {
+ result = system(p);
+ unlock_user(p, arg0, 0);
+ }
+ }
+ break;
+ default:
+ cpu_abort(CPU(nios2_env_get_cpu(env)),
+ "Unsupported semihosting syscall %d\n", nr);
+ result = 0;
+ }
+failed:
+ nios2_semi_return_u32(env, result, errno);
+}
--
2.8.1