Commit f7bbcfb5 authored by Michael Walle's avatar Michael Walle

target-lm32: add semihosting support

Intercept certain system calls if semihosting is enabled. This should
behave like the GDB simulator.
Signed-off-by: 's avatarMichael Walle <michael@walle.cc>
parent a946ce80
......@@ -3071,7 +3071,8 @@ STEXI
Set OpenBIOS nvram @var{variable} to given @var{value} (PPC, SPARC only).
ETEXI
DEF("semihosting", 0, QEMU_OPTION_semihosting,
"-semihosting semihosting mode\n", QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA)
"-semihosting semihosting mode\n",
QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32)
STEXI
@item -semihosting
@findex -semihosting
......
obj-y += translate.o op_helper.o helper.o cpu.o
obj-y += gdbstub.o
obj-y += lm32-semi.o
obj-$(CONFIG_SOFTMMU) += machine.o
......@@ -26,6 +26,15 @@ first BSP which instantiate this model. A (32 bit) write to 0xfff0000
causes a vm shutdown.
Semihosting
-----------
Semihosting on this target is supported. Some system calls like read, write
and exit are executed on the host if semihosting is enabled. See
target/lm32-semi.c for all supported system calls. Emulation aware programs
can use this mechanism to shut down the virtual machine and print to the
host console. See the tcg tests for an example.
Special instructions
--------------------
The translation recognizes one special instruction to halt the cpu:
......
......@@ -217,6 +217,7 @@ void lm32_breakpoint_remove(CPULM32State *env, int index);
void lm32_watchpoint_insert(CPULM32State *env, int index, target_ulong address,
lm32_wp_t wp_type);
void lm32_watchpoint_remove(CPULM32State *env, int index);
bool lm32_cpu_do_semihosting(CPUState *cs);
static inline CPULM32State *cpu_init(const char *cpu_model)
{
......
/*
* LatticeMico32 helper routines.
*
* Copyright (c) 2010 Michael Walle <michael@walle.cc>
* Copyright (c) 2010-2014 Michael Walle <michael@walle.cc>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
......@@ -19,6 +19,7 @@
#include "cpu.h"
#include "qemu/host-utils.h"
#include "sysemu/sysemu.h"
int lm32_cpu_handle_mmu_fault(CPUState *cs, vaddr address, int rw,
int mmu_idx)
......@@ -159,11 +160,20 @@ void lm32_cpu_do_interrupt(CPUState *cs)
"exception at pc=%x type=%x\n", env->pc, cs->exception_index);
switch (cs->exception_index) {
case EXCP_SYSTEMCALL:
if (unlikely(semihosting_enabled)) {
/* do_semicall() returns true if call was handled. Otherwise
* do the normal exception handling. */
if (lm32_cpu_do_semihosting(cs)) {
env->pc += 4;
break;
}
}
/* fall through */
case EXCP_INSN_BUS_ERROR:
case EXCP_DATA_BUS_ERROR:
case EXCP_DIVIDE_BY_ZERO:
case EXCP_IRQ:
case EXCP_SYSTEMCALL:
/* non-debug exceptions */
env->regs[R_EA] = env->pc;
env->ie |= (env->ie & IE_IE) ? IE_EIE : 0;
......
/*
* Lattice Mico32 semihosting syscall interface
*
* Copyright (c) 2014 Michael Walle <michael@walle.cc>
*
* Based on target-m68k/m68k-semi.c, which is
* Copyright (c) 2005-2007 CodeSourcery.
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <stddef.h>
#include "cpu.h"
#include "helper.h"
#include "qemu/log.h"
#include "exec/softmmu-semi.h"
enum {
TARGET_SYS_exit = 1,
TARGET_SYS_open = 2,
TARGET_SYS_close = 3,
TARGET_SYS_read = 4,
TARGET_SYS_write = 5,
TARGET_SYS_lseek = 6,
TARGET_SYS_fstat = 10,
TARGET_SYS_stat = 15,
};
enum {
NEWLIB_O_RDONLY = 0x0,
NEWLIB_O_WRONLY = 0x1,
NEWLIB_O_RDWR = 0x2,
NEWLIB_O_APPEND = 0x8,
NEWLIB_O_CREAT = 0x200,
NEWLIB_O_TRUNC = 0x400,
NEWLIB_O_EXCL = 0x800,
};
static int translate_openflags(int flags)
{
int hf;
if (flags & NEWLIB_O_WRONLY) {
hf = O_WRONLY;
} else if (flags & NEWLIB_O_RDWR) {
hf = O_RDWR;
} else {
hf = O_RDONLY;
}
if (flags & NEWLIB_O_APPEND) {
hf |= O_APPEND;
}
if (flags & NEWLIB_O_CREAT) {
hf |= O_CREAT;
}
if (flags & NEWLIB_O_TRUNC) {
hf |= O_TRUNC;
}
if (flags & NEWLIB_O_EXCL) {
hf |= O_EXCL;
}
return hf;
}
struct newlib_stat {
int16_t newlib_st_dev; /* device */
uint16_t newlib_st_ino; /* inode */
uint16_t newlib_st_mode; /* protection */
uint16_t newlib_st_nlink; /* number of hard links */
uint16_t newlib_st_uid; /* user ID of owner */
uint16_t newlib_st_gid; /* group ID of owner */
int16_t newlib_st_rdev; /* device type (if inode device) */
int32_t newlib_st_size; /* total size, in bytes */
int32_t newlib_st_atime; /* time of last access */
uint32_t newlib_st_spare1;
int32_t newlib_st_mtime; /* time of last modification */
uint32_t newlib_st_spare2;
int32_t newlib_st_ctime; /* time of last change */
uint32_t newlib_st_spare3;
} QEMU_PACKED;
static int translate_stat(CPULM32State *env, target_ulong addr,
struct stat *s)
{
struct newlib_stat *p;
p = lock_user(VERIFY_WRITE, addr, sizeof(struct newlib_stat), 0);
if (!p) {
return 0;
}
p->newlib_st_dev = cpu_to_be16(s->st_dev);
p->newlib_st_ino = cpu_to_be16(s->st_ino);
p->newlib_st_mode = cpu_to_be16(s->st_mode);
p->newlib_st_nlink = cpu_to_be16(s->st_nlink);
p->newlib_st_uid = cpu_to_be16(s->st_uid);
p->newlib_st_gid = cpu_to_be16(s->st_gid);
p->newlib_st_rdev = cpu_to_be16(s->st_rdev);
p->newlib_st_size = cpu_to_be32(s->st_size);
p->newlib_st_atime = cpu_to_be32(s->st_atime);
p->newlib_st_mtime = cpu_to_be32(s->st_mtime);
p->newlib_st_ctime = cpu_to_be32(s->st_ctime);
unlock_user(p, addr, sizeof(struct newlib_stat));
return 1;
}
bool lm32_cpu_do_semihosting(CPUState *cs)
{
LM32CPU *cpu = LM32_CPU(cs);
CPULM32State *env = &cpu->env;
int ret = -1;
target_ulong nr, arg0, arg1, arg2;
void *p;
struct stat s;
nr = env->regs[R_R8];
arg0 = env->regs[R_R1];
arg1 = env->regs[R_R2];
arg2 = env->regs[R_R3];
switch (nr) {
case TARGET_SYS_exit:
/* void _exit(int rc) */
exit(arg0);
case TARGET_SYS_open:
/* int open(const char *pathname, int flags) */
p = lock_user_string(arg0);
if (!p) {
ret = -1;
} else {
ret = open(p, translate_openflags(arg2));
unlock_user(p, arg0, 0);
}
break;
case TARGET_SYS_read:
/* ssize_t read(int fd, const void *buf, size_t count) */
p = lock_user(VERIFY_WRITE, arg1, arg2, 0);
if (!p) {
ret = -1;
} else {
ret = read(arg0, p, arg2);
unlock_user(p, arg1, arg2);
}
break;
case TARGET_SYS_write:
/* ssize_t write(int fd, const void *buf, size_t count) */
p = lock_user(VERIFY_READ, arg1, arg2, 1);
if (!p) {
ret = -1;
} else {
ret = write(arg0, p, arg2);
unlock_user(p, arg1, 0);
}
break;
case TARGET_SYS_close:
/* int close(int fd) */
/* don't close stdin/stdout/stderr */
if (arg0 > 2) {
ret = close(arg0);
} else {
ret = 0;
}
break;
case TARGET_SYS_lseek:
/* off_t lseek(int fd, off_t offset, int whence */
ret = lseek(arg0, arg1, arg2);
break;
case TARGET_SYS_stat:
/* int stat(const char *path, struct stat *buf) */
p = lock_user_string(arg0);
if (!p) {
ret = -1;
} else {
ret = stat(p, &s);
unlock_user(p, arg0, 0);
if (translate_stat(env, arg1, &s) == 0) {
ret = -1;
}
}
break;
case TARGET_SYS_fstat:
/* int stat(int fd, struct stat *buf) */
ret = fstat(arg0, &s);
if (ret == 0) {
if (translate_stat(env, arg1, &s) == 0) {
ret = -1;
}
}
break;
default:
/* unhandled */
return false;
}
env->regs[R_R1] = ret;
return true;
}
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