From f7bbcfb5c303a07322f1e0f258a936a720183169 Mon Sep 17 00:00:00 2001 From: Michael Walle Date: Tue, 22 Apr 2014 20:18:42 +0200 Subject: [PATCH] target-lm32: add semihosting support Intercept certain system calls if semihosting is enabled. This should behave like the GDB simulator. Signed-off-by: Michael Walle --- qemu-options.hx | 3 +- target-lm32/Makefile.objs | 1 + target-lm32/README | 9 ++ target-lm32/cpu.h | 1 + target-lm32/helper.c | 14 ++- target-lm32/lm32-semi.c | 215 ++++++++++++++++++++++++++++++++++++++ 6 files changed, 240 insertions(+), 3 deletions(-) create mode 100644 target-lm32/lm32-semi.c diff --git a/qemu-options.hx b/qemu-options.hx index c2c0823911..4011d46d62 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -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 diff --git a/target-lm32/Makefile.objs b/target-lm32/Makefile.objs index 40236876c8..c3e1bd6bd6 100644 --- a/target-lm32/Makefile.objs +++ b/target-lm32/Makefile.objs @@ -1,3 +1,4 @@ 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 diff --git a/target-lm32/README b/target-lm32/README index a1c2c7eb1e..03ddbffc54 100644 --- a/target-lm32/README +++ b/target-lm32/README @@ -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: diff --git a/target-lm32/cpu.h b/target-lm32/cpu.h index 24bde78502..70600aa47a 100644 --- a/target-lm32/cpu.h +++ b/target-lm32/cpu.h @@ -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) { diff --git a/target-lm32/helper.c b/target-lm32/helper.c index 783aa16a45..1bca1961af 100644 --- a/target-lm32/helper.c +++ b/target-lm32/helper.c @@ -1,7 +1,7 @@ /* * LatticeMico32 helper routines. * - * Copyright (c) 2010 Michael Walle + * Copyright (c) 2010-2014 Michael Walle * * 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; diff --git a/target-lm32/lm32-semi.c b/target-lm32/lm32-semi.c new file mode 100644 index 0000000000..fc9d2d1c73 --- /dev/null +++ b/target-lm32/lm32-semi.c @@ -0,0 +1,215 @@ +/* + * Lattice Mico32 semihosting syscall interface + * + * Copyright (c) 2014 Michael Walle + * + * 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 +#include +#include +#include +#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; +}