This provides two functions for handling console output that handle the common backend behaviour for semihosting.
Signed-off-by: Alex Bennée <alex.ben...@linaro.org> --- gdbstub.c | 5 +++ hw/semihosting/Makefile.objs | 1 + hw/semihosting/console.c | 70 ++++++++++++++++++++++++++++++++ include/exec/gdbstub.h | 11 +++++ include/hw/semihosting/console.h | 38 +++++++++++++++++ 5 files changed, 125 insertions(+) create mode 100644 hw/semihosting/console.c create mode 100644 include/hw/semihosting/console.h diff --git a/gdbstub.c b/gdbstub.c index 793218bb43a..b4334014373 100644 --- a/gdbstub.c +++ b/gdbstub.c @@ -1987,6 +1987,11 @@ void gdb_do_syscall(gdb_syscall_complete_cb cb, const char *fmt, ...) va_end(va); } +void gdb_do_console_out(target_ulong s, int len) +{ + gdb_do_syscall(NULL, "write,2,%x,1", s, len); +} + static void gdb_read_byte(GDBState *s, int ch) { uint8_t reply; diff --git a/hw/semihosting/Makefile.objs b/hw/semihosting/Makefile.objs index 09c19bf19ed..4ad47c05c06 100644 --- a/hw/semihosting/Makefile.objs +++ b/hw/semihosting/Makefile.objs @@ -1 +1,2 @@ obj-$(CONFIG_SEMIHOSTING) += config.o +obj-$(CONFIG_SEMIHOSTING) += console.o diff --git a/hw/semihosting/console.c b/hw/semihosting/console.c new file mode 100644 index 00000000000..ad6f67ecc71 --- /dev/null +++ b/hw/semihosting/console.c @@ -0,0 +1,70 @@ +/* + * Semihosting Console Support + * + * Copyright (c) 2015 Imagination Technologies + * Copyright (c) 2019 Linaro Ltd + * + * This provides support for outputting to a semihosting console. + * + * While most semihosting implementations support reading and writing + * to arbitrary file descriptors we treat the console as something + * specifically for debugging interaction. This means messages can be + * re-directed to gdb (if currently being used to debug) or even + * re-directed elsewhere. + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +#include "qemu/osdep.h" +#include "cpu.h" +#include "hw/semihosting/console.h" +#include "exec/gdbstub.h" +#include "qemu/log.h" + +int qemu_semihosting_log_out(const char *s, int len) +{ + return write(STDERR_FILENO, s, len); +} + +/* + * A re-implementation of lock_user_string that we can use locally + * instead of relying on softmmu-semi. Hopefully we can deprecate that + * in time. We either copy len bytes if specified or until we find a NULL. + */ +static GString *copy_user_string(CPUArchState *env, target_ulong addr, int len) +{ + CPUState *cpu = ENV_GET_CPU(env); + GString *s = g_string_sized_new(len ? len : 128); + uint8_t c; + bool done; + + do { + if (cpu_memory_rw_debug(cpu, addr++, &c, 1, 0) == 0) { + s = g_string_append_c(s, c); + done = len ? s->len == len : c == 0; + } else { + qemu_log_mask(LOG_GUEST_ERROR, + "%s: passed inaccessible address " TARGET_FMT_lx, + __func__, addr); + done = true; + } + } while (!done); + + return s; +} + + +int qemu_semihosting_console_out(CPUArchState *env, target_ulong addr, int len) +{ + GString *s = copy_user_string(env, addr, len); + int out = s->len; + + if (use_gdb_syscalls()) { + gdb_do_console_out(addr, s->len); + } else { + out = qemu_semihosting_log_out(s->str, s->len); + } + + g_string_free(s, true); + return out; +} diff --git a/include/exec/gdbstub.h b/include/exec/gdbstub.h index 08363969c14..b2963547c48 100644 --- a/include/exec/gdbstub.h +++ b/include/exec/gdbstub.h @@ -44,6 +44,17 @@ void gdb_do_syscall(gdb_syscall_complete_cb cb, const char *fmt, ...); * argument list. */ void gdb_do_syscallv(gdb_syscall_complete_cb cb, const char *fmt, va_list va); +/** + * gdb_do_console_out: + * @gs: guest address of string to send + * @len: length of string + * + * Sends a string to gdb console. Unlike the system call interface + * there is no callback and we assume the system call always + * succeeds. + */ +void gdb_do_console_out(target_ulong s, int len); + int use_gdb_syscalls(void); void gdb_set_stop_cpu(CPUState *cpu); void gdb_exit(CPUArchState *, int); diff --git a/include/hw/semihosting/console.h b/include/hw/semihosting/console.h new file mode 100644 index 00000000000..30e66ae20aa --- /dev/null +++ b/include/hw/semihosting/console.h @@ -0,0 +1,38 @@ +/* + * Semihosting Console + * + * Copyright (c) 2019 Linaro Ltd + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +#ifndef _SEMIHOST_CONSOLE_H_ +#define _SEMIHOST_CONSOLE_H_ + +/** + * qemu_semihosting_console_out: + * @env: CPUArchState + * @s: host address of guest string + * @len: length of string or 0 (string is null terminated) + * + * Send a guest string to the debug console. This may be the remote + * gdb session if a softmmu guest is currently being debugged. + * + * Returns: number of bytes written. + */ +int qemu_semihosting_console_out(CPUArchState *env, target_ulong s, int len); + +/** + * qemu_semihosting_log_out: + * @s: pointer to string + * @len: length of string + * + * Send a string to the debug output. Unlike console_out these strings + * can't be sent to a remote gdb instance as they don't exist in guest + * memory. + * + * Returns: number of bytes written + */ +int qemu_semihosting_log_out(const char *s, int len); + +#endif /* _SEMIHOST_CONSOLE_H_ */ -- 2.20.1