diff options
author | Kautuk Consul <kconsul@ventanamicro.com> | 2022-12-07 14:42:34 +0300 |
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committer | Leo Yu-Chi Liang <ycliang@andestech.com> | 2022-12-08 10:15:22 +0300 |
commit | 1c03ab9f4bdf19d1ac7afc157788bd0102ccd969 (patch) | |
tree | 6ba8dbdc7c9742719cdf35452392d40470584de2 /lib | |
parent | 14f2d087a3d6347ba0ff7a7e9aaff6955e53e7a8 (diff) | |
download | u-boot-1c03ab9f4bdf19d1ac7afc157788bd0102ccd969.tar.xz |
lib: Add common semihosting library
We factor out the arch-independent parts of the ARM semihosting
implementation as a common library so that it can be shared
with RISC-V.
Signed-off-by: Kautuk Consul <kconsul@ventanamicro.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Kconfig | 47 | ||||
-rw-r--r-- | lib/Makefile | 2 | ||||
-rw-r--r-- | lib/semihosting.c | 186 |
3 files changed, 235 insertions, 0 deletions
diff --git a/lib/Kconfig b/lib/Kconfig index 6abe1d0a86..b8833e0183 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -71,6 +71,53 @@ config HAVE_PRIVATE_LIBGCC config LIB_UUID bool +config SEMIHOSTING + bool "Support semihosting" + depends on ARM + help + Semihosting is a method for a target to communicate with a host + debugger. It uses special instructions which the debugger will trap + on and interpret. This allows U-Boot to read/write files, print to + the console, and execute arbitrary commands on the host system. + + Enabling this option will add support for reading and writing files + on the host system. If you don't have a debugger attached then trying + to do this will likely cause U-Boot to hang. Say 'n' if you are unsure. + +config SEMIHOSTING_FALLBACK + bool "Recover gracefully when semihosting fails" + depends on SEMIHOSTING && ARM64 + default y + help + Normally, if U-Boot makes a semihosting call and no debugger is + attached, then it will panic due to a synchronous abort + exception. This config adds an exception handler which will allow + U-Boot to recover. Say 'y' if unsure. + +config SPL_SEMIHOSTING + bool "Support semihosting in SPL" + depends on SPL && ARM + help + Semihosting is a method for a target to communicate with a host + debugger. It uses special instructions which the debugger will trap + on and interpret. This allows U-Boot to read/write files, print to + the console, and execute arbitrary commands on the host system. + + Enabling this option will add support for reading and writing files + on the host system. If you don't have a debugger attached then trying + to do this will likely cause U-Boot to hang. Say 'n' if you are unsure. + +config SPL_SEMIHOSTING_FALLBACK + bool "Recover gracefully when semihosting fails in SPL" + depends on SPL_SEMIHOSTING && ARM64 + select ARMV8_SPL_EXCEPTION_VECTORS + default y + help + Normally, if U-Boot makes a semihosting call and no debugger is + attached, then it will panic due to a synchronous abort + exception. This config adds an exception handler which will allow + U-Boot to recover. Say 'y' if unsure. + config PRINTF bool default y diff --git a/lib/Makefile b/lib/Makefile index f2cfd1e428..d77b33e7f4 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -146,6 +146,8 @@ obj-y += date.o obj-y += rtc-lib.o obj-$(CONFIG_LIB_ELF) += elf.o +obj-$(CONFIG_$(SPL_TPL_)SEMIHOSTING) += semihosting.o + # # Build a fast OID lookup registry from include/linux/oid_registry.h # diff --git a/lib/semihosting.c b/lib/semihosting.c new file mode 100644 index 0000000000..831774e356 --- /dev/null +++ b/lib/semihosting.c @@ -0,0 +1,186 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2022 Sean Anderson <sean.anderson@seco.com> + * Copyright 2014 Broadcom Corporation + */ + +#include <common.h> +#include <log.h> +#include <semihosting.h> + +#define SYSOPEN 0x01 +#define SYSCLOSE 0x02 +#define SYSWRITEC 0x03 +#define SYSWRITE0 0x04 +#define SYSWRITE 0x05 +#define SYSREAD 0x06 +#define SYSREADC 0x07 +#define SYSISERROR 0x08 +#define SYSSEEK 0x0A +#define SYSFLEN 0x0C +#define SYSERRNO 0x13 + +#if CONFIG_IS_ENABLED(SEMIHOSTING_FALLBACK) +static bool _semihosting_enabled = true; +static bool try_semihosting = true; + +bool semihosting_enabled(void) +{ + if (try_semihosting) { + smh_trap(SYSERRNO, NULL); + try_semihosting = false; + } + + return _semihosting_enabled; +} + +void disable_semihosting(void) +{ + _semihosting_enabled = false; +} +#endif + +/** + * smh_errno() - Read the host's errno + * + * This gets the value of the host's errno and negates it. The host's errno may + * or may not be set, so only call this function if a previous semihosting call + * has failed. + * + * Return: a negative error value + */ +static int smh_errno(void) +{ + long ret = smh_trap(SYSERRNO, NULL); + + if (ret > 0 && ret < INT_MAX) + return -ret; + return -EIO; +} + +long smh_open(const char *fname, enum smh_open_mode mode) +{ + long fd; + struct smh_open_s { + const char *fname; + unsigned long mode; + size_t len; + } open; + + debug("%s: file \'%s\', mode \'%u\'\n", __func__, fname, mode); + + open.fname = fname; + open.len = strlen(fname); + open.mode = mode; + + /* Open the file on the host */ + fd = smh_trap(SYSOPEN, &open); + if (fd == -1) + return smh_errno(); + return fd; +} + +/** + * struct smg_rdwr_s - Arguments for read and write + * @fd: A file descriptor returned from smh_open() + * @memp: Pointer to a buffer of memory of at least @len bytes + * @len: The number of bytes to read or write + */ +struct smh_rdwr_s { + long fd; + void *memp; + size_t len; +}; + +long smh_read(long fd, void *memp, size_t len) +{ + long ret; + struct smh_rdwr_s read; + + debug("%s: fd %ld, memp %p, len %zu\n", __func__, fd, memp, len); + + read.fd = fd; + read.memp = memp; + read.len = len; + + ret = smh_trap(SYSREAD, &read); + if (ret < 0) + return smh_errno(); + return len - ret; +} + +long smh_write(long fd, const void *memp, size_t len, ulong *written) +{ + long ret; + struct smh_rdwr_s write; + + debug("%s: fd %ld, memp %p, len %zu\n", __func__, fd, memp, len); + + write.fd = fd; + write.memp = (void *)memp; + write.len = len; + + ret = smh_trap(SYSWRITE, &write); + *written = len - ret; + if (ret) + return smh_errno(); + return 0; +} + +long smh_close(long fd) +{ + long ret; + + debug("%s: fd %ld\n", __func__, fd); + + ret = smh_trap(SYSCLOSE, &fd); + if (ret == -1) + return smh_errno(); + return 0; +} + +long smh_flen(long fd) +{ + long ret; + + debug("%s: fd %ld\n", __func__, fd); + + ret = smh_trap(SYSFLEN, &fd); + if (ret == -1) + return smh_errno(); + return ret; +} + +long smh_seek(long fd, long pos) +{ + long ret; + struct smh_seek_s { + long fd; + long pos; + } seek; + + debug("%s: fd %ld pos %ld\n", __func__, fd, pos); + + seek.fd = fd; + seek.pos = pos; + + ret = smh_trap(SYSSEEK, &seek); + if (ret) + return smh_errno(); + return 0; +} + +int smh_getc(void) +{ + return smh_trap(SYSREADC, NULL); +} + +void smh_putc(char ch) +{ + smh_trap(SYSWRITEC, &ch); +} + +void smh_puts(const char *s) +{ + smh_trap(SYSWRITE0, (char *)s); +} |