mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-09-21 15:12:04 +00:00
bbe310cdaf
If a debugger is not attached to U-Boot, semihosting calls will raise a synchronous abort exception. Try to catch this and disable semihosting so we can e.g. use another uart if one is available. In the immediate case, we return an error, since it is not always possible to check for semihosting beforehand (debug uart, user-initiated load command, etc.) We handle all possible semihosting instructions, which is probably overkill. However, we do need to keep track of what instruction set we're using so that we don't suppress an actual error. A future enhancement could try to determine semihosting capability by inspecting the processor state. There's an example of this at [1] for RISC-V. The equivalent for ARM would inspect the monitor modei enable/select bits of the DSCR. However, as the article notes, an exception handler is still helpful in order to catch disconnected debuggers. [1] https://tomverbeure.github.io/2021/12/30/Semihosting-on-RISCV.html#avoiding-hangs-when-a-debugger-is-not-connected Signed-off-by: Sean Anderson <sean.anderson@seco.com>
149 lines
3.9 KiB
C
149 lines
3.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
|
|
/*
|
|
* Copyright (C) 2022 Sean Anderson <sean.anderson@seco.com>
|
|
*/
|
|
|
|
#ifndef _SEMIHOSTING_H
|
|
#define _SEMIHOSTING_H
|
|
|
|
/*
|
|
* These are the encoded instructions used to indicate a semihosting trap. They
|
|
* are named like SMH_ISA_INSN, where ISA is the instruction set (e.g.
|
|
* AArch64), and INSN is the mneumonic for the instruction.
|
|
*/
|
|
#define SMH_A64_HLT 0xD45E0000
|
|
#define SMH_A32_SVC 0xEF123456
|
|
#define SMH_A32_HLT 0xE10F0070
|
|
#define SMH_T32_SVC 0xDFAB
|
|
#define SMH_T32_HLT 0xBABC
|
|
|
|
#if CONFIG_IS_ENABLED(SEMIHOSTING_FALLBACK)
|
|
/**
|
|
* semihosting_enabled() - Determine whether semihosting is supported
|
|
*
|
|
* Semihosting-based drivers should call this function before making other
|
|
* semihosting calls.
|
|
*
|
|
* Return: %true if a debugger is attached which supports semihosting, %false
|
|
* otherwise
|
|
*/
|
|
bool semihosting_enabled(void);
|
|
|
|
/**
|
|
* disable_semihosting() - Cause semihosting_enabled() to return false
|
|
*
|
|
* If U-Boot ever receives an unhandled exception caused by a semihosting trap,
|
|
* the trap handler should call this function.
|
|
*/
|
|
void disable_semihosting(void);
|
|
#else
|
|
static inline bool semihosting_enabled(void)
|
|
{
|
|
return CONFIG_IS_ENABLED(SEMIHOSTING);
|
|
}
|
|
|
|
static inline void disable_semihosting(void)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
/**
|
|
* enum smh_open_mode - Numeric file modes for use with smh_open()
|
|
* MODE_READ: 'r'
|
|
* MODE_BINARY: 'b'
|
|
* MODE_PLUS: '+'
|
|
* MODE_WRITE: 'w'
|
|
* MODE_APPEND: 'a'
|
|
*
|
|
* These modes represent the mode string used by fopen(3) in a form which can
|
|
* be passed to smh_open(). These do NOT correspond directly to %O_RDONLY,
|
|
* %O_CREAT, etc; see fopen(3) for details. In particular, @MODE_PLUS
|
|
* effectively results in adding %O_RDWR, and @MODE_WRITE will add %O_TRUNC.
|
|
* For compatibility, @MODE_BINARY should be added when opening non-text files
|
|
* (such as images).
|
|
*/
|
|
enum smh_open_mode {
|
|
MODE_READ = 0x0,
|
|
MODE_BINARY = 0x1,
|
|
MODE_PLUS = 0x2,
|
|
MODE_WRITE = 0x4,
|
|
MODE_APPEND = 0x8,
|
|
};
|
|
|
|
/**
|
|
* smh_open() - Open a file on the host
|
|
* @fname: The name of the file to open
|
|
* @mode: The mode to use when opening the file
|
|
*
|
|
* Return: Either a file descriptor or a negative error on failure
|
|
*/
|
|
long smh_open(const char *fname, enum smh_open_mode mode);
|
|
|
|
/**
|
|
* smh_read() - Read data from a file
|
|
* @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
|
|
*
|
|
* Return:
|
|
* * The number of bytes read on success, with 0 indicating %EOF
|
|
* * A negative error on failure
|
|
*/
|
|
long smh_read(long fd, void *memp, size_t len);
|
|
|
|
/**
|
|
* smh_write() - Write data to a file
|
|
* @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
|
|
* @written: Pointer which will be updated with the actual bytes written
|
|
*
|
|
* Return: 0 on success or negative error on failure
|
|
*/
|
|
long smh_write(long fd, const void *memp, size_t len, ulong *written);
|
|
|
|
/**
|
|
* smh_close() - Close an open file
|
|
* @fd: A file descriptor returned from smh_open()
|
|
*
|
|
* Return: 0 on success or negative error on failure
|
|
*/
|
|
long smh_close(long fd);
|
|
|
|
/**
|
|
* smh_flen() - Get the length of a file
|
|
* @fd: A file descriptor returned from smh_open()
|
|
*
|
|
* Return: The length of the file, in bytes, or a negative error on failure
|
|
*/
|
|
long smh_flen(long fd);
|
|
|
|
/**
|
|
* smh_seek() - Seek to a position in a file
|
|
* @fd: A file descriptor returned from smh_open()
|
|
* @pos: The offset (in bytes) to seek to
|
|
*
|
|
* Return: 0 on success or negative error on failure
|
|
*/
|
|
long smh_seek(long fd, long pos);
|
|
|
|
/**
|
|
* smh_getc() - Read a character from stdin
|
|
*
|
|
* Return: The character read, or a negative error on failure
|
|
*/
|
|
int smh_getc(void);
|
|
|
|
/**
|
|
* smh_putc() - Print a character on stdout
|
|
* @ch: The character to print
|
|
*/
|
|
void smh_putc(char ch);
|
|
|
|
/**
|
|
* smh_write0() - Print a nul-terminated string on stdout
|
|
* @s: The string to print
|
|
*/
|
|
void smh_puts(const char *s);
|
|
|
|
#endif /* _SEMIHOSTING_H */
|