sys64738
/
blackmagic
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

semihosting: improve handling of console I/O 

This implements special handling for SYS_OPEN to catch requests for
":tt" which is reserved by ARM for console input/output. They're
mapped to the appropriate GDB file descriptors automatically.

An additional file handle offset is introduced because ARM doesn't
consider zero handle to be valid.

Signed-off-by: Paul Fertser <fercerpav@gmail.com>
This commit is contained in:
Paul Fertser 2013-04-15 21:42:46 +04:00 committed by Gareth McMullin
parent 5020d1f05d
commit df32aad757
2 changed files with 42 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
README
View File

@ -47,15 +47,19 @@ RAM.
Semihosting support
===================
Basic armv6m/armv7m semihosting is supported, i.e. you can build your
application in a special way to use host's stdin and stdout right
inside gdb simply by calling printf(), scanf() and other input-output
functions. To make use of it, add --specs=rdimon.specs and -lrdimon to
Standard ARMv6-M/ARMv7-M semihosting is supported, i.e. you can build
your application in a special way to have calls to certain functions
(open(), close(), read(), write(), lseek(), rename(), unlink(),
stat(), isatty(), system()) executed on the debugging host itself. To
make use of these facilities, add --specs=rdimon.specs and -lrdimon to
the linker flags for your firmware.
All writes are treated as writes to the stdout, all reads are done
from stdin; SYS_ISTTY always returns true, SYS_ERRNO -- EINTR;
SYS_OPEN and SYS_FLEN return dummy non-zero values.
If you're going to use stdin, stdout or stderr (e.g. via
printf()/scanf()) and you're not using newlib's crt0 (by specifying
-nostartfiles), you need to add this to your initialisation:
void initialise_monitor_handles(void);
initialise_monitor_handles();
Project layout
==============

40
src/cortexm.c
View File

@ -28,6 +28,7 @@
* Issues:
* There are way too many magic numbers used here.
*/
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
@ -949,41 +950,60 @@ static int cortexm_hostio_request(target *t)
FILEIO_O_WRONLY | FILEIO_O_CREAT | FILEIO_O_APPEND,/*a*/
FILEIO_O_RDWR | FILEIO_O_CREAT | FILEIO_O_APPEND,/*a+*/
};
uint32_t pflag = flags[params[1] >> 1];
char filename[4];
target_mem_read_bytes(t, filename, params[0], sizeof(filename));
/* handle requests for console i/o */
if (!strcmp(filename, ":tt")) {
if (pflag == FILEIO_O_RDONLY)
arm_regs[0] = STDIN_FILENO;
else if (pflag & FILEIO_O_TRUNC)
arm_regs[0] = STDOUT_FILENO;
else
arm_regs[0] = STDERR_FILENO;
arm_regs[0]++;
target_regs_write(t, arm_regs);
return 1;
}
gdb_putpacket_f("Fopen,%08X/%X,%08X,%08X",
params[0], params[2] + 1,
flags[params[1] >> 1], 0644);
pflag, 0644);
break;
}
case SYS_CLOSE: /* close */
gdb_putpacket_f("Fclose,%08X", params[0]);
gdb_putpacket_f("Fclose,%08X", params[0] - 1);
break;
case SYS_READ: /* read */
priv->byte_count = params[2];
gdb_putpacket_f("Fread,%08X,%08X,%08X",
params[0], params[1], params[2]);
params[0] - 1, params[1], params[2]);
break;
case SYS_WRITE: /* write */
priv->byte_count = params[2];
gdb_putpacket_f("Fwrite,%08X,%08X,%08X",
params[0], params[1], params[2]);
params[0] - 1, params[1], params[2]);
break;
case SYS_ISTTY: /* isatty */
gdb_putpacket_f("Fisatty,%08X", params[0]);
gdb_putpacket_f("Fisatty,%08X", params[0] - 1);
break;
case SYS_SEEK: /* lseek */
gdb_putpacket_f("Flseek,%08X,%08X,%08X",
params[0], params[1], FILEIO_SEEK_SET);
params[0] - 1, params[1], FILEIO_SEEK_SET);
break;
case SYS_RENAME:/* rename */
gdb_putpacket_f("Frename,%08X/%X,%08X/%X",
params[0], params[1] + 1,
params[0] - 1, params[1] + 1,
params[2], params[3] + 1);
break;
case SYS_REMOVE:/* unlink */
gdb_putpacket_f("Funlink,%08X/%X", params[0], params[1] + 1);
gdb_putpacket_f("Funlink,%08X/%X", params[0] - 1,
params[1] + 1);
break;
case SYS_SYSTEM:/* system */
gdb_putpacket_f("Fsystem,%08X/%X", params[0], params[1] + 1);
gdb_putpacket_f("Fsystem,%08X/%X", params[0] - 1,
params[1] + 1);
break;
case SYS_FLEN: /* Not supported, fake success */
@ -1015,6 +1035,8 @@ static void cortexm_hostio_reply(target *t, int32_t retcode, uint32_t errcode)
if (((priv->syscall == SYS_READ) || (priv->syscall == SYS_WRITE)) &&
(retcode > 0))
retcode = priv->byte_count - retcode;
if ((priv->syscall == SYS_OPEN) && (retcode != -1))
retcode++;
arm_regs[0] = retcode;
target_regs_write(t, arm_regs);
priv->errno = errcode;