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semihosting: Split out semihost_sys_read

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Split out the non-ARM specific portions of SYS_READ to a
reusable function.  This handles all GuestFD.  Isolate the
curious ARM-specific return value processing to a new
callback, common_semi_rw_cb.

Note that gdb_do_syscall %x reads target_ulong, not int.

Reviewed-by: Luc Michel <lmichel@kalray.eu>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2022-04-28 11:40:41 -07:00
parent 5eadbbfca6
commit af0484b502
3 changed files with 113 additions and 65 deletions
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85
semihosting/syscalls.c
View file

@ -100,6 +100,13 @@ static void gdb_close(CPUState *cs, gdb_syscall_complete_cb complete,
gdb_do_syscall(complete, "close,%x", (target_ulong)gf->hostfd);
}
static void gdb_read(CPUState *cs, gdb_syscall_complete_cb complete,
GuestFD *gf, target_ulong buf, target_ulong len)
{
gdb_do_syscall(complete, "read,%x,%x,%x",
(target_ulong)gf->hostfd, buf, len);
}
/*
* Host semihosting syscall implementations.
*/
@ -163,6 +170,54 @@ static void host_close(CPUState *cs, gdb_syscall_complete_cb complete,
}
}
static void host_read(CPUState *cs, gdb_syscall_complete_cb complete,
GuestFD *gf, target_ulong buf, target_ulong len)
{
CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
void *ptr = lock_user(VERIFY_WRITE, buf, len, 0);
ssize_t ret;
if (!ptr) {
complete(cs, -1, EFAULT);
return;
}
do {
ret = read(gf->hostfd, ptr, len);
} while (ret == -1 && errno == EINTR);
if (ret == -1) {
complete(cs, -1, errno);
unlock_user(ptr, buf, 0);
} else {
complete(cs, ret, 0);
unlock_user(ptr, buf, ret);
}
}
/*
* Static file semihosting syscall implementations.
*/
static void staticfile_read(CPUState *cs, gdb_syscall_complete_cb complete,
GuestFD *gf, target_ulong buf, target_ulong len)
{
CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
target_ulong rest = gf->staticfile.len - gf->staticfile.off;
void *ptr;
if (len > rest) {
len = rest;
}
ptr = lock_user(VERIFY_WRITE, buf, len, 0);
if (!ptr) {
complete(cs, -1, EFAULT);
return;
}
memcpy(ptr, gf->staticfile.data + gf->staticfile.off, len);
gf->staticfile.off += len;
complete(cs, len, 0);
unlock_user(ptr, buf, len);
}
/*
* Syscall entry points.
*/
@ -201,3 +256,33 @@ void semihost_sys_close(CPUState *cs, gdb_syscall_complete_cb complete, int fd)
}
dealloc_guestfd(fd);
}
void semihost_sys_read_gf(CPUState *cs, gdb_syscall_complete_cb complete,
GuestFD *gf, target_ulong buf, target_ulong len)
{
switch (gf->type) {
case GuestFDGDB:
gdb_read(cs, complete, gf, buf, len);
break;
case GuestFDHost:
host_read(cs, complete, gf, buf, len);
break;
case GuestFDStatic:
staticfile_read(cs, complete, gf, buf, len);
break;
default:
g_assert_not_reached();
}
}
void semihost_sys_read(CPUState *cs, gdb_syscall_complete_cb complete,
int fd, target_ulong buf, target_ulong len)
{
GuestFD *gf = get_guestfd(fd);
if (gf) {
semihost_sys_read_gf(cs, complete, gf, buf, len);
} else {
complete(cs, -1, EBADF);
}
}