On 10/17/25 23:35, Sean Anderson wrote:
When semihosting 32-bit systems, the return value of FLEN will be stored
in a 32-bit integer. To prevent wraparound, return -1 and set EOVERFLOW.
This matches the behavior of stat(2). Static files don't need to be
checked, since are always small.
Signed-off-by: Sean Anderson <[email protected]>
---
semihosting/arm-compat-semi.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)
diff --git a/semihosting/arm-compat-semi.c b/semihosting/arm-compat-semi.c
index c5a07cb947..57453ca6be 100644
--- a/semihosting/arm-compat-semi.c
+++ b/semihosting/arm-compat-semi.c
@@ -305,8 +305,19 @@ static uint64_t common_semi_flen_buf(CPUState *cs)
return sp - 64;
}
+static void common_semi_flen_cb(CPUState *cs, uint64_t ret, int err)
+{
+ CPUArchState *env = cpu_env(cs);
+
+ if (!err && !is_64bit_semihosting(env) && ret > INT32_MAX) {
The issue with the current implementation is that files with file sizes
over 4 GiB will be reported as file size < 4 -GiB on 32bit systems.
Thanks for addressing this.
But unfortunately with your change you are additionally dropping support
for file sizes 2 GiB to 4 GiB on 32bit devices. This should be avoided.
The semihosting specification specifies that the value returned in r0
should be -1 if an error occurs. So on 32 bit systems 0xffffffff should
be returned.
As file sizes cannot be negative there is not reason to assume that the
value in r0 has to be interpreted by semihosting clients as signed.
Please, change your commit to check against 0xffffffff.
It might make sense to contact ARM to make their specification clearer.
Best regards
Heinrich
+ ret = -1, err = EOVERFLOW;
+ }
+ common_semi_cb(cs, ret, err);
+}
+
+
static void
-common_semi_flen_fstat_cb(CPUState *cs, uint64_t ret, int err)
+common_semi_flen_gdb_cb(CPUState *cs, uint64_t ret, int err)
{
if (!err) {
/* The size is always stored in big-endian order, extract the value.
*/
@@ -319,7 +330,7 @@ common_semi_flen_fstat_cb(CPUState *cs, uint64_t ret, int
err)
ret = be64_to_cpu(size);
}
}
- common_semi_cb(cs, ret, err);
+ common_semi_flen_cb(cs, ret, err);
}
static void
@@ -517,7 +528,7 @@ void do_common_semihosting(CPUState *cs)
case TARGET_SYS_FLEN:
GET_ARG(0);
- semihost_sys_flen(cs, common_semi_flen_fstat_cb, common_semi_cb,
+ semihost_sys_flen(cs, common_semi_flen_gdb_cb, common_semi_flen_cb,
arg0, common_semi_flen_buf(cs));
break;
