Ok I am an idiot. On 32 bits big-endian systems, it is needed to handle the

syscalls using __syscall but only actually returning 32bits, such as mmap(),
specially : they set the return value in td->td_retval[0], but the userland
functions will expect this in r1, and not in r0 as it is normally done, as it
is the LSB. So add a special case for all these syscalls (all except lseek,
which truly returns 64bits).

Many thanks to Peter Grehan for his patience while explaining me the issue.

1 files changed, 17 insertions, 2 deletions

diff --git a/sys/arm/arm/trap.c b/sys/arm/arm/trap.c
index fd187f7..c4c4518 100644
--- a/sys/arm/arm/trap.c
+++ b/sys/arm/arm/trap.c
@@ -940,8 +940,23 @@ syscall(struct thread *td, trapframe_t *frame, u_int32_t insn)
 	}
 	switch (error) {
 	case 0: 
-      		frame->tf_r0 = td->td_retval[0];
-		frame->tf_r1 = td->td_retval[1];
+#ifdef __ARMEB__
+		if ((insn & 0x000fffff) == SYS___syscall &&
+		    (code != SYS_lseek)) {
+			/*
+			 * 64-bit return, 32-bit syscall. Fixup byte order
+			 */ 
+			frame->tf_r0 = 0;
+			frame->tf_r1 = td->td_retval[0];
+		} else {
+			frame->tf_r0 = td->td_retval[0];
+			frame->tf_r1 = td->td_retval[1];
+		}
+#else
+		frame->tf_r0 = td->td_retval[0];
+	  	frame->tf_r1 = td->td_retval[1];
+#endif
+					      
 		frame->tf_spsr &= ~PSR_C_bit;   /* carry bit */
 		break;