On 19/07/23 10:49, Laurent Vivier wrote:
According to linux/glibc sourced, epoll is only packed for x86_64.
And, in recent glibc, also for i386, even it seems not necessary: even if the
__alignof__(long long) is 8, structures like epoll_event are only 12 bytes, maybe
"packed" for historical reasons. Ancient i386 gcc[s] (<3.0.0) have 4 bytes for
__alignof__(long long).
Perhaps the default alignment of long is not correctly defined in qemu for
openrisc?
__alignof__(long long):
- 8 bytes: all 64 bit targets + arm, hppa, mips, ppc, sparc, xtensa, x86
- 4 bytes: microblaze, nios2, or1k, sh4
- 2 bytes: m68k
- 1 byte : cris
offsetof(struct epoll_event,data):
- 8: all 64 bit targets + arm, hppa, mips, ppc, sparc, xtensa
- 4: cris, m68k, microblaze, nios2, or1k, sh4, x86
So, epoll_event is "naturally" packed on the following targets (checked in linux-user
container and/or with cross-compiler):
- cris, m68k, microblaze, nios2, or1k, sh4, x86 (32bit)
See include/exec/user/abitypes.h to update the value.
OK, abitypes.h should be updated with the following patch (discard the previous patch on
syscall_defs.h):
Signed-off-by: Luca Bonissi <qemu@bonslack.org>
---
diff -up a/include/exec/user/abitypes.h b/include/exec/user/abitypes.h
--- a/include/exec/user/abitypes.h 2023-03-27 15:41:42.511916232 +0200
+++ b/include/exec/user/abitypes.h 2023-07-19 12:09:03.001687788 +0200
@@ -15,7 +15,15 @@
#define ABI_LLONG_ALIGNMENT 2
#endif
+#ifdef TARGET_CRIS
+#define ABI_SHORT_ALIGNMENT 1
+#define ABI_INT_ALIGNMENT 1
+#define ABI_LONG_ALIGNMENT 1
+#define ABI_LLONG_ALIGNMENT 1
+#endif
+
-#if (defined(TARGET_I386) && !defined(TARGET_X86_64)) || defined(TARGET_SH4)
+#if (defined(TARGET_I386) && !defined(TARGET_X86_64)) || defined(TARGET_SH4)
|| \
+ defined(TARGET_OPENRISC) || defined(TARGET_NIOS2) ||
defined(TARGET_MICROBLAZE)
#define ABI_LLONG_ALIGNMENT 4
#endif