| Message ID | CAFEAcA-K6dc-1E8vZ4QOWc1K0MMuZjXxv1XtLduFkxuf2RFhZg@mail.gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
22.07.2016, 23:06, "Peter Maydell" <peter.maydell@linaro.org>: > On 22 July 2016 at 03:30, Icenowy Zheng <icenowy@aosc.xyz> wrote: >> According to comments in /usr/include/linux/eventpoll.h, x86_64 have >> the same memory layout of struct target_epoll_event as i386. So on a >> aligned host, if x86_64 should be packed, i386 will also need. >> >> This has been tested with a i386 guest on an arm host: without the >> patch, wineserver crashes (core). >> >> Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz> >> --- >> linux-user/syscall_defs.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h >> index b43966e..7380bf5 100644 >> --- a/linux-user/syscall_defs.h >> +++ b/linux-user/syscall_defs.h >> @@ -2547,7 +2547,7 @@ struct target_mq_attr { >> #define FUTEX_CMD_MASK ~(FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME) >> >> #ifdef CONFIG_EPOLL >> -#if defined(TARGET_X86_64) >> +#if defined(TARGET_X86_64) || defined(TARGET_I386) >> #define TARGET_EPOLL_PACKED QEMU_PACKED >> #else >> #define TARGET_EPOLL_PACKED > > We do indeed not get the right arrangement for this struct for > i386, but I don't think this is the right way to fix it. The > kernel headers only special case this for x86-64, not i386, > and so we should not need to special case i386 either. > > The underlying problem is that we get the alignment of the > 'unsigned long long' type for i386 wrong, treating it as 8-aligned > when it should be 4-aligned. This can be fixed by > > diff --git a/include/exec/user/abitypes.h b/include/exec/user/abitypes.h > index a09d6c6..ba18860 100644 > --- a/include/exec/user/abitypes.h > +++ b/include/exec/user/abitypes.h > @@ -15,6 +15,10 @@ > #define ABI_LLONG_ALIGNMENT 2 > #endif > > +#if defined(TARGET_I386) && !defined(TARGET_X86_64) > +#define ABI_LLONG_ALIGNMENT 4 > +#endif > + > #ifndef ABI_SHORT_ALIGNMENT > #define ABI_SHORT_ALIGNMENT 2 > #endif > > and if you do that I don't think you need to change the > handling of the target_epoll_event struct. > > (and that might in turn fix a bunch of other bugs, or if we're > unlucky introduce some new ones by breaking any lurking > workarounds for the previous misalignment...) > > thanks > -- PMM Congratulations! Your patch made epoll running correctly. I'm now running LTP syscall tests to check for hurt syscalls. Thanks Icenowy Zheng
diff --git a/include/exec/user/abitypes.h b/include/exec/user/abitypes.h index a09d6c6..ba18860 100644 --- a/include/exec/user/abitypes.h +++ b/include/exec/user/abitypes.h @@ -15,6 +15,10 @@ #define ABI_LLONG_ALIGNMENT 2 #endif +#if defined(TARGET_I386) && !defined(TARGET_X86_64) +#define ABI_LLONG_ALIGNMENT 4 +#endif + #ifndef ABI_SHORT_ALIGNMENT #define ABI_SHORT_ALIGNMENT 2 #endif