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Re: [Qemu-devel] [PATCH] linux-user: correctly align types in thunking c
From: |
Laurent Vivier |
Subject: |
Re: [Qemu-devel] [PATCH] linux-user: correctly align types in thunking code |
Date: |
Sat, 26 Jan 2013 12:20:29 +0100 |
Le mercredi 02 janvier 2013 à 00:08 +0100, Laurent Vivier a écrit :
> Ping !
ping
> Le jeudi 20 décembre 2012 à 21:55 +0100, Laurent Vivier a écrit :
> > This is a follow up
> > of patch:
> >
> > commit c2e3dee6e03527baf8698698cce76b1a3174969a
> > Author: Laurent Vivier <address@hidden>
> > Date: Sun Feb 13 23:37:34 2011 +0100
> >
> > linux-user: Define target alignment size
> >
> > In my case m68k aligns "int" on 2 not 4. You can check this with the
> > following program:
> >
> > int main(void)
> > {
> > struct rtentry rt;
> > printf("rt_pad1 %ld %zd\n", offsetof(struct rtentry, rt_pad1),
> > sizeof(rt.rt_pad1));
> > printf("rt_dst %ld %zd\n", offsetof(struct rtentry, rt_dst),
> > sizeof(rt.rt_dst));
> > printf("rt_gateway %ld %zd\n", offsetof(struct rtentry, rt_gateway),
> > sizeof(rt.rt_gateway));
> > printf("rt_genmask %ld %zd\n", offsetof(struct rtentry, rt_genmask),
> > sizeof(rt.rt_genmask));
> > printf("rt_flags %ld %zd\n", offsetof(struct rtentry, rt_flags),
> > sizeof(rt.rt_flags));
> > printf("rt_pad2 %ld %zd\n", offsetof(struct rtentry, rt_pad2),
> > sizeof(rt.rt_pad2));
> > printf("rt_pad3 %ld %zd\n", offsetof(struct rtentry, rt_pad3),
> > sizeof(rt.rt_pad3));
> > printf("rt_pad4 %ld %zd\n", offsetof(struct rtentry, rt_pad4),
> > sizeof(rt.rt_pad4));
> > printf("rt_metric %ld %zd\n", offsetof(struct rtentry, rt_metric),
> > sizeof(rt.rt_metric));
> > printf("rt_dev %ld %zd\n", offsetof(struct rtentry, rt_dev),
> > sizeof(rt.rt_dev));
> > printf("rt_mtu %ld %zd\n", offsetof(struct rtentry, rt_mtu),
> > sizeof(rt.rt_mtu));
> > printf("rt_window %ld %zd\n", offsetof(struct rtentry, rt_window),
> > sizeof(rt.rt_window));
> > printf("rt_irtt %ld %zd\n", offsetof(struct rtentry, rt_irtt),
> > sizeof(rt.rt_irtt));
> > }
> >
> > And result is :
> >
> > i386
> >
> > rt_pad1 0 4
> > rt_dst 4 16
> > rt_gateway 20 16
> > rt_genmask 36 16
> > rt_flags 52 2
> > rt_pad2 54 2
> > rt_pad3 56 4
> > rt_pad4 62 2
> > rt_metric 64 2
> > rt_dev 68 4
> > rt_mtu 72 4
> > rt_window 76 4
> > rt_irtt 80 2
> >
> > m68k
> >
> > rt_pad1 0 4
> > rt_dst 4 16
> > rt_gateway 20 16
> > rt_genmask 36 16
> > rt_flags 52 2
> > rt_pad2 54 2
> > rt_pad3 56 4
> > rt_pad4 62 2
> > rt_metric 64 2
> > rt_dev 66 4
> > rt_mtu 70 4
> > rt_window 74 4
> > rt_irtt 78 2
> >
> > This affects the "route" command :
> >
> > WITHOUT this patch:
> >
> > $ sudo route add -net default gw 10.0.3.1 window 1024 irtt 2 eth0
> > $ netstat -nr
> > Kernel IP routing table
> > Destination Gateway Genmask Flags MSS Window irtt
> > Iface
> > 0.0.0.0 10.0.3.1 0.0.0.0 UG 0 67108866 32768
> > eth0
> > 10.0.3.0 0.0.0.0 255.255.255.0 U 0 0 0
> > eth0
> >
> > WITH this patch:
> >
> > $ sudo route add -net default gw 10.0.3.1 window 1024 irtt 2 eth0
> > $ netstat -nr
> > Kernel IP routing table
> > Destination Gateway Genmask Flags MSS Window irtt
> > Iface
> > 0.0.0.0 10.0.3.1 0.0.0.0 UG 0 1024 2
> > eth0
> > 10.0.3.0 0.0.0.0 255.255.255.0 U 0 0 0
> > eth0
> >
> > Signed-off-by: Laurent Vivier <address@hidden>
> > ---
> > include/exec/user/thunk.h | 22 +++++++++++++++++-----
> > 1 file changed, 17 insertions(+), 5 deletions(-)
> >
> > diff --git a/include/exec/user/thunk.h b/include/exec/user/thunk.h
> > index 87025c3..d3e9f3d 100644
> > --- a/include/exec/user/thunk.h
> > +++ b/include/exec/user/thunk.h
> > @@ -151,20 +151,32 @@ static inline int thunk_type_align(const argtype
> > *type_ptr, int is_host)
> > case TYPE_CHAR:
> > return 1;
> > case TYPE_SHORT:
> > - return 2;
> > + if (is_host) {
> > + return __alignof__(short);
> > + } else {
> > + return TARGET_SHORT_ALIGNMENT;
> > + }
> > case TYPE_INT:
> > - return 4;
> > + if (is_host) {
> > + return __alignof__(int);
> > + } else {
> > + return TARGET_INT_ALIGNMENT;
> > + }
> > case TYPE_LONGLONG:
> > case TYPE_ULONGLONG:
> > - return 8;
> > + if (is_host) {
> > + return __alignof__(long long);
> > + } else {
> > + return TARGET_LLONG_ALIGNMENT;
> > + }
> > case TYPE_LONG:
> > case TYPE_ULONG:
> > case TYPE_PTRVOID:
> > case TYPE_PTR:
> > if (is_host) {
> > - return sizeof(void *);
> > + return __alignof__(long);
> > } else {
> > - return TARGET_ABI_BITS / 8;
> > + return TARGET_LONG_ALIGNMENT;
> > }
> > break;
> > case TYPE_OLDDEVT:
>
--
"Just play. Have fun. Enjoy the game."
- Michael Jordan
"Just play. Have fun. Enjoy the game."
- Michael Jordan