| Message ID | 20210324155530.52239-1-krebbel@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] linux-user/s390x: Use the guest pointer for the sigreturn stub | expand |
Le 24/03/2021 à 16:55, Andreas Krebbel a écrit : > When setting up the pointer for the sigreturn stub in the return > address register (r14) we have to use the guest frame pointer instead > of the host frame pointer. > > Note: This only caused problems if Qemu has been built with > --disable-pie (as it is in distros nowadays). Otherwise guest_base > defaults to 0 hiding the actual problem. > > Signed-off-by: Andreas Krebbel <krebbel@linux.ibm.com> > --- > linux-user/s390x/signal.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/linux-user/s390x/signal.c b/linux-user/s390x/signal.c > index ecfa2a14a9..e9bf865074 100644 > --- a/linux-user/s390x/signal.c > +++ b/linux-user/s390x/signal.c > @@ -213,7 +213,8 @@ void setup_rt_frame(int sig, struct target_sigaction *ka, > if (ka->sa_flags & TARGET_SA_RESTORER) { > env->regs[14] = (unsigned long) ka->sa_restorer | PSW_ADDR_AMODE; > } else { > - env->regs[14] = (unsigned long) frame->retcode | PSW_ADDR_AMODE; > + env->regs[14] = (target_ulong) (frame_addr + offsetof(rt_sigframe, retcode)) > + | PSW_ADDR_AMODE; > __put_user(S390_SYSCALL_OPCODE | TARGET_NR_rt_sigreturn, > (uint16_t *)(frame->retcode)); > } > Reviewed-by: Laurent Vivier <laurent@vivier.eu> but if you want to send a v3: - to be consistent with lines below, use "offsetof(typeof(*frame), ..." - in the line above, you can remove the (unsigned long) of the sa_restorer as it is an abi_ulong, - don't send the "v2" as a reply to the v1 as it can be hidden in the mail thread and missed by the maintainer :) Thanks, Laurent
On 3/24/21 6:53 PM, Laurent Vivier wrote: > Le 24/03/2021 à 16:55, Andreas Krebbel a écrit : >> When setting up the pointer for the sigreturn stub in the return >> address register (r14) we have to use the guest frame pointer instead >> of the host frame pointer. >> >> Note: This only caused problems if Qemu has been built with >> --disable-pie (as it is in distros nowadays). Otherwise guest_base >> defaults to 0 hiding the actual problem. >> >> Signed-off-by: Andreas Krebbel <krebbel@linux.ibm.com> >> --- >> linux-user/s390x/signal.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/linux-user/s390x/signal.c b/linux-user/s390x/signal.c >> index ecfa2a14a9..e9bf865074 100644 >> --- a/linux-user/s390x/signal.c >> +++ b/linux-user/s390x/signal.c >> @@ -213,7 +213,8 @@ void setup_rt_frame(int sig, struct target_sigaction *ka, >> if (ka->sa_flags & TARGET_SA_RESTORER) { >> env->regs[14] = (unsigned long) ka->sa_restorer | PSW_ADDR_AMODE; >> } else { >> - env->regs[14] = (unsigned long) frame->retcode | PSW_ADDR_AMODE; >> + env->regs[14] = (target_ulong) (frame_addr + offsetof(rt_sigframe, retcode)) >> + | PSW_ADDR_AMODE; >> __put_user(S390_SYSCALL_OPCODE | TARGET_NR_rt_sigreturn, >> (uint16_t *)(frame->retcode)); >> } >> > > Reviewed-by: Laurent Vivier <laurent@vivier.eu> > > but if you want to send a v3: Sure, will do. > - to be consistent with lines below, use "offsetof(typeof(*frame), ..." > - in the line above, you can remove the (unsigned long) of the sa_restorer as it is an abi_ulong, The (target_ulong) cast could probably go away as well since frame_addr is also abi_ulong. > - don't send the "v2" as a reply to the v1 as it can be hidden in the mail thread and missed by the > maintainer :) Ok. Andreas > > Thanks, > Laurent >
diff --git a/linux-user/s390x/signal.c b/linux-user/s390x/signal.c index ecfa2a14a9..e9bf865074 100644 --- a/linux-user/s390x/signal.c +++ b/linux-user/s390x/signal.c @@ -213,7 +213,8 @@ void setup_rt_frame(int sig, struct target_sigaction *ka, if (ka->sa_flags & TARGET_SA_RESTORER) { env->regs[14] = (unsigned long) ka->sa_restorer | PSW_ADDR_AMODE; } else { - env->regs[14] = (unsigned long) frame->retcode | PSW_ADDR_AMODE; + env->regs[14] = (target_ulong) (frame_addr + offsetof(rt_sigframe, retcode)) + | PSW_ADDR_AMODE; __put_user(S390_SYSCALL_OPCODE | TARGET_NR_rt_sigreturn, (uint16_t *)(frame->retcode)); }
When setting up the pointer for the sigreturn stub in the return address register (r14) we have to use the guest frame pointer instead of the host frame pointer. Note: This only caused problems if Qemu has been built with --disable-pie (as it is in distros nowadays). Otherwise guest_base defaults to 0 hiding the actual problem. Signed-off-by: Andreas Krebbel <krebbel@linux.ibm.com> --- linux-user/s390x/signal.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)