| Message ID | 1448275106-21493-1-git-send-email-laurent@vivier.eu |
|---|---|
| State | New |
| Headers | show |
On 11/23/2015 11:38 AM, Laurent Vivier wrote: > Signed-off-by: Laurent Vivier <laurent@vivier.eu> Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> This patch fixes crashes of qemu-sh4* on amd64 for me [1]. I also haven't seen any regressions ever since. Cheers, Adrian > [1] https://bugs.launchpad.net/ubuntu/+source/qemu-linaro/+bug/1254824
Ping ? Le 23/11/2015 11:38, Laurent Vivier a écrit : > To return from a signal, setup_frame() puts an instruction to > be executed in the stack. This sequence calls the syscall sigreturn(). > > The address of the instruction must be set in the PR register > to be executed. > > This patch fixes this: the current code sets the register to the address > of the instruction in the host address space (which can be 64bit whereas > PR is only 32bit), but the virtual CPU can't access this address space, > so we put in PR the address of the instruction in the guest address space. > > This patch also removes an useless variable (ret) in the modified functions. > > Signed-off-by: Laurent Vivier <laurent@vivier.eu> > --- > linux-user/signal.c | 16 ++++++---------- > 1 file changed, 6 insertions(+), 10 deletions(-) > > diff --git a/linux-user/signal.c b/linux-user/signal.c > index 55e5405..5e8f6d8 100644 > --- a/linux-user/signal.c > +++ b/linux-user/signal.c > @@ -3215,7 +3215,6 @@ static void setup_frame(int sig, struct target_sigaction *ka, > struct target_sigframe *frame; > abi_ulong frame_addr; > int i; > - int err = 0; > > frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame)); > if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) > @@ -3233,15 +3232,14 @@ static void setup_frame(int sig, struct target_sigaction *ka, > regs->pr = (unsigned long) ka->sa_restorer; > } else { > /* Generate return code (system call to sigreturn) */ > + abi_ulong retcode_addr = frame_addr + > + offsetof(struct target_sigframe, retcode); > __put_user(MOVW(2), &frame->retcode[0]); > __put_user(TRAP_NOARG, &frame->retcode[1]); > __put_user((TARGET_NR_sigreturn), &frame->retcode[2]); > - regs->pr = (unsigned long) frame->retcode; > + regs->pr = (unsigned long) retcode_addr; > } > > - if (err) > - goto give_sigsegv; > - > /* Set up registers for signal handler */ > regs->gregs[15] = frame_addr; > regs->gregs[4] = sig; /* Arg for signal handler */ > @@ -3264,7 +3262,6 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka, > struct target_rt_sigframe *frame; > abi_ulong frame_addr; > int i; > - int err = 0; > > frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame)); > if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) > @@ -3293,15 +3290,14 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka, > regs->pr = (unsigned long) ka->sa_restorer; > } else { > /* Generate return code (system call to sigreturn) */ > + abi_ulong retcode_addr = frame_addr + > + offsetof(struct target_rt_sigframe, retcode); > __put_user(MOVW(2), &frame->retcode[0]); > __put_user(TRAP_NOARG, &frame->retcode[1]); > __put_user((TARGET_NR_rt_sigreturn), &frame->retcode[2]); > - regs->pr = (unsigned long) frame->retcode; > + regs->pr = (unsigned long) retcode_addr; > } > > - if (err) > - goto give_sigsegv; > - > /* Set up registers for signal handler */ > regs->gregs[15] = frame_addr; > regs->gregs[4] = sig; /* Arg for signal handler */ >
Ping here as well: https://bugs.launchpad.net/qemu/+bug/1516408 Adrian On 12/18/2015 04:08 PM, Laurent Vivier wrote: > Ping ? > > Le 23/11/2015 11:38, Laurent Vivier a écrit : >> To return from a signal, setup_frame() puts an instruction to >> be executed in the stack. This sequence calls the syscall sigreturn(). >> >> The address of the instruction must be set in the PR register >> to be executed. >> >> This patch fixes this: the current code sets the register to the address >> of the instruction in the host address space (which can be 64bit whereas >> PR is only 32bit), but the virtual CPU can't access this address space, >> so we put in PR the address of the instruction in the guest address space. >> >> This patch also removes an useless variable (ret) in the modified functions. >> >> Signed-off-by: Laurent Vivier <laurent@vivier.eu> >> --- >> linux-user/signal.c | 16 ++++++---------- >> 1 file changed, 6 insertions(+), 10 deletions(-) >> >> diff --git a/linux-user/signal.c b/linux-user/signal.c >> index 55e5405..5e8f6d8 100644 >> --- a/linux-user/signal.c >> +++ b/linux-user/signal.c >> @@ -3215,7 +3215,6 @@ static void setup_frame(int sig, struct target_sigaction *ka, >> struct target_sigframe *frame; >> abi_ulong frame_addr; >> int i; >> - int err = 0; >> >> frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame)); >> if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) >> @@ -3233,15 +3232,14 @@ static void setup_frame(int sig, struct target_sigaction *ka, >> regs->pr = (unsigned long) ka->sa_restorer; >> } else { >> /* Generate return code (system call to sigreturn) */ >> + abi_ulong retcode_addr = frame_addr + >> + offsetof(struct target_sigframe, retcode); >> __put_user(MOVW(2), &frame->retcode[0]); >> __put_user(TRAP_NOARG, &frame->retcode[1]); >> __put_user((TARGET_NR_sigreturn), &frame->retcode[2]); >> - regs->pr = (unsigned long) frame->retcode; >> + regs->pr = (unsigned long) retcode_addr; >> } >> >> - if (err) >> - goto give_sigsegv; >> - >> /* Set up registers for signal handler */ >> regs->gregs[15] = frame_addr; >> regs->gregs[4] = sig; /* Arg for signal handler */ >> @@ -3264,7 +3262,6 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka, >> struct target_rt_sigframe *frame; >> abi_ulong frame_addr; >> int i; >> - int err = 0; >> >> frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame)); >> if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) >> @@ -3293,15 +3290,14 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka, >> regs->pr = (unsigned long) ka->sa_restorer; >> } else { >> /* Generate return code (system call to sigreturn) */ >> + abi_ulong retcode_addr = frame_addr + >> + offsetof(struct target_rt_sigframe, retcode); >> __put_user(MOVW(2), &frame->retcode[0]); >> __put_user(TRAP_NOARG, &frame->retcode[1]); >> __put_user((TARGET_NR_rt_sigreturn), &frame->retcode[2]); >> - regs->pr = (unsigned long) frame->retcode; >> + regs->pr = (unsigned long) retcode_addr; >> } >> >> - if (err) >> - goto give_sigsegv; >> - >> /* Set up registers for signal handler */ >> regs->gregs[15] = frame_addr; >> regs->gregs[4] = sig; /* Arg for signal handler */ >>
diff --git a/linux-user/signal.c b/linux-user/signal.c index 55e5405..5e8f6d8 100644 --- a/linux-user/signal.c +++ b/linux-user/signal.c @@ -3215,7 +3215,6 @@ static void setup_frame(int sig, struct target_sigaction *ka, struct target_sigframe *frame; abi_ulong frame_addr; int i; - int err = 0; frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame)); if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) @@ -3233,15 +3232,14 @@ static void setup_frame(int sig, struct target_sigaction *ka, regs->pr = (unsigned long) ka->sa_restorer; } else { /* Generate return code (system call to sigreturn) */ + abi_ulong retcode_addr = frame_addr + + offsetof(struct target_sigframe, retcode); __put_user(MOVW(2), &frame->retcode[0]); __put_user(TRAP_NOARG, &frame->retcode[1]); __put_user((TARGET_NR_sigreturn), &frame->retcode[2]); - regs->pr = (unsigned long) frame->retcode; + regs->pr = (unsigned long) retcode_addr; } - if (err) - goto give_sigsegv; - /* Set up registers for signal handler */ regs->gregs[15] = frame_addr; regs->gregs[4] = sig; /* Arg for signal handler */ @@ -3264,7 +3262,6 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka, struct target_rt_sigframe *frame; abi_ulong frame_addr; int i; - int err = 0; frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame)); if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) @@ -3293,15 +3290,14 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka, regs->pr = (unsigned long) ka->sa_restorer; } else { /* Generate return code (system call to sigreturn) */ + abi_ulong retcode_addr = frame_addr + + offsetof(struct target_rt_sigframe, retcode); __put_user(MOVW(2), &frame->retcode[0]); __put_user(TRAP_NOARG, &frame->retcode[1]); __put_user((TARGET_NR_rt_sigreturn), &frame->retcode[2]); - regs->pr = (unsigned long) frame->retcode; + regs->pr = (unsigned long) retcode_addr; } - if (err) - goto give_sigsegv; - /* Set up registers for signal handler */ regs->gregs[15] = frame_addr; regs->gregs[4] = sig; /* Arg for signal handler */
To return from a signal, setup_frame() puts an instruction to be executed in the stack. This sequence calls the syscall sigreturn(). The address of the instruction must be set in the PR register to be executed. This patch fixes this: the current code sets the register to the address of the instruction in the host address space (which can be 64bit whereas PR is only 32bit), but the virtual CPU can't access this address space, so we put in PR the address of the instruction in the guest address space. This patch also removes an useless variable (ret) in the modified functions. Signed-off-by: Laurent Vivier <laurent@vivier.eu> --- linux-user/signal.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-)