The function do_sigreturn() tries to store the PC, NPC and PSR in
uint32_t local variables, which implicitly drops the high half of
these fields for 64-bit guests.

The usual effect was that a guest which used signals would crash on
return from a signal unless it was lucky enough to take it while the
PC was in the low 4GB of the address space.  In particular, Debian
/bin/dash and /bin/bash would segfault after executing external
commands.

Use abi_ulong, which is the type these fields all have in the
__siginfo_t struct.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 linux-user/sparc/signal.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/linux-user/sparc/signal.c b/linux-user/sparc/signal.c
index c315704b389..d12adc8e6ff 100644
--- a/linux-user/sparc/signal.c
+++ b/linux-user/sparc/signal.c
@@ -247,7 +247,7 @@ long do_sigreturn(CPUSPARCState *env)
 {
     abi_ulong sf_addr;
     struct target_signal_frame *sf;
-    uint32_t up_psr, pc, npc;
+    abi_ulong up_psr, pc, npc;
     target_sigset_t set;
     sigset_t host_set;
     int i;
-- 
2.20.1

On 11/5/20 1:23 PM, Peter Maydell wrote:
> The function do_sigreturn() tries to store the PC, NPC and PSR in
> uint32_t local variables, which implicitly drops the high half of
> these fields for 64-bit guests.
> 
> The usual effect was that a guest which used signals would crash on
> return from a signal unless it was lucky enough to take it while the
> PC was in the low 4GB of the address space.  In particular, Debian
> /bin/dash and /bin/bash would segfault after executing external
> commands.
> 
> Use abi_ulong, which is the type these fields all have in the
> __siginfo_t struct.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  linux-user/sparc/signal.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~

Le 05/11/2020 à 22:23, Peter Maydell a écrit :
> The function do_sigreturn() tries to store the PC, NPC and PSR in
> uint32_t local variables, which implicitly drops the high half of
> these fields for 64-bit guests.
> 
> The usual effect was that a guest which used signals would crash on
> return from a signal unless it was lucky enough to take it while the
> PC was in the low 4GB of the address space.  In particular, Debian
> /bin/dash and /bin/bash would segfault after executing external
> commands.
> 
> Use abi_ulong, which is the type these fields all have in the
> __siginfo_t struct.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  linux-user/sparc/signal.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/linux-user/sparc/signal.c b/linux-user/sparc/signal.c
> index c315704b389..d12adc8e6ff 100644
> --- a/linux-user/sparc/signal.c
> +++ b/linux-user/sparc/signal.c
> @@ -247,7 +247,7 @@ long do_sigreturn(CPUSPARCState *env)
>  {
>      abi_ulong sf_addr;
>      struct target_signal_frame *sf;
> -    uint32_t up_psr, pc, npc;
> +    abi_ulong up_psr, pc, npc;
>      target_sigset_t set;
>      sigset_t host_set;
>      int i;
> 

Applied to my linux-user-for-5.2 branch.

Thanks,
Laurent