Re: [Qemu-devel] [PATCH 29/43] linux-user: Fix broken m68k signal handling on 64 bit hosts

[Laurent Vivier]

Hi,

 

I think you should use abi_long instead of  uint32_t.

 

abi_long has an "aligned" attribute, and on m68k long are aligned on a short boundary.

 

#ifdef TARGET_M68K
#define ABI_INT_ALIGNMENT 2
#define ABI_LONG_ALIGNMENT 2
#define ABI_LLONG_ALIGNMENT 2
#endif

typedef uint32_t abi_ulong __attribute__((aligned(ABI_LONG_ALIGNMENT)));

Regards,

Laurent

> Le 24 février 2015 à 22:48, Michael Roth <address@hidden> a écrit :
>
>
> From: Peter Maydell <address@hidden>
>
> The m68k signal frame setup code which writes the signal return
> trampoline code to the stack was assuming that a 'long' was 32 bits;
> on 64 bit systems this meant we would end up writing the 32 bit
> (2 insn) trampoline sequence to retaddr+4,retaddr+6 instead of
> the intended retaddr+0,retaddr+2, resulting in a guest crash when
> it tried to execute the invalid zero-bytes at retaddr+0.
> Fix by using uint32_t instead; also use uint16_t rather than short
> for consistency. This fixes bug LP:1404690.
>
> Reported-by: Michel Boaventura
> Signed-off-by: Peter Maydell <address@hidden>
> Signed-off-by: Riku Voipio <address@hidden>
> (cherry picked from commit 1669add752d9f29283f8ebf6a863d7b1e2d0f146)
> Signed-off-by: Michael Roth <address@hidden>
> ---
> linux-user/signal.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/linux-user/signal.c b/linux-user/signal.c
> index e11b208..a324fd1 100644
> --- a/linux-user/signal.c
> +++ b/linux-user/signal.c
> @@ -5091,7 +5091,7 @@ static void setup_frame(int sig, struct target_sigaction *ka,
> /* moveq #,d0; trap #0 */
>
> __put_user(0x70004e40 + (TARGET_NR_sigreturn << 16),
> - (long *)(frame->retcode));
> + (uint32_t *)(frame->retcode));
>
> /* Set up to return from userspace */
>
> @@ -5225,8 +5225,8 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka,
> /* moveq #,d0; notb d0; trap #0 */
>
> __put_user(0x70004600 + ((TARGET_NR_rt_sigreturn ^ 0xff) << 16),
> - (long *)(frame->retcode + 0));
> - __put_user(0x4e40, (short *)(frame->retcode + 4));
> + (uint32_t *)(frame->retcode + 0));
> + __put_user(0x4e40, (uint16_t *)(frame->retcode + 4));
>
> if (err)
> goto give_sigsegv;
> --
> 1.9.1
>
>