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Re: [Qemu-devel] [PATCH] linux-user, sh4: fix signal retcode address
From: |
John Paul Adrian Glaubitz |
Subject: |
Re: [Qemu-devel] [PATCH] linux-user, sh4: fix signal retcode address |
Date: |
Sat, 19 Dec 2015 11:23:23 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:42.0) Gecko/20100101 Icedove/42.0 |
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 <address@hidden>
>> ---
>> 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 */
>>
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer - address@hidden
`. `' Freie Universitaet Berlin - address@hidden
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913