Update AArch64 strace to also support tracing 32-bit ARM binaries

[Steve McIntyre]

On Tue, Feb 05, 2013 at 05:02:34PM +0100, Denys Vlasenko wrote:
>> @@ -1655,16 +1681,31 @@ get_syscall_result(struct tcb *tcp)
>>  		return -1;
>>  	if (upeek(tcp, PT_R10, &r10) < 0)
>>  		return -1;
>> -#elif defined(ARM)
>> -	/* Read complete register set in one go. */
>> -	if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, (void *)&regs) == -1)
>> -		return -1;
>>  #elif defined(AARCH64)
>>  	struct iovec io;
>> -	io.iov_base = ®s;
>> -	io.iov_len = sizeof(regs);
>> +	char buf[sizeof(aarch64_regs)];
>> +	io.iov_base = &buf;
>> +	io.iov_len = sizeof(aarch64_regs);
>>  	if (ptrace(PTRACE_GETREGSET, tcp->pid, NT_PRSTATUS, (void *)&io) == -1)
>>  		return -1;
>> +	switch (io.iov_len) {
>> +		case sizeof(aarch64_regs):
>> +			/* We are in 64-bit mode */		
>> +			memcpy(&aarch64_regs, buf, sizeof(aarch64_regs));
>> +			update_personality(tcp, 1);
>> +			break;
>> +		case sizeof(regs):
>> +			/* We are in 32-bit mode */		
>> +			memcpy(&regs, buf, sizeof(regs));
>> +			update_personality(tcp, 0);
>> +			break;
>> +		default:
>> +			return -1;
>> +	}
>
>No other architecture calls update_personality() on syscall exit
>(get_syscall_result() is called, naturally, only on exit).
>
>I think these update_personality() calls can be safely removed.

Hmmm, maybe. I've possibly got a belt-and-braces solution there. It
made sense to me at the time, but that was quite a while ago now. :-)

Cheers,
-- 
Steve McIntyre                                steve.mcintyre at linaro.org
<http://www.linaro.org/> Linaro.org | Open source software for ARM SoCs