Re: [LTP] [RFC PATCH 1/3] ARM64: ILP32: modify struct kernel_sigaction

[Jan Stancek <jstancek@redhat.com>]

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On 03/19/2015 12:33 PM, Jan Stancek wrote:
> 
> 
> 
> 
> ----- Original Message -----
>> From: "Zhang Jian(Bamvor)" <bamvor.zhangjian@huawei.com>
>> To: ltp-list@lists.sourceforge.net
>> Cc: "bintian wang" <bintian.wang@huawei.com>, yangyingliang@huawei.com, apinski@cavium.com, dingtianhong@huawei.com
>> Sent: Thursday, 19 March, 2015 6:16:36 AM
>> Subject: [LTP] [RFC PATCH 1/3] ARM64: ILP32: modify struct kernel_sigaction
>>
>> From: Yang Yingliang <yangyingliang@huawei.com>
>>
>> In ILP32, the sigaction struct is the same as AARCH64.
>> To allow for this to work, we use a long long fields and
>> then add extra casts when converting between the user
>> exposed struct and the kernel exposed struct.
>> The modify is came from a patch of glibc,
>> the commit is 9266f4b060f6("Add kernel_sigaction.h for AARCH64 ILP32").
>>
>> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
>> ---
>>  include/lapi/rt_sigaction.h | 12 ++++++------
>>  1 file changed, 6 insertions(+), 6 deletions(-)
>>
>> diff --git a/include/lapi/rt_sigaction.h b/include/lapi/rt_sigaction.h
>> index 46f6a50..2b1365a 100644
>> --- a/include/lapi/rt_sigaction.h
>> +++ b/include/lapi/rt_sigaction.h
>> @@ -34,9 +34,9 @@
>>  #define INVAL_SA_PTR ((void *)-1)
>>  
>>  struct kernel_sigaction {
>> -	__sighandler_t k_sa_handler;
>> -	unsigned long sa_flags;
>> -	void (*sa_restorer) (void);
>> +	unsigned long long k_sa_handler;
>> +	unsigned long long sa_flags;
>> +	unsigned long long sa_restorer;
> 
> Isn't this going to break i386? (long is 4, long long is 8).

Hi,

Attached is a testcase I put together to check how it behaves.
It's expected that signal handler will run on alternate stack and
testcase will print "frame_addr is within my_stack: 1"

# uname -m
i686

LTP HEAD:
# ./rt_sigaction04
my_stack: 0x0804d260 frame_addr: 0x0844cd08
frame_addr is within my_stack: 1

LTP HEAD + patch that changes kernel_sigaction to long long
# ./rt_sigaction04
my_stack: 0x0804d260 frame_addr: 0xbfda5068
frame_addr is within my_stack: 0

Regards,
Jan


[-- Attachment #2: rt_sigaction04.c --]
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#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <inttypes.h>
#include <errno.h>
#include <sys/syscall.h>
#include <string.h>

#include "test.h"
#include "linux_syscall_numbers.h"
#include "lapi/rt_sigaction.h"

char *TCID = "rt_sigaction01";
int TST_TOTAL = 1;

static char my_stack[4*1024*1024];

static void handler(int sig)
{
	(void) sig;
	uintptr_t frame_addr = (uintptr_t) __builtin_frame_address(0);
	uintptr_t stack_addr = (uintptr_t) &my_stack;
	uintptr_t stack_last = stack_addr + sizeof(my_stack);
	printf("my_stack: 0x%08"PRIxPTR " frame_addr: 0x%08"PRIxPTR "\n",
		stack_addr, frame_addr);
	printf("frame_addr is within my_stack: %d\n",
		(frame_addr > stack_addr && frame_addr < stack_last));
}

static int set_handler(int sig, int sig_to_mask, int mask_flags)
{
	struct sigaction sa, oldaction;

	(void) sig_to_mask;

	sa.sa_handler = (void *)handler;
	sa.sa_flags = mask_flags;
	sigemptyset(&sa.sa_mask);
	sigaddset(&sa.sa_mask, sig);

	ltp_rt_sigaction(sig, &sa, &oldaction, SIGSETSIZE);
	return 0;
}


int main(int ac, char **av)
{
	const char *msg;

	msg = parse_opts(ac, av, NULL, NULL);
	if (msg != NULL)
		tst_brkm(TBROK, NULL, "OPTION PARSING ERROR - %s", msg);

	stack_t stack = {
		.ss_sp = (void *)my_stack,
		.ss_flags = 0,
		.ss_size = sizeof(my_stack)
	};

	sigaltstack(&stack, NULL);
	set_handler(SIGRTMIN, 0, SA_ONSTACK);
	kill(getpid(), SIGRTMIN);

	tst_exit();
}

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