Re: [PATCH v2 2/3] selftests/powerpc: Add test for real address error handling

[Ganesh <ganeshgr@linux.ibm.com>]

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On 8/24/21 6:18 PM, Michael Ellerman wrote:

> Ganesh Goudar <ganeshgr@linux.ibm.com> writes:
>> Add test for real address or control memory address access
>> error handling, using NX-GZIP engine.
>>
>> The error is injected by accessing the control memory address
>> using illegal instruction, on successful handling the process
>> attempting to access control memory address using illegal
>> instruction receives SIGBUS.
> ...
>
>> diff --git a/tools/testing/selftests/powerpc/mce/inject-ra-err.sh b/tools/testing/selftests/powerpc/mce/inject-ra-err.sh
>> new file mode 100755
>> index 000000000000..3633cdc651a1
>> --- /dev/null
>> +++ b/tools/testing/selftests/powerpc/mce/inject-ra-err.sh
>> @@ -0,0 +1,18 @@
>> +#!/bin/bash
>> +# SPDX-License-Identifier: GPL-2.0-or-later
>> +
>> +if [[ ! -w /dev/crypto/nx-gzip ]]; then
>> +	echo "WARN: Can't access /dev/crypto/nx-gzip, skipping"
>> +	exit 0
>> +fi
>> +
>> +timeout 5 ./inject-ra-err
>> +
>> +# 128 + 7 (SIGBUS) = 135, 128 is a exit code with special meaning.
>> +if [ $? -ne 135 ]; then
>> +	echo "FAILED: Real address or Control memory access error not handled"
>> +	exit $?
>> +fi
>> +
>> +echo "OK: Real address or Control memory access error is handled"
>> +exit 0
> I don't think we really need the shell script, we should be able to do
> all that in the C code.
>
> Can you try this?

it works!, We need to set timeout, with 120 sec timeout we may flood the dmesg.
Thanks.

>
> cheers
>
> diff --git a/tools/testing/selftests/powerpc/mce/Makefile b/tools/testing/selftests/powerpc/mce/Makefile
> new file mode 100644
> index 000000000000..2424513982d9
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/mce/Makefile
> @@ -0,0 +1,7 @@
> +#SPDX-License-Identifier: GPL-2.0-or-later
> +
> +TEST_GEN_PROGS := inject-ra-err
> +
> +include ../../lib.mk
> +
> +$(TEST_GEN_PROGS): ../harness.c
> diff --git a/tools/testing/selftests/powerpc/mce/inject-ra-err.c b/tools/testing/selftests/powerpc/mce/inject-ra-err.c
> new file mode 100644
> index 000000000000..ba0f9c28f786
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/mce/inject-ra-err.c
> @@ -0,0 +1,64 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <signal.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <sys/ioctl.h>
> +#include <sys/mman.h>
> +#include <sys/stat.h>
> +#include <sys/types.h>
> +#include <unistd.h>
> +
> +#include "vas-api.h"
> +#include "utils.h"
> +
> +static bool faulted;
> +
> +static void sigbus_handler(int n, siginfo_t *info, void *ctxt_v)
> +{
> +	ucontext_t *ctxt = (ucontext_t *)ctxt_v;
> +	struct pt_regs *regs = ctxt->uc_mcontext.regs;
> +
> +	faulted = true;
> +	regs->nip += 4;
> +}
> +
> +static int test_ra_error(void)
> +{
> +	struct vas_tx_win_open_attr attr;
> +	int fd, *paste_addr;
> +	char *devname = "/dev/crypto/nx-gzip";
> +	struct sigaction act = {
> +		.sa_sigaction = sigbus_handler,
> +		.sa_flags = SA_SIGINFO,
> +	};
> +
> +	memset(&attr, 0, sizeof(attr));
> +	attr.version = 1;
> +	attr.vas_id = 0;
> +
> +	SKIP_IF(!access(devname, F_OK));
> +
> +	fd = open(devname, O_RDWR);
> +	FAIL_IF(fd < 0);
> +	FAIL_IF(ioctl(fd, VAS_TX_WIN_OPEN, &attr) < 0);
> +	FAIL_IF(sigaction(SIGBUS, &act, NULL) != 0);
> +
> +	paste_addr = mmap(NULL, 4096, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0ULL);
> +
> +	/* The following assignment triggers exception */
> +	mb();
> +	*paste_addr = 1;
> +	mb();
> +
> +	FAIL_IF(!faulted);
> +
> +	return 0;
> +}
> +
> +int main(void)
> +{
> +	return test_harness(test_ra_error, "inject-ra-err");
> +}

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