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

From: Michael Ellerman <[email-masked]>
Date: Tue, 24 Aug 2021 22:48:17 +1000

Ganesh Goudar <[email-masked]> 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?

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");
+}