[PATCH 00/11] kselftest/arm64: mte: Fix feature detection and compilation

[PATCH 00/11] kselftest/arm64: mte: Fix feature detection and compilation

[Andre Przywara]

When trying to run the arm64 MTE (Memory Tagging Extension) selftests
on a model with the new FEAT_MTE3 capability, the MTE feature detection
failed, because it was overzealously checking for one exact feature
version only (0b0010). Trying to fix that (patch 06/11) led me into the
rabbit hole of userland tool compilation, which triggered patches
01-05/11, to let me actually compile the selftests on an arm64
machine running Ubuntu 20.04. Before I actually fixed that, I tried some
other compiler and distro; patches 07 and 08 are my witnesses.
Then I got brave and tried clang: entering patches 09/11 and 10/11.
Eventually I tried to run the whole thing on that model again, and,
you guessed it, patch 11/11 concludes this apparent "2 minute job".

Eventually I can now compile the mte selftests on Ubuntu 20.04 with both
the native gcc and clang without warnings, also with some custom made
cross compiler. And they even run now!

Please have a look, also you may try to compile it on your setup, if you
feel adventurous:
$ make -C tools/testing/selftests TARGETS=arm64 ARM64_SUBTARGETS=mte

Cheers,
Andre

Andre Przywara (11):
  kselftest/arm64: mte: Fix compilation with native compiler
  kselftest/arm64: mte: Fix pthread linking
  kselftest/arm64: mte: ksm_options: Fix fscanf warning
  kselftest/arm64: mte: user_mem: Fix write() warning
  kselftest/arm64: mte: common: Fix write() warnings
  kselftest/arm64: mte: Fix MTE feature detection
  kselftest/arm64: mte: Use cross-compiler if specified
  kselftest/arm64: mte: Output warning about failing compiler
  kselftest/arm64: mte: Makefile: Fix clang compilation
  kselftest/arm64: mte: Fix clang warning
  kselftest/arm64: mte: Report filename on failing temp file creation

 tools/testing/selftests/arm64/mte/Makefile    | 15 +++++--
 .../selftests/arm64/mte/check_ksm_options.c   |  5 ++-
 .../selftests/arm64/mte/check_user_mem.c      |  3 +-
 .../selftests/arm64/mte/mte_common_util.c     | 39 +++++++++++--------
 4 files changed, 39 insertions(+), 23 deletions(-)

-- 
2.17.5

[PATCH 00/11] kselftest/arm64: mte: Fix feature detection and compilation

[Andre Przywara]

When trying to run the arm64 MTE (Memory Tagging Extension) selftests
on a model with the new FEAT_MTE3 capability, the MTE feature detection
failed, because it was overzealously checking for one exact feature
version only (0b0010). Trying to fix that (patch 06/11) led me into the
rabbit hole of userland tool compilation, which triggered patches
01-05/11, to let me actually compile the selftests on an arm64
machine running Ubuntu 20.04. Before I actually fixed that, I tried some
other compiler and distro; patches 07 and 08 are my witnesses.
Then I got brave and tried clang: entering patches 09/11 and 10/11.
Eventually I tried to run the whole thing on that model again, and,
you guessed it, patch 11/11 concludes this apparent "2 minute job".

Eventually I can now compile the mte selftests on Ubuntu 20.04 with both
the native gcc and clang without warnings, also with some custom made
cross compiler. And they even run now!

Please have a look, also you may try to compile it on your setup, if you
feel adventurous:
$ make -C tools/testing/selftests TARGETS=arm64 ARM64_SUBTARGETS=mte

Cheers,
Andre

Andre Przywara (11):
  kselftest/arm64: mte: Fix compilation with native compiler
  kselftest/arm64: mte: Fix pthread linking
  kselftest/arm64: mte: ksm_options: Fix fscanf warning
  kselftest/arm64: mte: user_mem: Fix write() warning
  kselftest/arm64: mte: common: Fix write() warnings
  kselftest/arm64: mte: Fix MTE feature detection
  kselftest/arm64: mte: Use cross-compiler if specified
  kselftest/arm64: mte: Output warning about failing compiler
  kselftest/arm64: mte: Makefile: Fix clang compilation
  kselftest/arm64: mte: Fix clang warning
  kselftest/arm64: mte: Report filename on failing temp file creation

 tools/testing/selftests/arm64/mte/Makefile    | 15 +++++--
 .../selftests/arm64/mte/check_ksm_options.c   |  5 ++-
 .../selftests/arm64/mte/check_user_mem.c      |  3 +-
 .../selftests/arm64/mte/mte_common_util.c     | 39 +++++++++++--------
 4 files changed, 39 insertions(+), 23 deletions(-)

-- 
2.17.5


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[PATCH 01/11] kselftest/arm64: mte: Fix compilation with native compiler

[Andre Przywara]

The mte selftest Makefile contains a check for GCC, to add the memtag
-march flag to the compiler options. This check fails if the compiler
is not explicitly specified, so reverts to the standard "cc", in which
case --version doesn't mention the "gcc" string we match against:
$ cc --version | head -n 1
cc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0

This will not add the -march switch to the command line, so compilation
fails:
mte_helper.S: Assembler messages:
mte_helper.S:25: Error: selected processor does not support `irg x0,x0,xzr'
mte_helper.S:38: Error: selected processor does not support `gmi x1,x0,xzr'
...

Actually clang accepts the same -march option as well, so we can just
drop this check and add this unconditionally to the command line, to avoid
any future issues with this check altogether (gcc actually prints
basename(argv[0]) when called with --version).

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/Makefile | 2 --
 1 file changed, 2 deletions(-)

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index 0b3af552632a..df15d44aeb8d 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -6,9 +6,7 @@ SRCS := $(filter-out mte_common_util.c,$(wildcard *.c))
 PROGS := $(patsubst %.c,%,$(SRCS))
 
 #Add mte compiler option
-ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep gcc),)
 CFLAGS += -march=armv8.5-a+memtag
-endif
 
 #check if the compiler works well
 mte_cc_support := $(shell if ($(CC) $(CFLAGS) -E -x c /dev/null -o /dev/null 2>&1) then echo "1"; fi)
-- 
2.17.5

[PATCH 01/11] kselftest/arm64: mte: Fix compilation with native compiler

[Andre Przywara]

The mte selftest Makefile contains a check for GCC, to add the memtag
-march flag to the compiler options. This check fails if the compiler
is not explicitly specified, so reverts to the standard "cc", in which
case --version doesn't mention the "gcc" string we match against:
$ cc --version | head -n 1
cc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0

This will not add the -march switch to the command line, so compilation
fails:
mte_helper.S: Assembler messages:
mte_helper.S:25: Error: selected processor does not support `irg x0,x0,xzr'
mte_helper.S:38: Error: selected processor does not support `gmi x1,x0,xzr'
...

Actually clang accepts the same -march option as well, so we can just
drop this check and add this unconditionally to the command line, to avoid
any future issues with this check altogether (gcc actually prints
basename(argv[0]) when called with --version).

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/Makefile | 2 --
 1 file changed, 2 deletions(-)

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index 0b3af552632a..df15d44aeb8d 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -6,9 +6,7 @@ SRCS := $(filter-out mte_common_util.c,$(wildcard *.c))
 PROGS := $(patsubst %.c,%,$(SRCS))
 
 #Add mte compiler option
-ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep gcc),)
 CFLAGS += -march=armv8.5-a+memtag
-endif
 
 #check if the compiler works well
 mte_cc_support := $(shell if ($(CC) $(CFLAGS) -E -x c /dev/null -o /dev/null 2>&1) then echo "1"; fi)
-- 
2.17.5


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[PATCH 02/11] kselftest/arm64: mte: Fix pthread linking

[Andre Przywara]

The GCC manual suggests to use -pthread, when linking with the PThread
library, also to add this switch to both the compilation and linking
stages.

Do as the manual says, to fix compilation with Ubuntu's 20.04 toolchain,
which was getting -lpthread too early on the command line:
------------
/usr/bin/ld: /tmp/cc5zbo2A.o: in function `execute_test':
tools/testing/selftests/arm64/mte/check_gcr_el1_cswitch.c:86:
	undefined reference to `pthread_create'
/usr/bin/ld: tools/testing/selftests/arm64/mte/check_gcr_el1_cswitch.c:90:
	undefined reference to `pthread_join'
------------

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index df15d44aeb8d..90aadd86fa0d 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -1,7 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
 # Copyright (C) 2020 ARM Limited
 
-CFLAGS += -std=gnu99 -I. -lpthread
+CFLAGS += -std=gnu99 -I. -pthread
+LDFLAGS += -pthread
 SRCS := $(filter-out mte_common_util.c,$(wildcard *.c))
 PROGS := $(patsubst %.c,%,$(SRCS))
 
-- 
2.17.5

[PATCH 02/11] kselftest/arm64: mte: Fix pthread linking

[Andre Przywara]

The GCC manual suggests to use -pthread, when linking with the PThread
library, also to add this switch to both the compilation and linking
stages.

Do as the manual says, to fix compilation with Ubuntu's 20.04 toolchain,
which was getting -lpthread too early on the command line:
------------
/usr/bin/ld: /tmp/cc5zbo2A.o: in function `execute_test':
tools/testing/selftests/arm64/mte/check_gcr_el1_cswitch.c:86:
	undefined reference to `pthread_create'
/usr/bin/ld: tools/testing/selftests/arm64/mte/check_gcr_el1_cswitch.c:90:
	undefined reference to `pthread_join'
------------

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index df15d44aeb8d..90aadd86fa0d 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -1,7 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
 # Copyright (C) 2020 ARM Limited
 
-CFLAGS += -std=gnu99 -I. -lpthread
+CFLAGS += -std=gnu99 -I. -pthread
+LDFLAGS += -pthread
 SRCS := $(filter-out mte_common_util.c,$(wildcard *.c))
 PROGS := $(patsubst %.c,%,$(SRCS))
 
-- 
2.17.5


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[PATCH 03/11] kselftest/arm64: mte: ksm_options: Fix fscanf warning

[Andre Przywara]

Out of the box Ubuntu's 20.04 compiler warns about missing return value
checks for fscanf() calls.

Make GCC happy by checking whether we actually parsed one integer.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/check_ksm_options.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/arm64/mte/check_ksm_options.c b/tools/testing/selftests/arm64/mte/check_ksm_options.c
index 3b23c4d61d38..88c74bc46d4f 100644
--- a/tools/testing/selftests/arm64/mte/check_ksm_options.c
+++ b/tools/testing/selftests/arm64/mte/check_ksm_options.c
@@ -33,7 +33,10 @@ static unsigned long read_sysfs(char *str)
 		ksft_print_msg("ERR: missing %s\n", str);
 		return 0;
 	}
-	fscanf(f, "%lu", &val);
+	if (fscanf(f, "%lu", &val) != 1) {
+		ksft_print_msg("ERR: parsing %s\n", str);
+		val = 0;
+	}
 	fclose(f);
 	return val;
 }
-- 
2.17.5

[PATCH 03/11] kselftest/arm64: mte: ksm_options: Fix fscanf warning

[Andre Przywara]

Out of the box Ubuntu's 20.04 compiler warns about missing return value
checks for fscanf() calls.

Make GCC happy by checking whether we actually parsed one integer.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/check_ksm_options.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/arm64/mte/check_ksm_options.c b/tools/testing/selftests/arm64/mte/check_ksm_options.c
index 3b23c4d61d38..88c74bc46d4f 100644
--- a/tools/testing/selftests/arm64/mte/check_ksm_options.c
+++ b/tools/testing/selftests/arm64/mte/check_ksm_options.c
@@ -33,7 +33,10 @@ static unsigned long read_sysfs(char *str)
 		ksft_print_msg("ERR: missing %s\n", str);
 		return 0;
 	}
-	fscanf(f, "%lu", &val);
+	if (fscanf(f, "%lu", &val) != 1) {
+		ksft_print_msg("ERR: parsing %s\n", str);
+		val = 0;
+	}
 	fclose(f);
 	return val;
 }
-- 
2.17.5


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[PATCH 04/11] kselftest/arm64: mte: user_mem: Fix write() warning

[Andre Przywara]

Out of the box Ubuntu's 20.04 compiler warns about missing return value
checks for write() (sys)calls.

Make GCC happy by checking whether we actually managed to write "val".

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/check_user_mem.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/arm64/mte/check_user_mem.c b/tools/testing/selftests/arm64/mte/check_user_mem.c
index 4bfa80f2a8c3..1de7a0abd0ae 100644
--- a/tools/testing/selftests/arm64/mte/check_user_mem.c
+++ b/tools/testing/selftests/arm64/mte/check_user_mem.c
@@ -33,7 +33,8 @@ static int check_usermem_access_fault(int mem_type, int mode, int mapping)
 	if (fd == -1)
 		return KSFT_FAIL;
 	for (i = 0; i < len; i++)
-		write(fd, &val, sizeof(val));
+		if (write(fd, &val, sizeof(val)) != sizeof(val))
+			return KSFT_FAIL;
 	lseek(fd, 0, 0);
 	ptr = mte_allocate_memory(len, mem_type, mapping, true);
 	if (check_allocated_memory(ptr, len, mem_type, true) != KSFT_PASS) {
-- 
2.17.5

[PATCH 04/11] kselftest/arm64: mte: user_mem: Fix write() warning

[Andre Przywara]

Out of the box Ubuntu's 20.04 compiler warns about missing return value
checks for write() (sys)calls.

Make GCC happy by checking whether we actually managed to write "val".

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/check_user_mem.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/arm64/mte/check_user_mem.c b/tools/testing/selftests/arm64/mte/check_user_mem.c
index 4bfa80f2a8c3..1de7a0abd0ae 100644
--- a/tools/testing/selftests/arm64/mte/check_user_mem.c
+++ b/tools/testing/selftests/arm64/mte/check_user_mem.c
@@ -33,7 +33,8 @@ static int check_usermem_access_fault(int mem_type, int mode, int mapping)
 	if (fd == -1)
 		return KSFT_FAIL;
 	for (i = 0; i < len; i++)
-		write(fd, &val, sizeof(val));
+		if (write(fd, &val, sizeof(val)) != sizeof(val))
+			return KSFT_FAIL;
 	lseek(fd, 0, 0);
 	ptr = mte_allocate_memory(len, mem_type, mapping, true);
 	if (check_allocated_memory(ptr, len, mem_type, true) != KSFT_PASS) {
-- 
2.17.5


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[PATCH 05/11] kselftest/arm64: mte: common: Fix write() warnings

[Andre Przywara]

Out of the box Ubuntu's 20.04 compiler warns about missing return value
checks for write() (sys)calls.

Make GCC happy by checking whether we actually managed to write out our
buffer.

Reviewed-by: Andre Przywara <andre.przywara@arm.com>
---
 .../selftests/arm64/mte/mte_common_util.c     | 23 +++++++++++++++----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
index 39f8908988ea..4e887dad762d 100644
--- a/tools/testing/selftests/arm64/mte/mte_common_util.c
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
@@ -181,10 +181,17 @@ void *mte_allocate_file_memory(size_t size, int mem_type, int mapping, bool tags
 	}
 	/* Initialize the file for mappable size */
 	lseek(fd, 0, SEEK_SET);
-	for (index = INIT_BUFFER_SIZE; index < size; index += INIT_BUFFER_SIZE)
-		write(fd, buffer, INIT_BUFFER_SIZE);
+	for (index = INIT_BUFFER_SIZE; index < size; index += INIT_BUFFER_SIZE) {
+		if (write(fd, buffer, INIT_BUFFER_SIZE) != INIT_BUFFER_SIZE) {
+			perror("initialising buffer");
+			return NULL;
+		}
+	}
 	index -= INIT_BUFFER_SIZE;
-	write(fd, buffer, size - index);
+	if (write(fd, buffer, size - index) != size - index) {
+		perror("initialising buffer");
+		return NULL;
+	}
 	return __mte_allocate_memory_range(size, mem_type, mapping, 0, 0, tags, fd);
 }
 
@@ -202,9 +209,15 @@ void *mte_allocate_file_memory_tag_range(size_t size, int mem_type, int mapping,
 	/* Initialize the file for mappable size */
 	lseek(fd, 0, SEEK_SET);
 	for (index = INIT_BUFFER_SIZE; index < map_size; index += INIT_BUFFER_SIZE)
-		write(fd, buffer, INIT_BUFFER_SIZE);
+		if (write(fd, buffer, INIT_BUFFER_SIZE) != INIT_BUFFER_SIZE) {
+			perror("initialising buffer");
+			return NULL;
+		}
 	index -= INIT_BUFFER_SIZE;
-	write(fd, buffer, map_size - index);
+	if (write(fd, buffer, map_size - index) != map_size - index) {
+		perror("initialising buffer");
+		return NULL;
+	}
 	return __mte_allocate_memory_range(size, mem_type, mapping, range_before,
 					   range_after, true, fd);
 }
-- 
2.17.5

[PATCH 05/11] kselftest/arm64: mte: common: Fix write() warnings

[Andre Przywara]

Out of the box Ubuntu's 20.04 compiler warns about missing return value
checks for write() (sys)calls.

Make GCC happy by checking whether we actually managed to write out our
buffer.

Reviewed-by: Andre Przywara <andre.przywara@arm.com>
---
 .../selftests/arm64/mte/mte_common_util.c     | 23 +++++++++++++++----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
index 39f8908988ea..4e887dad762d 100644
--- a/tools/testing/selftests/arm64/mte/mte_common_util.c
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
@@ -181,10 +181,17 @@ void *mte_allocate_file_memory(size_t size, int mem_type, int mapping, bool tags
 	}
 	/* Initialize the file for mappable size */
 	lseek(fd, 0, SEEK_SET);
-	for (index = INIT_BUFFER_SIZE; index < size; index += INIT_BUFFER_SIZE)
-		write(fd, buffer, INIT_BUFFER_SIZE);
+	for (index = INIT_BUFFER_SIZE; index < size; index += INIT_BUFFER_SIZE) {
+		if (write(fd, buffer, INIT_BUFFER_SIZE) != INIT_BUFFER_SIZE) {
+			perror("initialising buffer");
+			return NULL;
+		}
+	}
 	index -= INIT_BUFFER_SIZE;
-	write(fd, buffer, size - index);
+	if (write(fd, buffer, size - index) != size - index) {
+		perror("initialising buffer");
+		return NULL;
+	}
 	return __mte_allocate_memory_range(size, mem_type, mapping, 0, 0, tags, fd);
 }
 
@@ -202,9 +209,15 @@ void *mte_allocate_file_memory_tag_range(size_t size, int mem_type, int mapping,
 	/* Initialize the file for mappable size */
 	lseek(fd, 0, SEEK_SET);
 	for (index = INIT_BUFFER_SIZE; index < map_size; index += INIT_BUFFER_SIZE)
-		write(fd, buffer, INIT_BUFFER_SIZE);
+		if (write(fd, buffer, INIT_BUFFER_SIZE) != INIT_BUFFER_SIZE) {
+			perror("initialising buffer");
+			return NULL;
+		}
 	index -= INIT_BUFFER_SIZE;
-	write(fd, buffer, map_size - index);
+	if (write(fd, buffer, map_size - index) != map_size - index) {
+		perror("initialising buffer");
+		return NULL;
+	}
 	return __mte_allocate_memory_range(size, mem_type, mapping, range_before,
 					   range_after, true, fd);
 }
-- 
2.17.5


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[PATCH 06/11] kselftest/arm64: mte: Fix MTE feature detection

[Andre Przywara]

To check whether the CPU and kernel support the MTE features we want
to test, we use an (emulated) CPU ID register read. However we only
check against a very particular feature version (0b0010), even though
the ARM ARM promises ID register features to be backwards compatible.

While this could be fixed by using ">=" instead of "==", we should
actually use the explicit HWCAP2_MTE hardware capability, exposed by the
kernel via the ELF auxiliary vectors.

That moves this responsibility to the kernel, and fixes running the
tests on machines with FEAT_MTE3 capability.

Reviewed-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/mte_common_util.c | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
index 4e887dad762d..aa8a8a6b8b6d 100644
--- a/tools/testing/selftests/arm64/mte/mte_common_util.c
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
@@ -291,22 +291,13 @@ int mte_switch_mode(int mte_option, unsigned long incl_mask)
 	return 0;
 }
 
-#define ID_AA64PFR1_MTE_SHIFT		8
-#define ID_AA64PFR1_MTE			2
-
 int mte_default_setup(void)
 {
-	unsigned long hwcaps = getauxval(AT_HWCAP);
+	unsigned long hwcaps2 = getauxval(AT_HWCAP2);
 	unsigned long en = 0;
 	int ret;
 
-	if (!(hwcaps & HWCAP_CPUID)) {
-		ksft_print_msg("FAIL: CPUID registers unavailable\n");
-		return KSFT_FAIL;
-	}
-	/* Read ID_AA64PFR1_EL1 register */
-	asm volatile("mrs %0, id_aa64pfr1_el1" : "=r"(hwcaps) : : "memory");
-	if (((hwcaps >> ID_AA64PFR1_MTE_SHIFT) & MT_TAG_MASK) != ID_AA64PFR1_MTE) {
+	if (!(hwcaps2 & HWCAP2_MTE)) {
 		ksft_print_msg("FAIL: MTE features unavailable\n");
 		return KSFT_SKIP;
 	}
-- 
2.17.5

[PATCH 06/11] kselftest/arm64: mte: Fix MTE feature detection

[Andre Przywara]

To check whether the CPU and kernel support the MTE features we want
to test, we use an (emulated) CPU ID register read. However we only
check against a very particular feature version (0b0010), even though
the ARM ARM promises ID register features to be backwards compatible.

While this could be fixed by using ">=" instead of "==", we should
actually use the explicit HWCAP2_MTE hardware capability, exposed by the
kernel via the ELF auxiliary vectors.

That moves this responsibility to the kernel, and fixes running the
tests on machines with FEAT_MTE3 capability.

Reviewed-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/mte_common_util.c | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
index 4e887dad762d..aa8a8a6b8b6d 100644
--- a/tools/testing/selftests/arm64/mte/mte_common_util.c
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
@@ -291,22 +291,13 @@ int mte_switch_mode(int mte_option, unsigned long incl_mask)
 	return 0;
 }
 
-#define ID_AA64PFR1_MTE_SHIFT		8
-#define ID_AA64PFR1_MTE			2
-
 int mte_default_setup(void)
 {
-	unsigned long hwcaps = getauxval(AT_HWCAP);
+	unsigned long hwcaps2 = getauxval(AT_HWCAP2);
 	unsigned long en = 0;
 	int ret;
 
-	if (!(hwcaps & HWCAP_CPUID)) {
-		ksft_print_msg("FAIL: CPUID registers unavailable\n");
-		return KSFT_FAIL;
-	}
-	/* Read ID_AA64PFR1_EL1 register */
-	asm volatile("mrs %0, id_aa64pfr1_el1" : "=r"(hwcaps) : : "memory");
-	if (((hwcaps >> ID_AA64PFR1_MTE_SHIFT) & MT_TAG_MASK) != ID_AA64PFR1_MTE) {
+	if (!(hwcaps2 & HWCAP2_MTE)) {
 		ksft_print_msg("FAIL: MTE features unavailable\n");
 		return KSFT_SKIP;
 	}
-- 
2.17.5


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[PATCH 07/11] kselftest/arm64: mte: Use cross-compiler if specified

[Andre Przywara]

At the moment we either need to provide CC explicitly, or use a native
machine to get the ARM64 MTE selftest compiled.

It seems useful to use the same (cross-)compiler as we use for the
kernel, so copy the recipe we use in the pauth selftest.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/Makefile | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index 90aadd86fa0d..fa282e5f2069 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -1,6 +1,11 @@
 # SPDX-License-Identifier: GPL-2.0
 # Copyright (C) 2020 ARM Limited
 
+# preserve CC value from top level Makefile
+ifeq ($(CC),cc)
+CC := $(CROSS_COMPILE)gcc
+endif
+
 CFLAGS += -std=gnu99 -I. -pthread
 LDFLAGS += -pthread
 SRCS := $(filter-out mte_common_util.c,$(wildcard *.c))
-- 
2.17.5

[PATCH 07/11] kselftest/arm64: mte: Use cross-compiler if specified

[Andre Przywara]

At the moment we either need to provide CC explicitly, or use a native
machine to get the ARM64 MTE selftest compiled.

It seems useful to use the same (cross-)compiler as we use for the
kernel, so copy the recipe we use in the pauth selftest.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/Makefile | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index 90aadd86fa0d..fa282e5f2069 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -1,6 +1,11 @@
 # SPDX-License-Identifier: GPL-2.0
 # Copyright (C) 2020 ARM Limited
 
+# preserve CC value from top level Makefile
+ifeq ($(CC),cc)
+CC := $(CROSS_COMPILE)gcc
+endif
+
 CFLAGS += -std=gnu99 -I. -pthread
 LDFLAGS += -pthread
 SRCS := $(filter-out mte_common_util.c,$(wildcard *.c))
-- 
2.17.5


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[PATCH 08/11] kselftest/arm64: mte: Output warning about failing compiler

[Andre Przywara]

At the moment we check the compiler's ability to compile MTE enabled
code, but guard all the Makefile rules by it. As a consequence a broken
or not capable compiler just doesn't do anything, and make happily
returns without any error message, but with no programs created.

Since the MTE feature is only supported by recent aarch64 compilers (not
all stable distro compilers support it), having an explicit message
seems like a good idea. To not break building multiple targets, we let
make proceed without errors.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/Makefile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index fa282e5f2069..e0d43cea3cd1 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -23,6 +23,9 @@ TEST_GEN_PROGS := $(PROGS)
 
 # Get Kernel headers installed and use them.
 KSFT_KHDR_INSTALL := 1
+else
+    $(warning compiler "$(CC)" does not support the ARMv8.5 MTE extension.)
+    $(warning test program "mte" will not be created.)
 endif
 
 # Include KSFT lib.mk.
-- 
2.17.5

[PATCH 08/11] kselftest/arm64: mte: Output warning about failing compiler

[Andre Przywara]

At the moment we check the compiler's ability to compile MTE enabled
code, but guard all the Makefile rules by it. As a consequence a broken
or not capable compiler just doesn't do anything, and make happily
returns without any error message, but with no programs created.

Since the MTE feature is only supported by recent aarch64 compilers (not
all stable distro compilers support it), having an explicit message
seems like a good idea. To not break building multiple targets, we let
make proceed without errors.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/Makefile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index fa282e5f2069..e0d43cea3cd1 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -23,6 +23,9 @@ TEST_GEN_PROGS := $(PROGS)
 
 # Get Kernel headers installed and use them.
 KSFT_KHDR_INSTALL := 1
+else
+    $(warning compiler "$(CC)" does not support the ARMv8.5 MTE extension.)
+    $(warning test program "mte" will not be created.)
 endif
 
 # Include KSFT lib.mk.
-- 
2.17.5


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[PATCH 09/11] kselftest/arm64: mte: Makefile: Fix clang compilation

[Andre Przywara]

When clang finds a header file on the command line, it wants to
precompile that, which would end up in a separate output file.
Specifying -o on that same command line collides with that effort, so
the compiler complains:

clang: error: cannot specify -o when generating multiple output files

Since we are not really after a precompiled header, just drop the header
file from the command line, by removing it from the list of source
files in the Makefile.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index e0d43cea3cd1..409e3e53d00a 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -32,5 +32,5 @@ endif
 include ../../lib.mk
 
 ifeq ($(mte_cc_support),1)
-$(TEST_GEN_PROGS): mte_common_util.c mte_common_util.h mte_helper.S
+$(TEST_GEN_PROGS): mte_common_util.c mte_helper.S
 endif
-- 
2.17.5

[PATCH 09/11] kselftest/arm64: mte: Makefile: Fix clang compilation

[Andre Przywara]

When clang finds a header file on the command line, it wants to
precompile that, which would end up in a separate output file.
Specifying -o on that same command line collides with that effort, so
the compiler complains:

clang: error: cannot specify -o when generating multiple output files

Since we are not really after a precompiled header, just drop the header
file from the command line, by removing it from the list of source
files in the Makefile.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index e0d43cea3cd1..409e3e53d00a 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -32,5 +32,5 @@ endif
 include ../../lib.mk
 
 ifeq ($(mte_cc_support),1)
-$(TEST_GEN_PROGS): mte_common_util.c mte_common_util.h mte_helper.S
+$(TEST_GEN_PROGS): mte_common_util.c mte_helper.S
 endif
-- 
2.17.5


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[PATCH 10/11] kselftest/arm64: mte: Fix clang warning

[Andre Przywara]

if (!prctl(...) == 0) is not only cumbersome to read, it also upsets
clang and triggers a warning:
------------
mte_common_util.c:287:6: warning: logical not is only applied to the
left hand side of this comparison [-Wlogical-not-parentheses]
....

Fix that by just comparing against "not 0" instead.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/mte_common_util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
index aa8a8a6b8b6d..040abdca079d 100644
--- a/tools/testing/selftests/arm64/mte/mte_common_util.c
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
@@ -284,7 +284,7 @@ int mte_switch_mode(int mte_option, unsigned long incl_mask)
 
 	en |= (incl_mask << PR_MTE_TAG_SHIFT);
 	/* Enable address tagging ABI, mte error reporting mode and tag inclusion mask. */
-	if (!prctl(PR_SET_TAGGED_ADDR_CTRL, en, 0, 0, 0) == 0) {
+	if (prctl(PR_SET_TAGGED_ADDR_CTRL, en, 0, 0, 0) != 0) {
 		ksft_print_msg("FAIL:prctl PR_SET_TAGGED_ADDR_CTRL for mte mode\n");
 		return -EINVAL;
 	}
-- 
2.17.5

[PATCH 10/11] kselftest/arm64: mte: Fix clang warning

[Andre Przywara]

if (!prctl(...) == 0) is not only cumbersome to read, it also upsets
clang and triggers a warning:
------------
mte_common_util.c:287:6: warning: logical not is only applied to the
left hand side of this comparison [-Wlogical-not-parentheses]
....

Fix that by just comparing against "not 0" instead.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/mte_common_util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
index aa8a8a6b8b6d..040abdca079d 100644
--- a/tools/testing/selftests/arm64/mte/mte_common_util.c
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
@@ -284,7 +284,7 @@ int mte_switch_mode(int mte_option, unsigned long incl_mask)
 
 	en |= (incl_mask << PR_MTE_TAG_SHIFT);
 	/* Enable address tagging ABI, mte error reporting mode and tag inclusion mask. */
-	if (!prctl(PR_SET_TAGGED_ADDR_CTRL, en, 0, 0, 0) == 0) {
+	if (prctl(PR_SET_TAGGED_ADDR_CTRL, en, 0, 0, 0) != 0) {
 		ksft_print_msg("FAIL:prctl PR_SET_TAGGED_ADDR_CTRL for mte mode\n");
 		return -EINVAL;
 	}
-- 
2.17.5


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[PATCH 11/11] kselftest/arm64: mte: Report filename on failing temp file creation

[Andre Przywara]

The MTE selftests create temporary files in /dev/shm, for later mmap-ing
them. When there is no tmpfs mounted on /dev/shm, or /dev/shm does not
exist in the first place (on minimal filesystems), the error message is
not giving good hints:
    # FAIL: Unable to open temporary file
    # FAIL: memory allocation
    not ok 17 Check initial tags with private mapping, ...

Add a perror() call, that gives both the filename and the actual error
reason, so that users get a chance of correcting that.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/mte_common_util.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
index 040abdca079d..f50ac31920d1 100644
--- a/tools/testing/selftests/arm64/mte/mte_common_util.c
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
@@ -337,6 +337,7 @@ int create_temp_file(void)
 	/* Create a file in the tmpfs filesystem */
 	fd = mkstemp(&filename[0]);
 	if (fd == -1) {
+		perror(filename);
 		ksft_print_msg("FAIL: Unable to open temporary file\n");
 		return 0;
 	}
-- 
2.17.5

[PATCH 11/11] kselftest/arm64: mte: Report filename on failing temp file creation

[Andre Przywara]

The MTE selftests create temporary files in /dev/shm, for later mmap-ing
them. When there is no tmpfs mounted on /dev/shm, or /dev/shm does not
exist in the first place (on minimal filesystems), the error message is
not giving good hints:
    # FAIL: Unable to open temporary file
    # FAIL: memory allocation
    not ok 17 Check initial tags with private mapping, ...

Add a perror() call, that gives both the filename and the actual error
reason, so that users get a chance of correcting that.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/arm64/mte/mte_common_util.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
index 040abdca079d..f50ac31920d1 100644
--- a/tools/testing/selftests/arm64/mte/mte_common_util.c
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
@@ -337,6 +337,7 @@ int create_temp_file(void)
 	/* Create a file in the tmpfs filesystem */
 	fd = mkstemp(&filename[0]);
 	if (fd == -1) {
+		perror(filename);
 		ksft_print_msg("FAIL: Unable to open temporary file\n");
 		return 0;
 	}
-- 
2.17.5


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Re: [PATCH 00/11] kselftest/arm64: mte: Fix feature detection and compilation

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 467 bytes --]

On Fri, Mar 19, 2021 at 04:53:23PM +0000, Andre Przywara wrote:
> When trying to run the arm64 MTE (Memory Tagging Extension) selftests
> on a model with the new FEAT_MTE3 capability, the MTE feature detection
> failed, because it was overzealously checking for one exact feature
> version only (0b0010). Trying to fix that (patch 06/11) led me into the
> rabbit hole of userland tool compilation, which triggered patches

Reviewed-by: Mark Brown <broone@kernel.org>

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 484 bytes --]

Re: [PATCH 00/11] kselftest/arm64: mte: Fix feature detection and compilation

[Mark Brown]

[-- Attachment #1.1: Type: text/plain, Size: 467 bytes --]

On Fri, Mar 19, 2021 at 04:53:23PM +0000, Andre Przywara wrote:
> When trying to run the arm64 MTE (Memory Tagging Extension) selftests
> on a model with the new FEAT_MTE3 capability, the MTE feature detection
> failed, because it was overzealously checking for one exact feature
> version only (0b0010). Trying to fix that (patch 06/11) led me into the
> rabbit hole of userland tool compilation, which triggered patches

Reviewed-by: Mark Brown <broone@kernel.org>

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 484 bytes --]

[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

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Re: [PATCH 01/11] kselftest/arm64: mte: Fix compilation with native compiler

[Nick Desaulniers]

On Fri, Mar 19, 2021 at 9:53 AM Andre Przywara <andre.przywara@arm.com> wrote:
>
> The mte selftest Makefile contains a check for GCC, to add the memtag
> -march flag to the compiler options. This check fails if the compiler
> is not explicitly specified, so reverts to the standard "cc", in which
> case --version doesn't mention the "gcc" string we match against:
> $ cc --version | head -n 1
> cc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0
>
> This will not add the -march switch to the command line, so compilation
> fails:
> mte_helper.S: Assembler messages:
> mte_helper.S:25: Error: selected processor does not support `irg x0,x0,xzr'
> mte_helper.S:38: Error: selected processor does not support `gmi x1,x0,xzr'
> ...
>
> Actually clang accepts the same -march option as well, so we can just
> drop this check and add this unconditionally to the command line, to avoid
> any future issues with this check altogether (gcc actually prints
> basename(argv[0]) when called with --version).
>
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>

Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

> ---
>  tools/testing/selftests/arm64/mte/Makefile | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
> index 0b3af552632a..df15d44aeb8d 100644
> --- a/tools/testing/selftests/arm64/mte/Makefile
> +++ b/tools/testing/selftests/arm64/mte/Makefile
> @@ -6,9 +6,7 @@ SRCS := $(filter-out mte_common_util.c,$(wildcard *.c))
>  PROGS := $(patsubst %.c,%,$(SRCS))
>
>  #Add mte compiler option
> -ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep gcc),)
>  CFLAGS += -march=armv8.5-a+memtag
> -endif
>
>  #check if the compiler works well
>  mte_cc_support := $(shell if ($(CC) $(CFLAGS) -E -x c /dev/null -o /dev/null 2>&1) then echo "1"; fi)
> --
> 2.17.5
>


-- 
Thanks,
~Nick Desaulniers

Re: [PATCH 01/11] kselftest/arm64: mte: Fix compilation with native compiler

[Nick Desaulniers]

On Fri, Mar 19, 2021 at 9:53 AM Andre Przywara <andre.przywara@arm.com> wrote:
>
> The mte selftest Makefile contains a check for GCC, to add the memtag
> -march flag to the compiler options. This check fails if the compiler
> is not explicitly specified, so reverts to the standard "cc", in which
> case --version doesn't mention the "gcc" string we match against:
> $ cc --version | head -n 1
> cc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0
>
> This will not add the -march switch to the command line, so compilation
> fails:
> mte_helper.S: Assembler messages:
> mte_helper.S:25: Error: selected processor does not support `irg x0,x0,xzr'
> mte_helper.S:38: Error: selected processor does not support `gmi x1,x0,xzr'
> ...
>
> Actually clang accepts the same -march option as well, so we can just
> drop this check and add this unconditionally to the command line, to avoid
> any future issues with this check altogether (gcc actually prints
> basename(argv[0]) when called with --version).
>
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>

Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

> ---
>  tools/testing/selftests/arm64/mte/Makefile | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
> index 0b3af552632a..df15d44aeb8d 100644
> --- a/tools/testing/selftests/arm64/mte/Makefile
> +++ b/tools/testing/selftests/arm64/mte/Makefile
> @@ -6,9 +6,7 @@ SRCS := $(filter-out mte_common_util.c,$(wildcard *.c))
>  PROGS := $(patsubst %.c,%,$(SRCS))
>
>  #Add mte compiler option
> -ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep gcc),)
>  CFLAGS += -march=armv8.5-a+memtag
> -endif
>
>  #check if the compiler works well
>  mte_cc_support := $(shell if ($(CC) $(CFLAGS) -E -x c /dev/null -o /dev/null 2>&1) then echo "1"; fi)
> --
> 2.17.5
>


-- 
Thanks,
~Nick Desaulniers

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Re: [PATCH 10/11] kselftest/arm64: mte: Fix clang warning

[Nick Desaulniers]

On Fri, Mar 19, 2021 at 9:53 AM Andre Przywara <andre.przywara@arm.com> wrote:
>
> if (!prctl(...) == 0) is not only cumbersome to read, it also upsets
> clang and triggers a warning:
> ------------
> mte_common_util.c:287:6: warning: logical not is only applied to the
> left hand side of this comparison [-Wlogical-not-parentheses]
> ....
>
> Fix that by just comparing against "not 0" instead.
>
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
>  tools/testing/selftests/arm64/mte/mte_common_util.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
> index aa8a8a6b8b6d..040abdca079d 100644
> --- a/tools/testing/selftests/arm64/mte/mte_common_util.c
> +++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
> @@ -284,7 +284,7 @@ int mte_switch_mode(int mte_option, unsigned long incl_mask)
>
>         en |= (incl_mask << PR_MTE_TAG_SHIFT);
>         /* Enable address tagging ABI, mte error reporting mode and tag inclusion mask. */
> -       if (!prctl(PR_SET_TAGGED_ADDR_CTRL, en, 0, 0, 0) == 0) {
> +       if (prctl(PR_SET_TAGGED_ADDR_CTRL, en, 0, 0, 0) != 0) {

How about `if (prctl(...)) {`?

>                 ksft_print_msg("FAIL:prctl PR_SET_TAGGED_ADDR_CTRL for mte mode\n");
>                 return -EINVAL;
>         }
> --
> 2.17.5
>


-- 
Thanks,
~Nick Desaulniers

Re: [PATCH 10/11] kselftest/arm64: mte: Fix clang warning

[Nick Desaulniers]

On Fri, Mar 19, 2021 at 9:53 AM Andre Przywara <andre.przywara@arm.com> wrote:
>
> if (!prctl(...) == 0) is not only cumbersome to read, it also upsets
> clang and triggers a warning:
> ------------
> mte_common_util.c:287:6: warning: logical not is only applied to the
> left hand side of this comparison [-Wlogical-not-parentheses]
> ....
>
> Fix that by just comparing against "not 0" instead.
>
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
>  tools/testing/selftests/arm64/mte/mte_common_util.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
> index aa8a8a6b8b6d..040abdca079d 100644
> --- a/tools/testing/selftests/arm64/mte/mte_common_util.c
> +++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
> @@ -284,7 +284,7 @@ int mte_switch_mode(int mte_option, unsigned long incl_mask)
>
>         en |= (incl_mask << PR_MTE_TAG_SHIFT);
>         /* Enable address tagging ABI, mte error reporting mode and tag inclusion mask. */
> -       if (!prctl(PR_SET_TAGGED_ADDR_CTRL, en, 0, 0, 0) == 0) {
> +       if (prctl(PR_SET_TAGGED_ADDR_CTRL, en, 0, 0, 0) != 0) {

How about `if (prctl(...)) {`?

>                 ksft_print_msg("FAIL:prctl PR_SET_TAGGED_ADDR_CTRL for mte mode\n");
>                 return -EINVAL;
>         }
> --
> 2.17.5
>


-- 
Thanks,
~Nick Desaulniers

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Re: [PATCH 00/11] kselftest/arm64: mte: Fix feature detection and compilation

[Catalin Marinas]

On Fri, 19 Mar 2021 16:53:23 +0000, Andre Przywara wrote:
> When trying to run the arm64 MTE (Memory Tagging Extension) selftests
> on a model with the new FEAT_MTE3 capability, the MTE feature detection
> failed, because it was overzealously checking for one exact feature
> version only (0b0010). Trying to fix that (patch 06/11) led me into the
> rabbit hole of userland tool compilation, which triggered patches
> 01-05/11, to let me actually compile the selftests on an arm64
> machine running Ubuntu 20.04. Before I actually fixed that, I tried some
> other compiler and distro; patches 07 and 08 are my witnesses.
> Then I got brave and tried clang: entering patches 09/11 and 10/11.
> Eventually I tried to run the whole thing on that model again, and,
> you guessed it, patch 11/11 concludes this apparent "2 minute job".
> 
> [...]

Applied to arm64 (for-next/kselftest), thanks!

[01/11] kselftest/arm64: mte: Fix compilation with native compiler
        https://git.kernel.org/arm64/c/4a423645bc26
[02/11] kselftest/arm64: mte: Fix pthread linking
        https://git.kernel.org/arm64/c/e5decefd884d
[03/11] kselftest/arm64: mte: ksm_options: Fix fscanf warning
        https://git.kernel.org/arm64/c/31c88729a7ad
[04/11] kselftest/arm64: mte: user_mem: Fix write() warning
        https://git.kernel.org/arm64/c/40de85226fec
[05/11] kselftest/arm64: mte: common: Fix write() warnings
        https://git.kernel.org/arm64/c/4dfc9d30a8ab
[06/11] kselftest/arm64: mte: Fix MTE feature detection
        https://git.kernel.org/arm64/c/b17f265bb4cc
[07/11] kselftest/arm64: mte: Use cross-compiler if specified
        https://git.kernel.org/arm64/c/28cc9b3d8996
[08/11] kselftest/arm64: mte: Output warning about failing compiler
        https://git.kernel.org/arm64/c/6b9bbb7f934d
[09/11] kselftest/arm64: mte: Makefile: Fix clang compilation
        https://git.kernel.org/arm64/c/adb73140eec7
[10/11] kselftest/arm64: mte: Fix clang warning
        https://git.kernel.org/arm64/c/005a62f6d269
[11/11] kselftest/arm64: mte: Report filename on failing temp file creation
        https://git.kernel.org/arm64/c/b4985bb88afb

-- 
Catalin

Re: [PATCH 00/11] kselftest/arm64: mte: Fix feature detection and compilation

[Catalin Marinas]

On Fri, 19 Mar 2021 16:53:23 +0000, Andre Przywara wrote:
> When trying to run the arm64 MTE (Memory Tagging Extension) selftests
> on a model with the new FEAT_MTE3 capability, the MTE feature detection
> failed, because it was overzealously checking for one exact feature
> version only (0b0010). Trying to fix that (patch 06/11) led me into the
> rabbit hole of userland tool compilation, which triggered patches
> 01-05/11, to let me actually compile the selftests on an arm64
> machine running Ubuntu 20.04. Before I actually fixed that, I tried some
> other compiler and distro; patches 07 and 08 are my witnesses.
> Then I got brave and tried clang: entering patches 09/11 and 10/11.
> Eventually I tried to run the whole thing on that model again, and,
> you guessed it, patch 11/11 concludes this apparent "2 minute job".
> 
> [...]

Applied to arm64 (for-next/kselftest), thanks!

[01/11] kselftest/arm64: mte: Fix compilation with native compiler
        https://git.kernel.org/arm64/c/4a423645bc26
[02/11] kselftest/arm64: mte: Fix pthread linking
        https://git.kernel.org/arm64/c/e5decefd884d
[03/11] kselftest/arm64: mte: ksm_options: Fix fscanf warning
        https://git.kernel.org/arm64/c/31c88729a7ad
[04/11] kselftest/arm64: mte: user_mem: Fix write() warning
        https://git.kernel.org/arm64/c/40de85226fec
[05/11] kselftest/arm64: mte: common: Fix write() warnings
        https://git.kernel.org/arm64/c/4dfc9d30a8ab
[06/11] kselftest/arm64: mte: Fix MTE feature detection
        https://git.kernel.org/arm64/c/b17f265bb4cc
[07/11] kselftest/arm64: mte: Use cross-compiler if specified
        https://git.kernel.org/arm64/c/28cc9b3d8996
[08/11] kselftest/arm64: mte: Output warning about failing compiler
        https://git.kernel.org/arm64/c/6b9bbb7f934d
[09/11] kselftest/arm64: mte: Makefile: Fix clang compilation
        https://git.kernel.org/arm64/c/adb73140eec7
[10/11] kselftest/arm64: mte: Fix clang warning
        https://git.kernel.org/arm64/c/005a62f6d269
[11/11] kselftest/arm64: mte: Report filename on failing temp file creation
        https://git.kernel.org/arm64/c/b4985bb88afb

-- 
Catalin


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