Hi,
Jason A. Donenfeld, I've added you because I ended up looking through your latest "implement getrandom() in vDSO" series [1], which also touches this Makefile, so just a heads up about upcoming (minor) merge conflicts.
Changes since v2:
1. Added two patches, both of which apply solely to the Makefile. These provide a smaller, cleaner, and more accurate Makefile.
2. Added Reviewed-by and Tested-by tags for the original patch, which fixes all of the clang errors and warnings for this selftest.
3. Removed an obsolete blurb from the commit description of the original patch, now that Valentin Obst LLVM build fix has been merged.
[1] https://lore.kernel.org/20240614190646.2081057-1-Jason@zx2c4.com
John Hubbard (3): selftests/vDSO: fix clang build errors and warnings selftests/mm: remove partially duplicated "all:" target in Makefile selftests/vDSO: remove duplicate compiler invocations from Makefile
tools/testing/selftests/vDSO/Makefile | 29 ++++++++----------- tools/testing/selftests/vDSO/parse_vdso.c | 16 ++++++---- .../selftests/vDSO/vdso_standalone_test_x86.c | 18 ++++++++++-- 3 files changed, 39 insertions(+), 24 deletions(-)
base-commit: 2ccbdf43d5e758f8493a95252073cf9078a5fea5
When building with clang, via:
make LLVM=1 -C tools/testing/selftests
...there are several warnings, and an error. This fixes all of those and allows these tests to run and pass.
1. Fix linker error (undefined reference to memcpy) by providing a local version of memcpy.
2. clang complains about using this form:
if (g = h & 0xf0000000)
...so factor out the assignment into a separate step.
3. The code is passing a signed const char* to elf_hash(), which expects a const unsigned char *. There are several callers, so fix this at the source by allowing the function to accept a signed argument, and then converting to unsigned operations, once inside the function.
4. clang doesn't have __attribute__((externally_visible)) and generates a warning to that effect. Fortunately, gcc 12 and gcc 13 do not seem to require that attribute in order to build, run and pass tests here, so remove it.
Reviewed-by: Carlos Llamas cmllamas@google.com Reviewed-by: Edward Liaw edliaw@google.com Reviewed-by: Muhammad Usama Anjum usama.anjum@collabora.com Tested-by: Muhammad Usama Anjum usama.anjum@collabora.com Signed-off-by: John Hubbard jhubbard@nvidia.com --- tools/testing/selftests/vDSO/parse_vdso.c | 16 +++++++++++----- .../selftests/vDSO/vdso_standalone_test_x86.c | 18 ++++++++++++++++-- 2 files changed, 27 insertions(+), 7 deletions(-)
diff --git a/tools/testing/selftests/vDSO/parse_vdso.c b/tools/testing/selftests/vDSO/parse_vdso.c index 413f75620a35..4ae417372e9e 100644 --- a/tools/testing/selftests/vDSO/parse_vdso.c +++ b/tools/testing/selftests/vDSO/parse_vdso.c @@ -55,14 +55,20 @@ static struct vdso_info ELF(Verdef) *verdef; } vdso_info;
-/* Straight from the ELF specification. */ -static unsigned long elf_hash(const unsigned char *name) +/* + * Straight from the ELF specification...and then tweaked slightly, in order to + * avoid a few clang warnings. + */ +static unsigned long elf_hash(const char *name) { unsigned long h = 0, g; - while (*name) + const unsigned char *uch_name = (const unsigned char *)name; + + while (*uch_name) { - h = (h << 4) + *name++; - if (g = h & 0xf0000000) + h = (h << 4) + *uch_name++; + g = h & 0xf0000000; + if (g) h ^= g >> 24; h &= ~g; } diff --git a/tools/testing/selftests/vDSO/vdso_standalone_test_x86.c b/tools/testing/selftests/vDSO/vdso_standalone_test_x86.c index 8a44ff973ee1..27f6fdf11969 100644 --- a/tools/testing/selftests/vDSO/vdso_standalone_test_x86.c +++ b/tools/testing/selftests/vDSO/vdso_standalone_test_x86.c @@ -18,7 +18,7 @@
#include "parse_vdso.h"
-/* We need a libc functions... */ +/* We need some libc functions... */ int strcmp(const char *a, const char *b) { /* This implementation is buggy: it never returns -1. */ @@ -34,6 +34,20 @@ int strcmp(const char *a, const char *b) return 0; }
+/* + * The clang build needs this, although gcc does not. + * Stolen from lib/string.c. + */ +void *memcpy(void *dest, const void *src, size_t count) +{ + char *tmp = dest; + const char *s = src; + + while (count--) + *tmp++ = *s++; + return dest; +} + /* ...and two syscalls. This is x86-specific. */ static inline long x86_syscall3(long nr, long a0, long a1, long a2) { @@ -70,7 +84,7 @@ void to_base10(char *lastdig, time_t n) } }
-__attribute__((externally_visible)) void c_main(void **stack) +void c_main(void **stack) { /* Parse the stack */ long argc = (long)*stack;
Also Cc'ing Thomas Gleixner on this one, sorry for the omission.
On 6/14/24 4:31 PM, John Hubbard wrote:
When building with clang, via:
make LLVM=1 -C tools/testing/selftests...there are several warnings, and an error. This fixes all of those and allows these tests to run and pass.
Fix linker error (undefined reference to memcpy) by providing a local version of memcpy.
clang complains about using this form:
if (g = h & 0xf0000000)
...so factor out the assignment into a separate step.
The code is passing a signed const char* to elf_hash(), which expects a const unsigned char *. There are several callers, so fix this at the source by allowing the function to accept a signed argument, and then converting to unsigned operations, once inside the function.
clang doesn't have __attribute__((externally_visible)) and generates a warning to that effect. Fortunately, gcc 12 and gcc 13 do not seem to require that attribute in order to build, run and pass tests here, so remove it.
Reviewed-by: Carlos Llamas cmllamas@google.com Reviewed-by: Edward Liaw edliaw@google.com Reviewed-by: Muhammad Usama Anjum usama.anjum@collabora.com Tested-by: Muhammad Usama Anjum usama.anjum@collabora.com Signed-off-by: John Hubbard jhubbard@nvidia.com
tools/testing/selftests/vDSO/parse_vdso.c | 16 +++++++++++----- .../selftests/vDSO/vdso_standalone_test_x86.c | 18 ++++++++++++++++-- 2 files changed, 27 insertions(+), 7 deletions(-)
diff --git a/tools/testing/selftests/vDSO/parse_vdso.c b/tools/testing/selftests/vDSO/parse_vdso.c index 413f75620a35..4ae417372e9e 100644 --- a/tools/testing/selftests/vDSO/parse_vdso.c +++ b/tools/testing/selftests/vDSO/parse_vdso.c @@ -55,14 +55,20 @@ static struct vdso_info ELF(Verdef) *verdef; } vdso_info; -/* Straight from the ELF specification. */ -static unsigned long elf_hash(const unsigned char *name) +/*
- Straight from the ELF specification...and then tweaked slightly, in order to
- avoid a few clang warnings.
- */
+static unsigned long elf_hash(const char *name) { unsigned long h = 0, g;
- while (*name)
- const unsigned char *uch_name = (const unsigned char *)name;
- while (*uch_name) {
h = (h << 4) + *name++;if (g = h & 0xf0000000)
h = (h << 4) + *uch_name++;g = h & 0xf0000000;if (g) h ^= g >> 24;diff --git a/tools/testing/selftests/vDSO/vdso_standalone_test_x86.c b/tools/testing/selftests/vDSO/vdso_standalone_test_x86.c index 8a44ff973ee1..27f6fdf11969 100644 --- a/tools/testing/selftests/vDSO/vdso_standalone_test_x86.c +++ b/tools/testing/selftests/vDSO/vdso_standalone_test_x86.c @@ -18,7 +18,7 @@ #include "parse_vdso.h" -/* We need a libc functions... */ +/* We need some libc functions... */ int strcmp(const char *a, const char *b) { /* This implementation is buggy: it never returns -1. */ @@ -34,6 +34,20 @@ int strcmp(const char *a, const char *b) return 0; } +/*
- The clang build needs this, although gcc does not.
- Stolen from lib/string.c.
- */
+void *memcpy(void *dest, const void *src, size_t count) +{
- char *tmp = dest;
- const char *s = src;
- while (count--)
*tmp++ = *s++;- return dest;
+}
- /* ...and two syscalls. This is x86-specific. */ static inline long x86_syscall3(long nr, long a0, long a1, long a2) {
@@ -70,7 +84,7 @@ void to_base10(char *lastdig, time_t n) } } -__attribute__((externally_visible)) void c_main(void **stack) +void c_main(void **stack) { /* Parse the stack */ long argc = (long)*stack;
thanks,
On Fri, Jun 14, 2024 at 4:31 PM John Hubbard jhubbard@nvidia.com wrote:
When building with clang, via:
make LLVM=1 -C tools/testing/selftests...there are several warnings, and an error. This fixes all of those and allows these tests to run and pass.
Fix linker error (undefined reference to memcpy) by providing a local version of memcpy.
clang complains about using this form:
if (g = h & 0xf0000000)
...so factor out the assignment into a separate step.
The code is passing a signed const char* to elf_hash(), which expects a const unsigned char *. There are several callers, so fix this at the source by allowing the function to accept a signed argument, and then converting to unsigned operations, once inside the function.
clang doesn't have __attribute__((externally_visible)) and generates a warning to that effect. Fortunately, gcc 12 and gcc 13 do not seem to require that attribute in order to build, run and pass tests here, so remove it.
Reviewed-by: Carlos Llamas cmllamas@google.com Reviewed-by: Edward Liaw edliaw@google.com Reviewed-by: Muhammad Usama Anjum usama.anjum@collabora.com Tested-by: Muhammad Usama Anjum usama.anjum@collabora.com Signed-off-by: John Hubbard jhubbard@nvidia.com
tools/testing/selftests/vDSO/parse_vdso.c | 16 +++++++++++----- .../selftests/vDSO/vdso_standalone_test_x86.c | 18 ++++++++++++++++-- 2 files changed, 27 insertions(+), 7 deletions(-)
diff --git a/tools/testing/selftests/vDSO/parse_vdso.c b/tools/testing/selftests/vDSO/parse_vdso.c index 413f75620a35..4ae417372e9e 100644 --- a/tools/testing/selftests/vDSO/parse_vdso.c +++ b/tools/testing/selftests/vDSO/parse_vdso.c @@ -55,14 +55,20 @@ static struct vdso_info ELF(Verdef) *verdef; } vdso_info;
-/* Straight from the ELF specification. */ -static unsigned long elf_hash(const unsigned char *name) +/*
- Straight from the ELF specification...and then tweaked slightly, in order to
- avoid a few clang warnings.
- */
+static unsigned long elf_hash(const char *name) { unsigned long h = 0, g;
while (*name)
const unsigned char *uch_name = (const unsigned char *)name;while (*uch_name) {
h = (h << 4) + *name++;if (g = h & 0xf0000000)
h = (h << 4) + *uch_name++;g = h & 0xf0000000;if (g) h ^= g >> 24; h &= ~g; }diff --git a/tools/testing/selftests/vDSO/vdso_standalone_test_x86.c b/tools/testing/selftests/vDSO/vdso_standalone_test_x86.c index 8a44ff973ee1..27f6fdf11969 100644 --- a/tools/testing/selftests/vDSO/vdso_standalone_test_x86.c +++ b/tools/testing/selftests/vDSO/vdso_standalone_test_x86.c @@ -18,7 +18,7 @@
#include "parse_vdso.h"
-/* We need a libc functions... */ +/* We need some libc functions... */ int strcmp(const char *a, const char *b) { /* This implementation is buggy: it never returns -1. */ @@ -34,6 +34,20 @@ int strcmp(const char *a, const char *b) return 0; }
+/*
- The clang build needs this, although gcc does not.
- Stolen from lib/string.c.
- */
+void *memcpy(void *dest, const void *src, size_t count) +{
char *tmp = dest;const char *s = src;while (count--)*tmp++ = *s++;return dest;+}
/* ...and two syscalls. This is x86-specific. */ static inline long x86_syscall3(long nr, long a0, long a1, long a2) { @@ -70,7 +84,7 @@ void to_base10(char *lastdig, time_t n) } }
-__attribute__((externally_visible)) void c_main(void **stack) +void c_main(void **stack) { /* Parse the stack */ long argc = (long)*stack; -- 2.45.2
Hi John, Could you try re-submitting this series with the RESEND prefix?
Thanks, Edward
On 7/2/24 11:12 AM, Edward Liaw wrote:
On Fri, Jun 14, 2024 at 4:31 PM John Hubbard jhubbard@nvidia.com wrote:
...
Hi John, Could you try re-submitting this series with the RESEND prefix?
Thanks, Edward
Sure. Is that the key, for kselftests? Because I've got 5+ small patchsets that are languishing there, and I'm at a loss for how to even get a response, much less get something merged.
thanks,
On Tue, Jul 2, 2024 at 11:26 AM John Hubbard jhubbard@nvidia.com wrote:
On 7/2/24 11:12 AM, Edward Liaw wrote:
On Fri, Jun 14, 2024 at 4:31 PM John Hubbard jhubbard@nvidia.com wrote:
...
Hi John, Could you try re-submitting this series with the RESEND prefix?
Thanks, Edward
Sure. Is that the key, for kselftests? Because I've got 5+ small patchsets that are languishing there, and I'm at a loss for how to even get a response, much less get something merged.
I don't really know, but it was suggested to me that it can help to point out that the patch might have been missed before.
thanks,
John Hubbard NVIDIA
On 7/2/24 11:49 AM, Edward Liaw wrote:
On Tue, Jul 2, 2024 at 11:26 AM John Hubbard jhubbard@nvidia.com wrote:
On 7/2/24 11:12 AM, Edward Liaw wrote:
On Fri, Jun 14, 2024 at 4:31 PM John Hubbard jhubbard@nvidia.com wrote:
...
Hi John, Could you try re-submitting this series with the RESEND prefix?
Thanks, Edward
Sure. Is that the key, for kselftests? Because I've got 5+ small patchsets that are languishing there, and I'm at a loss for how to even get a response, much less get something merged.
I don't really know, but it was suggested to me that it can help to point out that the patch might have been missed before.
I wish. But we are three versions into it, plus a special email [1] specifically to point out that this is still pending.
I think either people are on vacation, or these fixes are not considered sufficiently important, or both. :)
[1] https://lore.kernel.org/e9de90dd-c541-45bf-a364-0e7aaf320314@nvidia.com
thanks,
There were a couple of errors here:
1. TEST_GEN_PROGS was incorrectly prepending $(OUTPUT) to each program to be built. However, lib.mk already does that because it assumes "bare" program names are passed in, so this ended up creating $(OUTPUT)/$(OUTPUT)/file.c, which of course won't work as intended.
2. lib.mk was included before TEST_GEN_PROGS was set, which led to lib.mk's "all:" target not seeing anything to rebuild.
So nothing worked, which caused the author to force things by creating an "all:" target locally--while still including ../lib.mk.
Fix all of this by including ../lib.mk at the right place, and removing the $(OUTPUT) prefix to the programs to be built, and removing the duplicate "all:" target.
Signed-off-by: John Hubbard jhubbard@nvidia.com --- tools/testing/selftests/vDSO/Makefile | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile index d53a4d8008f9..209ede5de208 100644 --- a/tools/testing/selftests/vDSO/Makefile +++ b/tools/testing/selftests/vDSO/Makefile @@ -1,16 +1,15 @@ # SPDX-License-Identifier: GPL-2.0 -include ../lib.mk - uname_M := $(shell uname -m 2>/dev/null || echo not) ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/x86/ -e s/x86_64/x86/)
-TEST_GEN_PROGS := $(OUTPUT)/vdso_test_gettimeofday $(OUTPUT)/vdso_test_getcpu -TEST_GEN_PROGS += $(OUTPUT)/vdso_test_abi -TEST_GEN_PROGS += $(OUTPUT)/vdso_test_clock_getres +TEST_GEN_PROGS := vdso_test_gettimeofday +TEST_GEN_PROGS += vdso_test_getcpu +TEST_GEN_PROGS += vdso_test_abi +TEST_GEN_PROGS += vdso_test_clock_getres ifeq ($(ARCH),$(filter $(ARCH),x86 x86_64)) -TEST_GEN_PROGS += $(OUTPUT)/vdso_standalone_test_x86 +TEST_GEN_PROGS += vdso_standalone_test_x86 endif -TEST_GEN_PROGS += $(OUTPUT)/vdso_test_correctness +TEST_GEN_PROGS += vdso_test_correctness
CFLAGS := -std=gnu99 CFLAGS_vdso_standalone_test_x86 := -nostdlib -fno-asynchronous-unwind-tables -fno-stack-protector @@ -19,7 +18,7 @@ ifeq ($(CONFIG_X86_32),y) LDLIBS += -lgcc_s endif
-all: $(TEST_GEN_PROGS) +include ../lib.mk $(OUTPUT)/vdso_test_gettimeofday: parse_vdso.c vdso_test_gettimeofday.c $(OUTPUT)/vdso_test_getcpu: parse_vdso.c vdso_test_getcpu.c $(OUTPUT)/vdso_test_abi: parse_vdso.c vdso_test_abi.c
The Makefile open-codes compiler invocations that ../lib.mk already provides.
Avoid this by using a Make feature that allows setting per-target variables, which in this case are: CFLAGS and LDFLAGS. This approach generates the exact same compiler invocations as before, but removes all of the code duplication, along with the quirky mangled variable names. So now the Makefile is smaller, less unusual, and easier to read.
The new dependencies are listed after including lib.mk, in order to let lib.mk provide the first target ("all:"), and are grouped together with their respective source file dependencies, for visual clarity.
Signed-off-by: John Hubbard jhubbard@nvidia.com --- tools/testing/selftests/vDSO/Makefile | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-)
diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile index 209ede5de208..98d8ba2afa00 100644 --- a/tools/testing/selftests/vDSO/Makefile +++ b/tools/testing/selftests/vDSO/Makefile @@ -12,8 +12,7 @@ endif TEST_GEN_PROGS += vdso_test_correctness
CFLAGS := -std=gnu99 -CFLAGS_vdso_standalone_test_x86 := -nostdlib -fno-asynchronous-unwind-tables -fno-stack-protector -LDFLAGS_vdso_test_correctness := -ldl + ifeq ($(CONFIG_X86_32),y) LDLIBS += -lgcc_s endif @@ -23,12 +22,9 @@ $(OUTPUT)/vdso_test_gettimeofday: parse_vdso.c vdso_test_gettimeofday.c $(OUTPUT)/vdso_test_getcpu: parse_vdso.c vdso_test_getcpu.c $(OUTPUT)/vdso_test_abi: parse_vdso.c vdso_test_abi.c $(OUTPUT)/vdso_test_clock_getres: vdso_test_clock_getres.c + $(OUTPUT)/vdso_standalone_test_x86: vdso_standalone_test_x86.c parse_vdso.c - $(CC) $(CFLAGS) $(CFLAGS_vdso_standalone_test_x86) \ - vdso_standalone_test_x86.c parse_vdso.c \ - -o $@ +$(OUTPUT)/vdso_standalone_test_x86: CFLAGS +=-nostdlib -fno-asynchronous-unwind-tables -fno-stack-protector + $(OUTPUT)/vdso_test_correctness: vdso_test_correctness.c - $(CC) $(CFLAGS) \ - vdso_test_correctness.c \ - -o $@ \ - $(LDFLAGS_vdso_test_correctness) +$(OUTPUT)/vdso_test_correctness: LDFLAGS += -ldl
On 6/14/24 4:31 PM, John Hubbard wrote:
Hi,
Jason A. Donenfeld, I've added you because I ended up looking through your latest "implement getrandom() in vDSO" series [1], which also touches this Makefile, so just a heads up about upcoming (minor) merge conflicts.
Belatedly adding Carlos Llamas and Thomas Gleixner to Cc.
Changes since v2:
- Added two patches, both of which apply solely to the Makefile.
These provide a smaller, cleaner, and more accurate Makefile.
- Added Reviewed-by and Tested-by tags for the original patch, which
fixes all of the clang errors and warnings for this selftest.
- Removed an obsolete blurb from the commit description of the original
patch, now that Valentin Obst LLVM build fix has been merged.
[1] https://lore.kernel.org/20240614190646.2081057-1-Jason@zx2c4.com
John Hubbard (3): selftests/vDSO: fix clang build errors and warnings selftests/mm: remove partially duplicated "all:" target in Makefile selftests/vDSO: remove duplicate compiler invocations from Makefile
tools/testing/selftests/vDSO/Makefile | 29 ++++++++----------- tools/testing/selftests/vDSO/parse_vdso.c | 16 ++++++---- .../selftests/vDSO/vdso_standalone_test_x86.c | 18 ++++++++++-- 3 files changed, 39 insertions(+), 24 deletions(-)
base-commit: 2ccbdf43d5e758f8493a95252073cf9078a5fea5
thanks,
On 6/14/24 4:34 PM, John Hubbard wrote:
On 6/14/24 4:31 PM, John Hubbard wrote:
Hi,
Jason A. Donenfeld, I've added you because I ended up looking through your latest "implement getrandom() in vDSO" series [1], which also touches this Makefile, so just a heads up about upcoming (minor) merge conflicts.
Belatedly adding Carlos Llamas and Thomas Gleixner to Cc.
Hi Shuah, Andy, Thomas,
Patches 2 and 3 fix up the Makefile, and I'm particularly eager to get those merged into 6.10, because the existing Makefile is leading people astray. See the thread in [2] for an example of that.
As a result, Jason Donenfeld is now waiting for this, for his "implement getrandom() in vDSO" series.
The Makefile is more of a kselftest infrastructure thing in a way, so maybe Shuah can pull this in? I'm casting about for ways to move forward.
[2] https://lore.kernel.org/13483c92-cac5-4a3a-891f-22eb006c533b@nvidia.com
thanks,
linux-kselftest-mirror@lists.linaro.org
-
Edward Liaw -
John Hubbard