Fixes clang compilation warnings by adding explicit unsigned conversion:
parse_vdso.c:206:22: warning: passing 'const char *' to parameter of type 'const unsigned char *' converts between pointers to integer types where one is of the unique plain 'char' type and the other is not [-Wpointer-sign] ver_hash = elf_hash(version); ^~~~~~~ parse_vdso.c:59:52: note: passing argument to parameter 'name' here static unsigned long elf_hash(const unsigned char *name) ^ parse_vdso.c:207:46: warning: passing 'const char *' to parameter of type 'const unsigned char *' converts between pointers to integer types where one is of the unique plain 'char' type and the other is not [-Wpointer-sign] ELF(Word) chain = vdso_info.bucket[elf_hash(name) % vdso_info.nbucket]; ^~~~ parse_vdso.c:59:52: note: passing argument to parameter 'name' here static unsigned long elf_hash(const unsigned char *name)
Fixes: 98eedc3a9dbf ("Document the vDSO and add a reference parser") Signed-off-by: Edward Liaw edliaw@google.com --- v2: update commit message with correct compiler warning v3: fix checkpatch errors and indentation --- tools/testing/selftests/vDSO/parse_vdso.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/vDSO/parse_vdso.c b/tools/testing/selftests/vDSO/parse_vdso.c index 413f75620a35..9e29ff0657ea 100644 --- a/tools/testing/selftests/vDSO/parse_vdso.c +++ b/tools/testing/selftests/vDSO/parse_vdso.c @@ -203,8 +203,9 @@ void *vdso_sym(const char *version, const char *name) if (!vdso_info.valid) return 0;
- ver_hash = elf_hash(version); - ELF(Word) chain = vdso_info.bucket[elf_hash(name) % vdso_info.nbucket]; + ver_hash = elf_hash((const unsigned char *)version); + ELF(Word) chain = vdso_info.bucket[ + elf_hash((const unsigned char *)name) % vdso_info.nbucket];
for (; chain != STN_UNDEF; chain = vdso_info.chain[chain]) { ELF(Sym) *sym = &vdso_info.symtab[chain]; -- 2.45.0.rc0.197.gbae5840b3b-goog
Hi,
On Wed, May 01, 2024 at 06:06:18PM +0000, Edward Liaw wrote:
Fixes clang compilation warnings by adding explicit unsigned conversion:
parse_vdso.c:206:22: warning: passing 'const char *' to parameter of type 'const unsigned char *' converts between pointers to integer types where one is of the unique plain 'char' type and the other is not [-Wpointer-sign] ver_hash = elf_hash(version); ^~~~~~~ parse_vdso.c:59:52: note: passing argument to parameter 'name' here static unsigned long elf_hash(const unsigned char *name) ^ parse_vdso.c:207:46: warning: passing 'const char *' to parameter of type 'const unsigned char *' converts between pointers to integer types where one is of the unique plain 'char' type and the other is not [-Wpointer-sign] ELF(Word) chain = vdso_info.bucket[elf_hash(name) % vdso_info.nbucket]; ^~~~ parse_vdso.c:59:52: note: passing argument to parameter 'name' here static unsigned long elf_hash(const unsigned char *name)
Fixes: 98eedc3a9dbf ("Document the vDSO and add a reference parser") Signed-off-by: Edward Liaw edliaw@google.com
v2: update commit message with correct compiler warning v3: fix checkpatch errors and indentation
tools/testing/selftests/vDSO/parse_vdso.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/vDSO/parse_vdso.c b/tools/testing/selftests/vDSO/parse_vdso.c index 413f75620a35..9e29ff0657ea 100644 --- a/tools/testing/selftests/vDSO/parse_vdso.c +++ b/tools/testing/selftests/vDSO/parse_vdso.c @@ -203,8 +203,9 @@ void *vdso_sym(const char *version, const char *name)
Is it possible to just change the types of the parameters of vdso_sym() or does that trigger even more warnings on the callsites of vdso_sym()?
Either way, this looks ok to me.
Acked-by: Justin Stitt justinstitt@google.com
if (!vdso_info.valid) return 0;
- ver_hash = elf_hash(version);
- ELF(Word) chain = vdso_info.bucket[elf_hash(name) % vdso_info.nbucket];
ver_hash = elf_hash((const unsigned char *)version);
ELF(Word) chain = vdso_info.bucket[
elf_hash((const unsigned char *)name) % vdso_info.nbucket];for (; chain != STN_UNDEF; chain = vdso_info.chain[chain]) { ELF(Sym) *sym = &vdso_info.symtab[chain];
-- 2.45.0.rc0.197.gbae5840b3b-goog
Thanks Justin
On Wed, May 1, 2024 at 12:54 PM Justin Stitt justinstitt@google.com wrote:
Hi,
On Wed, May 01, 2024 at 06:06:18PM +0000, Edward Liaw wrote:
Fixes clang compilation warnings by adding explicit unsigned conversion:
parse_vdso.c:206:22: warning: passing 'const char *' to parameter of type 'const unsigned char *' converts between pointers to integer types where one is of the unique plain 'char' type and the other is not [-Wpointer-sign] ver_hash = elf_hash(version); ^~~~~~~ parse_vdso.c:59:52: note: passing argument to parameter 'name' here static unsigned long elf_hash(const unsigned char *name) ^ parse_vdso.c:207:46: warning: passing 'const char *' to parameter of type 'const unsigned char *' converts between pointers to integer types where one is of the unique plain 'char' type and the other is not [-Wpointer-sign] ELF(Word) chain = vdso_info.bucket[elf_hash(name) % vdso_info.nbucket]; ^~~~ parse_vdso.c:59:52: note: passing argument to parameter 'name' here static unsigned long elf_hash(const unsigned char *name)
Fixes: 98eedc3a9dbf ("Document the vDSO and add a reference parser") Signed-off-by: Edward Liaw edliaw@google.com
v2: update commit message with correct compiler warning v3: fix checkpatch errors and indentation
tools/testing/selftests/vDSO/parse_vdso.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/vDSO/parse_vdso.c b/tools/testing/selftests/vDSO/parse_vdso.c index 413f75620a35..9e29ff0657ea 100644 --- a/tools/testing/selftests/vDSO/parse_vdso.c +++ b/tools/testing/selftests/vDSO/parse_vdso.c @@ -203,8 +203,9 @@ void *vdso_sym(const char *version, const char *name)
Is it possible to just change the types of the parameters of vdso_sym() or does that trigger even more warnings on the callsites of vdso_sym()?
It does trigger more warnings on the callsites unfortunately.
Either way, this looks ok to me.
Acked-by: Justin Stitt justinstitt@google.com
if (!vdso_info.valid) return 0;
ver_hash = elf_hash(version);ELF(Word) chain = vdso_info.bucket[elf_hash(name) % vdso_info.nbucket];
ver_hash = elf_hash((const unsigned char *)version);ELF(Word) chain = vdso_info.bucket[elf_hash((const unsigned char *)name) % vdso_info.nbucket]; for (; chain != STN_UNDEF; chain = vdso_info.chain[chain]) { ELF(Sym) *sym = &vdso_info.symtab[chain];-- 2.45.0.rc0.197.gbae5840b3b-goog
Thanks Justin
From: Justin Stitt
Sent: 01 May 2024 20:55
...
static unsigned long elf_hash(const unsigned char *name)
...
Is it possible to just change the types of the parameters of vdso_sym() or does that trigger even more warnings on the callsites of vdso_sym()?
Isn't the problem the definition of elf_hash()? A '\0' terminated string really ought to be 'char *' not 'unsigned char *'.
David
- Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
On Sun, May 5, 2024 at 6:21 AM David Laight David.Laight@aculab.com wrote:
From: Justin Stitt
Sent: 01 May 2024 20:55
...
static unsigned long elf_hash(const unsigned char *name)
...
Is it possible to just change the types of the parameters of vdso_sym() or does that trigger even more warnings on the callsites of vdso_sym()?
Isn't the problem the definition of elf_hash()? A '\0' terminated string really ought to be 'char *' not 'unsigned char *'.
Right, although note this comment just about its definition:
/* Straight from the ELF specification. */ static unsigned long elf_hash(const unsigned char *name) {
which indeed matches [1]
[1]: https://man.freebsd.org/cgi/man.cgi?query=elf_hash&sektion=3&apropos...
David
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
On Mon, May 6, 2024 at 10:16 AM Justin Stitt justinstitt@google.com wrote:
On Sun, May 5, 2024 at 6:21 AM David Laight David.Laight@aculab.com wrote:
From: Justin Stitt
Sent: 01 May 2024 20:55
...
static unsigned long elf_hash(const unsigned char *name)
...
Is it possible to just change the types of the parameters of vdso_sym() or does that trigger even more warnings on the callsites of vdso_sym()?
Isn't the problem the definition of elf_hash()? A '\0' terminated string really ought to be 'char *' not 'unsigned char *'.
Right, although note this comment just about its definition:
/* Straight from the ELF specification. */ static unsigned long elf_hash(const unsigned char *name) {
which indeed matches [1]
How about I move the type cast into elf_hash, like libelf does https://sourceforge.net/p/elftoolchain/code/HEAD/tree/trunk/libelf/elf_hash....
diff --git a/tools/testing/selftests/vDSO/parse_vdso.c b/tools/testing/selftests/vDSO/parse_vdso.c index 413f75620a35..33db8abd7d59 100644 --- a/tools/testing/selftests/vDSO/parse_vdso.c +++ b/tools/testing/selftests/vDSO/parse_vdso.c @@ -56,12 +56,15 @@ static struct vdso_info } vdso_info;
/* Straight from the ELF specification. */ -static unsigned long elf_hash(const unsigned char *name) +static unsigned long elf_hash(const char *name) { unsigned long h = 0, g; - while (*name) + const unsigned char *s; + + s = (const unsigned char *) name; + while (*s) { - h = (h << 4) + *name++; + h = (h << 4) + *s++; if (g = h & 0xf0000000) h ^= g >> 24; h &= ~g;
David
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
From: Edward Liaw
Sent: 06 May 2024 18:34
On Mon, May 6, 2024 at 10:16 AM Justin Stitt justinstitt@google.com wrote:
On Sun, May 5, 2024 at 6:21 AM David Laight David.Laight@aculab.com wrote:
From: Justin Stitt
Sent: 01 May 2024 20:55
...
static unsigned long elf_hash(const unsigned char *name)
...
Is it possible to just change the types of the parameters of vdso_sym() or does that trigger even more warnings on the callsites of vdso_sym()?
Isn't the problem the definition of elf_hash()? A '\0' terminated string really ought to be 'char *' not 'unsigned char *'.
Right, although note this comment just about its definition:
/* Straight from the ELF specification. */ static unsigned long elf_hash(const unsigned char *name) {
which indeed matches [1]
RELEASE
How about I move the type cast into elf_hash, like libelf does https://sourceforge.net/p/elftoolchain/code/HEAD/tree/trunk/libelf/elf_hash....
diff --git a/tools/testing/selftests/vDSO/parse_vdso.c b/tools/testing/selftests/vDSO/parse_vdso.c index 413f75620a35..33db8abd7d59 100644 --- a/tools/testing/selftests/vDSO/parse_vdso.c +++ b/tools/testing/selftests/vDSO/parse_vdso.c @@ -56,12 +56,15 @@ static struct vdso_info } vdso_info;
/* Straight from the ELF specification. */ -static unsigned long elf_hash(const unsigned char *name) +static unsigned long elf_hash(const char *name) { unsigned long h = 0, g;
- while (*name)
- const unsigned char *s;
- s = (const unsigned char *) name;
- while (*s) {
- h = (h << 4) + *name++;
- h = (h << 4) + *s++; if (g = h & 0xf0000000) h ^= g >> 24; h &= ~g;
That makes a lot more sense.
David
- Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
On Mon, May 6, 2024 at 12:32 PM David Laight David.Laight@aculab.com wrote:
That makes a lot more sense.
I sent v4 https://lore.kernel.org/all/20240506181951.1804451-1-edliaw@google.com/. I updated the commit log to reflect the change but I'm not sure if I did it right for the mailing list. Should I have added --in-reply-to this thread?
Edward
linux-kselftest-mirror@lists.linaro.org
-
David Laight -
Edward Liaw -
Justin Stitt