* [PATCH 1/1] x86, relocs: add function attributes to die()
@ 2016-09-03 14:50 Nicolas Iooss
2016-09-03 15:16 ` Nilay Vaish
0 siblings, 1 reply; 6+ messages in thread
From: Nicolas Iooss @ 2016-09-03 14:50 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, x86
Cc: linux-kernel, Nicolas Iooss
When building the kernel with clang and some warning flags, the compiler
reports the following warning:
arch/x86/tools/relocs.c:979:6: warning: variable 'do_reloc' is used
uninitialized whenever 'if' condition is false
[-Wsometimes-uninitialized]
if (!use_real_mode)
^~~~~~~~~~~~~~
arch/x86/tools/relocs.c:991:14: note: uninitialized use occurs here
walk_relocs(do_reloc);
^~~~~~~~
arch/x86/tools/relocs.c:979:2: note: remove the 'if' if its
condition is always true
if (!use_real_mode)
^~~~~~~~~~~~~~~~~~~
arch/x86/tools/relocs.c:976:24: note: initialize the variable
'do_reloc' to silence this warning
const char *symname);
^
= NULL
This is obviously a false positive: whenever the 'if' condition is
false, the program calls die(). Nevertheless the compiler did not know
this call makes the program quit because this function did not have a
noreturn attribute. Add it.
While at it, add a printf attribute too to die() and constify the format
parameter. This leads to some errors when compiling on x86_64:
arch/x86/tools/relocs.c:460:5: error: format specifies type 'int'
but the argument has type 'Elf64_Xword' (aka 'unsigned long')
[-Werror,-Wformat]
sec->shdr.sh_size);
^~~~~~~~~~~~~~~~~
arch/x86/tools/relocs.c:464:5: error: format specifies type 'int'
but the argument has type 'Elf64_Off' (aka 'unsigned long')
[-Werror,-Wformat]
sec->shdr.sh_offset, strerror(errno));
^~~~~~~~~~~~~~~~~~~
To support both 32-bit and 64-bit modes, add casts to long types and use
%lu and %ld to format the numbers.
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
---
arch/x86/tools/relocs.c | 28 ++++++++++++++--------------
arch/x86/tools/relocs.h | 3 ++-
arch/x86/tools/relocs_common.c | 2 +-
3 files changed, 17 insertions(+), 16 deletions(-)
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index 0c2fae8d929d..88d9595ee4de 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -397,8 +397,8 @@ static void read_shdrs(FILE *fp)
ehdr.e_shnum);
}
if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
- die("Seek to %d failed: %s\n",
- ehdr.e_shoff, strerror(errno));
+ die("Seek to %lu failed: %s\n",
+ (unsigned long)ehdr.e_shoff, strerror(errno));
}
for (i = 0; i < ehdr.e_shnum; i++) {
struct section *sec = &secs[i];
@@ -431,12 +431,12 @@ static void read_strtabs(FILE *fp)
}
sec->strtab = malloc(sec->shdr.sh_size);
if (!sec->strtab) {
- die("malloc of %d bytes for strtab failed\n",
- sec->shdr.sh_size);
+ die("malloc of %lu bytes for strtab failed\n",
+ (unsigned long)sec->shdr.sh_size);
}
if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
- die("Seek to %d failed: %s\n",
- sec->shdr.sh_offset, strerror(errno));
+ die("Seek to %ld failed: %s\n",
+ (long)sec->shdr.sh_offset, strerror(errno));
}
if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
!= sec->shdr.sh_size) {
@@ -456,12 +456,12 @@ static void read_symtabs(FILE *fp)
}
sec->symtab = malloc(sec->shdr.sh_size);
if (!sec->symtab) {
- die("malloc of %d bytes for symtab failed\n",
- sec->shdr.sh_size);
+ die("malloc of %lu bytes for symtab failed\n",
+ (unsigned long)sec->shdr.sh_size);
}
if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
- die("Seek to %d failed: %s\n",
- sec->shdr.sh_offset, strerror(errno));
+ die("Seek to %ld failed: %s\n",
+ (long)sec->shdr.sh_offset, strerror(errno));
}
if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
!= sec->shdr.sh_size) {
@@ -489,12 +489,12 @@ static void read_relocs(FILE *fp)
}
sec->reltab = malloc(sec->shdr.sh_size);
if (!sec->reltab) {
- die("malloc of %d bytes for relocs failed\n",
- sec->shdr.sh_size);
+ die("malloc of %lu bytes for relocs failed\n",
+ (unsigned long)sec->shdr.sh_size);
}
if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
- die("Seek to %d failed: %s\n",
- sec->shdr.sh_offset, strerror(errno));
+ die("Seek to %ld failed: %s\n",
+ (long)sec->shdr.sh_offset, strerror(errno));
}
if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
!= sec->shdr.sh_size) {
diff --git a/arch/x86/tools/relocs.h b/arch/x86/tools/relocs.h
index f59590645b68..6b7969719833 100644
--- a/arch/x86/tools/relocs.h
+++ b/arch/x86/tools/relocs.h
@@ -16,7 +16,8 @@
#include <regex.h>
#include <tools/le_byteshift.h>
-void die(char *fmt, ...);
+__attribute__((format(printf, 1, 2))) __attribute__((noreturn))
+void die(const char *fmt, ...);
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
diff --git a/arch/x86/tools/relocs_common.c b/arch/x86/tools/relocs_common.c
index acab636bcb34..30adb44eff79 100644
--- a/arch/x86/tools/relocs_common.c
+++ b/arch/x86/tools/relocs_common.c
@@ -1,6 +1,6 @@
#include "relocs.h"
-void die(char *fmt, ...)
+void die(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
--
2.9.3
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 1/1] x86, relocs: add function attributes to die()
2016-09-03 14:50 [PATCH 1/1] x86, relocs: add function attributes to die() Nicolas Iooss
@ 2016-09-03 15:16 ` Nilay Vaish
2016-09-03 15:51 ` Nicolas Iooss
0 siblings, 1 reply; 6+ messages in thread
From: Nilay Vaish @ 2016-09-03 15:16 UTC (permalink / raw)
To: Nicolas Iooss
Cc: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, x86, Linux Kernel list
On 3 September 2016 at 09:50, Nicolas Iooss <nicolas.iooss_linux@m4x.org> wrote:
>
> arch/x86/tools/relocs.c:460:5: error: format specifies type 'int'
> but the argument has type 'Elf64_Xword' (aka 'unsigned long')
> [-Werror,-Wformat]
> sec->shdr.sh_size);
> ^~~~~~~~~~~~~~~~~
> arch/x86/tools/relocs.c:464:5: error: format specifies type 'int'
> but the argument has type 'Elf64_Off' (aka 'unsigned long')
> [-Werror,-Wformat]
> sec->shdr.sh_offset, strerror(errno));
> ^~~~~~~~~~~~~~~~~~~
>
> To support both 32-bit and 64-bit modes, add casts to long types and use
> %lu and %ld to format the numbers.
>
Nicolas, should not just changing the format specifiers fix the
problem? How do those type casts help?
--
Nilay
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/1] x86, relocs: add function attributes to die()
2016-09-03 15:16 ` Nilay Vaish
@ 2016-09-03 15:51 ` Nicolas Iooss
2016-09-04 16:51 ` [PATCH v2 " Nicolas Iooss
0 siblings, 1 reply; 6+ messages in thread
From: Nicolas Iooss @ 2016-09-03 15:51 UTC (permalink / raw)
To: Nilay Vaish
Cc: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, x86, Linux Kernel list
On 03/09/16 17:16, Nilay Vaish wrote:
> On 3 September 2016 at 09:50, Nicolas Iooss <nicolas.iooss_linux@m4x.org> wrote:
>>
>> arch/x86/tools/relocs.c:460:5: error: format specifies type 'int'
>> but the argument has type 'Elf64_Xword' (aka 'unsigned long')
>> [-Werror,-Wformat]
>> sec->shdr.sh_size);
>> ^~~~~~~~~~~~~~~~~
>> arch/x86/tools/relocs.c:464:5: error: format specifies type 'int'
>> but the argument has type 'Elf64_Off' (aka 'unsigned long')
>> [-Werror,-Wformat]
>> sec->shdr.sh_offset, strerror(errno));
>> ^~~~~~~~~~~~~~~~~~~
>>
>> To support both 32-bit and 64-bit modes, add casts to long types and use
>> %lu and %ld to format the numbers.
>>
>
> Nicolas, should not just changing the format specifiers fix the
> problem? How do those type casts help?
The problem is that I did not found a simple format which would make
both arch/x86/tools/relocs_32.o and arch/x86/tools/relocs_64.o build
without any warning. Here are the types:
* When compiling relocs_32.c, sec->shdr.sh_size is of type Elf32_Word
(unsigned int) and sec->shdr.sh_offset is Elf32_Off (unsigned int).
* When compiling relocs_64.c, sec->shdr.sh_size is Elf64_Xword (long
long unsigned int when the compiler is in 32-bit mode, long unsigned int
in 64-bit mode) and sec->shdr.sh_offset is Elf64_Off (same real type as
sec->shdr.sh_size).
I though that casting everything to long integers was fine but now I
have realized this does not take into account compiling relocs_64.c on a
32-bit host system (where HOSTCC compiles in 32-bit mode and long
integers are 32-bit wide).
A possible solution would be using format definitions from <inittypes.h>
like PRIu32, PRIu64... in relocs.c depending on the file being compiled
(relocs_32.c or relocs_64.c). What would you think of such a solution?
-- Nicolas
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v2 1/1] x86, relocs: add function attributes to die()
2016-09-03 15:51 ` Nicolas Iooss
@ 2016-09-04 16:51 ` Nicolas Iooss
2016-09-05 15:28 ` Nilay Vaish
0 siblings, 1 reply; 6+ messages in thread
From: Nicolas Iooss @ 2016-09-04 16:51 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, x86
Cc: linux-kernel, Nilay Vaish, Nicolas Iooss
When building the kernel with clang and some warning flags, the compiler
reports the following warning:
arch/x86/tools/relocs.c:979:6: warning: variable 'do_reloc' is used
uninitialized whenever 'if' condition is false
[-Wsometimes-uninitialized]
if (!use_real_mode)
^~~~~~~~~~~~~~
arch/x86/tools/relocs.c:991:14: note: uninitialized use occurs here
walk_relocs(do_reloc);
^~~~~~~~
arch/x86/tools/relocs.c:979:2: note: remove the 'if' if its
condition is always true
if (!use_real_mode)
^~~~~~~~~~~~~~~~~~~
arch/x86/tools/relocs.c:976:24: note: initialize the variable
'do_reloc' to silence this warning
const char *symname);
^
= NULL
This is obviously a false positive: whenever the 'if' condition is
false, the program calls die(). Nevertheless the compiler did not know
this call makes the program quit because this function did not have a
noreturn attribute. Add it.
While at it, add a printf attribute too to die() and constify the format
parameter. This leads to some errors when compiling on x86_64:
arch/x86/tools/relocs.c:460:5: error: format specifies type 'int'
but the argument has type 'Elf64_Xword' (aka 'unsigned long')
[-Werror,-Wformat]
sec->shdr.sh_size);
^~~~~~~~~~~~~~~~~
arch/x86/tools/relocs.c:464:5: error: format specifies type 'int'
but the argument has type 'Elf64_Off' (aka 'unsigned long')
[-Werror,-Wformat]
sec->shdr.sh_offset, strerror(errno));
^~~~~~~~~~~~~~~~~~~
When relocs.c is included by relocs_32.c, sec->shdr.sh_size and
sec->shdr.sh_offset are 32-bit unsigned integers. When the file is
included by relocs_64.c, these expressions are 64-bit unsigned integers.
Introduce a PRIuELF macro to define the right format to use when
printing these expressions.
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
---
arch/x86/tools/relocs.c | 14 +++++++-------
arch/x86/tools/relocs.h | 3 ++-
arch/x86/tools/relocs_32.c | 3 +++
arch/x86/tools/relocs_64.c | 3 +++
arch/x86/tools/relocs_common.c | 2 +-
5 files changed, 16 insertions(+), 9 deletions(-)
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index 0c2fae8d929d..4cad603b8d58 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -397,7 +397,7 @@ static void read_shdrs(FILE *fp)
ehdr.e_shnum);
}
if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
- die("Seek to %d failed: %s\n",
+ die("Seek to %"PRIuELF" failed: %s\n",
ehdr.e_shoff, strerror(errno));
}
for (i = 0; i < ehdr.e_shnum; i++) {
@@ -431,11 +431,11 @@ static void read_strtabs(FILE *fp)
}
sec->strtab = malloc(sec->shdr.sh_size);
if (!sec->strtab) {
- die("malloc of %d bytes for strtab failed\n",
+ die("malloc of %"PRIuELF" bytes for strtab failed\n",
sec->shdr.sh_size);
}
if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
- die("Seek to %d failed: %s\n",
+ die("Seek to %"PRIuELF" failed: %s\n",
sec->shdr.sh_offset, strerror(errno));
}
if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
@@ -456,11 +456,11 @@ static void read_symtabs(FILE *fp)
}
sec->symtab = malloc(sec->shdr.sh_size);
if (!sec->symtab) {
- die("malloc of %d bytes for symtab failed\n",
+ die("malloc of %"PRIuELF" bytes for symtab failed\n",
sec->shdr.sh_size);
}
if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
- die("Seek to %d failed: %s\n",
+ die("Seek to %"PRIuELF" failed: %s\n",
sec->shdr.sh_offset, strerror(errno));
}
if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
@@ -489,11 +489,11 @@ static void read_relocs(FILE *fp)
}
sec->reltab = malloc(sec->shdr.sh_size);
if (!sec->reltab) {
- die("malloc of %d bytes for relocs failed\n",
+ die("malloc of %"PRIuELF" bytes for relocs failed\n",
sec->shdr.sh_size);
}
if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
- die("Seek to %d failed: %s\n",
+ die("Seek to %"PRIuELF" failed: %s\n",
sec->shdr.sh_offset, strerror(errno));
}
if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
diff --git a/arch/x86/tools/relocs.h b/arch/x86/tools/relocs.h
index f59590645b68..6b7969719833 100644
--- a/arch/x86/tools/relocs.h
+++ b/arch/x86/tools/relocs.h
@@ -16,7 +16,8 @@
#include <regex.h>
#include <tools/le_byteshift.h>
-void die(char *fmt, ...);
+__attribute__((format(printf, 1, 2))) __attribute__((noreturn))
+void die(const char *fmt, ...);
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
diff --git a/arch/x86/tools/relocs_32.c b/arch/x86/tools/relocs_32.c
index b2ade2bb4162..8024ec473e6a 100644
--- a/arch/x86/tools/relocs_32.c
+++ b/arch/x86/tools/relocs_32.c
@@ -14,4 +14,7 @@
#define ELF_ST_BIND(o) ELF32_ST_BIND(o)
#define ELF_ST_VISIBILITY(o) ELF32_ST_VISIBILITY(o)
+/* printf format for Elf32_Off */
+#define PRIuELF PRIu32
+
#include "relocs.c"
diff --git a/arch/x86/tools/relocs_64.c b/arch/x86/tools/relocs_64.c
index 56b61b743c4c..2cf4de5c9d99 100644
--- a/arch/x86/tools/relocs_64.c
+++ b/arch/x86/tools/relocs_64.c
@@ -14,4 +14,7 @@
#define ELF_ST_BIND(o) ELF64_ST_BIND(o)
#define ELF_ST_VISIBILITY(o) ELF64_ST_VISIBILITY(o)
+/* printf format for Elf64_Off */
+#define PRIuELF PRIu64
+
#include "relocs.c"
diff --git a/arch/x86/tools/relocs_common.c b/arch/x86/tools/relocs_common.c
index acab636bcb34..30adb44eff79 100644
--- a/arch/x86/tools/relocs_common.c
+++ b/arch/x86/tools/relocs_common.c
@@ -1,6 +1,6 @@
#include "relocs.h"
-void die(char *fmt, ...)
+void die(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
--
2.9.3
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v2 1/1] x86, relocs: add function attributes to die()
2016-09-04 16:51 ` [PATCH v2 " Nicolas Iooss
@ 2016-09-05 15:28 ` Nilay Vaish
2016-10-23 16:47 ` Nicolas Iooss
0 siblings, 1 reply; 6+ messages in thread
From: Nilay Vaish @ 2016-09-05 15:28 UTC (permalink / raw)
To: Nicolas Iooss
Cc: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, x86, Linux Kernel list
On 4 September 2016 at 11:51, Nicolas Iooss <nicolas.iooss_linux@m4x.org> wrote:
> When building the kernel with clang and some warning flags, the compiler
> reports the following warning:
>
> arch/x86/tools/relocs.c:979:6: warning: variable 'do_reloc' is used
> uninitialized whenever 'if' condition is false
> [-Wsometimes-uninitialized]
> if (!use_real_mode)
> ^~~~~~~~~~~~~~
> arch/x86/tools/relocs.c:991:14: note: uninitialized use occurs here
> walk_relocs(do_reloc);
> ^~~~~~~~
> arch/x86/tools/relocs.c:979:2: note: remove the 'if' if its
> condition is always true
> if (!use_real_mode)
> ^~~~~~~~~~~~~~~~~~~
> arch/x86/tools/relocs.c:976:24: note: initialize the variable
> 'do_reloc' to silence this warning
> const char *symname);
> ^
> = NULL
>
> This is obviously a false positive: whenever the 'if' condition is
> false, the program calls die(). Nevertheless the compiler did not know
> this call makes the program quit because this function did not have a
> noreturn attribute. Add it.
>
> While at it, add a printf attribute too to die() and constify the format
> parameter. This leads to some errors when compiling on x86_64:
>
> arch/x86/tools/relocs.c:460:5: error: format specifies type 'int'
> but the argument has type 'Elf64_Xword' (aka 'unsigned long')
> [-Werror,-Wformat]
> sec->shdr.sh_size);
> ^~~~~~~~~~~~~~~~~
> arch/x86/tools/relocs.c:464:5: error: format specifies type 'int'
> but the argument has type 'Elf64_Off' (aka 'unsigned long')
> [-Werror,-Wformat]
> sec->shdr.sh_offset, strerror(errno));
> ^~~~~~~~~~~~~~~~~~~
>
> When relocs.c is included by relocs_32.c, sec->shdr.sh_size and
> sec->shdr.sh_offset are 32-bit unsigned integers. When the file is
> included by relocs_64.c, these expressions are 64-bit unsigned integers.
>
> Introduce a PRIuELF macro to define the right format to use when
> printing these expressions.
>
> Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
> ---
> arch/x86/tools/relocs.c | 14 +++++++-------
> arch/x86/tools/relocs.h | 3 ++-
> arch/x86/tools/relocs_32.c | 3 +++
> arch/x86/tools/relocs_64.c | 3 +++
> arch/x86/tools/relocs_common.c | 2 +-
> 5 files changed, 16 insertions(+), 9 deletions(-)
>
> diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
> index 0c2fae8d929d..4cad603b8d58 100644
> --- a/arch/x86/tools/relocs.c
> +++ b/arch/x86/tools/relocs.c
> @@ -397,7 +397,7 @@ static void read_shdrs(FILE *fp)
> ehdr.e_shnum);
> }
> if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
> - die("Seek to %d failed: %s\n",
> + die("Seek to %"PRIuELF" failed: %s\n",
> ehdr.e_shoff, strerror(errno));
> }
> for (i = 0; i < ehdr.e_shnum; i++) {
> @@ -431,11 +431,11 @@ static void read_strtabs(FILE *fp)
> }
> sec->strtab = malloc(sec->shdr.sh_size);
> if (!sec->strtab) {
> - die("malloc of %d bytes for strtab failed\n",
> + die("malloc of %"PRIuELF" bytes for strtab failed\n",
> sec->shdr.sh_size);
> }
> if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
> - die("Seek to %d failed: %s\n",
> + die("Seek to %"PRIuELF" failed: %s\n",
> sec->shdr.sh_offset, strerror(errno));
> }
> if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
> @@ -456,11 +456,11 @@ static void read_symtabs(FILE *fp)
> }
> sec->symtab = malloc(sec->shdr.sh_size);
> if (!sec->symtab) {
> - die("malloc of %d bytes for symtab failed\n",
> + die("malloc of %"PRIuELF" bytes for symtab failed\n",
> sec->shdr.sh_size);
> }
> if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
> - die("Seek to %d failed: %s\n",
> + die("Seek to %"PRIuELF" failed: %s\n",
> sec->shdr.sh_offset, strerror(errno));
> }
> if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
> @@ -489,11 +489,11 @@ static void read_relocs(FILE *fp)
> }
> sec->reltab = malloc(sec->shdr.sh_size);
> if (!sec->reltab) {
> - die("malloc of %d bytes for relocs failed\n",
> + die("malloc of %"PRIuELF" bytes for relocs failed\n",
> sec->shdr.sh_size);
> }
> if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
> - die("Seek to %d failed: %s\n",
> + die("Seek to %"PRIuELF" failed: %s\n",
> sec->shdr.sh_offset, strerror(errno));
> }
> if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
> diff --git a/arch/x86/tools/relocs.h b/arch/x86/tools/relocs.h
> index f59590645b68..6b7969719833 100644
> --- a/arch/x86/tools/relocs.h
> +++ b/arch/x86/tools/relocs.h
> @@ -16,7 +16,8 @@
> #include <regex.h>
> #include <tools/le_byteshift.h>
>
> -void die(char *fmt, ...);
> +__attribute__((format(printf, 1, 2))) __attribute__((noreturn))
> +void die(const char *fmt, ...);
>
> #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
>
> diff --git a/arch/x86/tools/relocs_32.c b/arch/x86/tools/relocs_32.c
> index b2ade2bb4162..8024ec473e6a 100644
> --- a/arch/x86/tools/relocs_32.c
> +++ b/arch/x86/tools/relocs_32.c
> @@ -14,4 +14,7 @@
> #define ELF_ST_BIND(o) ELF32_ST_BIND(o)
> #define ELF_ST_VISIBILITY(o) ELF32_ST_VISIBILITY(o)
>
> +/* printf format for Elf32_Off */
> +#define PRIuELF PRIu32
> +
> #include "relocs.c"
> diff --git a/arch/x86/tools/relocs_64.c b/arch/x86/tools/relocs_64.c
> index 56b61b743c4c..2cf4de5c9d99 100644
> --- a/arch/x86/tools/relocs_64.c
> +++ b/arch/x86/tools/relocs_64.c
> @@ -14,4 +14,7 @@
> #define ELF_ST_BIND(o) ELF64_ST_BIND(o)
> #define ELF_ST_VISIBILITY(o) ELF64_ST_VISIBILITY(o)
>
> +/* printf format for Elf64_Off */
> +#define PRIuELF PRIu64
> +
> #include "relocs.c"
> diff --git a/arch/x86/tools/relocs_common.c b/arch/x86/tools/relocs_common.c
> index acab636bcb34..30adb44eff79 100644
> --- a/arch/x86/tools/relocs_common.c
> +++ b/arch/x86/tools/relocs_common.c
> @@ -1,6 +1,6 @@
> #include "relocs.h"
>
> -void die(char *fmt, ...)
> +void die(const char *fmt, ...)
> {
> va_list ap;
> va_start(ap, fmt);
> --
> 2.9.3
>
I have to admit that this is the first time I am looking at these
format specifier macros from inttypes.h. I looked at that file. Your
usage seems correct to me and should achieve the desired outcome.
Reviewed-by: Nilay Vaish <nilayvaish@gmail.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2 1/1] x86, relocs: add function attributes to die()
2016-09-05 15:28 ` Nilay Vaish
@ 2016-10-23 16:47 ` Nicolas Iooss
0 siblings, 0 replies; 6+ messages in thread
From: Nicolas Iooss @ 2016-10-23 16:47 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, x86
Cc: Nilay Vaish, Linux Kernel list
Hello,
A few weeks ago I sent the patch below and got a review, but this patch
has not been applied yet in linux-next. Does it cause a problem I need
to fix?
Thanks,
Nicolas
On 05/09/16 17:28, Nilay Vaish wrote:
> On 4 September 2016 at 11:51, Nicolas Iooss <nicolas.iooss_linux@m4x.org> wrote:
>> When building the kernel with clang and some warning flags, the compiler
>> reports the following warning:
>>
>> arch/x86/tools/relocs.c:979:6: warning: variable 'do_reloc' is used
>> uninitialized whenever 'if' condition is false
>> [-Wsometimes-uninitialized]
>> if (!use_real_mode)
>> ^~~~~~~~~~~~~~
>> arch/x86/tools/relocs.c:991:14: note: uninitialized use occurs here
>> walk_relocs(do_reloc);
>> ^~~~~~~~
>> arch/x86/tools/relocs.c:979:2: note: remove the 'if' if its
>> condition is always true
>> if (!use_real_mode)
>> ^~~~~~~~~~~~~~~~~~~
>> arch/x86/tools/relocs.c:976:24: note: initialize the variable
>> 'do_reloc' to silence this warning
>> const char *symname);
>> ^
>> = NULL
>>
>> This is obviously a false positive: whenever the 'if' condition is
>> false, the program calls die(). Nevertheless the compiler did not know
>> this call makes the program quit because this function did not have a
>> noreturn attribute. Add it.
>>
>> While at it, add a printf attribute too to die() and constify the format
>> parameter. This leads to some errors when compiling on x86_64:
>>
>> arch/x86/tools/relocs.c:460:5: error: format specifies type 'int'
>> but the argument has type 'Elf64_Xword' (aka 'unsigned long')
>> [-Werror,-Wformat]
>> sec->shdr.sh_size);
>> ^~~~~~~~~~~~~~~~~
>> arch/x86/tools/relocs.c:464:5: error: format specifies type 'int'
>> but the argument has type 'Elf64_Off' (aka 'unsigned long')
>> [-Werror,-Wformat]
>> sec->shdr.sh_offset, strerror(errno));
>> ^~~~~~~~~~~~~~~~~~~
>>
>> When relocs.c is included by relocs_32.c, sec->shdr.sh_size and
>> sec->shdr.sh_offset are 32-bit unsigned integers. When the file is
>> included by relocs_64.c, these expressions are 64-bit unsigned integers.
>>
>> Introduce a PRIuELF macro to define the right format to use when
>> printing these expressions.
>>
>> Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
>> ---
>> arch/x86/tools/relocs.c | 14 +++++++-------
>> arch/x86/tools/relocs.h | 3 ++-
>> arch/x86/tools/relocs_32.c | 3 +++
>> arch/x86/tools/relocs_64.c | 3 +++
>> arch/x86/tools/relocs_common.c | 2 +-
>> 5 files changed, 16 insertions(+), 9 deletions(-)
>>
>> diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
>> index 0c2fae8d929d..4cad603b8d58 100644
>> --- a/arch/x86/tools/relocs.c
>> +++ b/arch/x86/tools/relocs.c
>> @@ -397,7 +397,7 @@ static void read_shdrs(FILE *fp)
>> ehdr.e_shnum);
>> }
>> if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
>> - die("Seek to %d failed: %s\n",
>> + die("Seek to %"PRIuELF" failed: %s\n",
>> ehdr.e_shoff, strerror(errno));
>> }
>> for (i = 0; i < ehdr.e_shnum; i++) {
>> @@ -431,11 +431,11 @@ static void read_strtabs(FILE *fp)
>> }
>> sec->strtab = malloc(sec->shdr.sh_size);
>> if (!sec->strtab) {
>> - die("malloc of %d bytes for strtab failed\n",
>> + die("malloc of %"PRIuELF" bytes for strtab failed\n",
>> sec->shdr.sh_size);
>> }
>> if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
>> - die("Seek to %d failed: %s\n",
>> + die("Seek to %"PRIuELF" failed: %s\n",
>> sec->shdr.sh_offset, strerror(errno));
>> }
>> if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
>> @@ -456,11 +456,11 @@ static void read_symtabs(FILE *fp)
>> }
>> sec->symtab = malloc(sec->shdr.sh_size);
>> if (!sec->symtab) {
>> - die("malloc of %d bytes for symtab failed\n",
>> + die("malloc of %"PRIuELF" bytes for symtab failed\n",
>> sec->shdr.sh_size);
>> }
>> if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
>> - die("Seek to %d failed: %s\n",
>> + die("Seek to %"PRIuELF" failed: %s\n",
>> sec->shdr.sh_offset, strerror(errno));
>> }
>> if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
>> @@ -489,11 +489,11 @@ static void read_relocs(FILE *fp)
>> }
>> sec->reltab = malloc(sec->shdr.sh_size);
>> if (!sec->reltab) {
>> - die("malloc of %d bytes for relocs failed\n",
>> + die("malloc of %"PRIuELF" bytes for relocs failed\n",
>> sec->shdr.sh_size);
>> }
>> if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
>> - die("Seek to %d failed: %s\n",
>> + die("Seek to %"PRIuELF" failed: %s\n",
>> sec->shdr.sh_offset, strerror(errno));
>> }
>> if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
>> diff --git a/arch/x86/tools/relocs.h b/arch/x86/tools/relocs.h
>> index f59590645b68..6b7969719833 100644
>> --- a/arch/x86/tools/relocs.h
>> +++ b/arch/x86/tools/relocs.h
>> @@ -16,7 +16,8 @@
>> #include <regex.h>
>> #include <tools/le_byteshift.h>
>>
>> -void die(char *fmt, ...);
>> +__attribute__((format(printf, 1, 2))) __attribute__((noreturn))
>> +void die(const char *fmt, ...);
>>
>> #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
>>
>> diff --git a/arch/x86/tools/relocs_32.c b/arch/x86/tools/relocs_32.c
>> index b2ade2bb4162..8024ec473e6a 100644
>> --- a/arch/x86/tools/relocs_32.c
>> +++ b/arch/x86/tools/relocs_32.c
>> @@ -14,4 +14,7 @@
>> #define ELF_ST_BIND(o) ELF32_ST_BIND(o)
>> #define ELF_ST_VISIBILITY(o) ELF32_ST_VISIBILITY(o)
>>
>> +/* printf format for Elf32_Off */
>> +#define PRIuELF PRIu32
>> +
>> #include "relocs.c"
>> diff --git a/arch/x86/tools/relocs_64.c b/arch/x86/tools/relocs_64.c
>> index 56b61b743c4c..2cf4de5c9d99 100644
>> --- a/arch/x86/tools/relocs_64.c
>> +++ b/arch/x86/tools/relocs_64.c
>> @@ -14,4 +14,7 @@
>> #define ELF_ST_BIND(o) ELF64_ST_BIND(o)
>> #define ELF_ST_VISIBILITY(o) ELF64_ST_VISIBILITY(o)
>>
>> +/* printf format for Elf64_Off */
>> +#define PRIuELF PRIu64
>> +
>> #include "relocs.c"
>> diff --git a/arch/x86/tools/relocs_common.c b/arch/x86/tools/relocs_common.c
>> index acab636bcb34..30adb44eff79 100644
>> --- a/arch/x86/tools/relocs_common.c
>> +++ b/arch/x86/tools/relocs_common.c
>> @@ -1,6 +1,6 @@
>> #include "relocs.h"
>>
>> -void die(char *fmt, ...)
>> +void die(const char *fmt, ...)
>> {
>> va_list ap;
>> va_start(ap, fmt);
>> --
>> 2.9.3
>>
>
> I have to admit that this is the first time I am looking at these
> format specifier macros from inttypes.h. I looked at that file. Your
> usage seems correct to me and should achieve the desired outcome.
>
> Reviewed-by: Nilay Vaish <nilayvaish@gmail.com>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-10-23 16:47 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-09-03 14:50 [PATCH 1/1] x86, relocs: add function attributes to die() Nicolas Iooss
2016-09-03 15:16 ` Nilay Vaish
2016-09-03 15:51 ` Nicolas Iooss
2016-09-04 16:51 ` [PATCH v2 " Nicolas Iooss
2016-09-05 15:28 ` Nilay Vaish
2016-10-23 16:47 ` Nicolas Iooss
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).