diff mbox series

[v3] powerpc: Make setjmp/longjmp signature standard

Message ID 20200330080400.124803-1-courbet@google.com (mailing list archive)
State Accepted
Commit c17eb4dca5a353a9dbbb8ad6934fe57af7165e91
Headers show
Series [v3] powerpc: Make setjmp/longjmp signature standard | expand

Checks

Context Check Description
snowpatch_ozlabs/apply_patch success Successfully applied on branch powerpc/merge (c6624071c338732402e8c726df6a4074473eaa0e)
snowpatch_ozlabs/build-ppc64le success Build succeeded
snowpatch_ozlabs/build-ppc64be success Build succeeded
snowpatch_ozlabs/build-ppc64e success Build succeeded
snowpatch_ozlabs/build-pmac32 success Build succeeded
snowpatch_ozlabs/checkpatch warning total: 0 errors, 1 warnings, 2 checks, 29 lines checked
snowpatch_ozlabs/needsstable success Patch is tagged for stable

Commit Message

Clement Courbet March 30, 2020, 8:03 a.m. UTC 
Declaring setjmp()/longjmp() as taking longs makes the signature
non-standard, and makes clang complain. In the past, this has been
worked around by adding -ffreestanding to the compile flags.

The implementation looks like it only ever propagates the value
(in longjmp) or sets it to 1 (in setjmp), and we only call longjmp
with integer parameters.

This allows removing -ffreestanding from the compilation flags.

Context:
https://lore.kernel.org/patchwork/patch/1214060
https://lore.kernel.org/patchwork/patch/1216174

Signed-off-by: Clement Courbet <courbet@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Cc: stable@vger.kernel.org # v4.14+
Fixes: c9029ef9c957 ("powerpc: Avoid clang warnings around setjmp and longjmp")

---

v2:
Use and array type as suggested by Segher Boessenkool
Add fix tags.

v3:
Properly place tags.
---
 arch/powerpc/include/asm/setjmp.h | 6 ++++--
 arch/powerpc/kexec/Makefile       | 3 ---
 arch/powerpc/xmon/Makefile        | 3 ---
 3 files changed, 4 insertions(+), 8 deletions(-)

Comments

Nick Desaulniers March 30, 2020, 4:20 p.m. UTC | #1 
On Mon, Mar 30, 2020 at 1:04 AM Clement Courbet <courbet@google.com> wrote:
>
> Declaring setjmp()/longjmp() as taking longs makes the signature
> non-standard, and makes clang complain. In the past, this has been
> worked around by adding -ffreestanding to the compile flags.
>
> The implementation looks like it only ever propagates the value
> (in longjmp) or sets it to 1 (in setjmp), and we only call longjmp
> with integer parameters.
>
> This allows removing -ffreestanding from the compilation flags.
>
> Context:
> https://lore.kernel.org/patchwork/patch/1214060
> https://lore.kernel.org/patchwork/patch/1216174
>
> Signed-off-by: Clement Courbet <courbet@google.com>
> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> Tested-by: Nathan Chancellor <natechancellor@gmail.com>
> Cc: stable@vger.kernel.org # v4.14+
> Fixes: c9029ef9c957 ("powerpc: Avoid clang warnings around setjmp and longjmp")

Third time's a charm (for patches that tackle this warning). Thanks
for following up on this cleanup!
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>

The extent of my testing was compile testing with Clang.

>
> ---
>
> v2:
> Use and array type as suggested by Segher Boessenkool
> Add fix tags.
>
> v3:
> Properly place tags.
> ---
>  arch/powerpc/include/asm/setjmp.h | 6 ++++--
>  arch/powerpc/kexec/Makefile       | 3 ---
>  arch/powerpc/xmon/Makefile        | 3 ---
>  3 files changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/setjmp.h b/arch/powerpc/include/asm/setjmp.h
> index e9f81bb3f83b..f798e80e4106 100644
> --- a/arch/powerpc/include/asm/setjmp.h
> +++ b/arch/powerpc/include/asm/setjmp.h
> @@ -7,7 +7,9 @@
>
>  #define JMP_BUF_LEN    23
>
> -extern long setjmp(long *) __attribute__((returns_twice));
> -extern void longjmp(long *, long) __attribute__((noreturn));
> +typedef long jmp_buf[JMP_BUF_LEN];
> +
> +extern int setjmp(jmp_buf env) __attribute__((returns_twice));
> +extern void longjmp(jmp_buf env, int val) __attribute__((noreturn));
>
>  #endif /* _ASM_POWERPC_SETJMP_H */
> diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
> index 378f6108a414..86380c69f5ce 100644
> --- a/arch/powerpc/kexec/Makefile
> +++ b/arch/powerpc/kexec/Makefile
> @@ -3,9 +3,6 @@
>  # Makefile for the linux kernel.
>  #
>
> -# Avoid clang warnings around longjmp/setjmp declarations
> -CFLAGS_crash.o += -ffreestanding
> -
>  obj-y                          += core.o crash.o core_$(BITS).o
>
>  obj-$(CONFIG_PPC32)            += relocate_32.o
> diff --git a/arch/powerpc/xmon/Makefile b/arch/powerpc/xmon/Makefile
> index c3842dbeb1b7..6f9cccea54f3 100644
> --- a/arch/powerpc/xmon/Makefile
> +++ b/arch/powerpc/xmon/Makefile
> @@ -1,9 +1,6 @@
>  # SPDX-License-Identifier: GPL-2.0
>  # Makefile for xmon
>
> -# Avoid clang warnings around longjmp/setjmp declarations
> -subdir-ccflags-y := -ffreestanding
> -
>  GCOV_PROFILE := n
>  KCOV_INSTRUMENT := n
>  UBSAN_SANITIZE := n
> --
> 2.26.0.rc2.310.g2932bb562d-goog
>
Michael Ellerman April 1, 2020, 12:53 p.m. UTC | #2 
On Mon, 2020-03-30 at 08:03:56 UTC, Clement Courbet wrote:
> Declaring setjmp()/longjmp() as taking longs makes the signature
> non-standard, and makes clang complain. In the past, this has been
> worked around by adding -ffreestanding to the compile flags.
> 
> The implementation looks like it only ever propagates the value
> (in longjmp) or sets it to 1 (in setjmp), and we only call longjmp
> with integer parameters.
> 
> This allows removing -ffreestanding from the compilation flags.
> 
> Context:
> https://lore.kernel.org/patchwork/patch/1214060
> https://lore.kernel.org/patchwork/patch/1216174
> 
> Signed-off-by: Clement Courbet <courbet@google.com>
> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> Tested-by: Nathan Chancellor <natechancellor@gmail.com>
> Cc: stable@vger.kernel.org # v4.14+
> Fixes: c9029ef9c957 ("powerpc: Avoid clang warnings around setjmp and longjmp")

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/c17eb4dca5a353a9dbbb8ad6934fe57af7165e91

cheers
diff mbox series

Patch

diff --git a/arch/powerpc/include/asm/setjmp.h b/arch/powerpc/include/asm/setjmp.h
index e9f81bb3f83b..f798e80e4106 100644
--- a/arch/powerpc/include/asm/setjmp.h
+++ b/arch/powerpc/include/asm/setjmp.h
@@ -7,7 +7,9 @@ 
 
 #define JMP_BUF_LEN    23
 
-extern long setjmp(long *) __attribute__((returns_twice));
-extern void longjmp(long *, long) __attribute__((noreturn));
+typedef long jmp_buf[JMP_BUF_LEN];
+
+extern int setjmp(jmp_buf env) __attribute__((returns_twice));
+extern void longjmp(jmp_buf env, int val) __attribute__((noreturn));
 
 #endif /* _ASM_POWERPC_SETJMP_H */
diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
index 378f6108a414..86380c69f5ce 100644
--- a/arch/powerpc/kexec/Makefile
+++ b/arch/powerpc/kexec/Makefile
@@ -3,9 +3,6 @@ 
 # Makefile for the linux kernel.
 #
 
-# Avoid clang warnings around longjmp/setjmp declarations
-CFLAGS_crash.o += -ffreestanding
-
 obj-y				+= core.o crash.o core_$(BITS).o
 
 obj-$(CONFIG_PPC32)		+= relocate_32.o
diff --git a/arch/powerpc/xmon/Makefile b/arch/powerpc/xmon/Makefile
index c3842dbeb1b7..6f9cccea54f3 100644
--- a/arch/powerpc/xmon/Makefile
+++ b/arch/powerpc/xmon/Makefile
@@ -1,9 +1,6 @@ 
 # SPDX-License-Identifier: GPL-2.0
 # Makefile for xmon
 
-# Avoid clang warnings around longjmp/setjmp declarations
-subdir-ccflags-y := -ffreestanding
-
 GCOV_PROFILE := n
 KCOV_INSTRUMENT := n
 UBSAN_SANITIZE := n