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From: Clement Courbet <courbet@google.com>
To: unlisted-recipients:; (no To-header on input)
Cc: Nick Desaulniers <ndesaulniers@google.com>,
	Nathan Chancellor <natechancellor@gmail.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Clement Courbet <courbet@google.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Segher Boessenkool <segher@kernel.crashing.org>,
	Christophe Leroy <christophe.leroy@c-s.fr>,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	clang-built-linux@googlegroups.com
Subject: [PATCH v1] powerpc: Make setjmp/longjump signature standard
Date: Fri, 27 Mar 2020 11:07:56 +0100
Message-ID: <20200327100801.161671-1-courbet@google.com> (raw)

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>
---
 arch/powerpc/include/asm/setjmp.h | 6 ++++--
 arch/powerpc/kexec/Makefile       | 3 ---
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/include/asm/setjmp.h b/arch/powerpc/include/asm/setjmp.h
index e9f81bb3f83b..84bb0d140d59 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;
+
+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
-- 
2.25.1.696.g5e7596f4ac-goog


             reply index

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-27 10:07 Clement Courbet [this message]
2020-03-27 17:10 ` Nick Desaulniers
2020-03-27 17:27   ` Nathan Chancellor
2020-03-27 17:45 ` Christophe Leroy
2020-03-27 18:27   ` Nathan Chancellor
2020-03-30  6:42 ` Clement Courbet
2020-03-30  6:43 ` [PATCH v2] powerpc: Make setjmp/longjmp " Clement Courbet
2020-03-30  7:57   ` Nathan Chancellor
2020-03-30  8:03 ` [PATCH v3] " Clement Courbet
2020-03-30 16:20   ` Nick Desaulniers

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