linux-kernel - [PATCH 4.19 131/146] powerpc: Make setjmp/longjmp signature standard

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Message-Id: <20200416131300.399910196@linuxfoundation.org>
Date:   Thu, 16 Apr 2020 15:24:32 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Clement Courbet <courbet@...gle.com>,
        Nathan Chancellor <natechancellor@...il.com>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH 4.19 131/146] powerpc: Make setjmp/longjmp signature standard

From: Clement Courbet <courbet@...gle.com>

commit c17eb4dca5a353a9dbbb8ad6934fe57af7165e91 upstream.

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.

Fixes: c9029ef9c957 ("powerpc: Avoid clang warnings around setjmp and longjmp")
Cc: stable@...r.kernel.org # v4.14+
Signed-off-by: Clement Courbet <courbet@...gle.com>
Reviewed-by: Nathan Chancellor <natechancellor@...il.com>
Tested-by: Nathan Chancellor <natechancellor@...il.com>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Link: https://lore.kernel.org/r/20200330080400.124803-1-courbet@google.com
Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/powerpc/include/asm/setjmp.h |    6 ++++--
 arch/powerpc/kernel/Makefile      |    3 ---
 arch/powerpc/xmon/Makefile        |    3 ---
 3 files changed, 4 insertions(+), 8 deletions(-)

--- a/arch/powerpc/include/asm/setjmp.h
+++ b/arch/powerpc/include/asm/setjmp.h
@@ -12,7 +12,9 @@
 
 #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 */
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -5,9 +5,6 @@
 
 CFLAGS_ptrace.o		+= -DUTS_MACHINE='"$(UTS_MACHINE)"'
 
-# Avoid clang warnings around longjmp/setjmp declarations
-CFLAGS_crash.o += -ffreestanding
-
 subdir-ccflags-$(CONFIG_PPC_WERROR) := -Werror
 
 ifdef CONFIG_PPC64
--- 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
-
 subdir-ccflags-$(CONFIG_PPC_WERROR) += -Werror
 
 GCOV_PROFILE := n