On Fri, Mar 27, 2020 at 06:45:21PM +0100, Christophe Leroy wrote:

Subject line, change longjump to longjmp

Le 27/03/2020 à 11:07, Clement Courbet a écrit :

quoted

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 <redacted>
---
  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;

Do we need that new opaque typedef ? Why not just keep long * ?

Yes, otherwise the warning comes back:

In file included from arch/powerpc/kexec/crash.c:25:
arch/powerpc/include/asm/setjmp.h:10:12: error: declaration of built-in function 'setjmp' requires the declaration of the 'jmp_buf' type, commonly provided in the header <setjmp.h>. [-Werror,-Wincomplete-setjmp-declaration]
extern int setjmp(long *env) __attribute__((returns_twice));
           ^
arch/powerpc/include/asm/setjmp.h:11:13: error: declaration of built-in function 'longjmp' requires the declaration of the 'jmp_buf' type, commonly provided in the header <setjmp.h>. [-Werror,-Wincomplete-setjmp-declaration]
extern void longjmp(long *env, int val) __attribute__((noreturn));
            ^
2 errors generated.

quoted

+
+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

Christophe