FAILED: patch "[PATCH] powerpc: Avoid clang warnings around setjmp and longjmp" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From c9029ef9c95765e7b63c4d9aa780674447db1ec0 Mon Sep 17 00:00:00 2001
From: Nathan Chancellor <[email protected]>
Date: Mon, 18 Nov 2019 21:57:11 -0700
Subject: [PATCH] powerpc: Avoid clang warnings around setjmp and longjmp

Commit aea447141c7e ("powerpc: Disable -Wbuiltin-requires-header when setjmp is used") disabled -Wbuiltin-requires-header because of a warning about the setjmp and longjmp declarations.

r367387 in clang added another diagnostic around this, complaining that there is no jmp_buf declaration.

In file included from ../arch/powerpc/xmon/xmon.c:47:
../arch/powerpc/include/asm/setjmp.h:10:13: 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 long setjmp(long *);
              ^
  ../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 *, long);
              ^

2 errors generated.

We are not using the standard library's longjmp/setjmp implementations for obvious reasons; make this clear to clang by using -ffreestanding on these files.

index 16c1c5a19519..378f6108a414 100644
@@ -3,8 +3,8 @@
 # Makefile for the linux kernel.
 #
 
-# Disable clang warning for using setjmp without setjmp.h header
-CFLAGS_crash.o		+= $(call cc-disable-warning, builtin-requires-header)
+# Avoid clang warnings around longjmp/setjmp declarations
+CFLAGS_crash.o += -ffreestanding
 
 obj-y				+= core.o crash.o core_$(BITS).o
 

index f142570ad860..c3842dbeb1b7 100644
@@ -1,8 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
 # Makefile for xmon
 
-# Disable clang warning for using setjmp without setjmp.h header
-subdir-ccflags-y := $(call cc-disable-warning, builtin-requires-header)
+# Avoid clang warnings around longjmp/setjmp declarations
+subdir-ccflags-y := -ffreestanding
 
 GCOV_PROFILE := n
 KCOV_INSTRUMENT := n