Call __stack_chk_guard_setup() in decompress_kernel() is too late that
stack checking always fails for decompress_kernel() itself. So remove
__stack_chk_guard_setup() and initialize __stack_chk_guard before we
call decompress_kernel().

Original code comes from ARM but also used for MIPS and SH, so fix them
together. If without this fix, compressed booting of these archs will
fail because stack checking is enabled by default (>=4.16).

V1 -> V2: Fix build on ARM.
V2 -> V3: Fix build on SuperH.
V3 -> V4: Initialize __stack_chk_guard in C code as a constant.

Cc: stable at vger.kernel.org
Signed-off-by: Huacai Chen <redacted>
---
 arch/arm/boot/compressed/misc.c        | 9 +--------
 arch/mips/boot/compressed/decompress.c | 9 +--------
 arch/sh/boot/compressed/misc.c         | 9 +--------
 3 files changed, 3 insertions(+), 24 deletions(-)

[...]

diff --git a/arch/sh/boot/compressed/misc.c b/arch/sh/boot/compressed/misc.c
index 627ce8e..c15cac9 100644
--- a/arch/sh/boot/compressed/misc.c
+++ b/arch/sh/boot/compressed/misc.c

@@ -104,12 +104,7 @@ static void error(char *x)
 	while(1);	/* Halt */
 }
 
-unsigned long __stack_chk_guard;
-
-void __stack_chk_guard_setup(void)
-{
-	__stack_chk_guard = 0x000a0dff;
-}
+const unsigned long __stack_chk_guard = 0x000a0dff;
 
 void __stack_chk_fail(void)
 {

@@ -130,8 +125,6 @@ void decompress_kernel(void)
 {
 	unsigned long output_addr;
 
-	__stack_chk_guard_setup();
-
 #ifdef CONFIG_SUPERH64
 	output_addr = (CONFIG_MEMORY_START + 0x2000);
 #else

-- 
2.7.0