From a2ac1bb1f3ddbad8388b0ba4edf28ff501009cea Mon Sep 17 00:00:00 2001 From: Vasily Gorbik Date: Wed, 25 Jul 2018 13:27:27 +0200 Subject: [PATCH] s390/decompressor: get rid of .bss usage Using .bss in early code should be avoided. It might overlay initrd image or not yet be initialized. Clean up the last couple of places in the decompressor's code where .bss is used and enfore no .bss usage check on boot/compressed/misc.c. In particular: - initializing free_mem_ptr and free_mem_end_ptr with values guarantee that these variables won't end up in the .bss section. - define STATIC_RW_DATA to go into .data section. Reviewed-by: Martin Schwidefsky Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky --- arch/s390/boot/compressed/Makefile | 2 +- arch/s390/boot/compressed/misc.c | 17 +++++------------ 2 files changed, 6 insertions(+), 13 deletions(-) diff --git a/arch/s390/boot/compressed/Makefile b/arch/s390/boot/compressed/Makefile index 8262984..a69746c 100644 --- a/arch/s390/boot/compressed/Makefile +++ b/arch/s390/boot/compressed/Makefile @@ -62,6 +62,6 @@ OBJCOPYFLAGS_piggy.o := -I binary -O elf64-s390 -B s390:64-bit --rename-section $(obj)/piggy.o: $(obj)/vmlinux.bin$(suffix-y) FORCE $(call if_changed,objcopy) -chkbss := $(filter-out $(obj)/misc.o $(obj)/piggy.o $(obj)/info.o,$(OBJECTS)) +chkbss := $(filter-out $(obj)/piggy.o $(obj)/info.o,$(OBJECTS)) chkbss-target := $(obj)/vmlinux.bin include $(srctree)/arch/s390/scripts/Makefile.chkbss diff --git a/arch/s390/boot/compressed/misc.c b/arch/s390/boot/compressed/misc.c index 8b35af6..5dcf34e 100644 --- a/arch/s390/boot/compressed/misc.c +++ b/arch/s390/boot/compressed/misc.c @@ -11,12 +11,14 @@ #include #include #include +#include #include "decompressor.h" /* * gzip declarations */ #define STATIC static +#define STATIC_RW_DATA static __section(.data) #undef memset #undef memcpy @@ -26,21 +28,20 @@ /* Symbols defined by linker scripts */ extern char _end[]; -extern char _bss[], _ebss[]; extern unsigned char _compressed_start[]; extern unsigned char _compressed_end[]; static void error(char *m); -static unsigned long free_mem_ptr; -static unsigned long free_mem_end_ptr; - #ifdef CONFIG_HAVE_KERNEL_BZIP2 #define HEAP_SIZE 0x400000 #else #define HEAP_SIZE 0x10000 #endif +static unsigned long free_mem_ptr = (unsigned long) _end; +static unsigned long free_mem_end_ptr = (unsigned long) _end + HEAP_SIZE; + #ifdef CONFIG_KERNEL_GZIP #include "../../../../lib/decompress_inflate.c" #endif @@ -102,14 +103,6 @@ void *decompress_kernel(void) } #endif - /* - * Clear bss section. free_mem_ptr and free_mem_end_ptr need to be - * initialized afterwards since they reside in bss. - */ - memset(_bss, 0, _ebss - _bss); - free_mem_ptr = (unsigned long) _end; - free_mem_end_ptr = free_mem_ptr + HEAP_SIZE; - __decompress(_compressed_start, _compressed_end - _compressed_start, NULL, NULL, output, 0, NULL, error); return output; -- 2.7.4