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parisc: Unbreak bootloader due to gcc-7 optimizations

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gcc-7 optimizes the byte-wise accesses of get_unaligned_le32() into
word-wise accesses if the 32-bit integer output_len is declared as
external. This panics then the bootloader since we don't have the
unaligned access fault trap handler installed during boot time.

Avoid this optimization by declaring output_len as byte-aligned and thus
unbreak the bootloader code.

Additionally, compile the boot code optimized for size.

Signed-off-by: Helge Deller <deller@gmx.de>
This commit is contained in:
Helge Deller 2017-09-22 21:57:11 +02:00
parent af21b01d11
commit 8c031ba63f
2 changed files with 3 additions and 2 deletions
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2
arch/parisc/boot/compressed/Makefile
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@ -15,7 +15,7 @@ targets += misc.o piggy.o sizes.h head.o real2.o firmware.o
KBUILD_CFLAGS := -D__KERNEL__ -O2 -DBOOTLOADER
KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
KBUILD_CFLAGS += $(cflags-y) -fno-delete-null-pointer-checks
KBUILD_CFLAGS += -fno-PIE -mno-space-regs -mdisable-fpregs
KBUILD_CFLAGS += -fno-PIE -mno-space-regs -mdisable-fpregs -Os
ifndef CONFIG_64BIT
KBUILD_CFLAGS += -mfast-indirect-calls
endif

3
arch/parisc/boot/compressed/misc.c
View File

@ -24,7 +24,8 @@
/* Symbols defined by linker scripts */
extern char input_data[];
extern int input_len;
extern __le32 output_len; /* at unaligned address, little-endian */
/* output_len is inserted by the linker possibly at an unaligned address */
extern __le32 output_len __aligned(1);
extern char _text, _end;
extern char _bss, _ebss;
extern char _startcode_end;