parisc: Unbreak bootloader due to gcc-7 optimizations

8c031ba6 · Helge Deller <[email protected]> · 2017-09-22 21:57:11 +02:00

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 <[email protected]>

Commit: 8c031ba63f8f2a9efc471cb45b2ff18271556544
Parents: af21b01d

Changes

2 files changed · +3 −2

File	Status	Add	Del	Content
arch/parisc/boot/compressed/Makefile	modified	+1	−1	View file
arch/parisc/boot/compressed/misc.c	modified	+2	−1	View file

arch/parisc/boot/compressed/Makefile

View file

diff --git a/arch/parisc/boot/compressed/Makefile b/arch/parisc/boot/compressed/Makefile
index 5450a11..7d7e594 100644
--- a/arch/parisc/boot/compressed/Makefile
+++ b/arch/parisc/boot/compressed/Makefile
@@ -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

arch/parisc/boot/compressed/misc.c

View file

diff --git a/arch/parisc/boot/compressed/misc.c b/arch/parisc/boot/compressed/misc.c
index 13a4bf9..9345b44 100644
--- a/arch/parisc/boot/compressed/misc.c
+++ b/arch/parisc/boot/compressed/misc.c
@@ -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;