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ARM: 7877/1: use built-in byte swap function

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Enable the compiler intrinsic for byte swapping on arch ARM. This
allows the compiler to detect and be able to optimize out byte
swappings, and has a very modest benefit on vmlinux size (Linaro gcc
4.8):

text data bss dec hex filename
2840310 123932 61960 3026202 2e2d1a vmlinux-lart #orig
2840152 123932 61960 3026044 2e2c7c vmlinux-lart #builtin-bswap

6473120 314840 5616016 12403976 bd4508 vmlinux-mxs #orig
6472586 314848 5616016 12403450 bd42fa vmlinux-mxs #builtin-bswap

7419872 318372 379556 8117800 7bde28 vmlinux-imx_v6_v7 #orig
7419170 318364 379556 8117090 7bdb62 vmlinux-imx_v6_v7 #builtin-bswap

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Kim Phillips 2013-11-06 05:15:24 +01:00 • committed by Russell King
commit 017f161a55
5 changed files with 53 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

1
arch/arm/Kconfig
View file

@ -6,6 +6,7 @@ config ARM
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAVE_CUSTOM_GPIO_H select ARCH_HAVE_CUSTOM_GPIO_H
select ARCH_MIGHT_HAVE_PC_PARPORT select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_USE_BUILTIN_BSWAP
select ARCH_USE_CMPXCHG_LOCKREF select ARCH_USE_CMPXCHG_LOCKREF
select ARCH_WANT_IPC_PARSE_VERSION select ARCH_WANT_IPC_PARSE_VERSION
select BUILDTIME_EXTABLE_SORT if MMU select BUILDTIME_EXTABLE_SORT if MMU

15
arch/arm/boot/compressed/Makefile
View file

@ -108,12 +108,12 @@ endif
targets := vmlinux vmlinux.lds \ targets := vmlinux vmlinux.lds \
piggy.$(suffix_y) piggy.$(suffix_y).o \ piggy.$(suffix_y) piggy.$(suffix_y).o \
lib1funcs.o lib1funcs.S ashldi3.o ashldi3.S \ lib1funcs.o lib1funcs.S ashldi3.o ashldi3.S bswapsdi2.o \
font.o font.c head.o misc.o $(OBJS) bswapsdi2.S font.o font.c head.o misc.o $(OBJS)
# Make sure files are removed during clean # Make sure files are removed during clean
extra-y += piggy.gzip piggy.lzo piggy.lzma piggy.xzkern piggy.lz4 \ extra-y += piggy.gzip piggy.lzo piggy.lzma piggy.xzkern piggy.lz4 \
lib1funcs.S ashldi3.S $(libfdt) $(libfdt_hdrs) \ lib1funcs.S ashldi3.S bswapsdi2.S $(libfdt) $(libfdt_hdrs) \
hyp-stub.S hyp-stub.S
ifeq ($(CONFIG_FUNCTION_TRACER),y) ifeq ($(CONFIG_FUNCTION_TRACER),y)
@ -156,6 +156,12 @@ ashldi3 = $(obj)/ashldi3.o
$(obj)/ashldi3.S: $(srctree)/arch/$(SRCARCH)/lib/ashldi3.S $(obj)/ashldi3.S: $(srctree)/arch/$(SRCARCH)/lib/ashldi3.S
$(call cmd,shipped) $(call cmd,shipped)
# For __bswapsi2, __bswapdi2
bswapsdi2 = $(obj)/bswapsdi2.o
$(obj)/bswapsdi2.S: $(srctree)/arch/$(SRCARCH)/lib/bswapsdi2.S
$(call cmd,shipped)
# We need to prevent any GOTOFF relocs being used with references # We need to prevent any GOTOFF relocs being used with references
# to symbols in the .bss section since we cannot relocate them # to symbols in the .bss section since we cannot relocate them
# independently from the rest at run time. This can be achieved by # independently from the rest at run time. This can be achieved by
@ -177,7 +183,8 @@ if [ $(words $(ZRELADDR)) -gt 1 -a "$(CONFIG_AUTO_ZRELADDR)" = "" ]; then \
fi fi
$(obj)/vmlinux: $(obj)/vmlinux.lds $(obj)/$(HEAD) $(obj)/piggy.$(suffix_y).o \ $(obj)/vmlinux: $(obj)/vmlinux.lds $(obj)/$(HEAD) $(obj)/piggy.$(suffix_y).o \
$(addprefix $(obj)/, $(OBJS)) $(lib1funcs) $(ashldi3) FORCE $(addprefix $(obj)/, $(OBJS)) $(lib1funcs) $(ashldi3) \
$(bswapsdi2) FORCE
@$(check_for_multiple_zreladdr) @$(check_for_multiple_zreladdr)
$(call if_changed,ld) $(call if_changed,ld)
@$(check_for_bad_syms) @$(check_for_bad_syms)

4
arch/arm/kernel/armksyms.c
View file

@ -35,6 +35,8 @@ extern void __ucmpdi2(void);
extern void __udivsi3(void); extern void __udivsi3(void);
extern void __umodsi3(void); extern void __umodsi3(void);
extern void __do_div64(void); extern void __do_div64(void);
extern void __bswapsi2(void);
extern void __bswapdi2(void);
extern void __aeabi_idiv(void); extern void __aeabi_idiv(void);
extern void __aeabi_idivmod(void); extern void __aeabi_idivmod(void);
@ -114,6 +116,8 @@ EXPORT_SYMBOL(__ucmpdi2);
EXPORT_SYMBOL(__udivsi3); EXPORT_SYMBOL(__udivsi3);
EXPORT_SYMBOL(__umodsi3); EXPORT_SYMBOL(__umodsi3);
EXPORT_SYMBOL(__do_div64); EXPORT_SYMBOL(__do_div64);
EXPORT_SYMBOL(__bswapsi2);
EXPORT_SYMBOL(__bswapdi2);
#ifdef CONFIG_AEABI #ifdef CONFIG_AEABI
EXPORT_SYMBOL(__aeabi_idiv); EXPORT_SYMBOL(__aeabi_idiv);

2
arch/arm/lib/Makefile
View file

@ -13,7 +13,7 @@ lib-y := backtrace.o changebit.o csumipv6.o csumpartial.o \
ashldi3.o ashrdi3.o lshrdi3.o muldi3.o \ ashldi3.o ashrdi3.o lshrdi3.o muldi3.o \
ucmpdi2.o lib1funcs.o div64.o \ ucmpdi2.o lib1funcs.o div64.o \
io-readsb.o io-writesb.o io-readsl.o io-writesl.o \ io-readsb.o io-writesb.o io-readsl.o io-writesl.o \
call_with_stack.o call_with_stack.o bswapsdi2.o
mmu-y := clear_user.o copy_page.o getuser.o putuser.o mmu-y := clear_user.o copy_page.o getuser.o putuser.o

36
arch/arm/lib/bswapsdi2.S Normal file
View file

@ -0,0 +1,36 @@
#include <linux/linkage.h>
#if __LINUX_ARM_ARCH__ >= 6
ENTRY(__bswapsi2)
rev r0, r0
bx lr
ENDPROC(__bswapsi2)
ENTRY(__bswapdi2)
rev r3, r0
rev r0, r1
mov r1, r3
bx lr
ENDPROC(__bswapdi2)
#else
ENTRY(__bswapsi2)
eor r3, r0, r0, ror #16
mov r3, r3, lsr #8
bic r3, r3, #0xff00
eor r0, r3, r0, ror #8
mov pc, lr
ENDPROC(__bswapsi2)
ENTRY(__bswapdi2)
mov ip, r1
eor r3, ip, ip, ror #16
eor r1, r0, r0, ror #16
mov r1, r1, lsr #8
mov r3, r3, lsr #8
bic r3, r3, #0xff00
bic r1, r1, #0xff00
eor r1, r1, r0, ror #8
eor r0, r3, ip, ror #8
mov pc, lr
ENDPROC(__bswapdi2)
#endif