When building a Thumb-1-only target with CONFIG_SYS_THUMB_BUILD, some files fail to build, most of the time because they include mcr instructions, which only exist for Thumb-2.
This patch introduces a Kconfig option CONFIG_THUMB2 and uses it to select between Thumb-2 and ARM mode for the aforementioned files.
Signed-off-by: Albert ARIBAUD albert.u.boot@aribaud.net --- This patch has been build-tested and run-tested on ED Mini V2, above the "edmini: switch to SPL" patch, and found to reduce U-Boot size by 25% and SPL size by 14%... and to run fine. :)
This patch has also been tested against side effects on the non-Thumb wireless_space target. The binaries produced with and without this patch were found to differ only by their version string.
Changes in v7: None Changes in v6: None Changes in v5: None Changes in v4: None Changes in v3: - added arch/arm/lib/mem{set,cpy}.S to the list of modules which should always be built in ARM state. - Selected HAS_THUMB2 for CPU_V7M. - Fixed invalidate_l2_cache() when building for Thumb-1.
Changes in v2: - fixed a typo in the commit message - added file arch/arm/thumb1/include/asm/proc-armv/system.h, which overrides arch/arm/include/asm/proc-armv/system.h when building for Thumb-1 and provides non-functional but Thumb-compilable IRQ and FIQ related macros and functions.
Makefile | 2 + arch/arm/Kconfig | 5 ++ arch/arm/cpu/arm926ejs/Makefile | 11 ++++ arch/arm/cpu/arm926ejs/cache.c | 5 ++ arch/arm/include/asm/cache.h | 4 ++ arch/arm/lib/Makefile | 24 +++++++++ arch/arm/lib/cache.c | 11 ++++ arch/arm/lib/memcpy.S | 4 +- arch/arm/lib/memset.S | 2 +- arch/arm/mach-orion5x/Makefile | 10 ++++ arch/arm/thumb1/include/asm/proc-armv/system.h | 69 ++++++++++++++++++++++++++ examples/standalone/Makefile | 10 ++++ 12 files changed, 154 insertions(+), 3 deletions(-) create mode 100644 arch/arm/thumb1/include/asm/proc-armv/system.h
diff --git a/Makefile b/Makefile index d4c35ba..d7fbf95 100644 --- a/Makefile +++ b/Makefile @@ -605,6 +605,8 @@ KBUILD_CFLAGS += $(KCFLAGS) UBOOTINCLUDE := \ -Iinclude \ $(if $(KBUILD_SRC), -I$(srctree)/include) \ + $(if $(CONFIG_SYS_THUMB_BUILD), $(if $(CONFIG_HAS_THUMB2),, \ + -I$(srctree)/arch/$(ARCH)/thumb1/include),) \ -I$(srctree)/arch/$(ARCH)/include \ -include $(srctree)/include/linux/kconfig.h
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 2632099..18aca86 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -10,6 +10,9 @@ config ARM64 config HAS_VBAR bool
+config HAS_THUMB2 + bool + config CPU_ARM720T bool
@@ -32,9 +35,11 @@ config CPU_ARM1176 config CPU_V7 bool select HAS_VBAR + select HAS_THUMB2
config CPU_V7M bool + select HAS_THUMB2
config CPU_PXA bool diff --git a/arch/arm/cpu/arm926ejs/Makefile b/arch/arm/cpu/arm926ejs/Makefile index 63fa159..fe78922 100644 --- a/arch/arm/cpu/arm926ejs/Makefile +++ b/arch/arm/cpu/arm926ejs/Makefile @@ -20,3 +20,14 @@ obj-$(CONFIG_MX25) += mx25/ obj-$(CONFIG_MX27) += mx27/ obj-$(if $(filter mxs,$(SOC)),y) += mxs/ obj-$(if $(filter spear,$(SOC)),y) += spear/ + +# some files can only build in ARM or THUMB2, not THUMB1 + +ifdef CONFIG_SYS_THUMB_BUILD +ifndef CONFIG_HAS_THUMB2 + +CFLAGS_cpu.o := -marm +CFLAGS_cache.o := -marm + +endif +endif diff --git a/arch/arm/cpu/arm926ejs/cache.c b/arch/arm/cpu/arm926ejs/cache.c index e5c1a6a..2839c86 100644 --- a/arch/arm/cpu/arm926ejs/cache.c +++ b/arch/arm/cpu/arm926ejs/cache.c @@ -82,4 +82,9 @@ void flush_dcache_all(void) /* * Stub implementations for l2 cache operations */ + __weak void l2_cache_disable(void) {} + +#if defined CONFIG_SYS_THUMB_BUILD +__weak void invalidate_l2_cache(void) {} +#endif diff --git a/arch/arm/include/asm/cache.h b/arch/arm/include/asm/cache.h index a836e9f..1f63127 100644 --- a/arch/arm/include/asm/cache.h +++ b/arch/arm/include/asm/cache.h @@ -16,6 +16,9 @@ /* * Invalidate L2 Cache using co-proc instruction */ +#ifdef CONFIG_SYS_THUMB_BUILD +void invalidate_l2_cache(void); +#else static inline void invalidate_l2_cache(void) { unsigned int val=0; @@ -24,6 +27,7 @@ static inline void invalidate_l2_cache(void) : : "r" (val) : "cc"); isb(); } +#endif
void l2_cache_enable(void); void l2_cache_disable(void); diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile index 2bdfaba..f3db7b5 100644 --- a/arch/arm/lib/Makefile +++ b/arch/arm/lib/Makefile @@ -60,3 +60,27 @@ obj-$(CONFIG_DEBUG_LL) += debug.o ifneq (,$(findstring -mabi=aapcs-linux,$(PLATFORM_CPPFLAGS))) extra-y += eabi_compat.o endif + +# some files can only build in ARM or THUMB2, not THUMB1 + +ifdef CONFIG_SYS_THUMB_BUILD +ifndef CONFIG_HAS_THUMB2 + +# for C files, just apend -marm, which will override previous -mthumb* + +CFLAGS_cache.o := -marm +CFLAGS_cache-cp15.o := -marm + +# For .S, drop -mthumb* and other thumb-related options. +# CFLAGS_REMOVE_* would not have an effet, so AFLAGS_REMOVE_* +# was implemented and is used here. +# Also, define ${target}_NO_THUMB_BUILD for these two targets +# so that the code knows it should not use Thumb. + +AFLAGS_REMOVE_memset.o := -mthumb -mthumb-interwork +AFLAGS_REMOVE_memcpy.o := -mthumb -mthumb-interwork +AFLAGS_memset.o := -DMEMSET_NO_THUMB_BUILD +AFLAGS_memcpy.o := -DMEMCPY_NO_THUMB_BUILD + +endif +endif diff --git a/arch/arm/lib/cache.c b/arch/arm/lib/cache.c index cd13db3..3bd8710 100644 --- a/arch/arm/lib/cache.c +++ b/arch/arm/lib/cache.c @@ -88,3 +88,14 @@ phys_addr_t noncached_alloc(size_t size, size_t align) return next; } #endif /* CONFIG_SYS_NONCACHED_MEMORY */ + +#if defined(CONFIG_SYS_THUMB_BUILD) +void invalidate_l2_cache(void) +{ + unsigned int val = 0; + + asm volatile("mcr p15, 1, %0, c15, c11, 0 @ invl l2 cache" + : : "r" (val) : "cc"); + isb(); +} +#endif diff --git a/arch/arm/lib/memcpy.S b/arch/arm/lib/memcpy.S index eeaf003..7d9fc0f 100644 --- a/arch/arm/lib/memcpy.S +++ b/arch/arm/lib/memcpy.S @@ -13,7 +13,7 @@ #include <linux/linkage.h> #include <asm/assembler.h>
-#ifdef CONFIG_SYS_THUMB_BUILD +#if defined(CONFIG_SYS_THUMB_BUILD) && !defined(MEMCPY_NO_THUMB_BUILD) #define W(instr) instr.w #else #define W(instr) instr @@ -62,7 +62,7 @@
/* Prototype: void *memcpy(void *dest, const void *src, size_t n); */ .syntax unified -#ifdef CONFIG_SYS_THUMB_BUILD +#if defined(CONFIG_SYS_THUMB_BUILD) && !defined(MEMCPY_NO_THUMB_BUILD) .thumb .thumb_func #endif diff --git a/arch/arm/lib/memset.S b/arch/arm/lib/memset.S index 7208f20..df053a3 100644 --- a/arch/arm/lib/memset.S +++ b/arch/arm/lib/memset.S @@ -16,7 +16,7 @@ .align 5
.syntax unified -#ifdef CONFIG_SYS_THUMB_BUILD +#if defined(CONFIG_SYS_THUMB_BUILD) && !defined(MEMSET_NO_THUMB_BUILD) .thumb .thumb_func #endif diff --git a/arch/arm/mach-orion5x/Makefile b/arch/arm/mach-orion5x/Makefile index 546ebcb..33dcad4 100644 --- a/arch/arm/mach-orion5x/Makefile +++ b/arch/arm/mach-orion5x/Makefile @@ -16,3 +16,13 @@ obj-y += timer.o ifndef CONFIG_SKIP_LOWLEVEL_INIT obj-y += lowlevel_init.o endif + +# some files can only build in ARM or THUMB2, not THUMB1 + +ifdef CONFIG_SYS_THUMB_BUILD +ifndef CONFIG_HAS_THUMB2 + +CFLAGS_cpu.o := -marm + +endif +endif diff --git a/arch/arm/thumb1/include/asm/proc-armv/system.h b/arch/arm/thumb1/include/asm/proc-armv/system.h new file mode 100644 index 0000000..7dfbf3d --- /dev/null +++ b/arch/arm/thumb1/include/asm/proc-armv/system.h @@ -0,0 +1,69 @@ +/* + * Thumb-1 drop-in for the linux/include/asm-arm/proc-armv/system.h + * + * (C) Copyright 2015 + * Albert ARIBAUD albert.u.boot@aribaud.net + * + * The original file does not build in Thumb mode. However, in U-Boot + * we don't use interrupt context, so we can redefine these as empty + * memory barriers, which makes Thumb-1 compiler happy. + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +/* + * Use the same macro name as linux/include/asm-arm/proc-armv/system.h + * here, so that if the original ever gets included after us, it won't + * try to re-redefine anything. + */ + +#ifndef __ASM_PROC_SYSTEM_H +#define __ASM_PROC_SYSTEM_H + +/* + * Redefine all original macros with static inline functions containing + * a simple memory barrier, so that they produce the same instruction + * ordering constraints as their original counterparts. + * We use static inline functions rather than macros so that we can tell + * the compiler to not complain about unused arguments. + */ + +static inline void local_irq_save( + unsigned long flags __attribute__((unused))) +{ + __asm__ __volatile__ ("" : : : "memory"); +} + +static inline void local_irq_enable(void) +{ + __asm__ __volatile__ ("" : : : "memory"); +} + +static inline void local_irq_disable(void) +{ + __asm__ __volatile__ ("" : : : "memory"); +} + +static inline void __stf(void) +{ + __asm__ __volatile__ ("" : : : "memory"); +} + +static inline void __clf(void) +{ + __asm__ __volatile__ ("" : : : "memory"); +} + +static inline void local_save_flags( + unsigned long flags __attribute__((unused))) +{ + __asm__ __volatile__ ("" : : : "memory"); +} + +static inline void local_irq_restore( + unsigned long flags __attribute__((unused))) +{ + __asm__ __volatile__ ("" : : : "memory"); +} + +#endif /* __ASM_PROC_SYSTEM_H */ diff --git a/examples/standalone/Makefile b/examples/standalone/Makefile index 0863a8c..5a6ae00 100644 --- a/examples/standalone/Makefile +++ b/examples/standalone/Makefile @@ -73,3 +73,13 @@ $(obj)/%.srec: $(obj)/% FORCE $(obj)/%.bin: OBJCOPYFLAGS := -O binary $(obj)/%.bin: $(obj)/% FORCE $(call if_changed,objcopy) + +# some files can only build in ARM or THUMB2, not THUMB1 + +ifdef CONFIG_SYS_THUMB_BUILD +ifndef CONFIG_HAS_THUMB2 + +CFLAGS_stubs.o := -marm + +endif +endif