From 104a6a7ccfb7928ca5dc28c8cbe0ea231ffc45ee Mon Sep 17 00:00:00 2001 From: Sascha Hauer Date: Sat, 10 Dec 2011 16:41:07 +0100 Subject: ARM: Allow to compile in thumb-2 mode This shrinks the resulting binary size by ~25%. Exceptions are still handled in arm mode, so we have to explicitely put .arm directives into the exception code. Thumb-2 mode has been tested on i.MX51 Babbage board. Signed-off-by: Sascha Hauer --- arch/arm/Kconfig | 12 ++++++++++++ arch/arm/Makefile | 11 +++++++++-- arch/arm/cpu/cpu.c | 27 +++++++++++++++++++++++++++ arch/arm/cpu/exceptions.S | 1 + arch/arm/cpu/start.c | 1 + arch/arm/include/asm/barebox-arm-head.h | 12 ++++++++++++ arch/arm/include/asm/unified.h | 8 ++++---- arch/arm/lib/armlinux.c | 17 ++++++++++++++++- commands/go.c | 6 +++++- common/misc.c | 3 +++ include/common.h | 6 ++++++ 11 files changed, 96 insertions(+), 8 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 4c0ee58f09..adb020aa0f 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -101,6 +101,18 @@ config AEABI To use this you need GCC version 4.0.0 or later. +config THUMB2_BAREBOX + select ARM_ASM_UNIFIED + depends on CPU_V7 + bool "Compile barebox in thumb-2 mode (read help)" + help + This enables compilation of barebox in thumb-2 mode which generates + ~25% smaller binaries. Arm Assembly code needs some fixups to be able + to work correctly in thumb-2 mode. the barebox core should have these + fixups since most assembly code is derived from the Kernel. However, + your board lowlevel init code may break in thumb-2 mode. You have been + warned. + endmenu menu "Arm specific settings " diff --git a/arch/arm/Makefile b/arch/arm/Makefile index 9926280943..56f21aba50 100644 --- a/arch/arm/Makefile +++ b/arch/arm/Makefile @@ -39,8 +39,15 @@ ifeq ($(CONFIG_ARM_UNWIND),y) CFLAGS_ABI +=-funwind-tables endif -CPPFLAGS += $(CFLAGS_ABI) $(arch-y) $(tune-y) -msoft-float -AFLAGS += -include asm/unified.h -msoft-float +ifeq ($(CONFIG_THUMB2_BAREBOX),y) +AFLAGS_AUTOIT :=$(call as-option,-Wa$(comma)-mimplicit-it=always,-Wa$(comma)-mauto-it) +AFLAGS_NOWARN :=$(call as-option,-Wa$(comma)-mno-warn-deprecated,-Wa$(comma)-W) +CFLAGS_THUMB2 :=-mthumb $(AFLAGS_AUTOIT) $(AFLAGS_NOWARN) +AFLAGS_THUMB2 :=$(CFLAGS_THUMB2) -Wa$(comma)-mthumb +endif + +CPPFLAGS += $(CFLAGS_ABI) $(arch-y) $(tune-y) -msoft-float $(CFLAGS_THUMB2) +AFLAGS += -include asm/unified.h -msoft-float $(AFLAGS_THUMB2) # Machine directory name. This list is sorted alphanumerically # by CONFIG_* macro name. diff --git a/arch/arm/cpu/cpu.c b/arch/arm/cpu/cpu.c index cf31e8bb2e..71ef8c06d6 100644 --- a/arch/arm/cpu/cpu.c +++ b/arch/arm/cpu/cpu.c @@ -26,6 +26,7 @@ */ #include +#include #include #include #include @@ -89,3 +90,29 @@ void arch_shutdown(void) ); #endif } + +#ifdef CONFIG_THUMB2_BAREBOX +static void thumb2_execute(void *func, int argc, char *argv[]) +{ + /* + * Switch back to arm mode before executing external + * programs. + */ + __asm__ __volatile__ ( + "mov r0, #0\n" + "mov r1, %0\n" + "mov r2, %1\n" + "bx %2\n" + : + : "r" (argc - 1), "r" (&argv[1]), "r" (func) + : "r0", "r1", "r2" + ); +} + +static int execute_init(void) +{ + do_execute = thumb2_execute; + return 0; +} +postcore_initcall(execute_init); +#endif diff --git a/arch/arm/cpu/exceptions.S b/arch/arm/cpu/exceptions.S index 6f35d408f4..c08537a405 100644 --- a/arch/arm/cpu/exceptions.S +++ b/arch/arm/cpu/exceptions.S @@ -106,6 +106,7 @@ _STACK_START: * exception handlers */ .section ".text","ax" + .arm .align 5 .globl undefined_instruction diff --git a/arch/arm/cpu/start.c b/arch/arm/cpu/start.c index 89aff1dc05..f65b46d1d1 100644 --- a/arch/arm/cpu/start.c +++ b/arch/arm/cpu/start.c @@ -36,6 +36,7 @@ void __naked __section(.text_entry) start(void) void __naked __section(.text_exceptions) exception_vectors(void) { __asm__ __volatile__ ( + ".arm\n" "b reset\n" /* reset */ #ifdef CONFIG_ARM_EXCEPTIONS "ldr pc, =undefined_instruction\n" /* undefined instruction */ diff --git a/arch/arm/include/asm/barebox-arm-head.h b/arch/arm/include/asm/barebox-arm-head.h index fdbee8cdda..0dc3074a27 100644 --- a/arch/arm/include/asm/barebox-arm-head.h +++ b/arch/arm/include/asm/barebox-arm-head.h @@ -4,6 +4,17 @@ static inline void barebox_arm_head(void) { __asm__ __volatile__ ( +#ifdef CONFIG_THUMB2_BAREBOX + ".arm\n" + "adr r9, 1f + 1\n" + "bx r9\n" + ".thumb\n" + "1:\n" + "bl reset\n" + ".rept 10\n" + "1: b 1b\n" + ".endr\n" +#else "b reset\n" "1: b 1b\n" "1: b 1b\n" @@ -12,6 +23,7 @@ static inline void barebox_arm_head(void) "1: b 1b\n" "1: b 1b\n" "1: b 1b\n" +#endif ".word 0x65726162\n" /* 'bare' */ ".word 0x00786f62\n" /* 'box' */ ".word _text\n" /* text base. If copied there, diff --git a/arch/arm/include/asm/unified.h b/arch/arm/include/asm/unified.h index bc631161e9..4d855c8352 100644 --- a/arch/arm/include/asm/unified.h +++ b/arch/arm/include/asm/unified.h @@ -24,10 +24,10 @@ .syntax unified #endif -#ifdef CONFIG_THUMB2_KERNEL +#ifdef CONFIG_THUMB2_BAREBOX #if __GNUC__ < 4 -#error Thumb-2 kernel requires gcc >= 4 +#error Thumb-2 barebox requires gcc >= 4 #endif /* The CPSR bit describing the instruction set (Thumb) */ @@ -40,7 +40,7 @@ #endif #define BSYM(sym) sym + 1 -#else /* !CONFIG_THUMB2_KERNEL */ +#else /* !CONFIG_THUMB2_BAREBOX */ /* The CPSR bit describing the instruction set (ARM) */ #define PSR_ISETSTATE 0 @@ -52,7 +52,7 @@ #endif #define BSYM(sym) sym -#endif /* CONFIG_THUMB2_KERNEL */ +#endif /* CONFIG_THUMB2_BAREBOX */ #ifndef CONFIG_ARM_ASM_UNIFIED diff --git a/arch/arm/lib/armlinux.c b/arch/arm/lib/armlinux.c index 85fe2b9f66..a167036db5 100644 --- a/arch/arm/lib/armlinux.c +++ b/arch/arm/lib/armlinux.c @@ -255,6 +255,7 @@ void start_linux(void *adr, int swap, unsigned long initrd_address, { void (*kernel)(int zero, int arch, void *params) = adr; void *params = NULL; + int architecture; if (oftree) { printf("booting Linux kernel with devicetree\n"); @@ -272,5 +273,19 @@ void start_linux(void *adr, int swap, unsigned long initrd_address, __asm__ __volatile__("mcr p15, 0, %0, c1, c0" :: "r" (reg)); } - kernel(0, armlinux_get_architecture(), params); + architecture = armlinux_get_architecture(); + +#ifdef CONFIG_THUMB2_BAREBOX + __asm__ __volatile__ ( + "mov r0, #0\n" + "mov r1, %0\n" + "mov r2, %1\n" + "bx %2\n" + : + : "r" (architecture), "r" (params), "r" (kernel) + : "r0", "r1", "r2" + ); +#else + kernel(0, architecture, params); +#endif } diff --git a/commands/go.c b/commands/go.c index 6082fe54e3..bc984c8ae0 100644 --- a/commands/go.c +++ b/commands/go.c @@ -62,7 +62,11 @@ static int do_go(struct command *cmdtp, int argc, char *argv[]) func = addr; shutdown_barebox(); - func(argc - 1, &argv[1]); + + if (do_execute) + do_execute(func, argc - 1, &argv[1]); + else + func(argc - 1, &argv[1]); /* * The application returned. Since we have shutdown barebox and diff --git a/common/misc.c b/common/misc.c index a0059c1b79..b31a45c1a4 100644 --- a/common/misc.c +++ b/common/misc.c @@ -125,3 +125,6 @@ void perror(const char *s) #endif } EXPORT_SYMBOL(perror); + +void (*do_execute)(void *func, int argc, char *argv[]); +EXPORT_SYMBOL(do_execute); diff --git a/include/common.h b/include/common.h index d22787542e..d2347f8629 100644 --- a/include/common.h +++ b/include/common.h @@ -146,6 +146,12 @@ unsigned long strtoul_suffix(const char *str, char **endp, int base); void start_barebox(void); void shutdown_barebox(void); +/* + * architectures which have special calling conventions for + * executing programs should set this. Used by the 'go' command + */ +extern void (*do_execute)(void *func, int argc, char *argv[]); + void arch_shutdown(void); int run_shell(void); -- cgit v1.2.3