[U-Boot] [PATCH v4 2/4] arm: support Thumb-1 with CONFIG_SYS_THUMB_BUILD
Albert ARIBAUD
albert.u.boot at aribaud.net
Sun Jul 5 17:13:45 CEST 2015
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.
Thos 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 at 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 ths patch were found to differ only by their
version string.
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 ++++
scripts/Makefile.lib | 3 +-
13 files changed, 156 insertions(+), 4 deletions(-)
create mode 100644 arch/arm/thumb1/include/asm/proc-armv/system.h
diff --git a/Makefile b/Makefile
index 37cc4c3..dc881fa 100644
--- a/Makefile
+++ b/Makefile
@@ -606,6 +606,8 @@ 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 $(srctree)/include/linux/kconfig.h
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 0829235..906afd0 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -10,6 +10,9 @@ config ARM64
config HAS_VBAR
bool
+config HAS_THUMB2
+ bool
+
config CPU_ARM720T
bool
@@ -32,9 +35,11 @@ config CPU_ARM1176
config CPU_V7
bool
select HAS_VBAR
+ select HAS_THUMB2
config CPU_V7M
bool
+ select HAS_THUMB2
config CPU_PXA
bool
diff --git a/arch/arm/cpu/arm926ejs/Makefile b/arch/arm/cpu/arm926ejs/Makefile
index 63fa159..fe78922 100644
--- a/arch/arm/cpu/arm926ejs/Makefile
+++ b/arch/arm/cpu/arm926ejs/Makefile
@@ -20,3 +20,14 @@ obj-$(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 8d7873c..f12e365 100644
--- a/arch/arm/cpu/arm926ejs/cache.c
+++ b/arch/arm/cpu/arm926ejs/cache.c
@@ -99,4 +99,9 @@ void flush_cache(unsigned long start, unsigned long size)
/*
* 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 9a631d1..4272d2f 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 74cfde6..7c8878d 100644
--- a/arch/arm/lib/cache.c
+++ b/arch/arm/lib/cache.c
@@ -95,3 +95,14 @@ 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 ffaee74..409d5f7 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 49bdff7..b586055 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 at 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
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 8731fc6..3d5c872 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -104,8 +104,9 @@ modname_flags = $(if $(filter 1,$(words $(modname))),\
orig_c_flags = $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(KBUILD_SUBDIR_CCFLAGS) \
$(ccflags-y) $(CFLAGS_$(basetarget).o)
_c_flags = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(orig_c_flags))
-_a_flags = $(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(KBUILD_SUBDIR_ASFLAGS) \
+orig_a_flags = $(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(KBUILD_SUBDIR_ASFLAGS) \
$(asflags-y) $(AFLAGS_$(basetarget).o)
+_a_flags = $(filter-out $(AFLAGS_REMOVE_$(basetarget).o), $(orig_a_flags))
_cpp_flags = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(@F))
#
--
2.1.0
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