[U-Boot] [PATCH v6] arm: support Thumb-1 with CONFIG_SYS_THUMB_BUILD
Stefan Roese
sr at denx.de
Wed Sep 2 11:06:40 CEST 2015
From: Albert ARIBAUD <albert.u.boot at aribaud.net>
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 at aribaud.net>
Signed-off-by: Stefan Roese <sr at denx.de
---
This patch is necessary for the SPEAr600 x600 U-Boot port to
fit into the onboard NOR flash again. Reducing the size by about
200KiB. So, if nothing is really missing here, then please
let's apply it after the v2015.10 release.
Thanks,
Stefan
Here the original comment from Albert, from v5:
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 v6 (by Stefan):
- Rebased on top of current mainline U-Boot
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 4fe1d88..4393e41 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 $(srctree)/include/linux/kconfig.h
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index cd88df4..0753fcf 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -10,6 +10,9 @@ config ARM64
config HAS_VBAR
bool
+config HAS_THUMB2
+ bool
+
config CPU_ARM720T
bool
@@ -32,9 +35,11 @@ config CPU_ARM1176
config CPU_V7
bool
select HAS_VBAR
+ select HAS_THUMB2
config CPU_V7M
bool
+ select HAS_THUMB2
config CPU_PXA
bool
diff --git a/arch/arm/cpu/arm926ejs/Makefile b/arch/arm/cpu/arm926ejs/Makefile
index 63fa159..fe78922 100644
--- a/arch/arm/cpu/arm926ejs/Makefile
+++ b/arch/arm/cpu/arm926ejs/Makefile
@@ -20,3 +20,14 @@ obj-$(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 31a5c8d..4c7e3f9 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 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
--
2.5.1
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