[PATCH v2] arm: Add ARMv8-M aarch32 support
Marek Vasut
marek.vasut+renesas at mailbox.org
Mon Mar 30 01:14:12 CEST 2026
Add configuration for ARMv8-M aarch32 core, which are currently
Cortex-M23/M33 cores. These cores are treated similar to ARMv7-M
cores, except the code has to be compiled with matching compiler
-march=armv8-m.main flag . These cores have no MMU, they have MPU,
which is currently not configured.
Unlike ARMv7-M, these cores have 512 interrupt vectors. While the
SYS_ARM_ARCH should be set to 8, it is set to 7 because all of the
initialization code is built from from arch/arm/cpu/armv7m and not
armv8. Furthermore, CONFIG_ARM64 must be disabled, although DTs
for devices using these cores do come from arch/arm64/boot/dts .
To avoid excess duplication in Makefiles, introduce one new Kconfig
symbol, CPU_V7M_V8M. The CPU_V7M_V8M cover both ARMv7-M and ARMv8-M
cores.
Signed-off-by: Marek Vasut <marek.vasut+renesas at mailbox.org>
---
Cc: Casey Connolly <casey.connolly at linaro.org>
Cc: Heinrich Schuchardt <xypron.glpk at gmx.de>
Cc: Ilias Apalodimas <ilias.apalodimas at linaro.org>
Cc: Jerome Forissier <jerome.forissier at arm.com> <jerome at forissier.org>
Cc: Tom Rini <trini at konsulko.com>
Cc: Udit Kumar <u-kumar1 at ti.com>
Cc: u-boot at lists.denx.de
---
V2: - Rename CPU_V78M to CPU_V7M_V8M
- Isolate V7M specific and otherwise option bits in cpu.c
---
Makefile | 8 ++++++--
arch/arm/Kconfig | 15 +++++++++++++--
arch/arm/Makefile | 2 ++
arch/arm/cpu/armv7m/cpu.c | 10 ++++++++--
arch/arm/include/asm/armv7_mpu.h | 2 +-
arch/arm/include/asm/unified.h | 2 +-
arch/arm/lib/Makefile | 6 +++---
arch/arm/lib/bootm.c | 2 +-
arch/arm/lib/crt0.S | 2 +-
arch/arm/lib/relocate.S | 4 ++--
arch/arm/lib/semihosting.S | 2 +-
arch/arm/lib/vectors_m.S | 6 +++++-
cmd/Kconfig | 2 +-
dts/Makefile | 4 ++++
lib/efi_selftest/Makefile | 2 +-
15 files changed, 50 insertions(+), 19 deletions(-)
diff --git a/Makefile b/Makefile
index 8295cd4e5e8..cb4b5a2635e 100644
--- a/Makefile
+++ b/Makefile
@@ -531,7 +531,7 @@ UBOOTINCLUDE := \
-I$(srctree)/lib/mbedtls/external/mbedtls/include) \
$(if $(CONFIG_$(PHASE_)SYS_THUMB_BUILD), \
$(if $(CONFIG_HAS_THUMB2), \
- $(if $(CONFIG_CPU_V7M), \
+ $(if $(CONFIG_CPU_V7M_V8M), \
-I$(srctree)/arch/arm/thumb1/include), \
-I$(srctree)/arch/arm/thumb1/include)) \
-I$(srctree)/arch/$(ARCH)/include \
@@ -1050,7 +1050,7 @@ UBOOTINCLUDE := \
-I$(srctree)/lib/mbedtls/external/mbedtls/include) \
$(if $(CONFIG_$(PHASE_)SYS_THUMB_BUILD), \
$(if $(CONFIG_HAS_THUMB2), \
- $(if $(CONFIG_CPU_V7M), \
+ $(if $(CONFIG_CPU_V7M_V8M), \
-I$(srctree)/arch/arm/thumb1/include), \
-I$(srctree)/arch/arm/thumb1/include)) \
-I$(srctree)/arch/$(ARCH)/include \
@@ -1446,11 +1446,15 @@ quiet_cmd_copy = COPY $@
cmd_copy = cp $< $@
ifeq ($(CONFIG_OF_UPSTREAM),y)
+ifeq ($(CONFIG_CPU_V8M),y)
+dt_dir := dts/upstream/src/arm64
+else
ifeq ($(CONFIG_ARM64),y)
dt_dir := dts/upstream/src/arm64
else
dt_dir := dts/upstream/src/$(ARCH)
endif
+endif
else
dt_dir := arch/$(ARCH)/dts
endif
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 03416c55265..f624675eadf 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -363,7 +363,8 @@ config CPU_V7A
select SYS_CACHE_SHIFT_6
imply SYS_ARM_MMU
-config CPU_V7M
+# ARMv7-M/ARMv8-M
+config CPU_V7M_V8M
bool
select HAS_THUMB2
select SYS_ARM_MPU
@@ -372,6 +373,10 @@ config CPU_V7M
select THUMB2_KERNEL
select NVIC
+config CPU_V7M
+ bool
+ select CPU_V7M_V8M
+
config CPU_V7R
bool
select HAS_THUMB2
@@ -379,6 +384,10 @@ config CPU_V7R
select SYS_ARM_MPU
select SYS_CACHE_SHIFT_6
+config CPU_V8M
+ bool
+ select CPU_V7M_V8M
+
config SYS_CPU
default "arm720t" if CPU_ARM720T
default "arm920t" if CPU_ARM920T
@@ -389,6 +398,7 @@ config SYS_CPU
default "armv7" if CPU_V7A
default "armv7" if CPU_V7R
default "armv7m" if CPU_V7M
+ default "armv7m" if CPU_V8M
default "armv8" if ARM64
config SYS_ARM_ARCH
@@ -402,6 +412,7 @@ config SYS_ARM_ARCH
default 7 if CPU_V7A
default 7 if CPU_V7M
default 7 if CPU_V7R
+ default 7 if CPU_V8M
default 8 if ARM64
choice
@@ -445,7 +456,7 @@ config ARCH_CPU_INIT
config SYS_ARCH_TIMER
bool "ARM Generic Timer support"
- depends on CPU_V7A || CPU_V7M || ARM64
+ depends on CPU_V7A || CPU_V7M_V8M || ARM64
default y if ARM64
help
The ARM Generic Timer (aka arch-timer) provides an architected
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index b36b0742580..de975fc9368 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -16,6 +16,7 @@ arch-$(CONFIG_CPU_V7A) =$(call cc-option, -march=armv7-a, \
$(call cc-option, -march=armv7))
arch-$(CONFIG_CPU_V7M) =-march=armv7-m
arch-$(CONFIG_CPU_V7R) =-march=armv7-r
+arch-$(CONFIG_CPU_V8M) =-march=armv8-m.main
ifeq ($(CONFIG_ARM64_CRC32),y)
arch-$(CONFIG_ARM64) =-march=armv8-a+crc
else
@@ -42,6 +43,7 @@ tune-$(CONFIG_CPU_ARM1136) =
tune-$(CONFIG_CPU_ARM1176) =
tune-$(CONFIG_CPU_V7A) =-mtune=generic-armv7-a
tune-$(CONFIG_CPU_V7R) =
+tune-$(CONFIG_CPU_V8M) =
tune-$(CONFIG_ARM64) =
# Evaluate tune cc-option calls now
diff --git a/arch/arm/cpu/armv7m/cpu.c b/arch/arm/cpu/armv7m/cpu.c
index bea0e1d3263..292730c1d7c 100644
--- a/arch/arm/cpu/armv7m/cpu.c
+++ b/arch/arm/cpu/armv7m/cpu.c
@@ -19,6 +19,9 @@
*/
int cleanup_before_linux(void)
{
+ if (!CONFIG_IS_ENABLED(LIB_BOOTM) && !CONFIG_IS_ENABLED(LIB_BOOTZ))
+ return 0;
+
/*
* this function is called just before we call linux
* it prepares the processor for linux
@@ -45,8 +48,9 @@ int cleanup_before_linux(void)
}
/*
- * Perform the low-level reset.
+ * Perform the low-level reset. ARMv7M only.
*/
+#if IS_ENABLED(CONFIG_CPU_V7M)
void reset_cpu(void)
{
/*
@@ -56,8 +60,10 @@ void reset_cpu(void)
| (V7M_SCB->aircr & V7M_AIRCR_PRIGROUP_MSK)
| V7M_AIRCR_SYSRESET, &V7M_SCB->aircr);
}
+#endif
void spl_perform_arch_fixups(struct spl_image_info *spl_image)
{
- spl_image->entry_point |= 0x1;
+ if (IS_ENABLED(CONFIG_XPL_BUILD))
+ spl_image->entry_point |= 0x1;
}
diff --git a/arch/arm/include/asm/armv7_mpu.h b/arch/arm/include/asm/armv7_mpu.h
index 16b9d0d1aeb..4a6524290d3 100644
--- a/arch/arm/include/asm/armv7_mpu.h
+++ b/arch/arm/include/asm/armv7_mpu.h
@@ -11,7 +11,7 @@
#include <linux/bitops.h>
#endif
-#ifdef CONFIG_CPU_V7M
+#ifdef CONFIG_CPU_V7M_V8M
#define AP_SHIFT 24
#define XN_SHIFT 28
#define TEX_SHIFT 19
diff --git a/arch/arm/include/asm/unified.h b/arch/arm/include/asm/unified.h
index 2fae54ebd89..53715db4207 100644
--- a/arch/arm/include/asm/unified.h
+++ b/arch/arm/include/asm/unified.h
@@ -12,7 +12,7 @@
.syntax unified
#endif
-#ifdef CONFIG_CPU_V7M
+#ifdef CONFIG_CPU_V7M_V8M
#define AR_CLASS(x...)
#define M_CLASS(x...) x
#else
diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index 11cb3a7145e..7b60cecbd49 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -11,7 +11,7 @@ obj-$(CONFIG_$(PHASE_)LIB_BOOTI) += image.o
obj-$(CONFIG_$(PHASE_)LIB_BOOTZ) += zimage.o
obj-$(CONFIG_$(PHASE_)LIB_BOOTM) += bootm.o
-ifdef CONFIG_CPU_V7M
+ifdef CONFIG_CPU_V7M_V8M
obj-y += vectors_m.o crt0.o
else ifdef CONFIG_ARM64
obj-y += crt0_64.o
@@ -32,7 +32,7 @@ else
obj-y += relocate.o
endif
-obj-$(CONFIG_CPU_V7M) += cmd_boot.o
+obj-$(CONFIG_CPU_V7M_V8M) += cmd_boot.o
obj-$(CONFIG_OF_LIBFDT) += bootm-fdt.o
obj-$(CONFIG_CMD_BOOTM) += bootm.o
else
@@ -62,7 +62,7 @@ obj-y += sections.o
CFLAGS_REMOVE_sections.o := $(LTO_CFLAGS)
obj-y += stack.o
-ifdef CONFIG_CPU_V7M
+ifdef CONFIG_CPU_V7M_V8M
obj-y += interrupts_m.o
else ifdef CONFIG_ARM64
obj-$(CONFIG_FSL_LAYERSCAPE) += ccn504.o
diff --git a/arch/arm/lib/bootm.c b/arch/arm/lib/bootm.c
index 727b9c5ca5b..1cde655bc80 100644
--- a/arch/arm/lib/bootm.c
+++ b/arch/arm/lib/bootm.c
@@ -304,7 +304,7 @@ static void boot_jump_linux(struct bootm_headers *images, int flag)
void (*kernel_entry)(int zero, int arch, uint params);
unsigned long r2;
kernel_entry = (void (*)(int, int, uint))images->ep;
-#ifdef CONFIG_CPU_V7M
+#ifdef CONFIG_CPU_V7M_V8M
ulong addr = (ulong)kernel_entry | 1;
kernel_entry = (void *)addr;
#endif
diff --git a/arch/arm/lib/crt0.S b/arch/arm/lib/crt0.S
index f2c5aa37a8f..a2c03f3d2f9 100644
--- a/arch/arm/lib/crt0.S
+++ b/arch/arm/lib/crt0.S
@@ -153,7 +153,7 @@ ENTRY(_main)
#endif
ldr r0, [r9, #GD_RELOC_OFF] /* r0 = gd->reloc_off */
add lr, lr, r0
-#if defined(CONFIG_CPU_V7M)
+#if defined(CONFIG_CPU_V7M_V8M)
orr lr, #1 /* As required by Thumb-only */
#endif
ldr r0, [r9, #GD_RELOCADDR] /* r0 = gd->relocaddr */
diff --git a/arch/arm/lib/relocate.S b/arch/arm/lib/relocate.S
index b6a648708f4..21d89e49f13 100644
--- a/arch/arm/lib/relocate.S
+++ b/arch/arm/lib/relocate.S
@@ -10,7 +10,7 @@
#include <config.h>
#include <elf.h>
#include <linux/linkage.h>
-#ifdef CONFIG_CPU_V7M
+#ifdef CONFIG_CPU_V7M_V8M
#include <asm/armv7m.h>
#endif
@@ -26,7 +26,7 @@
WEAK(relocate_vectors)
-#ifdef CONFIG_CPU_V7M
+#ifdef CONFIG_CPU_V7M_V8M
/*
* On ARMv7-M we only have to write the new vector address
* to VTOR register.
diff --git a/arch/arm/lib/semihosting.S b/arch/arm/lib/semihosting.S
index 6e1691a832c..d50c19f3f8d 100644
--- a/arch/arm/lib/semihosting.S
+++ b/arch/arm/lib/semihosting.S
@@ -13,7 +13,7 @@ ENTRY(smh_trap)
#if defined(CONFIG_ARM64)
hlt #0xf000
-#elif defined(CONFIG_CPU_V7M)
+#elif defined(CONFIG_CPU_V7M_V8M)
bkpt #0xab
#elif defined(CONFIG_SYS_THUMB_BUILD)
svc #0xab
diff --git a/arch/arm/lib/vectors_m.S b/arch/arm/lib/vectors_m.S
index 8d88cc756fc..38b32d87152 100644
--- a/arch/arm/lib/vectors_m.S
+++ b/arch/arm/lib/vectors_m.S
@@ -52,6 +52,10 @@ ENTRY(_start)
.long __invalid_entry @ 13 - Reserved
.long __invalid_entry @ 14 - PendSV
.long __invalid_entry @ 15 - SysTick
- .rept 255 - 16
+#ifdef CONFIG_CPU_V7M
+ .rept 256 - 16
+#else /* V8M / V8R */
+ .rept 512 - 16
+#endif
.long __invalid_entry @ 16..255 - External Interrupts
.endr
diff --git a/cmd/Kconfig b/cmd/Kconfig
index 71c0db601aa..366ae771d9b 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -2093,7 +2093,7 @@ config BOOTP_PXE_DHCP_OPTION
config BOOTP_VCI_STRING
string
depends on CMD_BOOTP
- default "U-Boot.armv7" if CPU_V7A || CPU_V7M || CPU_V7R
+ default "U-Boot.armv7" if CPU_V7A || CPU_V7M_V8M || CPU_V7R
default "U-Boot.armv8" if ARM64
default "U-Boot.arm" if ARM
default "U-Boot"
diff --git a/dts/Makefile b/dts/Makefile
index bec6c49da2c..befc6de1805 100644
--- a/dts/Makefile
+++ b/dts/Makefile
@@ -11,11 +11,15 @@ DEVICE_TREE := unset
endif
ifeq ($(CONFIG_OF_UPSTREAM),y)
+ifeq ($(CONFIG_CPU_V8M),y)
+dt_dir := dts/upstream/src/arm64
+else
ifeq ($(CONFIG_ARM64),y)
dt_dir := dts/upstream/src/arm64
else
dt_dir := dts/upstream/src/$(ARCH)
endif
+endif
else
dt_dir := arch/$(ARCH)/dts
endif
diff --git a/lib/efi_selftest/Makefile b/lib/efi_selftest/Makefile
index 842433f68aa..67102648703 100644
--- a/lib/efi_selftest/Makefile
+++ b/lib/efi_selftest/Makefile
@@ -60,7 +60,7 @@ obj-$(CONFIG_EFI_DEVICE_PATH_TO_TEXT) += efi_selftest_devicepath.o
obj-$(CONFIG_EFI_UNICODE_COLLATION_PROTOCOL2) += \
efi_selftest_unicode_collation.o
-ifeq ($(CONFIG_CPU_V7A)$(CONFIG_CPU_V7M)$(CONFIG_CPU_V7R),y)
+ifeq ($(CONFIG_CPU_V7A)$(CONFIG_CPU_V7M_V8M)$(CONFIG_CPU_V7R),y)
obj-y += efi_selftest_unaligned.o
endif
obj-$(CONFIG_EFI_LOADER_HII) += efi_selftest_hii.o
--
2.53.0
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