ARM: Add ARMv7-M support
Signed-off-by: Kamil Lulko <rev13@wp.pl>
diff --git a/arch/arm/lib/crt0.S b/arch/arm/lib/crt0.S
index 92d3732..afd4f10 100644
--- a/arch/arm/lib/crt0.S
+++ b/arch/arm/lib/crt0.S
@@ -9,6 +9,9 @@
#include <config.h>
#include <asm-offsets.h>
#include <linux/linkage.h>
+#ifdef CONFIG_CPU_V7M
+#include <asm/armv7m.h>
+#endif
/*
* This file handles the target-independent stages of the U-Boot
@@ -66,15 +69,30 @@
#else
ldr sp, =(CONFIG_SYS_INIT_SP_ADDR)
#endif
+#if defined(CONFIG_CPU_V7M) /* v7M forbids using SP as BIC destination */
+ mov r3, sp
+ bic r3, r3, #7
+ mov sp, r3
+#else
bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
+#endif
mov r2, sp
sub sp, sp, #GD_SIZE /* allocate one GD above SP */
+#if defined(CONFIG_CPU_V7M) /* v7M forbids using SP as BIC destination */
+ mov r3, sp
+ bic r3, r3, #7
+ mov sp, r3
+#else
bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
+#endif
mov r9, sp /* GD is above SP */
mov r1, sp
mov r0, #0
clr_gd:
cmp r1, r2 /* while not at end of GD */
+#if defined(CONFIG_CPU_V7M)
+ itt lo
+#endif
strlo r0, [r1] /* clear 32-bit GD word */
addlo r1, r1, #4 /* move to next */
blo clr_gd
@@ -94,13 +112,22 @@
*/
ldr sp, [r9, #GD_START_ADDR_SP] /* sp = gd->start_addr_sp */
+#if defined(CONFIG_CPU_V7M) /* v7M forbids using SP as BIC destination */
+ mov r3, sp
+ bic r3, r3, #7
+ mov sp, r3
+#else
bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
+#endif
ldr r9, [r9, #GD_BD] /* r9 = gd->bd */
sub r9, r9, #GD_SIZE /* new GD is below bd */
adr lr, here
ldr r0, [r9, #GD_RELOC_OFF] /* r0 = gd->reloc_off */
add lr, lr, r0
+#if defined(CONFIG_CPU_V7M)
+ orr lr, #1 /* As required by Thumb-only */
+#endif
ldr r0, [r9, #GD_RELOCADDR] /* r0 = gd->relocaddr */
b relocate_code
here:
@@ -134,6 +161,9 @@
mov r2, #0x00000000 /* prepare zero to clear BSS */
clbss_l:cmp r0, r1 /* while not at end of BSS */
+#if defined(CONFIG_CPU_V7M)
+ itt lo
+#endif
strlo r2, [r0] /* clear 32-bit BSS word */
addlo r0, r0, #4 /* move to next */
blo clbss_l