AArch32: Add `memcpy4` function in assembly
At present the `el3_entrypoint_common` macro uses `memcpy`
function defined in lib/stdlib/mem.c file, to copy data
from ROM to RAM for BL1. Depending on the compiler being
used the stack could potentially be used, in `memcpy`,
for storing the local variables. Since the stack is
initialized much later in `el3_entrypoint_common` it
may result in unknown behaviour.
This patch adds `memcpy4` function definition in assembly so
that it can be used before the stack is initialized and it
also replaces `memcpy` by `memcpy4` in `el3_entrypoint_common`
macro, to copy data from ROM to RAM for BL1.
Change-Id: I3357a0e8095f05f71bbbf0b185585d9499bfd5e0
diff --git a/include/common/aarch32/el3_common_macros.S b/include/common/aarch32/el3_common_macros.S
index a572ef9..50ce952 100644
--- a/include/common/aarch32/el3_common_macros.S
+++ b/include/common/aarch32/el3_common_macros.S
@@ -261,7 +261,7 @@
ldr r0, =__DATA_RAM_START__
ldr r1, =__DATA_ROM_START__
ldr r2, =__DATA_SIZE__
- bl memcpy
+ bl memcpy4
#endif
.endif /* _init_c_runtime */
diff --git a/lib/aarch32/misc_helpers.S b/lib/aarch32/misc_helpers.S
index fd7c6dd..bf4084a 100644
--- a/lib/aarch32/misc_helpers.S
+++ b/lib/aarch32/misc_helpers.S
@@ -34,6 +34,7 @@
.globl smc
.globl zeromem
+ .globl memcpy4
.globl disable_mmu_icache_secure
.globl disable_mmu_secure
@@ -73,6 +74,40 @@
bx lr
endfunc zeromem
+/* --------------------------------------------------------------------------
+ * void memcpy4(void *dest, const void *src, unsigned int length)
+ *
+ * Copy length bytes from memory area src to memory area dest.
+ * The memory areas should not overlap.
+ * Destination and source addresses must be 4-byte aligned.
+ * --------------------------------------------------------------------------
+ */
+func memcpy4
+#if ASM_ASSERTION
+ orr r3, r0, r1
+ tst r3, #0x3
+ ASM_ASSERT(eq)
+#endif
+/* copy 4 bytes at a time */
+m_loop4:
+ cmp r2, #4
+ blt m_loop1
+ ldr r3, [r1], #4
+ str r3, [r0], #4
+ sub r2, r2, #4
+ b m_loop4
+/* copy byte per byte */
+m_loop1:
+ cmp r2,#0
+ beq m_end
+ ldrb r3, [r1], #1
+ strb r3, [r0], #1
+ subs r2, r2, #1
+ bne m_loop1
+m_end:
+ bx lr
+endfunc memcpy4
+
/* ---------------------------------------------------------------------------
* Disable the MMU in Secure State
* ---------------------------------------------------------------------------
