Add GCC_ARM support for the target AN382 of MPS2.

Add files MPS2.ld and startup_MPS2.S to support GCC_ARM of the target
AN382(ARM_MPS2_M0). Add "GCC_ARM" to supported_toolchains list.

Change-Id: I7046b698834c82e94015e51eef9a0f5e1315ddaa
Signed-off-by: Shawn Shan <[email protected]>

Author: ChangwuShan

targets/TARGET_ARM_SSG/TARGET_MPS2/TARGET_MPS2_M0/device/TOOLCHAIN_GCC_ARM/MPS2.ld

@@ -0,0 +1,204 @@
+/*
+ * Copyright (c) 2009-2019 Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * This file is derivative of mbed-os V5.10.4 CM3DS MPS2.ld for GCC_ARM
+ *
+ * Linker script for AN382
+ */
+
+
+MEMORY
+{
+  FLASH (rx)            : ORIGIN = 0x00000000, LENGTH = 0x00400000    /* 4MB  ZBTSRAM1 */
+  RAM (rwx)             : ORIGIN = 0x20000000, LENGTH = 0x00400000    /* 4MB  ZBTSRAM2 & ZBTSRAM3 */
+}
+
+/* Linker script to place sections and symbol values. Should be used together
+ * with other linker script that defines memory regions FLASH and RAM.
+ * It references following symbols, which must be defined in code:
+ *   Reset_Handler : Entry of reset handler
+ *
+ * It defines following symbols, which code can use without definition:
+ *   __exidx_start
+ *   __exidx_end
+ *   __etext
+ *   __data_start__
+ *   __preinit_array_start
+ *   __preinit_array_end
+ *   __init_array_start
+ *   __init_array_end
+ *   __fini_array_start
+ *   __fini_array_end
+ *   __data_end__
+ *   __bss_start__
+ *   __bss_end__
+ *   __end__
+ *   end
+ *   __HeapLimit
+ *   __StackLimit
+ *   __StackTop
+ *   __stack
+ */
+ENTRY(Reset_Handler)
+
+HEAP_SIZE  = 0x1000;
+STACK_SIZE = 0x400;
+
+/* Size of the vector table in SRAM */
+NVIC_NUM_VECTORS = (16 + 48);
+M_VECTOR_RAM_SIZE = NVIC_NUM_VECTORS * 4;
+
+SECTIONS
+{
+    .isr_vector :
+    {
+        __vector_table = .;
+        KEEP(*(.vector_table))
+         . = ALIGN(4);
+    } > FLASH
+
+    .text :
+    {
+        . = ALIGN(4);
+        *(.text*)
+
+        KEEP(*(.init))
+        KEEP(*(.fini))
+
+        /* .ctors */
+        *crtbegin.o(.ctors)
+        *crtbegin?.o(.ctors)
+        *(EXCLUDE_FILE(*crtend?.o *crtend.o) .ctors)
+        *(SORT(.ctors.*))
+        *(.ctors)
+
+        /* .dtors */
+        *crtbegin.o(.dtors)
+        *crtbegin?.o(.dtors)
+        *(EXCLUDE_FILE(*crtend?.o *crtend.o) .dtors)
+        *(SORT(.dtors.*))
+        *(.dtors)
+
+        *(.rodata*)
+
+        KEEP(*(.eh_frame*))
+    } > FLASH
+
+    .ARM.extab :
+    {
+        *(.ARM.extab* .gnu.linkonce.armextab.*)
+    } > FLASH
+
+    __exidx_start = .;
+    .ARM.exidx :
+    {
+        *(.ARM.exidx* .gnu.linkonce.armexidx.*)
+    } > FLASH
+    __exidx_end = .;
+
+    .interrupts_ram :
+    {
+        . = ALIGN(4);
+        __VECTOR_RAM__ = .;
+        __interrupts_ram_start__ = .;   /* Create a global symbol at data start */
+        . += M_VECTOR_RAM_SIZE;
+        . = ALIGN(4);
+        __interrupts_ram_end__ = .;     /* Define a global symbol at data end */
+    } > RAM
+
+    .data :
+    {
+        PROVIDE(__etext = LOADADDR(.data));
+        . = ALIGN(4);
+        __data_start__ = .;
+        *(.data*)
+
+        . = ALIGN(4);
+        /* preinit data */
+        PROVIDE (__preinit_array_start = .);
+        KEEP(*(.preinit_array))
+        PROVIDE (__preinit_array_end = .);
+
+        . = ALIGN(4);
+        /* init data */
+        PROVIDE (__init_array_start = .);
+        KEEP(*(SORT(.init_array.*)))
+        KEEP(*(.init_array))
+        PROVIDE (__init_array_end = .);
+
+
+        . = ALIGN(4);
+        /* finit data */
+        PROVIDE (__fini_array_start = .);
+        KEEP(*(SORT(.fini_array.*)))
+        KEEP(*(.fini_array))
+        PROVIDE (__fini_array_end = .);
+
+        . = ALIGN(4);
+        /* All data end */
+        __data_end__ = .;
+
+    } > RAM AT > FLASH
+
+    .uninitialized (NOLOAD):
+    {
+        . = ALIGN(32);
+        __uninitialized_start = .;
+        *(.uninitialized)
+        KEEP(*(.keep.uninitialized))
+        . = ALIGN(32);
+        __uninitialized_end = .;
+    } > RAM
+
+    .bss :
+    {
+        . = ALIGN(4);
+        __START_BSS = .;
+        __bss_start__ = .;
+        *(.bss*)
+        *(COMMON)
+        . = ALIGN(4);
+        __bss_end__ = .;
+        __END_BSS = .;
+
+    } > RAM
+
+    bss_size = __bss_end__ - __bss_start__;
+
+    .heap :
+    {
+        . = ALIGN(8);
+        __end__ = .;
+        PROVIDE(end = .);
+        __HeapBase = .;
+        . += HEAP_SIZE;
+        __HeapLimit = .;
+        __heap_limit = .; /* Add for _sbrk */
+    } > RAM
+
+    /* Set stack top to end of RAM, and stack limit move down by
+     * size of stack_dummy section */
+    __StackTop = ORIGIN(RAM) + LENGTH(RAM);
+    __StackLimit = __StackTop - STACK_SIZE;
+    PROVIDE(__stack = __StackTop);
+
+    /* Check if data + heap + stack exceeds RAM limit */
+    ASSERT(__StackLimit >= __HeapLimit, "region RAM overflowed with stack")
+
+}   /* End of sections */