Various improvements/cleanups on the linker scripts
- Check at link-time that bootloader images will fit in memory
at run time and that they won't overlap each other.
- Remove text and rodata orphan sections.
- Define new linker symbols to remove the need for platform setup
code to know the order of sections.
- Reduce the size of the raw binary images by cutting some sections
out of the disk image and allocating them at load time, whenever
possible.
- Rework alignment constraints on sections.
- Remove unused linker symbols.
- Homogenize linker symbols names across all BLs.
- Add some comments in the linker scripts.
Change-Id: I47a328af0ccc7c8ab47fcc0dc6e7dd26160610b9
diff --git a/bl2/bl2.ld.S b/bl2/bl2.ld.S
index 8a8ed35..7e9e5a5 100644
--- a/bl2/bl2.ld.S
+++ b/bl2/bl2.ld.S
@@ -34,7 +34,6 @@
OUTPUT_ARCH(PLATFORM_LINKER_ARCH)
MEMORY {
- /* RAM is read/write and Initialised */
RAM (rwx): ORIGIN = TZRAM_BASE, LENGTH = TZRAM_SIZE
}
@@ -42,44 +41,69 @@
SECTIONS
{
. = BL2_BASE;
+ ASSERT(. == ALIGN(4096),
+ "BL2_BASE address is not aligned on a page boundary.")
- BL2_RO NEXT (4096): {
- *(entry_code)
- *(.text .rodata)
+ ro . : {
+ __RO_START__ = .;
+ *bl2_entrypoint.o(.text)
+ *(.text)
+ *(.rodata*)
+ __RO_END_UNALIGNED__ = .;
+ /*
+ * Memory page(s) mapped to this section will be marked as
+ * read-only, executable. No RW data from the next section must
+ * creep in. Ensure the rest of the current memory page is unused.
+ */
+ . = NEXT(4096);
+ __RO_END__ = .;
} >RAM
- BL2_STACKS NEXT (4096): {
- *(tzfw_normal_stacks)
+ .data . : {
+ __DATA_START__ = .;
+ *(.data)
+ __DATA_END__ = .;
} >RAM
- BL2_COHERENT_RAM NEXT (4096): {
- *(tzfw_coherent_mem)
- /* . += 0x1000;*/
- /* Do we need to ensure at least 4k here? */
- . = NEXT(4096);
+ stacks (NOLOAD) : {
+ __STACKS_START__ = .;
+ *(tzfw_normal_stacks)
+ __STACKS_END__ = .;
} >RAM
- __BL2_DATA_START__ = .;
- .bss NEXT (4096): {
+ /*
+ * The .bss section gets initialised to 0 at runtime.
+ * Its base address must be 16-byte aligned.
+ */
+ .bss : ALIGN(16) {
+ __BSS_START__ = .;
*(SORT_BY_ALIGNMENT(.bss))
*(COMMON)
+ __BSS_END__ = .;
} >RAM
- .data : {
- *(.data)
+ /*
+ * The base address of the coherent memory section must be page-aligned (4K)
+ * to guarantee that the coherent data are stored on their own pages and
+ * are not mixed with normal data. This is required to set up the correct
+ * memory attributes for the coherent data page tables.
+ */
+ coherent_ram (NOLOAD) : ALIGN(4096) {
+ __COHERENT_RAM_START__ = .;
+ *(tzfw_coherent_mem)
+ __COHERENT_RAM_END_UNALIGNED__ = .;
+ /*
+ * Memory page(s) mapped to this section will be marked
+ * as device memory. No other unexpected data must creep in.
+ * Ensure the rest of the current memory page is unused.
+ */
+ . = NEXT(4096);
+ __COHERENT_RAM_END__ = .;
} >RAM
- __BL2_DATA_STOP__ = .;
-
- __BL2_RO_BASE__ = LOADADDR(BL2_RO);
- __BL2_RO_SIZE__ = SIZEOF(BL2_RO);
-
- __BL2_STACKS_BASE__ = LOADADDR(BL2_STACKS);
- __BL2_STACKS_SIZE__ = SIZEOF(BL2_STACKS);
-
- __BL2_COHERENT_RAM_BASE__ = LOADADDR(BL2_COHERENT_RAM);
- __BL2_COHERENT_RAM_SIZE__ = SIZEOF(BL2_COHERENT_RAM);
+ __BL2_END__ = .;
- __BL2_RW_BASE__ = __BL2_DATA_START__;
- __BL2_RW_SIZE__ = __BL2_DATA_STOP__ - __BL2_DATA_START__;
+ __BSS_SIZE__ = SIZEOF(.bss);
+ __COHERENT_RAM_UNALIGNED_SIZE__ =
+ __COHERENT_RAM_END_UNALIGNED__ - __COHERENT_RAM_START__;
}