@@ -20,8 +20,14 @@
#endif
#include <asm/kasan_def.h>
-/* PAGE_OFFSET - the virtual address of the start of the kernel image */
+/*
+ * PAGE_OFFSET: the virtual address of the start of lowmem, memory above
+ * the virtual address range for userspace.
+ * KERNEL_OFFSET: the virtual address of the start of the kernel image.
+ * we may further offset this with TEXT_OFFSET in practice.
+ */
#define PAGE_OFFSET UL(CONFIG_PAGE_OFFSET)
+#define KERNEL_OFFSET (PAGE_OFFSET)
#ifdef CONFIG_MMU
@@ -23,7 +23,6 @@
#if defined(CONFIG_DEBUG_LL) && !defined(CONFIG_DEBUG_SEMIHOSTING)
#include CONFIG_DEBUG_LL_INCLUDE
#endif
-
/*
* swapper_pg_dir is the virtual address of the initial page table.
* We place the page tables 16K below KERNEL_RAM_VADDR. Therefore, we must
@@ -31,7 +30,7 @@
* the least significant 16 bits to be 0x8000, but we could probably
* relax this restriction to KERNEL_RAM_VADDR >= PAGE_OFFSET + 0x4000.
*/
-#define KERNEL_RAM_VADDR (PAGE_OFFSET + TEXT_OFFSET)
+#define KERNEL_RAM_VADDR (KERNEL_OFFSET + TEXT_OFFSET)
#if (KERNEL_RAM_VADDR & 0xffff) != 0x8000
#error KERNEL_RAM_VADDR must start at 0xXXXX8000
#endif
@@ -47,7 +47,7 @@ SECTIONS
#endif
}
- . = PAGE_OFFSET + TEXT_OFFSET;
+ . = KERNEL_OFFSET + TEXT_OFFSET;
.head.text : {
_text = .;
HEAD_TEXT
We want to be able to compile the kernel into an address different from PAGE_OFFSET (start of lowmem) + TEXT_OFFSET, so start to pry apart the address of where the kernel is located from the address where the lowmem is located by defining and using KERNEL_OFFSET in a few key places. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> --- arch/arm/include/asm/memory.h | 8 +++++++- arch/arm/kernel/head.S | 3 +-- arch/arm/kernel/vmlinux.lds.S | 2 +- 3 files changed, 9 insertions(+), 4 deletions(-)