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x86: set up linker ROM region for MMU

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For virtual kernels this represents where the kernel
is loaded in physical memory.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2020-11-06 15:17:06 -08:00 • committed by Anas Nashif
commit f2e4edf51a
1 changed files with 29 additions and 16 deletions
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45
include/arch/x86/memory.ld
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@ -22,6 +22,12 @@
* are set up, such that read/write data/bss have their VMA addresses
* in RAM and are copied from flash at boot. Text/rodata linked in-place in
* flash.
*
* If CONFIG_MMU is enabled, then the ROM region in MEMORY is used to set the
* LMA for all sections relative to physical address. The virtual address VMAs
* for all sections are relative to the base virtual address for the kernel.
* Setting LMAs here helps let QEMU or any other ELF-aware loader know where to
* physically load the image.
*/
#ifndef ARCH_X86_MEMORY_LD
@ -29,28 +35,26 @@
#include <autoconf.h>
#include <devicetree.h>
#include <sys/mem_manage.h>
/* Bounds of physical RAM from DTS */
#define PHYS_RAM_ADDR DT_REG_ADDR(DT_CHOSEN(zephyr_sram))
#define PHYS_RAM_SIZE DT_REG_SIZE(DT_CHOSEN(zephyr_sram))
#ifdef CONFIG_KERNEL_LINK_IN_VIRT
/* Linked at virtual address space */
#define KERNEL_BASE_ADDR \
(CONFIG_KERNEL_VM_BASE + CONFIG_KERNEL_VM_OFFSET)
#define KERNEL_RAM_SIZE \
(CONFIG_KERNEL_VM_SIZE - CONFIG_KERNEL_VM_OFFSET)
/* Virtual base address for the kernel; with CONFIG_MMU this is not necessarily
* the same as its physical location, although an identity mapping for RAM
* is still supported by setting CONFIG_KERNEL_VM_BASE=CONFIG_SRAM_BASE_ADDRESS.
*/
#ifdef Z_VM_KERNEL
#define KERNEL_BASE_ADDR (CONFIG_KERNEL_VM_BASE + CONFIG_KERNEL_VM_OFFSET)
#define KERNEL_RAM_SIZE (CONFIG_KERNEL_VM_SIZE - CONFIG_KERNEL_VM_OFFSET)
#define PHYS_RAM_AVAIL (PHYS_RAM_SIZE - CONFIG_SRAM_OFFSET)
#else
#define KERNEL_BASE_ADDR (PHYS_RAM_ADDR + CONFIG_SRAM_OFFSET)
#define KERNEL_RAM_SIZE (PHYS_RAM_SIZE - CONFIG_SRAM_OFFSET)
#endif
/* Linked at physical address */
#define KERNEL_BASE_ADDR \
(PHYS_RAM_ADDR + CONFIG_SRAM_OFFSET)
#define KERNEL_RAM_SIZE \
(PHYS_RAM_SIZE - CONFIG_SRAM_OFFSET)
#endif /* CONFIG_DEMAND_PAGING */
/* "kernel RAM" for linker VMA allocations starts at the offset */
#ifdef CONFIG_XIP
/* "ROM" is flash, we leave rodata and text there and just copy in data.
@ -59,7 +63,10 @@
*/
#define FLASH_ROM_SIZE DT_REG_SIZE(DT_CHOSEN(zephyr_flash))
#define PHYS_LOAD_ADDR DT_REG_ADDR(DT_CHOSEN(zephyr_flash))
#endif
#else
/* Physical RAM location where the kernel image is loaded */
#define PHYS_LOAD_ADDR (PHYS_RAM_ADDR + CONFIG_SRAM_OFFSET)
#endif /* CONFIG_XIP */
#ifdef CONFIG_X86_64
/* Locore must be addressable by real mode and so cannot extend past 64K.
@ -67,7 +74,11 @@
*/
#define LOCORE_BASE 0x1000
#define LOCORE_SIZE (0x10000 - LOCORE_BASE)
#if PHYS_RAM_ADDR != CONFIG_KERNEL_VM_BASE
#error Virtual kernel linking is not yet implemented for 64-bit
#endif
#endif /* CONFIG_X86_64 */
MEMORY
{
@ -76,6 +87,8 @@ MEMORY
* or copied into physical RAM by a loader (MMU)
*/
ROM (rx) : ORIGIN = PHYS_LOAD_ADDR, LENGTH = FLASH_ROM_SIZE
#elif defined(Z_VM_KERNEL)
ROM (rx) : ORIGIN = PHYS_LOAD_ADDR, LENGTH = PHYS_RAM_AVAIL
#endif
/* Linear address range to link the kernel. If non-XIP, everything is
* linked in this space. Otherwise, rodata and text are linked at their