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mmu: ensure gperf data is mapped

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Page tables created at build time may not include the
gperf data at the very end of RAM. Ensure this is mapped
properly at runtime to work around this.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2020-12-18 15:18:04 -08:00 • committed by Anas Nashif
commit ecb25fec51
5 changed files with 31 additions and 1 deletions
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1
include/linker/kobject.ld
View file

@ -5,6 +5,7 @@
*/
#ifdef CONFIG_USERSPACE
z_kobject_data_begin = .;
/* Constraints:
*
* - changes to the size of this section between build phases

1
include/linker/linker-defs.h
View file

@ -303,6 +303,7 @@ extern char z_priv_stacks_ram_start[];
extern char z_priv_stacks_ram_end[];
extern char z_user_stacks_start[];
extern char z_user_stacks_end[];
extern char z_kobject_data_begin[];
#endif /* CONFIG_USERSPACE */
#ifdef CONFIG_THREAD_LOCAL_STORAGE

3
kernel/include/kernel_internal.h
View file

@ -197,6 +197,9 @@ void z_thread_mark_switched_out(void);
*/
void z_mem_manage_init(void);
/* Workaround for build-time page table mapping of the kernel */
void z_kernel_map_fixup(void);
#ifdef __cplusplus
}
#endif

4
kernel/init.c
View file

@ -391,7 +391,9 @@ FUNC_NORETURN void z_cstart(void)
z_dummy_thread_init(&dummy_thread);
#endif
#if defined(CONFIG_MMU) && defined(CONFIG_USERSPACE)
z_kernel_map_fixup();
#endif
/* perform basic hardware initialization */
z_sys_init_run_level(_SYS_INIT_LEVEL_PRE_KERNEL_1);
z_sys_init_run_level(_SYS_INIT_LEVEL_PRE_KERNEL_2);

23
kernel/mmu.c
View file

@ -453,6 +453,29 @@ size_t k_mem_region_align(uintptr_t *aligned_phys, size_t *aligned_size,
*/
#define BOOT_VIRT_TO_PHYS(virt) ((uintptr_t)(((uint8_t *)virt) + VM_OFFSET))
#ifdef CONFIG_USERSPACE
void z_kernel_map_fixup(void)
{
/* XXX: Gperf kernel object data created at build time will not have
* visibility in zephyr_prebuilt.elf. There is a possibility that this
* data would not be memory-mapped if it shifts z_mapped_end between
* builds. Ensure this area is mapped.
*
* A third build phase for page tables would solve this.
*/
uint8_t *kobject_page_begin =
(uint8_t *)ROUND_DOWN((uintptr_t)&z_kobject_data_begin,
CONFIG_MMU_PAGE_SIZE);
size_t kobject_size = (size_t)(Z_KERNEL_VIRT_END - kobject_page_begin);
if (kobject_size != 0) {
arch_mem_map(kobject_page_begin,
BOOT_VIRT_TO_PHYS(kobject_page_begin),
kobject_size, K_MEM_PERM_RW | K_MEM_CACHE_WB);
}
}
#endif /* CONFIG_USERSPACE */
void z_mem_manage_init(void)
{
uintptr_t phys;