mmu: ensure gperf data is mapped
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>
diff --git a/include/linker/kobject.ld b/include/linker/kobject.ld
index d5499ef..c02c107 100644
--- a/include/linker/kobject.ld
+++ b/include/linker/kobject.ld
@@ -5,6 +5,7 @@
*/
#ifdef CONFIG_USERSPACE
+ z_kobject_data_begin = .;
/* Constraints:
*
* - changes to the size of this section between build phases
diff --git a/include/linker/linker-defs.h b/include/linker/linker-defs.h
index 48d3cc8..383fef1 100644
--- a/include/linker/linker-defs.h
+++ b/include/linker/linker-defs.h
@@ -303,6 +303,7 @@
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
diff --git a/kernel/include/kernel_internal.h b/kernel/include/kernel_internal.h
index 3e0c4f2..702d5c5 100644
--- a/kernel/include/kernel_internal.h
+++ b/kernel/include/kernel_internal.h
@@ -197,6 +197,9 @@
*/
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
diff --git a/kernel/init.c b/kernel/init.c
index 7d1ce4a..b12db35 100644
--- a/kernel/init.c
+++ b/kernel/init.c
@@ -391,7 +391,9 @@
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);
diff --git a/kernel/mmu.c b/kernel/mmu.c
index 15d984c..9cead31 100644
--- a/kernel/mmu.c
+++ b/kernel/mmu.c
@@ -453,6 +453,29 @@
*/
#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;
