x86: MMU: Memory domain implementation for x86

Added support for memory domain implementation. zephyrproject-rtosGH-3852 Signed-off-by: Adithya Baglody <[email protected]>
praveenmunagapati · Oct 20, 2017 · d0f6ce2 · d0f6ce2
1 parent 7add3cd
commit d0f6ce2
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Showing 3 changed files with 175 additions and 1 deletion.
diff --git a/arch/x86/core/x86_mmu.c b/arch/x86/core/x86_mmu.c
@@ -113,6 +113,7 @@ static inline void tlb_flush_page(void *addr)
 	 * specified address
 	 */
 	char *page = (char *)addr;
+
 	__asm__ ("invlpg %0" :: "m" (*page));
 }
 
@@ -140,3 +141,107 @@ void _x86_mmu_set_flags(void *ptr, size_t size, u32_t flags, u32_t mask)
 		addr += MMU_PAGE_SIZE;
 	}
 }
+
+#ifdef CONFIG_X86_USERSPACE
+
+/* Helper macros needed to be passed to x86_update_mem_domain_pages */
+#define X86_MEM_DOMAIN_SET_PAGES   (0U)
+#define X86_MEM_DOMAIN_RESET_PAGES (1U)
+/* Pass 1 to page_conf if reset of mem domain pages is needed else pass a 0*/
+static inline void x86_update_mem_domain_pages(struct k_mem_domain *mem_domain,
+					       u32_t page_conf)
+{
+	u32_t partition_index;
+	u32_t total_partitions;
+	struct k_mem_partition partition;
+	u32_t partitions_count;
+
+	/* If mem_domain doesn't point to a valid location return.*/
+	if (mem_domain == NULL) {
+		goto out;
+	}
+
+	/* Get the total number of partitions*/
+	total_partitions = mem_domain->num_partitions;
+
+	/* Iterate over all the partitions for the given mem_domain
+	 * For x86: interate over all the partitions and set the
+	 * required flags in the correct MMU page tables.
+	 */
+	partitions_count = 0;
+	for (partition_index = 0;
+	     partitions_count < total_partitions;
+	     partition_index++) {
+
+		/* Get the partition info */
+		partition = mem_domain->partitions[partition_index];
+		if (partition.size == 0) {
+			continue;
+		}
+		partitions_count++;
+		if (page_conf == X86_MEM_DOMAIN_SET_PAGES) {
+			/* Set the partition attributes */
+			_x86_mmu_set_flags((void *)partition.start,
+					   partition.size,
+					   partition.attr,
+					   K_MEM_PARTITION_PERM_MASK);
+		} else {
+			/* Reset the pages to supervisor RW only */
+			_x86_mmu_set_flags((void *)partition.start,
+					   partition.size,
+					   K_MEM_PARTITION_P_RW_U_NA,
+					   K_MEM_PARTITION_PERM_MASK);
+		}
+	}
+ out:
+	return;
+}
+
+
+/* Load the required parttions of the new incoming thread */
+void _x86_load_mmu_mem_domain(struct k_thread *thread)
+{
+	x86_update_mem_domain_pages(thread->mem_domain_info.mem_domain,
+				    X86_MEM_DOMAIN_SET_PAGES);
+}
+
+/* Destroy or reset the mmu page tables when necessary.
+ * Needed when either swap takes place or k_mem_domain_destroy is called.
+ */
+void _arch_mem_domain_destroy(struct k_mem_domain *domain)
+{
+	x86_update_mem_domain_pages(domain, X86_MEM_DOMAIN_RESET_PAGES);
+}
+
+/* Reset/destroy one partition spcified in the argument of the API. */
+void _arch_mem_domain_remove_partition(struct k_mem_domain *domain,
+				       u32_t  partition_id)
+{
+	u32_t total_partitions;
+	struct k_mem_partition partition;
+
+	if (domain == NULL) {
+		goto out;
+	}
+
+	total_partitions = domain->num_partitions;
+	__ASSERT(partition_id <= total_partitions,
+		 "invalid partitions");
+
+	partition = domain->partitions[partition_id];
+
+	_x86_mmu_set_flags((void *)partition.start,
+			   partition.size,
+			   K_MEM_PARTITION_P_RW_U_NA,
+			   K_MEM_PARTITION_PERM_MASK);
+
+ out:
+	return;
+}
+
+u8_t _arch_mem_domain_max_partitions_get(void)
+{
+	return CONFIG_MAX_DOMAIN_PARTITIONS;
+}
+
+#endif	/* CONFIG_X86_USERSPACE*/
diff --git a/arch/x86/include/mmustructs.h b/arch/x86/include/mmustructs.h
@@ -137,7 +137,6 @@
 #define MMU_ENTRY_RUNTIME_WRITE	    0x20000000
 
 
-
 /* Helper macros to ease the usage of the MMU page table structures.
  * Returns the Page table address for the particular address.
  * Page Table address(returned value) is always 4KBytes aligned.
@@ -168,6 +167,63 @@
 	((union x86_mmu_pde_4mb *)\
 	 (&X86_MMU_PD->entry[MMU_PDE_NUM(addr)].fourmb))
 
+#ifdef CONFIG_X86_USERSPACE
+
+/* Flags which are only available for PAE mode page tables  */
+#ifdef CONFIG_X86_PAE_MODE
+
+/* memory partition arch/soc independent attribute */
+#define K_MEM_PARTITION_P_RW_U_RW   (MMU_ENTRY_WRITE | \
+				     MMU_ENTRY_USER  | \
+				     MMU_ENTRY_EXECUTE_DISABLE)
+
+#define K_MEM_PARTITION_P_RW_U_NA   (MMU_ENTRY_WRITE | \
+				     MMU_ENTRY_SUPERVISOR | \
+				     MMU_ENTRY_EXECUTE_DISABLE)
+
+#define K_MEM_PARTITION_P_RO_U_RO   (MMU_ENTRY_READ | \
+				     MMU_ENTRY_USER | \
+				     MMU_ENTRY_EXECUTE_DISABLE)
+
+#define K_MEM_PARTITION_P_RO_U_NA   (MMU_ENTRY_READ  | \
+				     MMU_ENTRY_SUPERVISOR | \
+				     MMU_ENTRY_EXECUTE_DISABLE)
+
+/* Execution-allowed attributes */
+#define K_MEM_PARTITION_P_RWX_U_RWX (MMU_ENTRY_WRITE | MMU_ENTRY_USER)
+
+#define K_MEM_PARTITION_P_RWX_U_NA  (MMU_ENTRY_WRITE | MMU_ENTRY_SUPERVISOR)
+
+#define K_MEM_PARTITION_P_RX_U_RX   (MMU_ENTRY_READ | MMU_ENTRY_USER)
+
+#define K_MEM_PARTITION_P_RX_U_NA   (MMU_ENTRY_READ | MMU_ENTRY_SUPERVISOR)
+
+
+ /* memory partition access permission mask */
+#define K_MEM_PARTITION_PERM_MASK   (MMU_PTE_RW_MASK |\
+				     MMU_PTE_US_MASK |\
+				     MMU_PTE_XD_MASK)
+
+
+#else  /* 32-bit paging mode enabled */
+
+/* memory partition arch/soc independent attribute */
+#define K_MEM_PARTITION_P_RW_U_RW   (MMU_ENTRY_WRITE | MMU_ENTRY_USER)
+
+#define K_MEM_PARTITION_P_RW_U_NA   (MMU_ENTRY_WRITE | MMU_ENTRY_SUPERVISOR)
+
+#define K_MEM_PARTITION_P_RO_U_RO   (MMU_ENTRY_READ | MMU_ENTRY_USER)
+
+#define K_MEM_PARTITION_P_RO_U_NA   (MMU_ENTRY_READ  | MMU_ENTRY_SUPERVISOR)
+
+/* memory partition access permission mask */
+#define K_MEM_PARTITION_PERM_MASK   (MMU_PTE_RW_MASK | MMU_PTE_US_MASK)
+
+#endif	/* CONFIG_X86_PAE_MODE */
+
+#endif	 /* CONFIG_X86_USERSPACE */
+
+
 #ifndef _ASMLANGUAGE
 #include <zephyr/types.h>
 

diff --git a/include/arch/x86/arch.h b/include/arch/x86/arch.h
@@ -787,6 +787,19 @@ void _x86_mmu_get_flags(void *addr, u32_t *pde_flags, u32_t *pte_flags);
  *	 modify
  */
 void _x86_mmu_set_flags(void *ptr, size_t size, u32_t flags, u32_t mask);
+
+#ifdef CONFIG_USERSPACE
+/**
+ * @brief Load the memory domain for the thread.
+ *
+ * If the memory domain is used this API will configure the page tables
+ * according to the memory domain partition attributes.
+ *
+ * @param thread k_thread structure for the thread which is to configured.
+ */
+void _x86_load_mmu_mem_domain(struct k_thread *thread);
+#endif
+
 #endif /* CONFIG_X86_MMU */
 
 #endif /* !_ASMLANGUAGE */