michaelh/zephyr
1
0
Fork 0
Code Releases Activity

aarch64: mmu: make page table pool global

Browse source 
There is no real reason for keeping page tables into separate pools.
Make it global which allows for more efficient memory usage and
simplifies the code.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
This commit is contained in:
Nicolas Pitre 2021-02-11 23:26:21 -05:00 • committed by Anas Nashif
commit b696090bb7
2 changed files with 38 additions and 40 deletions
Download patch file Download diff file Expand all files Collapse all files

75
arch/arm/core/aarch64/mmu/arm_mmu.c
View file

@ -19,23 +19,20 @@
LOG_MODULE_DECLARE(os, CONFIG_KERNEL_LOG_LEVEL);
static uint64_t kernel_xlat_tables[CONFIG_MAX_XLAT_TABLES * Ln_XLAT_NUM_ENTRIES]
static uint64_t xlat_tables[CONFIG_MAX_XLAT_TABLES * Ln_XLAT_NUM_ENTRIES]
__aligned(Ln_XLAT_NUM_ENTRIES * sizeof(uint64_t));
static uint16_t xlat_use_count[CONFIG_MAX_XLAT_TABLES];
static struct arm_mmu_ptables kernel_ptables = {
.xlat_tables = kernel_xlat_tables,
};
/* Returns a new preallocated table */
static uint64_t *new_prealloc_table(struct arm_mmu_ptables *ptables)
/* Returns a reference to a free table */
static uint64_t *new_table(void)
{
unsigned int i;
/* Look for a free table. Table 0 is always allocated. */
for (i = 1; i < CONFIG_MAX_XLAT_TABLES; i++) {
if (ptables->use_count[i] == 0) {
ptables->use_count[i] = 1;
return &ptables->xlat_tables[i * Ln_XLAT_NUM_ENTRIES];
/* Look for a free table. */
for (i = 0; i < CONFIG_MAX_XLAT_TABLES; i++) {
if (xlat_use_count[i] == 0) {
xlat_use_count[i] = 1;
return &xlat_tables[i * Ln_XLAT_NUM_ENTRIES];
}
}
@ -43,30 +40,30 @@ static uint64_t *new_prealloc_table(struct arm_mmu_ptables *ptables)
return NULL;
}
static void free_prealloc_table(struct arm_mmu_ptables *ptables, uint64_t *table)
/* Makes a table free for reuse. */
static void free_table(uint64_t *table)
{
unsigned int i = (table - ptables->xlat_tables) / Ln_XLAT_NUM_ENTRIES;
unsigned int i = (table - xlat_tables) / Ln_XLAT_NUM_ENTRIES;
__ASSERT(i < CONFIG_MAX_XLAT_TABLES, "table out of range");
__ASSERT(ptables->use_count[i] == 1, "table still in use");
ptables->use_count[i] = 0;
__ASSERT(xlat_use_count[i] == 1, "table still in use");
xlat_use_count[i] = 0;
}
static int prealloc_table_usage(struct arm_mmu_ptables *ptables,
uint64_t *table, int adjustment)
/* Adjusts usage count and returns current count. */
static int table_usage(uint64_t *table, int adjustment)
{
unsigned int i = (table - ptables->xlat_tables) / Ln_XLAT_NUM_ENTRIES;
unsigned int i = (table - xlat_tables) / Ln_XLAT_NUM_ENTRIES;
__ASSERT(i < CONFIG_MAX_XLAT_TABLES, "table out of range");
ptables->use_count[i] += adjustment;
__ASSERT(ptables->use_count[i] > 0, "usage count underflow");
return ptables->use_count[i];
xlat_use_count[i] += adjustment;
__ASSERT(xlat_use_count[i] > 0, "usage count underflow");
return xlat_use_count[i];
}
static inline bool is_prealloc_table_unused(struct arm_mmu_ptables *ptables,
uint64_t *table)
static inline bool is_table_unused(uint64_t *table)
{
return prealloc_table_usage(ptables, table, 0) == 1;
return table_usage(table, 0) == 1;
}
static uint64_t get_region_desc(uint32_t attrs)
@ -222,7 +219,7 @@ static int set_mapping(struct arm_mmu_ptables *ptables,
{
uint64_t *pte, *ptes[XLAT_LAST_LEVEL + 1];
uint64_t level_size;
uint64_t *table = ptables->xlat_tables;
uint64_t *table = ptables->base_xlat_table;
unsigned int level = BASE_XLAT_LEVEL;
/* check minimum alignment requirement for given mmap region */
@ -267,7 +264,7 @@ static int set_mapping(struct arm_mmu_ptables *ptables,
if ((size < level_size) || (virt & (level_size - 1))) {
/* Range doesn't fit, create subtable */
table = new_prealloc_table(ptables);
table = new_table();
if (!table) {
return -ENOMEM;
}
@ -276,12 +273,12 @@ static int set_mapping(struct arm_mmu_ptables *ptables,
* then we need to reflect that in the new table.
*/
if (is_block_desc(*pte)) {
prealloc_table_usage(ptables, table, Ln_XLAT_NUM_ENTRIES);
table_usage(table, Ln_XLAT_NUM_ENTRIES);
populate_table(table, *pte, level + 1);
}
/* Adjust usage count for parent table */
if (is_free_desc(*pte)) {
prealloc_table_usage(ptables, pte, 1);
table_usage(pte, 1);
}
/* And link it. */
set_pte_table_desc(pte, table, level);
@ -291,21 +288,21 @@ static int set_mapping(struct arm_mmu_ptables *ptables,
/* Adjust usage count for corresponding table */
if (is_free_desc(*pte)) {
prealloc_table_usage(ptables, pte, 1);
table_usage(pte, 1);
}
if (!desc) {
prealloc_table_usage(ptables, pte, -1);
table_usage(pte, -1);
}
/* Create (or erase) block/page descriptor */
set_pte_block_desc(pte, desc, level);
/* recursively free unused tables if any */
while (level != BASE_XLAT_LEVEL &&
is_prealloc_table_unused(ptables, pte)) {
free_prealloc_table(ptables, pte);
is_table_unused(pte)) {
free_table(pte);
pte = ptes[--level];
set_pte_block_desc(pte, 0, level);
prealloc_table_usage(ptables, pte, -1);
table_usage(pte, -1);
}
move_on:
@ -314,7 +311,7 @@ move_on:
size -= level_size;
/* Range is mapped, start again for next range */
table = ptables->xlat_tables;
table = ptables->base_xlat_table;
level = BASE_XLAT_LEVEL;
}
@ -379,8 +376,7 @@ static void setup_page_tables(struct arm_mmu_ptables *ptables)
MMU_DEBUG("xlat tables:\n");
for (index = 0; index < CONFIG_MAX_XLAT_TABLES; index++)
MMU_DEBUG("%d: %p\n", index, (uint64_t *)(ptables->xlat_tables +
(index * Ln_XLAT_NUM_ENTRIES)));
MMU_DEBUG("%d: %p\n", index, xlat_tables + index * Ln_XLAT_NUM_ENTRIES);
for (index = 0; index < mmu_config.num_regions; index++) {
region = &mmu_config.mmu_regions[index];
@ -453,7 +449,7 @@ static void enable_mmu_el1(struct arm_mmu_ptables *ptables, unsigned int flags)
: "memory", "cc");
__asm__ volatile("msr ttbr0_el1, %0"
:
: "r" ((uint64_t)ptables->xlat_tables)
: "r" ((uint64_t)ptables->base_xlat_table)
: "memory", "cc");
/* Ensure these changes are seen before MMU is enabled */
@ -474,6 +470,8 @@ static void enable_mmu_el1(struct arm_mmu_ptables *ptables, unsigned int flags)
/* ARM MMU Driver Initial Setup */
static struct arm_mmu_ptables kernel_ptables;
/*
* @brief MMU default configuration
*
@ -498,6 +496,7 @@ static int arm_mmu_init(const struct device *arg)
__asm__ volatile("mrs %0, sctlr_el1" : "=r" (val));
__ASSERT((val & SCTLR_M) == 0, "MMU is already enabled\n");
kernel_ptables.base_xlat_table = new_table();
setup_page_tables(&kernel_ptables);
/* currently only EL1 is supported */

3
include/arch/arm/aarch64/arm_mmu.h
View file

@ -165,8 +165,7 @@ struct arm_mmu_config {
};
struct arm_mmu_ptables {
uint64_t *xlat_tables;
uint16_t use_count[CONFIG_MAX_XLAT_TABLES];
uint64_t *base_xlat_table;
};
/* Convenience macros to represent the ARMv8-A-specific