michaelh/zephyr
1
0
Fork 0
Code Releases Activity

aarch64: mmu: apply proper locking

Browse source 
We need to protect against concurrent modifications to page tables and
their use counts.

It would have been nice to have one lock per domain, but we heavily
share page tables across domains. Hence the global lock.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
This commit is contained in:
Nicolas Pitre 2021-02-24 21:31:22 -05:00 • committed by Anas Nashif
commit c77ffebb24
1 changed files with 35 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

42
arch/arm/core/aarch64/mmu/arm_mmu.c
View file

@ -16,6 +16,7 @@
#include <arch/arm/aarch64/lib_helpers.h>
#include <arch/arm/aarch64/arm_mmu.h>
#include <linker/linker-defs.h>
#include <spinlock.h>
#include <sys/util.h>
#include "arm_mmu.h"
@ -25,6 +26,7 @@ LOG_MODULE_DECLARE(os, CONFIG_KERNEL_LOG_LEVEL);
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 k_spinlock xlat_lock;
/* Returns a reference to a free table */
static uint64_t *new_table(void)
@ -217,6 +219,10 @@ static int set_mapping(struct arm_mmu_ptables *ptables,
uint64_t level_size;
uint64_t *table = ptables->base_xlat_table;
unsigned int level = BASE_XLAT_LEVEL;
k_spinlock_key_t key;
int ret = 0;
key = k_spin_lock(&xlat_lock);
while (size) {
__ASSERT(level <= XLAT_LAST_LEVEL,
@ -238,7 +244,8 @@ static int set_mapping(struct arm_mmu_ptables *ptables,
LOG_ERR("entry already in use: "
"level %d pte %p *pte 0x%016llx",
level, pte, *pte);
return -EBUSY;
ret = -EBUSY;
break;
}
level_size = 1ULL << LEVEL_TO_VA_SIZE_SHIFT(level);
@ -256,7 +263,8 @@ static int set_mapping(struct arm_mmu_ptables *ptables,
/* Range doesn't fit, create subtable */
table = expand_to_table(pte, level);
if (!table) {
return -ENOMEM;
ret = -ENOMEM;
break;
}
level++;
continue;
@ -291,7 +299,9 @@ move_on:
level = BASE_XLAT_LEVEL;
}
return 0;
k_spin_unlock(&xlat_lock, key);
return ret;
}
#ifdef CONFIG_USERSPACE
@ -379,10 +389,19 @@ static int privatize_page_range(struct arm_mmu_ptables *dst_pt,
uintptr_t virt_start, size_t size,
const char *name)
{
k_spinlock_key_t key;
int ret;
MMU_DEBUG("privatize [%s]: virt %lx size %lx\n",
name, virt_start, size);
return privatize_table(dst_pt->base_xlat_table, src_pt->base_xlat_table,
virt_start, size, BASE_XLAT_LEVEL);
key = k_spin_lock(&xlat_lock);
ret = privatize_table(dst_pt->base_xlat_table, src_pt->base_xlat_table,
virt_start, size, BASE_XLAT_LEVEL);
k_spin_unlock(&xlat_lock, key);
return ret;
}
static void discard_table(uint64_t *table, unsigned int level)
@ -474,10 +493,19 @@ static int globalize_page_range(struct arm_mmu_ptables *dst_pt,
uintptr_t virt_start, size_t size,
const char *name)
{
k_spinlock_key_t key;
int ret;
MMU_DEBUG("globalize [%s]: virt %lx size %lx\n",
name, virt_start, size);
return globalize_table(dst_pt->base_xlat_table, src_pt->base_xlat_table,
virt_start, size, BASE_XLAT_LEVEL);
key = k_spin_lock(&xlat_lock);
ret = globalize_table(dst_pt->base_xlat_table, src_pt->base_xlat_table,
virt_start, size, BASE_XLAT_LEVEL);
k_spin_unlock(&xlat_lock, key);
return ret;
}
#endif /* CONFIG_USERSPACE */