UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

scs: Move accounting into alloc/free functions 

There's no need to perform the shadow stack page accounting independently
of the lifetime of the underlying allocation, so call the accounting code
from the {alloc,free}() functions and simplify the code in the process.

Tested-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Will Deacon 2020-05-15 14:43:11 +01:00
parent 51189c7a7e
commit bee348fab0
1 changed files with 20 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
kernel/scs.c
View File

@ -14,25 +14,35 @@
static struct kmem_cache *scs_cache;
static void __scs_account(void *s, int account)
{
struct page *scs_page = virt_to_page(s);
mod_zone_page_state(page_zone(scs_page), NR_KERNEL_SCS_KB,
account * (SCS_SIZE / SZ_1K));
}
static void *scs_alloc(int node)
{
void *s;
void *s = kmem_cache_alloc_node(scs_cache, GFP_SCS, node);
s = kmem_cache_alloc_node(scs_cache, GFP_SCS, node);
if (s) {
*__scs_magic(s) = SCS_END_MAGIC;
/*
* Poison the allocation to catch unintentional accesses to
* the shadow stack when KASAN is enabled.
*/
kasan_poison_object_data(scs_cache, s);
}
if (!s)
return NULL;
*__scs_magic(s) = SCS_END_MAGIC;
/*
* Poison the allocation to catch unintentional accesses to
* the shadow stack when KASAN is enabled.
*/
kasan_poison_object_data(scs_cache, s);
__scs_account(s, 1);
return s;
}
static void scs_free(void *s)
{
__scs_account(s, -1);
kasan_unpoison_object_data(scs_cache, s);
kmem_cache_free(scs_cache, s);
}
@ -42,17 +52,6 @@ void __init scs_init(void)
scs_cache = kmem_cache_create("scs_cache", SCS_SIZE, 0, 0, NULL);
}
static struct page *__scs_page(struct task_struct *tsk)
{
return virt_to_page(task_scs(tsk));
}
static void scs_account(struct task_struct *tsk, int account)
{
mod_zone_page_state(page_zone(__scs_page(tsk)), NR_KERNEL_SCS_KB,
account * (SCS_SIZE / 1024));
}
int scs_prepare(struct task_struct *tsk, int node)
{
void *s = scs_alloc(node);
@ -61,7 +60,6 @@ int scs_prepare(struct task_struct *tsk, int node)
return -ENOMEM;
task_scs(tsk) = task_scs_sp(tsk) = s;
scs_account(tsk, 1);
return 0;
}
@ -102,6 +100,5 @@ void scs_release(struct task_struct *tsk)
WARN(scs_corrupted(tsk), "corrupted shadow stack detected when freeing task\n");
scs_check_usage(tsk);
scs_account(tsk, -1);
scs_free(s);
}