malhuda/msm-4.14
1
0
Fork 0
mirror of https://github.com/rd-stuffs/msm-4.14.git synced 2025-02-20 11:45:48 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

arm: highmem: Add support for flushing kmap_atomic mappings

Browse Source 
The highmem code provides kmap_flush_unused to ensure all kmap
mappings are really removed if they are unused. This code does not
handle kmap_atomic mappings since they are managed separately.
This prevents an issue for any code which relies on having absolutely
no mappings for a particular page. Rather than pay the penalty of
having CONFIG_DEBUG_HIGHMEM on all the time, add functionality
to remove the kmap_atomic mappings in a similar way to kmap_flush_unused.

Change-Id: I9d73abad693c18f2daa1647353e7592b255475b0
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
This commit is contained in:
Laura Abbott 2013-04-05 14:12:53 -07:00 committed by Gerrit - the friendly Code Review server
parent 19e308d6ca
commit 5fa884ffd4
2 changed files with 60 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/arm/Kconfig
View File

@ -241,6 +241,9 @@ config NEED_RET_TO_USER
config ARCH_MTD_XIP
bool
config ARCH_WANT_KMAP_ATOMIC_FLUSH
bool
config VECTORS_BASE
hex
default 0xffff0000 if MMU || CPU_HIGH_VECTOR
@ -568,6 +571,7 @@ config ARCH_QCOM
select SPARSE_IRQ
select USE_OF
select PINCTRL
select ARCH_WANT_KMAP_ATOMIC_FLUSH
help
Support for Qualcomm MSM/QSD based systems. This runs on the
apps processor of the MSM/QSD and depends on a shared memory

56
arch/arm/mm/highmem.c
View File

@ -10,6 +10,7 @@
* published by the Free Software Foundation.
*/
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/highmem.h>
#include <linux/interrupt.h>
@ -147,3 +148,58 @@ void *kmap_atomic_pfn(unsigned long pfn)
return (void *)vaddr;
}
#ifdef CONFIG_ARCH_WANT_KMAP_ATOMIC_FLUSH
static void kmap_remove_unused_cpu(int cpu)
{
int start_idx, idx, type;
pagefault_disable();
type = kmap_atomic_idx();
start_idx = type + 1 + KM_TYPE_NR * cpu;
for (idx = start_idx; idx < KM_TYPE_NR + KM_TYPE_NR * cpu; idx++) {
unsigned long vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
pte_t ptep;
ptep = get_top_pte(vaddr);
if (ptep)
set_top_pte(vaddr, __pte(0));
}
pagefault_enable();
}
static void kmap_remove_unused(void *unused)
{
kmap_remove_unused_cpu(smp_processor_id());
}
void kmap_atomic_flush_unused(void)
{
on_each_cpu(kmap_remove_unused, NULL, 1);
}
static int hotplug_kmap_atomic_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
switch (action & (~CPU_TASKS_FROZEN)) {
case CPU_DYING:
kmap_remove_unused_cpu((int)hcpu);
break;
default:
break;
}
return NOTIFY_OK;
}
static struct notifier_block hotplug_kmap_atomic_notifier = {
.notifier_call = hotplug_kmap_atomic_callback,
};
static int __init init_kmap_atomic(void)
{
return register_hotcpu_notifier(&hotplug_kmap_atomic_notifier);
}
early_initcall(init_kmap_atomic);
#endif