mirror of https://github.com/hak5/openwrt.git
102 lines
2.5 KiB
Diff
102 lines
2.5 KiB
Diff
From: Felix Fietkau <nbd@openwrt.org>
|
|
Date: Sun, 24 Jan 2016 01:03:51 +0100
|
|
Subject: [PATCH] MIPS: fix cache flushing for highmem pages
|
|
|
|
Most cache flush ops were no-op for highmem pages. This led to nasty
|
|
segfaults and (in the case of page_address(page) == NULL) kernel
|
|
crashes.
|
|
|
|
Fix this by always flushing highmem pages using kmap/kunmap_atomic
|
|
around the actual cache flush. This might be a bit inefficient, but at
|
|
least it's stable.
|
|
|
|
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
|
|
---
|
|
|
|
--- a/arch/mips/mm/cache.c
|
|
+++ b/arch/mips/mm/cache.c
|
|
@@ -14,6 +14,7 @@
|
|
#include <linux/sched.h>
|
|
#include <linux/syscalls.h>
|
|
#include <linux/mm.h>
|
|
+#include <linux/highmem.h>
|
|
|
|
#include <asm/cacheflush.h>
|
|
#include <asm/processor.h>
|
|
@@ -78,18 +79,29 @@ SYSCALL_DEFINE3(cacheflush, unsigned lon
|
|
return 0;
|
|
}
|
|
|
|
+static void
|
|
+flush_highmem_page(struct page *page)
|
|
+{
|
|
+ void *addr = kmap_atomic(page);
|
|
+ flush_data_cache_page((unsigned long)addr);
|
|
+ kunmap_atomic(addr);
|
|
+}
|
|
+
|
|
void __flush_dcache_page(struct page *page)
|
|
{
|
|
struct address_space *mapping = page_mapping(page);
|
|
unsigned long addr;
|
|
|
|
- if (PageHighMem(page))
|
|
- return;
|
|
if (mapping && !mapping_mapped(mapping)) {
|
|
SetPageDcacheDirty(page);
|
|
return;
|
|
}
|
|
|
|
+ if (PageHighMem(page)) {
|
|
+ flush_highmem_page(page);
|
|
+ return;
|
|
+ }
|
|
+
|
|
/*
|
|
* We could delay the flush for the !page_mapping case too. But that
|
|
* case is for exec env/arg pages and those are %99 certainly going to
|
|
@@ -105,6 +117,11 @@ void __flush_anon_page(struct page *page
|
|
{
|
|
unsigned long addr = (unsigned long) page_address(page);
|
|
|
|
+ if (PageHighMem(page)) {
|
|
+ flush_highmem_page(page);
|
|
+ return;
|
|
+ }
|
|
+
|
|
if (pages_do_alias(addr, vmaddr)) {
|
|
if (page_mapped(page) && !Page_dcache_dirty(page)) {
|
|
void *kaddr;
|
|
@@ -123,8 +140,10 @@ void __flush_icache_page(struct vm_area_
|
|
{
|
|
unsigned long addr;
|
|
|
|
- if (PageHighMem(page))
|
|
+ if (PageHighMem(page)) {
|
|
+ flush_highmem_page(page);
|
|
return;
|
|
+ }
|
|
|
|
addr = (unsigned long) page_address(page);
|
|
flush_data_cache_page(addr);
|
|
@@ -142,12 +161,17 @@ void __update_cache(struct vm_area_struc
|
|
if (unlikely(!pfn_valid(pfn)))
|
|
return;
|
|
page = pfn_to_page(pfn);
|
|
- if (page_mapping(page) && Page_dcache_dirty(page)) {
|
|
+ if (!Page_dcache_dirty(page) || !page_mapping(page))
|
|
+ return;
|
|
+
|
|
+ if (PageHighMem(page)) {
|
|
+ flush_highmem_page(page);
|
|
+ } else {
|
|
addr = (unsigned long) page_address(page);
|
|
if (exec || pages_do_alias(addr, address & PAGE_MASK))
|
|
flush_data_cache_page(addr);
|
|
- ClearPageDcacheDirty(page);
|
|
}
|
|
+ ClearPageDcacheDirty(page);
|
|
}
|
|
|
|
unsigned long _page_cachable_default;
|