diff options
Diffstat (limited to 'target/linux/generic/pending-4.9/100-MIPS-fix-cache-flushing-for-highmem-pages.patch')
| -rw-r--r-- | target/linux/generic/pending-4.9/100-MIPS-fix-cache-flushing-for-highmem-pages.patch | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/target/linux/generic/pending-4.9/100-MIPS-fix-cache-flushing-for-highmem-pages.patch b/target/linux/generic/pending-4.9/100-MIPS-fix-cache-flushing-for-highmem-pages.patch new file mode 100644 index 0000000000..622fab65b7 --- /dev/null +++ b/target/linux/generic/pending-4.9/100-MIPS-fix-cache-flushing-for-highmem-pages.patch @@ -0,0 +1,30 @@ +From: Felix Fietkau <nbd@nbd.name> +Subject: 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@nbd.name> +--- + +--- a/arch/mips/mm/cache.c ++++ b/arch/mips/mm/cache.c +@@ -115,6 +115,13 @@ void __flush_anon_page(struct page *page + { + unsigned long addr = (unsigned long) page_address(page); + ++ if (PageHighMem(page)) { ++ addr = (unsigned long)kmap_atomic(page); ++ flush_data_cache_page(addr); ++ __kunmap_atomic((void *)addr); ++ return; ++ } ++ + if (pages_do_alias(addr, vmaddr)) { + if (page_mapcount(page) && !Page_dcache_dirty(page)) { + void *kaddr; |