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31 lines
886 B
31 lines
886 B
6 years ago
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From: Felix Fietkau <nbd@nbd.name>
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Subject: MIPS: fix cache flushing for highmem pages
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Most cache flush ops were no-op for highmem pages. This led to nasty
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segfaults and (in the case of page_address(page) == NULL) kernel
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crashes.
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Fix this by always flushing highmem pages using kmap/kunmap_atomic
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around the actual cache flush. This might be a bit inefficient, but at
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least it's stable.
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Signed-off-by: Felix Fietkau <nbd@nbd.name>
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---
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--- a/arch/mips/mm/cache.c
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+++ b/arch/mips/mm/cache.c
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@@ -116,6 +116,13 @@ void __flush_anon_page(struct page *page
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{
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unsigned long addr = (unsigned long) page_address(page);
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+ if (PageHighMem(page)) {
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+ addr = (unsigned long)kmap_atomic(page);
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+ flush_data_cache_page(addr);
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+ __kunmap_atomic((void *)addr);
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+ return;
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+ }
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+
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if (pages_do_alias(addr, vmaddr)) {
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if (page_mapcount(page) && !Page_dcache_dirty(page)) {
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void *kaddr;
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