From a31e9c4e7247d182192e9b85abbea498d63dd850 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Sun, 10 Jan 2021 19:05:09 +0100 Subject: Revert "um: support some of ARCH_HAS_SET_MEMORY" This reverts commit 963285b0b47a ("um: support some of ARCH_HAS_SET_MEMORY"), as it turns out that it's not only not working (due to um never using the protection bits in the page tables) but also corrupts the page tables if used on a non-vmalloc page, since um never allocates proper page tables for the 'physmem' in the first place. Fixing all this will take more effort, so for now revert it. Reported-by: Benjamin Berg Fixes: 963285b0b47a ("um: support some of ARCH_HAS_SET_MEMORY") Signed-off-by: Johannes Berg Signed-off-by: Richard Weinberger --- arch/um/kernel/tlb.c | 54 ---------------------------------------------------- 1 file changed, 54 deletions(-) (limited to 'arch/um/kernel') diff --git a/arch/um/kernel/tlb.c b/arch/um/kernel/tlb.c index 437d1f1cc5ec..61776790cd67 100644 --- a/arch/um/kernel/tlb.c +++ b/arch/um/kernel/tlb.c @@ -608,57 +608,3 @@ void force_flush_all(void) vma = vma->vm_next; } } - -struct page_change_data { - unsigned int set_mask, clear_mask; -}; - -static int change_page_range(pte_t *ptep, unsigned long addr, void *data) -{ - struct page_change_data *cdata = data; - pte_t pte = READ_ONCE(*ptep); - - pte_clear_bits(pte, cdata->clear_mask); - pte_set_bits(pte, cdata->set_mask); - - set_pte(ptep, pte); - return 0; -} - -static int change_memory(unsigned long start, unsigned long pages, - unsigned int set_mask, unsigned int clear_mask) -{ - unsigned long size = pages * PAGE_SIZE; - struct page_change_data data; - int ret; - - data.set_mask = set_mask; - data.clear_mask = clear_mask; - - ret = apply_to_page_range(&init_mm, start, size, change_page_range, - &data); - - flush_tlb_kernel_range(start, start + size); - - return ret; -} - -int set_memory_ro(unsigned long addr, int numpages) -{ - return change_memory(addr, numpages, 0, _PAGE_RW); -} - -int set_memory_rw(unsigned long addr, int numpages) -{ - return change_memory(addr, numpages, _PAGE_RW, 0); -} - -int set_memory_nx(unsigned long addr, int numpages) -{ - return -EOPNOTSUPP; -} - -int set_memory_x(unsigned long addr, int numpages) -{ - return -EOPNOTSUPP; -} -- cgit