From 50c25ee97cf6ab011542167ab590c17012cea4ed Mon Sep 17 00:00:00 2001 From: Thomas Bogendoerfer Date: Fri, 4 Jun 2021 20:01:08 -0700 Subject: Revert "MIPS: make userspace mapping young by default" This reverts commit f685a533a7fab35c5d069dcd663f59c8e4171a75. The MIPS cache flush logic needs to know whether the mapping was already established to decide how to flush caches. This is done by checking the valid bit in the PTE. The commit above breaks this logic by setting the valid in the PTE in new mappings, which causes kernel crashes. Link: https://lkml.kernel.org/r/20210526094335.92948-1-tsbogend@alpha.franken.de Fixes: f685a533a7f ("MIPS: make userspace mapping young by default") Reported-by: Zhou Yanjie Signed-off-by: Thomas Bogendoerfer Cc: Huang Pei Cc: Nicholas Piggin Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/mips/mm/cache.c | 30 ++++++++++++++---------------- include/linux/pgtable.h | 8 ++++++++ mm/memory.c | 4 ++++ 3 files changed, 26 insertions(+), 16 deletions(-) diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c index a7bf0c80371c..830ab91e574f 100644 --- a/arch/mips/mm/cache.c +++ b/arch/mips/mm/cache.c @@ -158,31 +158,29 @@ unsigned long _page_cachable_default; EXPORT_SYMBOL(_page_cachable_default); #define PM(p) __pgprot(_page_cachable_default | (p)) -#define PVA(p) PM(_PAGE_VALID | _PAGE_ACCESSED | (p)) static inline void setup_protection_map(void) { protection_map[0] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); - protection_map[1] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC); - protection_map[2] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); - protection_map[3] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC); - protection_map[4] = PVA(_PAGE_PRESENT); - protection_map[5] = PVA(_PAGE_PRESENT); - protection_map[6] = PVA(_PAGE_PRESENT); - protection_map[7] = PVA(_PAGE_PRESENT); + protection_map[1] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC); + protection_map[2] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); + protection_map[3] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC); + protection_map[4] = PM(_PAGE_PRESENT); + protection_map[5] = PM(_PAGE_PRESENT); + protection_map[6] = PM(_PAGE_PRESENT); + protection_map[7] = PM(_PAGE_PRESENT); protection_map[8] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); - protection_map[9] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC); - protection_map[10] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | + protection_map[9] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC); + protection_map[10] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | _PAGE_NO_READ); - protection_map[11] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE); - protection_map[12] = PVA(_PAGE_PRESENT); - protection_map[13] = PVA(_PAGE_PRESENT); - protection_map[14] = PVA(_PAGE_PRESENT); - protection_map[15] = PVA(_PAGE_PRESENT); + protection_map[11] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE); + protection_map[12] = PM(_PAGE_PRESENT); + protection_map[13] = PM(_PAGE_PRESENT); + protection_map[14] = PM(_PAGE_PRESENT | _PAGE_WRITE); + protection_map[15] = PM(_PAGE_PRESENT | _PAGE_WRITE); } -#undef _PVA #undef PM void cpu_cache_init(void) diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 46b13780c2c8..a43047b1030d 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -432,6 +432,14 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres * To be differentiate with macro pte_mkyoung, this macro is used on platforms * where software maintains page access bit. */ +#ifndef pte_sw_mkyoung +static inline pte_t pte_sw_mkyoung(pte_t pte) +{ + return pte; +} +#define pte_sw_mkyoung pte_sw_mkyoung +#endif + #ifndef pte_savedwrite #define pte_savedwrite pte_write #endif diff --git a/mm/memory.c b/mm/memory.c index 730daa00952b..f3ffab9b9e39 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2939,6 +2939,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) } flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); entry = mk_pte(new_page, vma->vm_page_prot); + entry = pte_sw_mkyoung(entry); entry = maybe_mkwrite(pte_mkdirty(entry), vma); /* @@ -3602,6 +3603,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf) __SetPageUptodate(page); entry = mk_pte(page, vma->vm_page_prot); + entry = pte_sw_mkyoung(entry); if (vma->vm_flags & VM_WRITE) entry = pte_mkwrite(pte_mkdirty(entry)); @@ -3786,6 +3788,8 @@ void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr) if (prefault && arch_wants_old_prefaulted_pte()) entry = pte_mkold(entry); + else + entry = pte_sw_mkyoung(entry); if (write) entry = maybe_mkwrite(pte_mkdirty(entry), vma); -- cgit v1.2.3