Commit 50c25ee9 authored by Thomas Bogendoerfer's avatar Thomas Bogendoerfer Committed by Linus Torvalds
Browse files

Revert "MIPS: make userspace mapping young by default" 

This reverts commit f685a533.

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: f685a533 ("MIPS: make userspace mapping young by default")
Reported-by: default avatarZhou Yanjie <zhouyanjie@wanyeetech.com>
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Huang Pei <huangpei@loongson.cn>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 16f0596f

arch/mips/mm/cache.c

+14 −16
Original line number Diff line number Diff line
@@ -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)

include/linux/pgtable.h

+8 −0
Original line number Diff line number Diff line
@@ -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

mm/memory.c

+4 −0
Original line number Diff line number Diff line
@@ -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);