The patch titled
Subject: Revert "MIPS: make userspace mapping young by default"
has been added to the -mm tree. Its filename is
revert-mips-make-userspace-mapping-young-by-default.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/revert-mips-make-userspace-mapping-young-by-default.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/revert-mips-make-userspace-mapping-young-by-default.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Subject: Revert "MIPS: make userspace mapping young by default"
This reverts commit f685a533a7fab35c5d069dcd663f59c8e4171a75.
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@xxxxxxxxxxxxxxxx
Fixes: f685a533a7f ("MIPS: make userspace mapping young by default")
Reported-by: Zhou Yanjie <zhouyanjie@xxxxxxxxxxxxxx>
Signed-off-by: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Huang Pei <huangpei@xxxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/mips/mm/cache.c | 30 ++++++++++++++----------------
include/linux/pgtable.h | 8 ++++++++
mm/memory.c | 4 ++++
3 files changed, 26 insertions(+), 16 deletions(-)
--- a/arch/mips/mm/cache.c~revert-mips-make-userspace-mapping-young-by-default
+++ a/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)
--- a/include/linux/pgtable.h~revert-mips-make-userspace-mapping-young-by-default
+++ a/include/linux/pgtable.h
@@ -432,6 +432,14 @@ static inline void ptep_set_wrprotect(st
* 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
--- a/mm/memory.c~revert-mips-make-userspace-mapping-young-by-default
+++ a/mm/memory.c
@@ -2939,6 +2939,7 @@ static vm_fault_t wp_page_copy(struct vm
}
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(stru
__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, st
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);
_
Patches currently in -mm which might be from tsbogend@xxxxxxxxxxxxxxxx are
revert-mips-make-userspace-mapping-young-by-default.patch
