[PATCH 5.4 096/141] ARC: mm: PAE: use 40-bit physical page mask

From: Greg Kroah-Hartman
Date: Mon May 17 2021 - 11:21:54 EST


From: Vladimir Isaev <isaev@xxxxxxxxxxxx>

commit c5f756d8c6265ebb1736a7787231f010a3b782e5 upstream.

32-bit PAGE_MASK can not be used as a mask for physical addresses
when PAE is enabled. PAGE_MASK_PHYS must be used for physical
addresses instead of PAGE_MASK.

Without this, init gets SIGSEGV if pte_modify was called:

| potentially unexpected fatal signal 11.
| Path: /bin/busybox
| CPU: 0 PID: 1 Comm: init Not tainted 5.12.0-rc5-00003-g1e43c377a79f-dirty
| Insn could not be fetched
| @No matching VMA found
| ECR: 0x00040000 EFA: 0x00000000 ERET: 0x00000000
| STAT: 0x80080082 [IE U ] BTA: 0x00000000
| SP: 0x5f9ffe44 FP: 0x00000000 BLK: 0xaf3d4
| LPS: 0x000d093e LPE: 0x000d0950 LPC: 0x00000000
| r00: 0x00000002 r01: 0x5f9fff14 r02: 0x5f9fff20
| ...
| Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

Signed-off-by: Vladimir Isaev <isaev@xxxxxxxxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arc/include/asm/page.h | 12 ++++++++++++
arch/arc/include/asm/pgtable.h | 12 +++---------
arch/arc/include/uapi/asm/page.h | 1 -
arch/arc/mm/ioremap.c | 5 +++--
arch/arc/mm/tlb.c | 2 +-
5 files changed, 19 insertions(+), 13 deletions(-)

--- a/arch/arc/include/asm/page.h
+++ b/arch/arc/include/asm/page.h
@@ -7,6 +7,18 @@

#include <uapi/asm/page.h>

+#ifdef CONFIG_ARC_HAS_PAE40
+
+#define MAX_POSSIBLE_PHYSMEM_BITS 40
+#define PAGE_MASK_PHYS (0xff00000000ull | PAGE_MASK)
+
+#else /* CONFIG_ARC_HAS_PAE40 */
+
+#define MAX_POSSIBLE_PHYSMEM_BITS 32
+#define PAGE_MASK_PHYS PAGE_MASK
+
+#endif /* CONFIG_ARC_HAS_PAE40 */
+
#ifndef __ASSEMBLY__

#define clear_page(paddr) memset((paddr), 0, PAGE_SIZE)
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -108,8 +108,8 @@
#define ___DEF (_PAGE_PRESENT | _PAGE_CACHEABLE)

/* Set of bits not changed in pte_modify */
-#define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_SPECIAL)
-
+#define _PAGE_CHG_MASK (PAGE_MASK_PHYS | _PAGE_ACCESSED | _PAGE_DIRTY | \
+ _PAGE_SPECIAL)
/* More Abbrevaited helpers */
#define PAGE_U_NONE __pgprot(___DEF)
#define PAGE_U_R __pgprot(___DEF | _PAGE_READ)
@@ -133,13 +133,7 @@
#define PTE_BITS_IN_PD0 (_PAGE_GLOBAL | _PAGE_PRESENT | _PAGE_HW_SZ)
#define PTE_BITS_RWX (_PAGE_EXECUTE | _PAGE_WRITE | _PAGE_READ)

-#ifdef CONFIG_ARC_HAS_PAE40
-#define PTE_BITS_NON_RWX_IN_PD1 (0xff00000000 | PAGE_MASK | _PAGE_CACHEABLE)
-#define MAX_POSSIBLE_PHYSMEM_BITS 40
-#else
-#define PTE_BITS_NON_RWX_IN_PD1 (PAGE_MASK | _PAGE_CACHEABLE)
-#define MAX_POSSIBLE_PHYSMEM_BITS 32
-#endif
+#define PTE_BITS_NON_RWX_IN_PD1 (PAGE_MASK_PHYS | _PAGE_CACHEABLE)

/**************************************************************************
* Mapping of vm_flags (Generic VM) to PTE flags (arch specific)
--- a/arch/arc/include/uapi/asm/page.h
+++ b/arch/arc/include/uapi/asm/page.h
@@ -33,5 +33,4 @@

#define PAGE_MASK (~(PAGE_SIZE-1))

-
#endif /* _UAPI__ASM_ARC_PAGE_H */
--- a/arch/arc/mm/ioremap.c
+++ b/arch/arc/mm/ioremap.c
@@ -53,9 +53,10 @@ EXPORT_SYMBOL(ioremap);
void __iomem *ioremap_prot(phys_addr_t paddr, unsigned long size,
unsigned long flags)
{
+ unsigned int off;
unsigned long vaddr;
struct vm_struct *area;
- phys_addr_t off, end;
+ phys_addr_t end;
pgprot_t prot = __pgprot(flags);

/* Don't allow wraparound, zero size */
@@ -72,7 +73,7 @@ void __iomem *ioremap_prot(phys_addr_t p

/* Mappings have to be page-aligned */
off = paddr & ~PAGE_MASK;
- paddr &= PAGE_MASK;
+ paddr &= PAGE_MASK_PHYS;
size = PAGE_ALIGN(end + 1) - paddr;

/*
--- a/arch/arc/mm/tlb.c
+++ b/arch/arc/mm/tlb.c
@@ -597,7 +597,7 @@ void update_mmu_cache(struct vm_area_str
pte_t *ptep)
{
unsigned long vaddr = vaddr_unaligned & PAGE_MASK;
- phys_addr_t paddr = pte_val(*ptep) & PAGE_MASK;
+ phys_addr_t paddr = pte_val(*ptep) & PAGE_MASK_PHYS;
struct page *page = pfn_to_page(pte_pfn(*ptep));

create_tlb(vma, vaddr, ptep);