[PATCH v2] ARC: Use 40-bit physical page mask for PAE

From: Vladimir Isaev
Date: Tue Apr 27 2021 - 08:13:02 EST

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
r03: 0x00000000 r04: 0x00000a48 r05: 0x001855b8
r06: 0x00186654 r07: 0x00010034 r08: 0x000000e2
r09: 0x00000007 r10: 0x00000000 r11: 0x00000000
r12: 0x00000000 r13: 0x00000001 r14: 0x00000002
r15: 0x5f9fff14 r16: 0x5f9fff20 r17: 0x001855d0
r18: 0x00000001 r19: 0x00000000 r20: 0x00000000
r21: 0x00000000 r22: 0x00000000 r23: 0x00000000
r24: 0x00000000 r25: 0x0018a488
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
---
Changes for v2:
- PHYSICAL_PAGE_MASK -> PAGE_MASK_PHYS
- off variable in ioremap_prot is now unsigned int and uses PAGE_MASK
- Revised commit message
---
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(-)

diff --git a/arch/arc/include/asm/page.h b/arch/arc/include/asm/page.h
index ad9b7fe4dba3..4a9d33372fe2 100644
--- 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)
diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index 163641726a2b..5878846f00cf 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -107,8 +107,8 @@
#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)
@@ -132,13 +132,7 @@
#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)
diff --git a/arch/arc/include/uapi/asm/page.h b/arch/arc/include/uapi/asm/page.h
index 2a97e2718a21..2a4ad619abfb 100644
--- 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 */
diff --git a/arch/arc/mm/ioremap.c b/arch/arc/mm/ioremap.c
index fac4adc90204..95c649fbc95a 100644
--- 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 paddr, unsigned long size,

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

/*
diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c
index 9bb3c24f3677..9c7c68247289 100644
--- a/arch/arc/mm/tlb.c
+++ b/arch/arc/mm/tlb.c
@@ -576,7 +576,7 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long vaddr_unaligned,
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);
--
2.16.2