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

[Vineet Gupta]

On 4/27/21 5:12 AM, Vladimir Isaev wrote:
> 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

Applied to for-curr !

Thx,
-Vineet

> ---
> 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);