From 2519d753676bdf2460fbbcde276d5b6ba8d6b695 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Thu, 5 May 2016 14:53:48 +0530 Subject: [PATCH] ARC: Fix PAE40 boot failures due to PTE truncation So a benign looking cleanup which macro'ized PAGE_SHIFT shifts turned out to be bad (since it was done non-sensically across the board). It caused boot failures with PAE40 as forced cast to (unsigned long) from newly introduced virt_to_pfn() was causing truncatiion of the (long long) pte/paddr values. It is OK to use this in accessors dealing with kernel virtual address, pointers etc, but not for PTE values themelves. Fixes: cJ2ff5cf2735c ("ARC: mm: Use virt_to_pfn() for addr >> PAGE_SHIFT pattern) Signed-off-by: Vineet Gupta --- arch/arc/include/asm/page.h | 9 ++++++++- arch/arc/include/asm/pgtable.h | 13 ++++++------- 2 files changed, 14 insertions(+), 8 deletions(-) diff --git a/arch/arc/include/asm/page.h b/arch/arc/include/asm/page.h index 36da89e2c853..533e5a0c6ba5 100644 --- a/arch/arc/include/asm/page.h +++ b/arch/arc/include/asm/page.h @@ -72,6 +72,13 @@ typedef unsigned long pgprot_t; typedef pte_t * pgtable_t; +/* + * Use virt_to_pfn with caution: + * If used in pte or paddr related macros, it could cause truncation + * in PAE40 builds + * As a rule of thumb, only use it in helpers starting with virt_ + * You have been warned ! + */ #define virt_to_pfn(kaddr) (__pa(kaddr) >> PAGE_SHIFT) #define ARCH_PFN_OFFSET virt_to_pfn(CONFIG_LINUX_LINK_BASE) @@ -85,7 +92,7 @@ typedef pte_t * pgtable_t; * virt here means link-address/program-address as embedded in object code. * And for ARC, link-addr = physical address */ -#define __pa(vaddr) ((unsigned long)vaddr) +#define __pa(vaddr) ((unsigned long)(vaddr)) #define __va(paddr) ((void *)((unsigned long)(paddr))) #define virt_to_page(kaddr) \ diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h index 7d6c93e63adf..10d4b8b8e545 100644 --- a/arch/arc/include/asm/pgtable.h +++ b/arch/arc/include/asm/pgtable.h @@ -278,14 +278,13 @@ static inline void pmd_set(pmd_t *pmdp, pte_t *ptep) #define pmd_present(x) (pmd_val(x)) #define pmd_clear(xp) do { pmd_val(*(xp)) = 0; } while (0) -#define pte_page(pte) \ - (mem_map + virt_to_pfn(pte_val(pte) - CONFIG_LINUX_LINK_BASE)) - +#define pte_page(pte) pfn_to_page(pte_pfn(pte)) #define mk_pte(page, prot) pfn_pte(page_to_pfn(page), prot) -#define pte_pfn(pte) virt_to_pfn(pte_val(pte)) -#define pfn_pte(pfn, prot) (__pte(((pte_t)(pfn) << PAGE_SHIFT) | \ - pgprot_val(prot))) -#define __pte_index(addr) (virt_to_pfn(addr) & (PTRS_PER_PTE - 1)) +#define pfn_pte(pfn, prot) (__pte(((pte_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot))) + +/* Don't use virt_to_pfn for macros below: could cause truncations for PAE40*/ +#define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT) +#define __pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) /* * pte_offset gets a @ptr to PMD entry (PGD in our 2-tier paging system) -- 2.34.1