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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 <vgupta@synopsys.com>
This commit is contained in:
Vineet Gupta 2016-05-05 14:53:48 +05:30
parent e5bc0478ab
commit 2519d75367
2 changed files with 14 additions and 8 deletions
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9
arch/arc/include/asm/page.h
View File

@ -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) \

13
arch/arc/include/asm/pgtable.h
View File

@ -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)