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Commit 2519d753 authored by Vineet Gupta's avatar Vineet Gupta
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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: default avatarVineet Gupta <vgupta@synopsys.com>
parent e5bc0478

arch/arc/include/asm/page.h

+8 −1
Original line number Diff line number Diff line
@@ -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)	\

arch/arc/include/asm/pgtable.h

+6 −7
Original line number Diff line number Diff line
@@ -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)