Unverified Commit 100631b4 authored by Heiko Stuebner's avatar Heiko Stuebner Committed by Palmer Dabbelt
Browse files

riscv: Fix accessing pfn bits in PTEs for non-32bit variants 



On rv32 the PFN part of PTEs is defined to use bits [xlen-1:10]
while on rv64 it is defined to use bits [53:10], leaving [63:54]
as reserved.

With upcoming optional extensions like svpbmt these previously
reserved bits will get used so simply right-shifting the PTE
to get the PFN won't be enough.

So introduce a _PAGE_PFN_MASK constant to mask the correct bits
for both rv32 and rv64 before shifting.

Signed-off-by: default avatarHeiko Stuebner <heiko@sntech.de>
Reviewed-by: default avatarPhilipp Tomsich <philipp.tomsich@vrull.eu>
Link: https://lore.kernel.org/r/20220511192921.2223629-9-heiko@sntech.de


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent ffb0b0af

arch/riscv/include/asm/pgtable-32.h

+8 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#define _ASM_RISCV_PGTABLE_32_H



#include <asm-generic/pgtable-nopmd.h>

#include <linux/bits.h>

#include <linux/const.h>



/* Size of region mapped by a page global directory */
@@ -16,4 +17,11 @@ 


#define MAX_POSSIBLE_PHYSMEM_BITS 34



/*

 * rv32 PTE format:

 * | XLEN-1  10 | 9             8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0

 *       PFN      reserved for SW   D   A   G   U   X   W   R   V

 */

#define _PAGE_PFN_MASK  GENMASK(31, 10)



#endif /* _ASM_RISCV_PGTABLE_32_H */

arch/riscv/include/asm/pgtable-64.h

+11 −3
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#ifndef _ASM_RISCV_PGTABLE_64_H

#define _ASM_RISCV_PGTABLE_64_H



#include <linux/bits.h>

#include <linux/const.h>



extern bool pgtable_l4_enabled;
@@ -65,6 +66,13 @@ typedef struct { 


#define PTRS_PER_PMD    (PAGE_SIZE / sizeof(pmd_t))



/*

 * rv64 PTE format:

 * | 63 | 62 61 | 60 54 | 53  10 | 9             8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0

 *   N      MT     RSV    PFN      reserved for SW   D   A   G   U   X   W   R   V

 */

#define _PAGE_PFN_MASK  GENMASK(53, 10)



static inline int pud_present(pud_t pud)

{

	return (pud_val(pud) & _PAGE_PRESENT);
@@ -108,12 +116,12 @@ static inline unsigned long _pud_pfn(pud_t pud) 


static inline pmd_t *pud_pgtable(pud_t pud)

{

	return (pmd_t *)pfn_to_virt(pud_val(pud) >> _PAGE_PFN_SHIFT);

	return (pmd_t *)pfn_to_virt(__page_val_to_pfn(pud_val(pud)));

}



static inline struct page *pud_page(pud_t pud)

{

	return pfn_to_page(pud_val(pud) >> _PAGE_PFN_SHIFT);

	return pfn_to_page(__page_val_to_pfn(pud_val(pud)));

}



#define mm_p4d_folded  mm_p4d_folded
@@ -143,7 +151,7 @@ static inline pmd_t pfn_pmd(unsigned long pfn, pgprot_t prot) 


static inline unsigned long _pmd_pfn(pmd_t pmd)

{

	return pmd_val(pmd) >> _PAGE_PFN_SHIFT;

	return __page_val_to_pfn(pmd_val(pmd));

}



#define mk_pmd(page, prot)    pfn_pmd(page_to_pfn(page), prot)

arch/riscv/include/asm/pgtable-bits.h

+0 −6
Original line number Diff line number Diff line
@@ -6,12 +6,6 @@ 
#ifndef _ASM_RISCV_PGTABLE_BITS_H

#define _ASM_RISCV_PGTABLE_BITS_H



/*

 * PTE format:

 * | XLEN-1  10 | 9             8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0

 *       PFN      reserved for SW   D   A   G   U   X   W   R   V

 */



#define _PAGE_ACCESSED_OFFSET 6



#define _PAGE_PRESENT   (1 << 0)

arch/riscv/include/asm/pgtable.h

+5 −3
Original line number Diff line number Diff line
@@ -108,6 +108,8 @@ 
#include <asm/tlbflush.h>

#include <linux/mm_types.h>



#define __page_val_to_pfn(_val)  (((_val) & _PAGE_PFN_MASK) >> _PAGE_PFN_SHIFT)



#ifdef CONFIG_64BIT

#include <asm/pgtable-64.h>

#else
@@ -261,12 +263,12 @@ static inline unsigned long _pgd_pfn(pgd_t pgd) 


static inline struct page *pmd_page(pmd_t pmd)

{

	return pfn_to_page(pmd_val(pmd) >> _PAGE_PFN_SHIFT);

	return pfn_to_page(__page_val_to_pfn(pmd_val(pmd)));

}



static inline unsigned long pmd_page_vaddr(pmd_t pmd)

{

	return (unsigned long)pfn_to_virt(pmd_val(pmd) >> _PAGE_PFN_SHIFT);

	return (unsigned long)pfn_to_virt(__page_val_to_pfn(pmd_val(pmd)));

}



static inline pte_t pmd_pte(pmd_t pmd)
@@ -282,7 +284,7 @@ static inline pte_t pud_pte(pud_t pud) 
/* Yields the page frame number (PFN) of a page table entry */

static inline unsigned long pte_pfn(pte_t pte)

{

	return (pte_val(pte) >> _PAGE_PFN_SHIFT);

	return __page_val_to_pfn(pte_val(pte));

}



#define pte_page(x)     pfn_to_page(pte_pfn(x))