Unverified Commit 216e04bf authored by Björn Töpel's avatar Björn Töpel Committed by Palmer Dabbelt
Browse files

riscv: mm: Add support for ZONE_DEVICE 



ZONE_DEVICE pages need DEVMAP PTEs support to function
(ARCH_HAS_PTE_DEVMAP). Claim another RSW (reserved for software) bit
in the PTE for DEVMAP mark, add the corresponding helpers, and enable
ARCH_HAS_PTE_DEVMAP for riscv64.

Reviewed-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: default avatarBjörn Töpel <bjorn@rivosinc.com>
Link: https://lore.kernel.org/r/20240605114100.315918-11-bjorn@kernel.org


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 0546d704

arch/riscv/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ config RISCV 
	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

	select ARCH_HAS_PMEM_API

	select ARCH_HAS_PREPARE_SYNC_CORE_CMD

	select ARCH_HAS_PTE_DEVMAP if 64BIT && MMU

	select ARCH_HAS_PTE_SPECIAL

	select ARCH_HAS_SET_DIRECT_MAP if MMU

	select ARCH_HAS_SET_MEMORY if MMU

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

+20 −0
Original line number Diff line number Diff line
@@ -398,4 +398,24 @@ static inline struct page *pgd_page(pgd_t pgd) 
#define p4d_offset p4d_offset

p4d_t *p4d_offset(pgd_t *pgd, unsigned long address);



#ifdef CONFIG_TRANSPARENT_HUGEPAGE

static inline int pte_devmap(pte_t pte);

static inline pte_t pmd_pte(pmd_t pmd);



static inline int pmd_devmap(pmd_t pmd)

{

	return pte_devmap(pmd_pte(pmd));

}



static inline int pud_devmap(pud_t pud)

{

	return 0;

}



static inline int pgd_devmap(pgd_t pgd)

{

	return 0;

}

#endif



#endif /* _ASM_RISCV_PGTABLE_64_H */

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

+1 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#define _PAGE_SOFT      (3 << 8)    /* Reserved for software */



#define _PAGE_SPECIAL   (1 << 8)    /* RSW: 0x1 */

#define _PAGE_DEVMAP    (1 << 9)    /* RSW, devmap */

#define _PAGE_TABLE     _PAGE_PRESENT



/*

arch/riscv/include/asm/pgtable.h

+17 −0
Original line number Diff line number Diff line
@@ -390,6 +390,13 @@ static inline int pte_special(pte_t pte) 
	return pte_val(pte) & _PAGE_SPECIAL;

}



#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP

static inline int pte_devmap(pte_t pte)

{

	return pte_val(pte) & _PAGE_DEVMAP;

}

#endif



/* static inline pte_t pte_rdprotect(pte_t pte) */



static inline pte_t pte_wrprotect(pte_t pte)
@@ -431,6 +438,11 @@ static inline pte_t pte_mkspecial(pte_t pte) 
	return __pte(pte_val(pte) | _PAGE_SPECIAL);

}



static inline pte_t pte_mkdevmap(pte_t pte)

{

	return __pte(pte_val(pte) | _PAGE_DEVMAP);

}



static inline pte_t pte_mkhuge(pte_t pte)

{

	return pte;
@@ -721,6 +733,11 @@ static inline pmd_t pmd_mkdirty(pmd_t pmd) 
	return pte_pmd(pte_mkdirty(pmd_pte(pmd)));

}



static inline pmd_t pmd_mkdevmap(pmd_t pmd)

{

	return pte_pmd(pte_mkdevmap(pmd_pte(pmd)));

}



static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,

				pmd_t *pmdp, pmd_t pmd)

{