Unverified Commit d3ab332a authored by Zong Li's avatar Zong Li Committed by Palmer Dabbelt
Browse files

riscv: add ARCH_HAS_SET_MEMORY support 



Add set_memory_ro/rw/x/nx architecture hooks to change the page
attribution.

Use own set_memory.h rather than generic set_memory.h
(i.e. include/asm-generic/set_memory.h), because we want to add other
function prototypes here.

Signed-off-by: default avatarZong Li <zong.li@sifive.com>
Signed-off-by: default avatarPalmer Dabbelt <palmerdabbelt@google.com>
parent 9f40b6e7

arch/riscv/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -59,6 +59,7 @@ config RISCV 
	select HAVE_EBPF_JIT if 64BIT

	select EDAC_SUPPORT

	select ARCH_HAS_GIGANTIC_PAGE

	select ARCH_HAS_SET_MEMORY

	select ARCH_WANT_HUGE_PMD_SHARE if 64BIT

	select SPARSEMEM_STATIC if 32BIT

	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU

arch/riscv/include/asm/set_memory.h

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Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0-only */

/*

 * Copyright (C) 2019 SiFive

 */



#ifndef _ASM_RISCV_SET_MEMORY_H

#define _ASM_RISCV_SET_MEMORY_H



/*

 * Functions to change memory attributes.

 */

#ifdef CONFIG_MMU

int set_memory_ro(unsigned long addr, int numpages);

int set_memory_rw(unsigned long addr, int numpages);

int set_memory_x(unsigned long addr, int numpages);

int set_memory_nx(unsigned long addr, int numpages);

#else

static inline int set_memory_ro(unsigned long addr, int numpages) { return 0; }

static inline int set_memory_rw(unsigned long addr, int numpages) { return 0; }

static inline int set_memory_x(unsigned long addr, int numpages) { return 0; }

static inline int set_memory_nx(unsigned long addr, int numpages) { return 0; }

#endif



#endif /* _ASM_RISCV_SET_MEMORY_H */

arch/riscv/mm/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -7,7 +7,7 @@ endif 


obj-y += init.o

obj-y += extable.o

obj-$(CONFIG_MMU) += fault.o

obj-$(CONFIG_MMU) += fault.o pageattr.o

obj-y += cacheflush.o

obj-y += context.o

arch/riscv/mm/pageattr.c

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// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (C) 2019 SiFive

 */



#include <linux/pagewalk.h>

#include <asm/pgtable.h>

#include <asm/tlbflush.h>

#include <asm/bitops.h>



struct pageattr_masks {

	pgprot_t set_mask;

	pgprot_t clear_mask;

};



static unsigned long set_pageattr_masks(unsigned long val, struct mm_walk *walk)

{

	struct pageattr_masks *masks = walk->private;

	unsigned long new_val = val;



	new_val &= ~(pgprot_val(masks->clear_mask));

	new_val |= (pgprot_val(masks->set_mask));



	return new_val;

}



static int pageattr_pgd_entry(pgd_t *pgd, unsigned long addr,

			      unsigned long next, struct mm_walk *walk)

{

	pgd_t val = READ_ONCE(*pgd);



	if (pgd_leaf(val)) {

		val = __pgd(set_pageattr_masks(pgd_val(val), walk));

		set_pgd(pgd, val);

	}



	return 0;

}



static int pageattr_p4d_entry(p4d_t *p4d, unsigned long addr,

			      unsigned long next, struct mm_walk *walk)

{

	p4d_t val = READ_ONCE(*p4d);



	if (p4d_leaf(val)) {

		val = __p4d(set_pageattr_masks(p4d_val(val), walk));

		set_p4d(p4d, val);

	}



	return 0;

}



static int pageattr_pud_entry(pud_t *pud, unsigned long addr,

			      unsigned long next, struct mm_walk *walk)

{

	pud_t val = READ_ONCE(*pud);



	if (pud_leaf(val)) {

		val = __pud(set_pageattr_masks(pud_val(val), walk));

		set_pud(pud, val);

	}



	return 0;

}



static int pageattr_pmd_entry(pmd_t *pmd, unsigned long addr,

			      unsigned long next, struct mm_walk *walk)

{

	pmd_t val = READ_ONCE(*pmd);



	if (pmd_leaf(val)) {

		val = __pmd(set_pageattr_masks(pmd_val(val), walk));

		set_pmd(pmd, val);

	}



	return 0;

}



static int pageattr_pte_entry(pte_t *pte, unsigned long addr,

			      unsigned long next, struct mm_walk *walk)

{

	pte_t val = READ_ONCE(*pte);



	val = __pte(set_pageattr_masks(pte_val(val), walk));

	set_pte(pte, val);



	return 0;

}



static int pageattr_pte_hole(unsigned long addr, unsigned long next,

			     int depth, struct mm_walk *walk)

{

	/* Nothing to do here */

	return 0;

}



const static struct mm_walk_ops pageattr_ops = {

	.pgd_entry = pageattr_pgd_entry,

	.p4d_entry = pageattr_p4d_entry,

	.pud_entry = pageattr_pud_entry,

	.pmd_entry = pageattr_pmd_entry,

	.pte_entry = pageattr_pte_entry,

	.pte_hole = pageattr_pte_hole,

};



static int __set_memory(unsigned long addr, int numpages, pgprot_t set_mask,

			pgprot_t clear_mask)

{

	int ret;

	unsigned long start = addr;

	unsigned long end = start + PAGE_SIZE * numpages;

	struct pageattr_masks masks = {

		.set_mask = set_mask,

		.clear_mask = clear_mask

	};



	if (!numpages)

		return 0;



	down_read(&init_mm.mmap_sem);

	ret =  walk_page_range_novma(&init_mm, start, end, &pageattr_ops, NULL,

				     &masks);

	up_read(&init_mm.mmap_sem);



	flush_tlb_kernel_range(start, end);



	return ret;

}



int set_memory_ro(unsigned long addr, int numpages)

{

	return __set_memory(addr, numpages, __pgprot(_PAGE_READ),

			    __pgprot(_PAGE_WRITE));

}



int set_memory_rw(unsigned long addr, int numpages)

{

	return __set_memory(addr, numpages, __pgprot(_PAGE_READ | _PAGE_WRITE),

			    __pgprot(0));

}



int set_memory_x(unsigned long addr, int numpages)

{

	return __set_memory(addr, numpages, __pgprot(_PAGE_EXEC), __pgprot(0));

}



int set_memory_nx(unsigned long addr, int numpages)

{

	return __set_memory(addr, numpages, __pgprot(0), __pgprot(_PAGE_EXEC));

}