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Commit 4ac3ef99 authored by Laura Abbott's avatar Laura Abbott
Browse files

arm64: Add alternate CONFIG_DEBUG_SET_MODULE_RONX support 



Commit 802ae1e1
(arm64: mm: Introduce PTE_WRITE) changed pte_wrprotect
and pte_mkwrite to use software read only bits instead
of the hardware bits explicitly. The hardware read only
bits are updated in set_pte_at. Unfortunately, the check
in set_pte_at only works for user page tables which breaks
support for the read only functions in modules. Move to an
alternative implementation which does not use pte_mkwrite/pte_wrprotect.

Change-Id: I4251a0929b1fe6f43f84b14f0a64fed30769700e
Signed-off-by: default avatarLaura Abbott <lauraa@codeaurora.org>
parent ff1ff8e0

arch/arm64/mm/Makefile

+1 −1
Original line number Diff line number Diff line 
obj-y				:= dma-mapping.o extable.o fault.o init.o \

				   cache.o copypage.o flush.o \

				   ioremap.o iomap.o mmap.o pgd.o mmu.o \

				   context.o tlb.o proc.o

				   context.o tlb.o proc.o pageattr.o

obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o

arch/arm64/mm/mmu.c

+0 −42
Original line number Diff line number Diff line
@@ -122,48 +122,6 @@ static int __init early_cachepolicy(char *p) 
}

early_param("cachepolicy", early_cachepolicy);



#define PTE_SET_FN(_name, pteop) \

static int pte_set_##_name(pte_t *ptep, pgtable_t token, unsigned long addr, \

			void *data) \

{ \

	pte_t pte = pteop(*ptep); \

\

	set_pte(ptep, pte); \

	return 0; \

} \



#define SET_MEMORY_FN(_name, callback) \

int set_memory_##_name(unsigned long addr, int numpages) \

{ \

	unsigned long start = addr; \

	unsigned long size = PAGE_SIZE*numpages; \

	unsigned long end = start + size; \

\

	if (start < MODULES_VADDR || start >= MODULES_END) \

		return -EINVAL;\

\

	if (end < MODULES_VADDR || end >= MODULES_END) \

		return -EINVAL; \

\

	apply_to_page_range(&init_mm, start, size, callback, NULL); \

	flush_tlb_kernel_range(start, end); \

	return 0;\

}



PTE_SET_FN(ro, pte_wrprotect)

PTE_SET_FN(rw, pte_mkwrite)

PTE_SET_FN(x, pte_mkexec)

PTE_SET_FN(nx, pte_mknexec)



SET_MEMORY_FN(ro, pte_set_ro)

EXPORT_SYMBOL(set_memory_ro);

SET_MEMORY_FN(rw, pte_set_rw)

EXPORT_SYMBOL(set_memory_rw);

SET_MEMORY_FN(x, pte_set_x)

EXPORT_SYMBOL(set_memory_x);

SET_MEMORY_FN(nx, pte_set_nx)

EXPORT_SYMBOL(set_memory_nx);



/*

 * Adjust the PMD section entries according to the CPU in use.

 */

arch/arm64/mm/pageattr.c

0 → 100644
+121 −0
Original line number Diff line number Diff line 
/*

 * Copyright (c) 2014, The Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and

 * only version 2 as published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */

#include <linux/kernel.h>

#include <linux/mm.h>

#include <linux/sched.h>



#include <asm/pgtable.h>

#include <asm/tlbflush.h>



static pte_t clear_pte_bit(pte_t pte, pgprot_t prot)

{

	pte_val(pte) &= ~pgprot_val(prot);

	return pte;

}



static pte_t set_pte_bit(pte_t pte, pgprot_t prot)

{

	pte_val(pte) |= pgprot_val(prot);

	return pte;

}



static int __change_memory(pte_t *ptep, pgtable_t token, unsigned long addr,

			pgprot_t prot, bool set)

{

	pte_t pte;



	if (set)

		pte = set_pte_bit(*ptep, prot);

	else

		pte = clear_pte_bit(*ptep, prot);

	set_pte(ptep, pte);

	return 0;

}



static int set_page_range(pte_t *ptep, pgtable_t token, unsigned long addr,

			void *data)

{

	pgprot_t prot = (pgprot_t)data;



	return __change_memory(ptep, token, addr, prot, true);

}



static int clear_page_range(pte_t *ptep, pgtable_t token, unsigned long addr,

			void *data)

{

	pgprot_t prot = (pgprot_t)data;



	return __change_memory(ptep, token, addr, prot, false);

}



static int change_memory_common(unsigned long addr, int numpages,

				pgprot_t prot, bool set)

{

	unsigned long start = addr;

	unsigned long size = PAGE_SIZE*numpages;

	unsigned long end = start + size;

	int ret;



	if (start < MODULES_VADDR || start >= MODULES_END)

		return -EINVAL;



	if (end < MODULES_VADDR || end >= MODULES_END)

		return -EINVAL;



	if (set)

		ret = apply_to_page_range(&init_mm, start, size,

					set_page_range, (void *)prot);

	else

		ret = apply_to_page_range(&init_mm, start, size,

					clear_page_range, (void *)prot);



	flush_tlb_kernel_range(start, end);

	isb();

	return ret;

}



static int change_memory_set_bit(unsigned long addr, int numpages,

					pgprot_t prot)

{

	return change_memory_common(addr, numpages, prot, true);

}



static int change_memory_clear_bit(unsigned long addr, int numpages,

					pgprot_t prot)

{

	return change_memory_common(addr, numpages, prot, false);

}



int set_memory_ro(unsigned long addr, int numpages)

{

	return change_memory_set_bit(addr, numpages, __pgprot(PTE_RDONLY));

}

EXPORT_SYMBOL(set_memory_ro);



int set_memory_rw(unsigned long addr, int numpages)

{

	return change_memory_clear_bit(addr, numpages, __pgprot(PTE_RDONLY));

}

EXPORT_SYMBOL(set_memory_rw);



int set_memory_nx(unsigned long addr, int numpages)

{

	return change_memory_set_bit(addr, numpages, __pgprot(PTE_PXN));

}

EXPORT_SYMBOL(set_memory_nx);



int set_memory_x(unsigned long addr, int numpages)

{

	return change_memory_clear_bit(addr, numpages, __pgprot(PTE_PXN));

}

EXPORT_SYMBOL(set_memory_x);