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Commit 95f5c800 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Will Deacon
Browse files

arm64: allow vmalloc regions to be set with set_memory_* 



The range of set_memory_* is currently restricted to the module address
range because of difficulties in breaking down larger block sizes.
vmalloc maps PAGE_SIZE pages so it is safe to use as well. Update the
function ranges and add a comment explaining why the range is restricted
the way it is.

Suggested-by: default avatarLaura Abbott <labbott@fedoraproject.org>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 36f90b0a

arch/arm64/mm/pageattr.c

+19 −4
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <linux/mm.h>

#include <linux/module.h>

#include <linux/sched.h>

#include <linux/vmalloc.h>



#include <asm/pgtable.h>

#include <asm/tlbflush.h>
@@ -44,6 +45,7 @@ static int change_memory_common(unsigned long addr, int numpages, 
	unsigned long end = start + size;

	int ret;

	struct page_change_data data;

	struct vm_struct *area;



	if (!PAGE_ALIGNED(addr)) {

		start &= PAGE_MASK;
@@ -51,10 +53,23 @@ static int change_memory_common(unsigned long addr, int numpages, 
		WARN_ON_ONCE(1);

	}



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

		return -EINVAL;



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

	/*

	 * Kernel VA mappings are always live, and splitting live section

	 * mappings into page mappings may cause TLB conflicts. This means

	 * we have to ensure that changing the permission bits of the range

	 * we are operating on does not result in such splitting.

	 *

	 * Let's restrict ourselves to mappings created by vmalloc (or vmap).

	 * Those are guaranteed to consist entirely of page mappings, and

	 * splitting is never needed.

	 *

	 * So check whether the [addr, addr + size) interval is entirely

	 * covered by precisely one VM area that has the VM_ALLOC flag set.

	 */

	area = find_vm_area((void *)addr);

	if (!area ||

	    end > (unsigned long)area->addr + area->size ||

	    !(area->flags & VM_ALLOC))

		return -EINVAL;



	if (!numpages)