Commit 963285b0 authored by Johannes Berg's avatar Johannes Berg Committed by Richard Weinberger
Browse files

um: support some of ARCH_HAS_SET_MEMORY 



For now, only support set_memory_ro()/rw() which we need for
the stack protection in the next patch.

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
parent 58b09f68

arch/um/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ config UML 
	select HAVE_DEBUG_KMEMLEAK

	select HAVE_DEBUG_BUGVERBOSE

	select NO_DMA

	select ARCH_HAS_SET_MEMORY

	select GENERIC_IRQ_SHOW

	select GENERIC_CPU_DEVICES

	select GENERIC_CLOCKEVENTS

arch/um/include/asm/pgtable.h

+3 −0
Original line number Diff line number Diff line
@@ -55,12 +55,15 @@ extern unsigned long end_iomem; 
#define _PAGE_CHG_MASK	(PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)

#define __PAGE_KERNEL_EXEC                                              \

	 (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)

#define __PAGE_KERNEL_RO						\

	 (_PAGE_PRESENT | _PAGE_DIRTY | _PAGE_ACCESSED)

#define PAGE_NONE	__pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)

#define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED)

#define PAGE_COPY	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)

#define PAGE_READONLY	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)

#define PAGE_KERNEL	__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)

#define PAGE_KERNEL_EXEC	__pgprot(__PAGE_KERNEL_EXEC)

#define PAGE_KERNEL_RO		__pgprot(__PAGE_KERNEL_RO)



/*

 * The i386 can't do page protection for execute, and considers that the same

arch/um/include/asm/set_memory.h

0 → 100644
+1 −0
Original line number Diff line number Diff line 
#include <asm-generic/set_memory.h>

arch/um/kernel/tlb.c

+54 −0
Original line number Diff line number Diff line
@@ -608,3 +608,57 @@ void force_flush_all(void) 
		vma = vma->vm_next;

	}

}



struct page_change_data {

	unsigned int set_mask, clear_mask;

};



static int change_page_range(pte_t *ptep, unsigned long addr, void *data)

{

	struct page_change_data *cdata = data;

	pte_t pte = READ_ONCE(*ptep);



	pte_clear_bits(pte, cdata->clear_mask);

	pte_set_bits(pte, cdata->set_mask);



	set_pte(ptep, pte);

	return 0;

}



static int change_memory(unsigned long start, unsigned long pages,

			 unsigned int set_mask, unsigned int clear_mask)

{

	unsigned long size = pages * PAGE_SIZE;

	struct page_change_data data;

	int ret;



	data.set_mask = set_mask;

	data.clear_mask = clear_mask;



	ret = apply_to_page_range(&init_mm, start, size, change_page_range,

				  &data);



	flush_tlb_kernel_range(start, start + size);



	return ret;

}



int set_memory_ro(unsigned long addr, int numpages)

{

	return change_memory(addr, numpages, 0, _PAGE_RW);

}



int set_memory_rw(unsigned long addr, int numpages)

{

	return change_memory(addr, numpages, _PAGE_RW, 0);

}



int set_memory_nx(unsigned long addr, int numpages)

{

	return -EOPNOTSUPP;

}



int set_memory_x(unsigned long addr, int numpages)

{

	return -EOPNOTSUPP;

}

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