Commit 42a54772 authored by Borislav Petkov's avatar Borislav Petkov Committed by Matt Fleming
Browse files

x86, pageattr: Export page unmapping interface 



We will use it in efi so expose it.

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Tested-by: default avatarToshi Kani <toshi.kani@hp.com>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
parent 11cc8512

arch/x86/include/asm/pgtable_types.h

+2 −0
Original line number Diff line number Diff line
@@ -385,6 +385,8 @@ extern pte_t *lookup_address(unsigned long address, unsigned int *level); 
extern phys_addr_t slow_virt_to_phys(void *__address);

extern int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address,

				   unsigned numpages, unsigned long page_flags);

void kernel_unmap_pages_in_pgd(pgd_t *root, unsigned long address,

			       unsigned numpages);

#endif	/* !__ASSEMBLY__ */



#endif /* _ASM_X86_PGTABLE_DEFS_H */

arch/x86/mm/pageattr.c

+31 −13
Original line number Diff line number Diff line
@@ -692,6 +692,18 @@ static bool try_to_free_pmd_page(pmd_t *pmd) 
	return true;

}



static bool try_to_free_pud_page(pud_t *pud)

{

	int i;



	for (i = 0; i < PTRS_PER_PUD; i++)

		if (!pud_none(pud[i]))

			return false;



	free_page((unsigned long)pud);

	return true;

}



static bool unmap_pte_range(pmd_t *pmd, unsigned long start, unsigned long end)

{

	pte_t *pte = pte_offset_kernel(pmd, start);
@@ -805,6 +817,16 @@ static void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end) 
	 */

}



static void unmap_pgd_range(pgd_t *root, unsigned long addr, unsigned long end)

{

	pgd_t *pgd_entry = root + pgd_index(addr);



	unmap_pud_range(pgd_entry, addr, end);



	if (try_to_free_pud_page((pud_t *)pgd_page_vaddr(*pgd_entry)))

		pgd_clear(pgd_entry);

}



static int alloc_pte_page(pmd_t *pmd)

{

	pte_t *pte = (pte_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK);
@@ -999,9 +1021,8 @@ static int populate_pud(struct cpa_data *cpa, unsigned long start, pgd_t *pgd, 
static int populate_pgd(struct cpa_data *cpa, unsigned long addr)

{

	pgprot_t pgprot = __pgprot(_KERNPG_TABLE);

	bool allocd_pgd = false;

	pgd_t *pgd_entry;

	pud_t *pud = NULL;	/* shut up gcc */

	pgd_t *pgd_entry;

	int ret;



	pgd_entry = cpa->pgd + pgd_index(addr);
@@ -1015,7 +1036,6 @@ static int populate_pgd(struct cpa_data *cpa, unsigned long addr) 
			return -1;



		set_pgd(pgd_entry, __pgd(__pa(pud) | _KERNPG_TABLE));

		allocd_pgd = true;

	}



	pgprot_val(pgprot) &= ~pgprot_val(cpa->mask_clr);
@@ -1023,19 +1043,11 @@ static int populate_pgd(struct cpa_data *cpa, unsigned long addr) 


	ret = populate_pud(cpa, addr, pgd_entry, pgprot);

	if (ret < 0) {

		unmap_pud_range(pgd_entry, addr,

		unmap_pgd_range(cpa->pgd, addr,

				addr + (cpa->numpages << PAGE_SHIFT));



		if (allocd_pgd) {

			/*

			 * If I allocated this PUD page, I can just as well

			 * free it in this error path.

			 */

			pgd_clear(pgd_entry);

			free_page((unsigned long)pud);

		}

		return ret;

	}



	cpa->numpages = ret;

	return 0;

}
@@ -1861,6 +1873,12 @@ int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, 
	return retval;

}



void kernel_unmap_pages_in_pgd(pgd_t *root, unsigned long address,

			       unsigned numpages)

{

	unmap_pgd_range(root, address, address + (numpages << PAGE_SHIFT));

}



/*

 * The testcases use internal knowledge of the implementation that shouldn't

 * be exposed to the rest of the kernel. Include these directly here.