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Commit bab247ff authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
Browse files

s390/vmem: simplify vmem code for read-only mappings 



For the kernel identity mapping map everything read-writeable and
subsequently call set_memory_ro() to make the ro section read-only.
This simplifies the code a lot.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent e8a97e42

arch/s390/mm/vmem.c

+9 −28
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/hugetlb.h>

#include <linux/slab.h>

#include <linux/memblock.h>

#include <asm/cacheflush.h>

#include <asm/pgalloc.h>

#include <asm/pgtable.h>

#include <asm/setup.h>
@@ -77,7 +78,7 @@ pte_t __ref *vmem_pte_alloc(void) 
/*

 * Add a physical memory range to the 1:1 mapping.

 */

static int vmem_add_mem(unsigned long start, unsigned long size, int ro)

static int vmem_add_mem(unsigned long start, unsigned long size)

{

	unsigned long end = start + size;

	unsigned long address = start;
@@ -99,8 +100,7 @@ static int vmem_add_mem(unsigned long start, unsigned long size, int ro) 
		if (MACHINE_HAS_EDAT2 && pud_none(*pu_dir) && address &&

		    !(address & ~PUD_MASK) && (address + PUD_SIZE <= end) &&

		     !debug_pagealloc_enabled()) {

			pud_val(*pu_dir) = address |

				pgprot_val(ro ? REGION3_KERNEL_RO : REGION3_KERNEL);

			pud_val(*pu_dir) = address | pgprot_val(REGION3_KERNEL);

			address += PUD_SIZE;

			continue;

		}
@@ -114,8 +114,7 @@ static int vmem_add_mem(unsigned long start, unsigned long size, int ro) 
		if (MACHINE_HAS_EDAT1 && pmd_none(*pm_dir) && address &&

		    !(address & ~PMD_MASK) && (address + PMD_SIZE <= end) &&

		    !debug_pagealloc_enabled()) {

			pmd_val(*pm_dir) = address |

				pgprot_val(ro ? SEGMENT_KERNEL_RO : SEGMENT_KERNEL);

			pmd_val(*pm_dir) = address | pgprot_val(SEGMENT_KERNEL);

			address += PMD_SIZE;

			continue;

		}
@@ -127,8 +126,7 @@ static int vmem_add_mem(unsigned long start, unsigned long size, int ro) 
		}



		pt_dir = pte_offset_kernel(pm_dir, address);

		pte_val(*pt_dir) = address |

			pgprot_val(ro ? PAGE_KERNEL_RO : PAGE_KERNEL);

		pte_val(*pt_dir) = address |  pgprot_val(PAGE_KERNEL);

		address += PAGE_SIZE;

	}

	ret = 0;
@@ -338,7 +336,7 @@ int vmem_add_mapping(unsigned long start, unsigned long size) 
	if (ret)

		goto out_free;



	ret = vmem_add_mem(start, size, 0);

	ret = vmem_add_mem(start, size);

	if (ret)

		goto out_remove;

	goto out;
@@ -361,29 +359,12 @@ void __init vmem_map_init(void) 
{

	unsigned long ro_start, ro_end;

	struct memblock_region *reg;

	phys_addr_t start, end;



	for_each_memblock(memory, reg)

		vmem_add_mem(reg->base, reg->size);

	ro_start = PFN_ALIGN((unsigned long)&_stext);

	ro_end = (unsigned long)&_eshared & PAGE_MASK;

	for_each_memblock(memory, reg) {

		start = reg->base;

		end = reg->base + reg->size;

		if (start >= ro_end || end <= ro_start)

			vmem_add_mem(start, end - start, 0);

		else if (start >= ro_start && end <= ro_end)

			vmem_add_mem(start, end - start, 1);

		else if (start >= ro_start) {

			vmem_add_mem(start, ro_end - start, 1);

			vmem_add_mem(ro_end, end - ro_end, 0);

		} else if (end < ro_end) {

			vmem_add_mem(start, ro_start - start, 0);

			vmem_add_mem(ro_start, end - ro_start, 1);

		} else {

			vmem_add_mem(start, ro_start - start, 0);

			vmem_add_mem(ro_start, ro_end - ro_start, 1);

			vmem_add_mem(ro_end, end - ro_end, 0);

		}

	}

	set_memory_ro(ro_start, (ro_end - ro_start) >> PAGE_SHIFT);

}



/*