aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86_64/mm/pageattr.c
diff options
context:
space:
mode:
authorVivek Goyal <vgoyal@in.ibm.com>2007-05-02 13:27:07 -0400
committerAndi Kleen <andi@basil.nowhere.org>2007-05-02 13:27:07 -0400
commit0dbf7028c0c1f266c9631139450a1502d3cd457e (patch)
tree2616edcd32d92b6539d2810fd3043b054baabb92 /arch/x86_64/mm/pageattr.c
parent1b29c1643c0d82512477ccd97dc290198fe23e22 (diff)
[PATCH] x86: __pa and __pa_symbol address space separation
Currently __pa_symbol is for use with symbols in the kernel address map and __pa is for use with pointers into the physical memory map. But the code is implemented so you can usually interchange the two. __pa which is much more common can be implemented much more cheaply if it is it doesn't have to worry about any other kernel address spaces. This is especially true with a relocatable kernel as __pa_symbol needs to peform an extra variable read to resolve the address. There is a third macro that is added for the vsyscall data __pa_vsymbol for finding the physical addesses of vsyscall pages. Most of this patch is simply sorting through the references to __pa or __pa_symbol and using the proper one. A little of it is continuing to use a physical address when we have it instead of recalculating it several times. swapper_pgd is now NULL. leave_mm now uses init_mm.pgd and init_mm.pgd is initialized at boot (instead of compile time) to the physmem virtual mapping of init_level4_pgd. The physical address changed. Except for the for EMPTY_ZERO page all of the remaining references to __pa_symbol appear to be during kernel initialization. So this should reduce the cost of __pa in the common case, even on a relocated kernel. As this is technically a semantic change we need to be on the lookout for anything I missed. But it works for me (tm). Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch/x86_64/mm/pageattr.c')
-rw-r--r--arch/x86_64/mm/pageattr.c16
1 files changed, 8 insertions, 8 deletions
diff --git a/arch/x86_64/mm/pageattr.c b/arch/x86_64/mm/pageattr.c
index 081409aa3452..76ee90a5abe0 100644
--- a/arch/x86_64/mm/pageattr.c
+++ b/arch/x86_64/mm/pageattr.c
@@ -51,7 +51,6 @@ static struct page *split_large_page(unsigned long address, pgprot_t prot,
51 SetPagePrivate(base); 51 SetPagePrivate(base);
52 page_private(base) = 0; 52 page_private(base) = 0;
53 53
54 address = __pa(address);
55 addr = address & LARGE_PAGE_MASK; 54 addr = address & LARGE_PAGE_MASK;
56 pbase = (pte_t *)page_address(base); 55 pbase = (pte_t *)page_address(base);
57 for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE) { 56 for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE) {
@@ -101,13 +100,12 @@ static inline void save_page(struct page *fpage)
101 * No more special protections in this 2/4MB area - revert to a 100 * No more special protections in this 2/4MB area - revert to a
102 * large page again. 101 * large page again.
103 */ 102 */
104static void revert_page(unsigned long address, pgprot_t ref_prot) 103static void revert_page(unsigned long address, unsigned long pfn, pgprot_t ref_prot)
105{ 104{
106 pgd_t *pgd; 105 pgd_t *pgd;
107 pud_t *pud; 106 pud_t *pud;
108 pmd_t *pmd; 107 pmd_t *pmd;
109 pte_t large_pte; 108 pte_t large_pte;
110 unsigned long pfn;
111 109
112 pgd = pgd_offset_k(address); 110 pgd = pgd_offset_k(address);
113 BUG_ON(pgd_none(*pgd)); 111 BUG_ON(pgd_none(*pgd));
@@ -115,7 +113,6 @@ static void revert_page(unsigned long address, pgprot_t ref_prot)
115 BUG_ON(pud_none(*pud)); 113 BUG_ON(pud_none(*pud));
116 pmd = pmd_offset(pud, address); 114 pmd = pmd_offset(pud, address);
117 BUG_ON(pmd_val(*pmd) & _PAGE_PSE); 115 BUG_ON(pmd_val(*pmd) & _PAGE_PSE);
118 pfn = (__pa(address) & LARGE_PAGE_MASK) >> PAGE_SHIFT;
119 large_pte = pfn_pte(pfn, ref_prot); 116 large_pte = pfn_pte(pfn, ref_prot);
120 large_pte = pte_mkhuge(large_pte); 117 large_pte = pte_mkhuge(large_pte);
121 set_pte((pte_t *)pmd, large_pte); 118 set_pte((pte_t *)pmd, large_pte);
@@ -141,7 +138,8 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot,
141 */ 138 */
142 struct page *split; 139 struct page *split;
143 ref_prot2 = pte_pgprot(pte_clrhuge(*kpte)); 140 ref_prot2 = pte_pgprot(pte_clrhuge(*kpte));
144 split = split_large_page(address, prot, ref_prot2); 141 split = split_large_page(pfn << PAGE_SHIFT, prot,
142 ref_prot2);
145 if (!split) 143 if (!split)
146 return -ENOMEM; 144 return -ENOMEM;
147 set_pte(kpte, mk_pte(split, ref_prot2)); 145 set_pte(kpte, mk_pte(split, ref_prot2));
@@ -160,7 +158,7 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot,
160 158
161 if (page_private(kpte_page) == 0) { 159 if (page_private(kpte_page) == 0) {
162 save_page(kpte_page); 160 save_page(kpte_page);
163 revert_page(address, ref_prot); 161 revert_page(address, pfn, ref_prot);
164 } 162 }
165 return 0; 163 return 0;
166} 164}
@@ -180,6 +178,7 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot,
180 */ 178 */
181int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot) 179int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot)
182{ 180{
181 unsigned long phys_base_pfn = __pa_symbol(__START_KERNEL_map) >> PAGE_SHIFT;
183 int err = 0; 182 int err = 0;
184 int i; 183 int i;
185 184
@@ -192,10 +191,11 @@ int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot)
192 break; 191 break;
193 /* Handle kernel mapping too which aliases part of the 192 /* Handle kernel mapping too which aliases part of the
194 * lowmem */ 193 * lowmem */
195 if (__pa(address) < KERNEL_TEXT_SIZE) { 194 if ((pfn >= phys_base_pfn) &&
195 ((pfn - phys_base_pfn) < (KERNEL_TEXT_SIZE >> PAGE_SHIFT))) {
196 unsigned long addr2; 196 unsigned long addr2;
197 pgprot_t prot2; 197 pgprot_t prot2;
198 addr2 = __START_KERNEL_map + __pa(address); 198 addr2 = __START_KERNEL_map + ((pfn - phys_base_pfn) << PAGE_SHIFT);
199 /* Make sure the kernel mappings stay executable */ 199 /* Make sure the kernel mappings stay executable */
200 prot2 = pte_pgprot(pte_mkexec(pfn_pte(0, prot))); 200 prot2 = pte_pgprot(pte_mkexec(pfn_pte(0, prot)));
201 err = __change_page_attr(addr2, pfn, prot2, 201 err = __change_page_attr(addr2, pfn, prot2,