aboutsummaryrefslogtreecommitdiffstats
path: root/arch/s390/mm
diff options
context:
space:
mode:
authorMartin Schwidefsky <schwidefsky@de.ibm.com>2015-01-14 11:51:17 -0500
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2015-01-22 06:15:59 -0500
commit1f6b83e5e4d3aed46eac1d219322fba9c7341cd8 (patch)
treea7839cd769ec8637746d5e20a7eb7117373caaf0 /arch/s390/mm
parentf8b2dcbd9e6d1479b9b5a9e9e78bbaf783bde819 (diff)
s390: avoid z13 cache aliasing
Avoid cache aliasing on z13 by aligning shared objects to multiples of 512K. The virtual addresses of a page from a shared file needs to have identical bits in the range 2^12 to 2^18. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/mm')
-rw-r--r--arch/s390/mm/init.c9
-rw-r--r--arch/s390/mm/mmap.c142
2 files changed, 146 insertions, 5 deletions
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index c7235e01fd67..d35b15113b17 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -71,13 +71,16 @@ static void __init setup_zero_pages(void)
71 break; 71 break;
72 case 0x2827: /* zEC12 */ 72 case 0x2827: /* zEC12 */
73 case 0x2828: /* zEC12 */ 73 case 0x2828: /* zEC12 */
74 default:
75 order = 5; 74 order = 5;
76 break; 75 break;
76 case 0x2964: /* z13 */
77 default:
78 order = 7;
79 break;
77 } 80 }
78 /* Limit number of empty zero pages for small memory sizes */ 81 /* Limit number of empty zero pages for small memory sizes */
79 if (order > 2 && totalram_pages <= 16384) 82 while (order > 2 && (totalram_pages >> 10) < (1UL << order))
80 order = 2; 83 order--;
81 84
82 empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order); 85 empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
83 if (!empty_zero_page) 86 if (!empty_zero_page)
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index 9b436c21195e..d008f638b2cd 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -28,8 +28,12 @@
28#include <linux/module.h> 28#include <linux/module.h>
29#include <linux/random.h> 29#include <linux/random.h>
30#include <linux/compat.h> 30#include <linux/compat.h>
31#include <linux/security.h>
31#include <asm/pgalloc.h> 32#include <asm/pgalloc.h>
32 33
34unsigned long mmap_rnd_mask;
35unsigned long mmap_align_mask;
36
33static unsigned long stack_maxrandom_size(void) 37static unsigned long stack_maxrandom_size(void)
34{ 38{
35 if (!(current->flags & PF_RANDOMIZE)) 39 if (!(current->flags & PF_RANDOMIZE))
@@ -60,8 +64,10 @@ static unsigned long mmap_rnd(void)
60{ 64{
61 if (!(current->flags & PF_RANDOMIZE)) 65 if (!(current->flags & PF_RANDOMIZE))
62 return 0; 66 return 0;
63 /* 8MB randomization for mmap_base */ 67 if (is_32bit_task())
64 return (get_random_int() & 0x7ffUL) << PAGE_SHIFT; 68 return (get_random_int() & 0x7ff) << PAGE_SHIFT;
69 else
70 return (get_random_int() & mmap_rnd_mask) << PAGE_SHIFT;
65} 71}
66 72
67static unsigned long mmap_base_legacy(void) 73static unsigned long mmap_base_legacy(void)
@@ -81,6 +87,106 @@ static inline unsigned long mmap_base(void)
81 return STACK_TOP - stack_maxrandom_size() - mmap_rnd() - gap; 87 return STACK_TOP - stack_maxrandom_size() - mmap_rnd() - gap;
82} 88}
83 89
90unsigned long
91arch_get_unmapped_area(struct file *filp, unsigned long addr,
92 unsigned long len, unsigned long pgoff, unsigned long flags)
93{
94 struct mm_struct *mm = current->mm;
95 struct vm_area_struct *vma;
96 struct vm_unmapped_area_info info;
97 int do_color_align;
98
99 if (len > TASK_SIZE - mmap_min_addr)
100 return -ENOMEM;
101
102 if (flags & MAP_FIXED)
103 return addr;
104
105 if (addr) {
106 addr = PAGE_ALIGN(addr);
107 vma = find_vma(mm, addr);
108 if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
109 (!vma || addr + len <= vma->vm_start))
110 return addr;
111 }
112
113 do_color_align = 0;
114 if (filp || (flags & MAP_SHARED))
115 do_color_align = !is_32bit_task();
116
117 info.flags = 0;
118 info.length = len;
119 info.low_limit = mm->mmap_base;
120 info.high_limit = TASK_SIZE;
121 info.align_mask = do_color_align ? (mmap_align_mask << PAGE_SHIFT) : 0;
122 info.align_offset = pgoff << PAGE_SHIFT;
123 return vm_unmapped_area(&info);
124}
125
126unsigned long
127arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
128 const unsigned long len, const unsigned long pgoff,
129 const unsigned long flags)
130{
131 struct vm_area_struct *vma;
132 struct mm_struct *mm = current->mm;
133 unsigned long addr = addr0;
134 struct vm_unmapped_area_info info;
135 int do_color_align;
136
137 /* requested length too big for entire address space */
138 if (len > TASK_SIZE - mmap_min_addr)
139 return -ENOMEM;
140
141 if (flags & MAP_FIXED)
142 return addr;
143
144 /* requesting a specific address */
145 if (addr) {
146 addr = PAGE_ALIGN(addr);
147 vma = find_vma(mm, addr);
148 if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
149 (!vma || addr + len <= vma->vm_start))
150 return addr;
151 }
152
153 do_color_align = 0;
154 if (filp || (flags & MAP_SHARED))
155 do_color_align = !is_32bit_task();
156
157 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
158 info.length = len;
159 info.low_limit = max(PAGE_SIZE, mmap_min_addr);
160 info.high_limit = mm->mmap_base;
161 info.align_mask = do_color_align ? (mmap_align_mask << PAGE_SHIFT) : 0;
162 info.align_offset = pgoff << PAGE_SHIFT;
163 addr = vm_unmapped_area(&info);
164
165 /*
166 * A failed mmap() very likely causes application failure,
167 * so fall back to the bottom-up function here. This scenario
168 * can happen with large stack limits and large mmap()
169 * allocations.
170 */
171 if (addr & ~PAGE_MASK) {
172 VM_BUG_ON(addr != -ENOMEM);
173 info.flags = 0;
174 info.low_limit = TASK_UNMAPPED_BASE;
175 info.high_limit = TASK_SIZE;
176 addr = vm_unmapped_area(&info);
177 }
178
179 return addr;
180}
181
182unsigned long randomize_et_dyn(void)
183{
184 unsigned long base;
185
186 base = (STACK_TOP / 3 * 2) & (~mmap_align_mask << PAGE_SHIFT);
187 return base + mmap_rnd();
188}
189
84#ifndef CONFIG_64BIT 190#ifndef CONFIG_64BIT
85 191
86/* 192/*
@@ -177,4 +283,36 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
177 } 283 }
178} 284}
179 285
286static int __init setup_mmap_rnd(void)
287{
288 struct cpuid cpu_id;
289
290 get_cpu_id(&cpu_id);
291 switch (cpu_id.machine) {
292 case 0x9672:
293 case 0x2064:
294 case 0x2066:
295 case 0x2084:
296 case 0x2086:
297 case 0x2094:
298 case 0x2096:
299 case 0x2097:
300 case 0x2098:
301 case 0x2817:
302 case 0x2818:
303 case 0x2827:
304 case 0x2828:
305 mmap_rnd_mask = 0x7ffUL;
306 mmap_align_mask = 0UL;
307 break;
308 case 0x2964: /* z13 */
309 default:
310 mmap_rnd_mask = 0x3ff80UL;
311 mmap_align_mask = 0x7fUL;
312 break;
313 }
314 return 0;
315}
316early_initcall(setup_mmap_rnd);
317
180#endif 318#endif