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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>
hifive-unleashed-5.1
Martin Schwidefsky 2015-01-14 17:51:17 +01:00
parent f8b2dcbd9e
commit 1f6b83e5e4
5 changed files with 155 additions and 18 deletions
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8
arch/s390/include/asm/elf.h
View File

@ -163,8 +163,8 @@ extern unsigned int vdso_enabled;
the loader. We need to make sure that it is out of the way of the program
that it will "exec", and that there is sufficient room for the brk. */
extern unsigned long randomize_et_dyn(unsigned long base);
#define ELF_ET_DYN_BASE (randomize_et_dyn(STACK_TOP / 3 * 2))
extern unsigned long randomize_et_dyn(void);
#define ELF_ET_DYN_BASE randomize_et_dyn()
/* This yields a mask that user programs can use to figure out what
instruction set this CPU supports. */
@ -209,7 +209,9 @@ do { \
} while (0)
#endif /* CONFIG_COMPAT */
#define STACK_RND_MASK 0x7ffUL
extern unsigned long mmap_rnd_mask;
#define STACK_RND_MASK (mmap_rnd_mask)
#define ARCH_DLINFO \
do { \

4
arch/s390/include/asm/pgtable.h
View File

@ -1779,6 +1779,10 @@ extern int s390_enable_sie(void);
extern int s390_enable_skey(void);
extern void s390_reset_cmma(struct mm_struct *mm);
/* s390 has a private copy of get unmapped area to deal with cache synonyms */
#define HAVE_ARCH_UNMAPPED_AREA
#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
/*
* No page table caches to initialise
*/

10
arch/s390/kernel/process.c
View File

@ -243,13 +243,3 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
ret = PAGE_ALIGN(mm->brk + brk_rnd());
return (ret > mm->brk) ? ret : mm->brk;
}
unsigned long randomize_et_dyn(unsigned long base)
{
unsigned long ret;
if (!(current->flags & PF_RANDOMIZE))
return base;
ret = PAGE_ALIGN(base + brk_rnd());
return (ret > base) ? ret : base;
}

9
arch/s390/mm/init.c
View File

@ -71,13 +71,16 @@ static void __init setup_zero_pages(void)
break;
case 0x2827: /* zEC12 */
case 0x2828: /* zEC12 */
default:
order = 5;
break;
case 0x2964: /* z13 */
default:
order = 7;
break;
}
/* Limit number of empty zero pages for small memory sizes */
if (order > 2 && totalram_pages <= 16384)
order = 2;
while (order > 2 && (totalram_pages >> 10) < (1UL << order))
order--;
empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
if (!empty_zero_page)

142
arch/s390/mm/mmap.c
View File

@ -28,8 +28,12 @@
#include <linux/module.h>
#include <linux/random.h>
#include <linux/compat.h>
#include <linux/security.h>
#include <asm/pgalloc.h>
unsigned long mmap_rnd_mask;
unsigned long mmap_align_mask;
static unsigned long stack_maxrandom_size(void)
{
if (!(current->flags & PF_RANDOMIZE))
@ -60,8 +64,10 @@ static unsigned long mmap_rnd(void)
{
if (!(current->flags & PF_RANDOMIZE))
return 0;
/* 8MB randomization for mmap_base */
return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
if (is_32bit_task())
return (get_random_int() & 0x7ff) << PAGE_SHIFT;
else
return (get_random_int() & mmap_rnd_mask) << PAGE_SHIFT;
}
static unsigned long mmap_base_legacy(void)
@ -81,6 +87,106 @@ static inline unsigned long mmap_base(void)
return STACK_TOP - stack_maxrandom_size() - mmap_rnd() - gap;
}
unsigned long
arch_get_unmapped_area(struct file *filp, unsigned long addr,
unsigned long len, unsigned long pgoff, unsigned long flags)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
struct vm_unmapped_area_info info;
int do_color_align;
if (len > TASK_SIZE - mmap_min_addr)
return -ENOMEM;
if (flags & MAP_FIXED)
return addr;
if (addr) {
addr = PAGE_ALIGN(addr);
vma = find_vma(mm, addr);
if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
(!vma || addr + len <= vma->vm_start))
return addr;
}
do_color_align = 0;
if (filp || (flags & MAP_SHARED))
do_color_align = !is_32bit_task();
info.flags = 0;
info.length = len;
info.low_limit = mm->mmap_base;
info.high_limit = TASK_SIZE;
info.align_mask = do_color_align ? (mmap_align_mask << PAGE_SHIFT) : 0;
info.align_offset = pgoff << PAGE_SHIFT;
return vm_unmapped_area(&info);
}
unsigned long
arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
const unsigned long len, const unsigned long pgoff,
const unsigned long flags)
{
struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
unsigned long addr = addr0;
struct vm_unmapped_area_info info;
int do_color_align;
/* requested length too big for entire address space */
if (len > TASK_SIZE - mmap_min_addr)
return -ENOMEM;
if (flags & MAP_FIXED)
return addr;
/* requesting a specific address */
if (addr) {
addr = PAGE_ALIGN(addr);
vma = find_vma(mm, addr);
if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
(!vma || addr + len <= vma->vm_start))
return addr;
}
do_color_align = 0;
if (filp || (flags & MAP_SHARED))
do_color_align = !is_32bit_task();
info.flags = VM_UNMAPPED_AREA_TOPDOWN;
info.length = len;
info.low_limit = max(PAGE_SIZE, mmap_min_addr);
info.high_limit = mm->mmap_base;
info.align_mask = do_color_align ? (mmap_align_mask << PAGE_SHIFT) : 0;
info.align_offset = pgoff << PAGE_SHIFT;
addr = vm_unmapped_area(&info);
/*
* A failed mmap() very likely causes application failure,
* so fall back to the bottom-up function here. This scenario
* can happen with large stack limits and large mmap()
* allocations.
*/
if (addr & ~PAGE_MASK) {
VM_BUG_ON(addr != -ENOMEM);
info.flags = 0;
info.low_limit = TASK_UNMAPPED_BASE;
info.high_limit = TASK_SIZE;
addr = vm_unmapped_area(&info);
}
return addr;
}
unsigned long randomize_et_dyn(void)
{
unsigned long base;
base = (STACK_TOP / 3 * 2) & (~mmap_align_mask << PAGE_SHIFT);
return base + mmap_rnd();
}
#ifndef CONFIG_64BIT
/*
@ -177,4 +283,36 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
}
}
static int __init setup_mmap_rnd(void)
{
struct cpuid cpu_id;
get_cpu_id(&cpu_id);
switch (cpu_id.machine) {
case 0x9672:
case 0x2064:
case 0x2066:
case 0x2084:
case 0x2086:
case 0x2094:
case 0x2096:
case 0x2097:
case 0x2098:
case 0x2817:
case 0x2818:
case 0x2827:
case 0x2828:
mmap_rnd_mask = 0x7ffUL;
mmap_align_mask = 0UL;
break;
case 0x2964: /* z13 */
default:
mmap_rnd_mask = 0x3ff80UL;
mmap_align_mask = 0x7fUL;
break;
}
return 0;
}
early_initcall(setup_mmap_rnd);
#endif