diff options
Diffstat (limited to 'arch/mips/kernel/vdso.c')
| -rw-r--r-- | arch/mips/kernel/vdso.c | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c index 019035d7225c..48a9c6b90e07 100644 --- a/arch/mips/kernel/vdso.c +++ b/arch/mips/kernel/vdso.c @@ -13,13 +13,16 @@ #include <linux/err.h> #include <linux/init.h> #include <linux/ioport.h> +#include <linux/kernel.h> #include <linux/mm.h> +#include <linux/random.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/timekeeper_internal.h> #include <asm/abi.h> #include <asm/mips-cps.h> +#include <asm/page.h> #include <asm/vdso.h> /* Kernel-provided data used by the VDSO. */ @@ -95,6 +98,21 @@ void update_vsyscall_tz(void) } } +static unsigned long vdso_base(void) +{ + unsigned long base; + + /* Skip the delay slot emulation page */ + base = STACK_TOP + PAGE_SIZE; + + if (current->flags & PF_RANDOMIZE) { + base += get_random_int() & (VDSO_RANDOMIZE_SIZE - 1); + base = PAGE_ALIGN(base); + } + + return base; +} + int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) { struct mips_vdso_image *image = current->thread.abi->vdso; @@ -128,12 +146,30 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) vvar_size = gic_size + PAGE_SIZE; size = vvar_size + image->size; - base = get_unmapped_area(NULL, 0, size, 0, 0); + /* + * Find a region that's large enough for us to perform the + * colour-matching alignment below. + */ + if (cpu_has_dc_aliases) + size += shm_align_mask + 1; + + base = get_unmapped_area(NULL, vdso_base(), size, 0, 0); if (IS_ERR_VALUE(base)) { ret = base; goto out; } + /* + * If we suffer from dcache aliasing, ensure that the VDSO data page + * mapping is coloured the same as the kernel's mapping of that memory. + * This ensures that when the kernel updates the VDSO data userland + * will observe it without requiring cache invalidations. + */ + if (cpu_has_dc_aliases) { + base = __ALIGN_MASK(base, shm_align_mask); + base += ((unsigned long)&vdso_data - gic_size) & shm_align_mask; + } + data_addr = base + gic_size; vdso_addr = data_addr + PAGE_SIZE; |