diff options
| -rw-r--r-- | arch/mips/include/asm/processor.h | 10 | ||||
| -rw-r--r-- | arch/mips/kernel/process.c | 25 | ||||
| -rw-r--r-- | arch/mips/kernel/vdso.c | 18 |
3 files changed, 47 insertions, 6 deletions
diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h index eb1f6030ab85..8bbbab611a3f 100644 --- a/arch/mips/include/asm/processor.h +++ b/arch/mips/include/asm/processor.h @@ -13,6 +13,7 @@ #include <linux/atomic.h> #include <linux/cpumask.h> +#include <linux/sizes.h> #include <linux/threads.h> #include <asm/cachectl.h> @@ -80,11 +81,10 @@ extern unsigned int vced_count, vcei_count; #endif -/* - * One page above the stack is used for branch delay slot "emulation". - * See dsemul.c for details. - */ -#define STACK_TOP ((TASK_SIZE & PAGE_MASK) - PAGE_SIZE) +#define VDSO_RANDOMIZE_SIZE (TASK_IS_32BIT_ADDR ? SZ_1M : SZ_256M) + +extern unsigned long mips_stack_top(void); +#define STACK_TOP mips_stack_top() /* * This decides where the kernel will search for a free chunk of vm diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c index e8d772a2597d..e8b166e9146a 100644 --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -31,6 +31,7 @@ #include <linux/prctl.h> #include <linux/nmi.h> +#include <asm/abi.h> #include <asm/asm.h> #include <asm/bootinfo.h> #include <asm/cpu.h> @@ -38,6 +39,7 @@ #include <asm/dsp.h> #include <asm/fpu.h> #include <asm/irq.h> +#include <asm/mips-cps.h> #include <asm/msa.h> #include <asm/pgtable.h> #include <asm/mipsregs.h> @@ -644,6 +646,29 @@ out: return pc; } +unsigned long mips_stack_top(void) +{ + unsigned long top = TASK_SIZE & PAGE_MASK; + + /* One page for branch delay slot "emulation" */ + top -= PAGE_SIZE; + + /* Space for the VDSO, data page & GIC user page */ + top -= PAGE_ALIGN(current->thread.abi->vdso->size); + top -= PAGE_SIZE; + top -= mips_gic_present() ? PAGE_SIZE : 0; + + /* Space for cache colour alignment */ + if (cpu_has_dc_aliases) + top -= shm_align_mask + 1; + + /* Space to randomize the VDSO base */ + if (current->flags & PF_RANDOMIZE) + top -= VDSO_RANDOMIZE_SIZE; + + return top; +} + /* * Don't forget that the stack pointer must be aligned on a 8 bytes * boundary for 32-bits ABI and 16 bytes for 64-bits ABI. diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c index 8f845f6e5f42..48a9c6b90e07 100644 --- a/arch/mips/kernel/vdso.c +++ b/arch/mips/kernel/vdso.c @@ -15,6 +15,7 @@ #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> @@ -97,6 +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; @@ -137,7 +153,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) if (cpu_has_dc_aliases) size += shm_align_mask + 1; - base = get_unmapped_area(NULL, 0, size, 0, 0); + base = get_unmapped_area(NULL, vdso_base(), size, 0, 0); if (IS_ERR_VALUE(base)) { ret = base; goto out; |