diff options
Diffstat (limited to 'arch/x86/vdso')
| -rw-r--r-- | arch/x86/vdso/vdso2c.h | 12 | ||||
| -rw-r--r-- | arch/x86/vdso/vgetcpu.c | 2 | ||||
| -rw-r--r-- | arch/x86/vdso/vma.c | 128 |
3 files changed, 101 insertions, 41 deletions
diff --git a/arch/x86/vdso/vdso2c.h b/arch/x86/vdso/vdso2c.h index fd57829b30d8..0224987556ce 100644 --- a/arch/x86/vdso/vdso2c.h +++ b/arch/x86/vdso/vdso2c.h @@ -109,16 +109,18 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len, /* Validate mapping addresses. */ for (i = 0; i < sizeof(special_pages) / sizeof(special_pages[0]); i++) { - if (!syms[i]) + INT_BITS symval = syms[special_pages[i]]; + + if (!symval) continue; /* The mapping isn't used; ignore it. */ - if (syms[i] % 4096) + if (symval % 4096) fail("%s must be a multiple of 4096\n", required_syms[i].name); - if (syms[sym_vvar_start] > syms[i] + 4096) - fail("%s underruns begin_vvar\n", + if (symval + 4096 < syms[sym_vvar_start]) + fail("%s underruns vvar_start\n", required_syms[i].name); - if (syms[i] + 4096 > 0) + if (symval + 4096 > 0) fail("%s is on the wrong side of the vdso text\n", required_syms[i].name); } diff --git a/arch/x86/vdso/vgetcpu.c b/arch/x86/vdso/vgetcpu.c index 2f94b039e55b..8ec3d1f4ce9a 100644 --- a/arch/x86/vdso/vgetcpu.c +++ b/arch/x86/vdso/vgetcpu.c @@ -7,9 +7,7 @@ #include <linux/kernel.h> #include <linux/getcpu.h> -#include <linux/jiffies.h> #include <linux/time.h> -#include <asm/vsyscall.h> #include <asm/vgtod.h> notrace long diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c index 970463b566cf..1c9f750c3859 100644 --- a/arch/x86/vdso/vma.c +++ b/arch/x86/vdso/vma.c @@ -1,7 +1,8 @@ /* - * Set up the VMAs to tell the VM about the vDSO. * Copyright 2007 Andi Kleen, SUSE Labs. * Subject to the GPL, v.2 + * + * This contains most of the x86 vDSO kernel-side code. */ #include <linux/mm.h> #include <linux/err.h> @@ -10,17 +11,17 @@ #include <linux/init.h> #include <linux/random.h> #include <linux/elf.h> -#include <asm/vsyscall.h> +#include <linux/cpu.h> #include <asm/vgtod.h> #include <asm/proto.h> #include <asm/vdso.h> +#include <asm/vvar.h> #include <asm/page.h> #include <asm/hpet.h> +#include <asm/desc.h> #if defined(CONFIG_X86_64) unsigned int __read_mostly vdso64_enabled = 1; - -extern unsigned short vdso_sync_cpuid; #endif void __init init_vdso_image(const struct vdso_image *image) @@ -38,28 +39,19 @@ void __init init_vdso_image(const struct vdso_image *image) image->alt_len)); } -#if defined(CONFIG_X86_64) -static int __init init_vdso(void) -{ - init_vdso_image(&vdso_image_64); - -#ifdef CONFIG_X86_X32_ABI - init_vdso_image(&vdso_image_x32); -#endif - - return 0; -} -subsys_initcall(init_vdso); -#endif - struct linux_binprm; -/* Put the vdso above the (randomized) stack with another randomized offset. - This way there is no hole in the middle of address space. - To save memory make sure it is still in the same PTE as the stack top. - This doesn't give that many random bits. - - Only used for the 64-bit and x32 vdsos. */ +/* + * Put the vdso above the (randomized) stack with another randomized + * offset. This way there is no hole in the middle of address space. + * To save memory make sure it is still in the same PTE as the stack + * top. This doesn't give that many random bits. + * + * Note that this algorithm is imperfect: the distribution of the vdso + * start address within a PMD is biased toward the end. + * + * Only used for the 64-bit and x32 vdsos. + */ static unsigned long vdso_addr(unsigned long start, unsigned len) { #ifdef CONFIG_X86_32 @@ -67,22 +59,30 @@ static unsigned long vdso_addr(unsigned long start, unsigned len) #else unsigned long addr, end; unsigned offset; - end = (start + PMD_SIZE - 1) & PMD_MASK; + + /* + * Round up the start address. It can start out unaligned as a result + * of stack start randomization. + */ + start = PAGE_ALIGN(start); + + /* Round the lowest possible end address up to a PMD boundary. */ + end = (start + len + PMD_SIZE - 1) & PMD_MASK; if (end >= TASK_SIZE_MAX) end = TASK_SIZE_MAX; end -= len; - /* This loses some more bits than a modulo, but is cheaper */ - offset = get_random_int() & (PTRS_PER_PTE - 1); - addr = start + (offset << PAGE_SHIFT); - if (addr >= end) - addr = end; + + if (end > start) { + offset = get_random_int() % (((end - start) >> PAGE_SHIFT) + 1); + addr = start + (offset << PAGE_SHIFT); + } else { + addr = start; + } /* - * page-align it here so that get_unmapped_area doesn't - * align it wrongfully again to the next page. addr can come in 4K - * unaligned here as a result of stack start randomization. + * Forcibly align the final address in case we have a hardware + * issue that requires alignment for performance reasons. */ - addr = PAGE_ALIGN(addr); addr = align_vdso_addr(addr); return addr; @@ -238,3 +238,63 @@ static __init int vdso_setup(char *s) } __setup("vdso=", vdso_setup); #endif + +#ifdef CONFIG_X86_64 +static void vgetcpu_cpu_init(void *arg) +{ + int cpu = smp_processor_id(); + struct desc_struct d = { }; + unsigned long node = 0; +#ifdef CONFIG_NUMA + node = cpu_to_node(cpu); +#endif + if (cpu_has(&cpu_data(cpu), X86_FEATURE_RDTSCP)) + write_rdtscp_aux((node << 12) | cpu); + + /* + * Store cpu number in limit so that it can be loaded + * quickly in user space in vgetcpu. (12 bits for the CPU + * and 8 bits for the node) + */ + d.limit0 = cpu | ((node & 0xf) << 12); + d.limit = node >> 4; + d.type = 5; /* RO data, expand down, accessed */ + d.dpl = 3; /* Visible to user code */ + d.s = 1; /* Not a system segment */ + d.p = 1; /* Present */ + d.d = 1; /* 32-bit */ + + write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_PER_CPU, &d, DESCTYPE_S); +} + +static int +vgetcpu_cpu_notifier(struct notifier_block *n, unsigned long action, void *arg) +{ + long cpu = (long)arg; + + if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN) + smp_call_function_single(cpu, vgetcpu_cpu_init, NULL, 1); + + return NOTIFY_DONE; +} + +static int __init init_vdso(void) +{ + init_vdso_image(&vdso_image_64); + +#ifdef CONFIG_X86_X32_ABI + init_vdso_image(&vdso_image_x32); +#endif + + cpu_notifier_register_begin(); + + on_each_cpu(vgetcpu_cpu_init, NULL, 1); + /* notifier priority > KVM */ + __hotcpu_notifier(vgetcpu_cpu_notifier, 30); + + cpu_notifier_register_done(); + + return 0; +} +subsys_initcall(init_vdso); +#endif /* CONFIG_X86_64 */ |