diff options
Diffstat (limited to 'arch/x86/xen')
| -rw-r--r-- | arch/x86/xen/Makefile | 2 | ||||
| -rw-r--r-- | arch/x86/xen/enlighten.c | 150 | ||||
| -rw-r--r-- | arch/x86/xen/smp.c | 1 | ||||
| -rw-r--r-- | arch/x86/xen/spinlock.c | 28 |
4 files changed, 147 insertions, 34 deletions
diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile index 7410640db173..3bb4fc21f4f2 100644 --- a/arch/x86/xen/Makefile +++ b/arch/x86/xen/Makefile @@ -8,6 +8,7 @@ endif # Make sure early boot has no stackprotector nostackp := $(call cc-option, -fno-stack-protector) CFLAGS_enlighten.o := $(nostackp) +CFLAGS_mmu.o := $(nostackp) obj-y := enlighten.o setup.o multicalls.o mmu.o irq.o \ time.o xen-asm.o xen-asm_$(BITS).o \ @@ -16,3 +17,4 @@ obj-y := enlighten.o setup.o multicalls.o mmu.o irq.o \ obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= spinlock.o obj-$(CONFIG_XEN_DEBUG_FS) += debugfs.o + diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index eb33aaa8415d..a11a115d82d3 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -51,6 +51,7 @@ #include <asm/pgtable.h> #include <asm/tlbflush.h> #include <asm/reboot.h> +#include <asm/stackprotector.h> #include "xen-ops.h" #include "mmu.h" @@ -177,6 +178,7 @@ static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0; static void xen_cpuid(unsigned int *ax, unsigned int *bx, unsigned int *cx, unsigned int *dx) { + unsigned maskebx = ~0; unsigned maskecx = ~0; unsigned maskedx = ~0; @@ -184,9 +186,16 @@ static void xen_cpuid(unsigned int *ax, unsigned int *bx, * Mask out inconvenient features, to try and disable as many * unsupported kernel subsystems as possible. */ - if (*ax == 1) { + switch (*ax) { + case 1: maskecx = cpuid_leaf1_ecx_mask; maskedx = cpuid_leaf1_edx_mask; + break; + + case 0xb: + /* Suppress extended topology stuff */ + maskebx = 0; + break; } asm(XEN_EMULATE_PREFIX "cpuid" @@ -196,6 +205,7 @@ static void xen_cpuid(unsigned int *ax, unsigned int *bx, "=d" (*dx) : "0" (*ax), "2" (*cx)); + *bx &= maskebx; *cx &= maskecx; *dx &= maskedx; } @@ -330,18 +340,28 @@ static void xen_load_gdt(const struct desc_ptr *dtr) unsigned long frames[pages]; int f; - /* A GDT can be up to 64k in size, which corresponds to 8192 - 8-byte entries, or 16 4k pages.. */ + /* + * A GDT can be up to 64k in size, which corresponds to 8192 + * 8-byte entries, or 16 4k pages.. + */ BUG_ON(size > 65536); BUG_ON(va & ~PAGE_MASK); for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { int level; - pte_t *ptep = lookup_address(va, &level); + pte_t *ptep; unsigned long pfn, mfn; void *virt; + /* + * The GDT is per-cpu and is in the percpu data area. + * That can be virtually mapped, so we need to do a + * page-walk to get the underlying MFN for the + * hypercall. The page can also be in the kernel's + * linear range, so we need to RO that mapping too. + */ + ptep = lookup_address(va, &level); BUG_ON(ptep == NULL); pfn = pte_pfn(*ptep); @@ -358,6 +378,44 @@ static void xen_load_gdt(const struct desc_ptr *dtr) BUG(); } +/* + * load_gdt for early boot, when the gdt is only mapped once + */ +static __init void xen_load_gdt_boot(const struct desc_ptr *dtr) +{ + unsigned long va = dtr->address; + unsigned int size = dtr->size + 1; + unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; + unsigned long frames[pages]; + int f; + + /* + * A GDT can be up to 64k in size, which corresponds to 8192 + * 8-byte entries, or 16 4k pages.. + */ + + BUG_ON(size > 65536); + BUG_ON(va & ~PAGE_MASK); + + for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { + pte_t pte; + unsigned long pfn, mfn; + + pfn = virt_to_pfn(va); + mfn = pfn_to_mfn(pfn); + + pte = pfn_pte(pfn, PAGE_KERNEL_RO); + + if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0)) + BUG(); + + frames[f] = mfn; + } + + if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct))) + BUG(); +} + static void load_TLS_descriptor(struct thread_struct *t, unsigned int cpu, unsigned int i) { @@ -581,6 +639,29 @@ static void xen_write_gdt_entry(struct desc_struct *dt, int entry, preempt_enable(); } +/* + * Version of write_gdt_entry for use at early boot-time needed to + * update an entry as simply as possible. + */ +static __init void xen_write_gdt_entry_boot(struct desc_struct *dt, int entry, + const void *desc, int type) +{ + switch (type) { + case DESC_LDT: + case DESC_TSS: + /* ignore */ + break; + + default: { + xmaddr_t maddr = virt_to_machine(&dt[entry]); + + if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) + dt[entry] = *(struct desc_struct *)desc; + } + + } +} + static void xen_load_sp0(struct tss_struct *tss, struct thread_struct *thread) { @@ -965,6 +1046,23 @@ static const struct machine_ops __initdata xen_machine_ops = { .emergency_restart = xen_emergency_restart, }; +/* + * Set up the GDT and segment registers for -fstack-protector. Until + * we do this, we have to be careful not to call any stack-protected + * function, which is most of the kernel. + */ +static void __init xen_setup_stackprotector(void) +{ + pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot; + pv_cpu_ops.load_gdt = xen_load_gdt_boot; + + setup_stack_canary_segment(0); + switch_to_new_gdt(0); + + pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry; + pv_cpu_ops.load_gdt = xen_load_gdt; +} + /* First C function to be called on Xen boot */ asmlinkage void __init xen_start_kernel(void) { @@ -983,14 +1081,34 @@ asmlinkage void __init xen_start_kernel(void) pv_apic_ops = xen_apic_ops; pv_mmu_ops = xen_mmu_ops; -#ifdef CONFIG_X86_64 /* - * Setup percpu state. We only need to do this for 64-bit - * because 32-bit already has %fs set properly. + * Set up some pagetable state before starting to set any ptes. */ - load_percpu_segment(0); + + /* Prevent unwanted bits from being set in PTEs. */ + __supported_pte_mask &= ~_PAGE_GLOBAL; + if (!xen_initial_domain()) + __supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD); + + __supported_pte_mask |= _PAGE_IOMAP; + +#ifdef CONFIG_X86_64 + /* Work out if we support NX */ + check_efer(); #endif + xen_setup_features(); + + /* Get mfn list */ + if (!xen_feature(XENFEAT_auto_translated_physmap)) + xen_build_dynamic_phys_to_machine(); + + /* + * Set up kernel GDT and segment registers, mainly so that + * -fstack-protector code can be executed. + */ + xen_setup_stackprotector(); + xen_init_irq_ops(); xen_init_cpuid_mask(); @@ -1001,8 +1119,6 @@ asmlinkage void __init xen_start_kernel(void) set_xen_basic_apic_ops(); #endif - xen_setup_features(); - if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) { pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start; pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit; @@ -1019,22 +1135,8 @@ asmlinkage void __init xen_start_kernel(void) xen_smp_init(); - /* Get mfn list */ - if (!xen_feature(XENFEAT_auto_translated_physmap)) - xen_build_dynamic_phys_to_machine(); - pgd = (pgd_t *)xen_start_info->pt_base; - /* Prevent unwanted bits from being set in PTEs. */ - __supported_pte_mask &= ~_PAGE_GLOBAL; - if (!xen_initial_domain()) - __supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD); - -#ifdef CONFIG_X86_64 - /* Work out if we support NX */ - check_efer(); -#endif - /* Don't do the full vcpu_info placement stuff until we have a possible map and a non-dummy shared_info. */ per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index 429834ec1687..fe03eeed7b48 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -236,6 +236,7 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle) ctxt->user_regs.ss = __KERNEL_DS; #ifdef CONFIG_X86_32 ctxt->user_regs.fs = __KERNEL_PERCPU; + ctxt->user_regs.gs = __KERNEL_STACK_CANARY; #else ctxt->gs_base_kernel = per_cpu_offset(cpu); #endif diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c index 5601506f2dd9..36a5141108df 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -187,7 +187,6 @@ static noinline int xen_spin_lock_slow(struct raw_spinlock *lock, bool irq_enabl struct xen_spinlock *prev; int irq = __get_cpu_var(lock_kicker_irq); int ret; - unsigned long flags; u64 start; /* If kicker interrupts not initialized yet, just spin */ @@ -199,16 +198,12 @@ static noinline int xen_spin_lock_slow(struct raw_spinlock *lock, bool irq_enabl /* announce we're spinning */ prev = spinning_lock(xl); - flags = __raw_local_save_flags(); - if (irq_enable) { - ADD_STATS(taken_slow_irqenable, 1); - raw_local_irq_enable(); - } - ADD_STATS(taken_slow, 1); ADD_STATS(taken_slow_nested, prev != NULL); do { + unsigned long flags; + /* clear pending */ xen_clear_irq_pending(irq); @@ -228,6 +223,12 @@ static noinline int xen_spin_lock_slow(struct raw_spinlock *lock, bool irq_enabl goto out; } + flags = __raw_local_save_flags(); + if (irq_enable) { + ADD_STATS(taken_slow_irqenable, 1); + raw_local_irq_enable(); + } + /* * Block until irq becomes pending. If we're * interrupted at this point (after the trylock but @@ -238,13 +239,15 @@ static noinline int xen_spin_lock_slow(struct raw_spinlock *lock, bool irq_enabl * pending. */ xen_poll_irq(irq); + + raw_local_irq_restore(flags); + ADD_STATS(taken_slow_spurious, !xen_test_irq_pending(irq)); } while (!xen_test_irq_pending(irq)); /* check for spurious wakeups */ kstat_incr_irqs_this_cpu(irq, irq_to_desc(irq)); out: - raw_local_irq_restore(flags); unspinning_lock(xl, prev); spin_time_accum_blocked(start); @@ -323,8 +326,13 @@ static void xen_spin_unlock(struct raw_spinlock *lock) smp_wmb(); /* make sure no writes get moved after unlock */ xl->lock = 0; /* release lock */ - /* make sure unlock happens before kick */ - barrier(); + /* + * Make sure unlock happens before checking for waiting + * spinners. We need a strong barrier to enforce the + * write-read ordering to different memory locations, as the + * CPU makes no implied guarantees about their ordering. + */ + mb(); if (unlikely(xl->spinners)) xen_spin_unlock_slow(xl); |