diff options
Diffstat (limited to 'arch/x86/xen/enlighten.c')
| -rw-r--r-- | arch/x86/xen/enlighten.c | 131 |
1 files changed, 112 insertions, 19 deletions
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index b62ccb840cf..0dd0c2c6cae 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" @@ -330,18 +331,28 @@ 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 +369,44 @@ 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 +630,29 @@ 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 +1037,23 @@ 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) { @@ -983,13 +1072,28 @@ 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); -#endif + + /* 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; + + 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 +1105,6 @@ 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; @@ -1019,17 +1121,8 @@ 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(); |