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Diffstat (limited to '')
| -rw-r--r-- | arch/x86/kernel/paravirt.c | 483 |
1 files changed, 483 insertions, 0 deletions
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c new file mode 100644 index 000000000..8dc69d825 --- /dev/null +++ b/arch/x86/kernel/paravirt.c @@ -0,0 +1,483 @@ +/* Paravirtualization interfaces + Copyright (C) 2006 Rusty Russell IBM Corporation + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + + 2007 - x86_64 support added by Glauber de Oliveira Costa, Red Hat Inc +*/ + +#include <linux/errno.h> +#include <linux/init.h> +#include <linux/export.h> +#include <linux/efi.h> +#include <linux/bcd.h> +#include <linux/highmem.h> +#include <linux/kprobes.h> + +#include <asm/bug.h> +#include <asm/paravirt.h> +#include <asm/debugreg.h> +#include <asm/desc.h> +#include <asm/setup.h> +#include <asm/pgtable.h> +#include <asm/time.h> +#include <asm/pgalloc.h> +#include <asm/irq.h> +#include <asm/delay.h> +#include <asm/fixmap.h> +#include <asm/apic.h> +#include <asm/tlbflush.h> +#include <asm/timer.h> +#include <asm/special_insns.h> +#include <asm/tlb.h> + +/* + * nop stub, which must not clobber anything *including the stack* to + * avoid confusing the entry prologues. + */ +extern void _paravirt_nop(void); +asm (".pushsection .entry.text, \"ax\"\n" + ".global _paravirt_nop\n" + "_paravirt_nop:\n\t" + "ret\n\t" + ".size _paravirt_nop, . - _paravirt_nop\n\t" + ".type _paravirt_nop, @function\n\t" + ".popsection"); + +/* identity function, which can be inlined */ +u32 notrace _paravirt_ident_32(u32 x) +{ + return x; +} + +u64 notrace _paravirt_ident_64(u64 x) +{ + return x; +} + +void __init default_banner(void) +{ + printk(KERN_INFO "Booting paravirtualized kernel on %s\n", + pv_info.name); +} + +/* Undefined instruction for dealing with missing ops pointers. */ +static const unsigned char ud2a[] = { 0x0f, 0x0b }; + +struct branch { + unsigned char opcode; + u32 delta; +} __attribute__((packed)); + +unsigned paravirt_patch_call(void *insnbuf, + const void *target, u16 tgt_clobbers, + unsigned long addr, u16 site_clobbers, + unsigned len) +{ + struct branch *b = insnbuf; + unsigned long delta = (unsigned long)target - (addr+5); + + if (len < 5) { +#ifdef CONFIG_RETPOLINE + WARN_ONCE(1, "Failing to patch indirect CALL in %ps\n", (void *)addr); +#endif + return len; /* call too long for patch site */ + } + + b->opcode = 0xe8; /* call */ + b->delta = delta; + BUILD_BUG_ON(sizeof(*b) != 5); + + return 5; +} + +unsigned paravirt_patch_jmp(void *insnbuf, const void *target, + unsigned long addr, unsigned len) +{ + struct branch *b = insnbuf; + unsigned long delta = (unsigned long)target - (addr+5); + + if (len < 5) { +#ifdef CONFIG_RETPOLINE + WARN_ONCE(1, "Failing to patch indirect JMP in %ps\n", (void *)addr); +#endif + return len; /* call too long for patch site */ + } + + b->opcode = 0xe9; /* jmp */ + b->delta = delta; + + return 5; +} + +DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key); + +void __init native_pv_lock_init(void) +{ + if (!static_cpu_has(X86_FEATURE_HYPERVISOR)) + static_branch_disable(&virt_spin_lock_key); +} + +/* + * Neat trick to map patch type back to the call within the + * corresponding structure. + */ +static void *get_call_destination(u8 type) +{ + struct paravirt_patch_template tmpl = { + .pv_init_ops = pv_init_ops, + .pv_time_ops = pv_time_ops, + .pv_cpu_ops = pv_cpu_ops, + .pv_irq_ops = pv_irq_ops, + .pv_mmu_ops = pv_mmu_ops, +#ifdef CONFIG_PARAVIRT_SPINLOCKS + .pv_lock_ops = pv_lock_ops, +#endif + }; + return *((void **)&tmpl + type); +} + +unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf, + unsigned long addr, unsigned len) +{ + void *opfunc = get_call_destination(type); + unsigned ret; + + if (opfunc == NULL) + /* If there's no function, patch it with a ud2a (BUG) */ + ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a)); + else if (opfunc == _paravirt_nop) + ret = 0; + + /* identity functions just return their single argument */ + else if (opfunc == _paravirt_ident_32) + ret = paravirt_patch_ident_32(insnbuf, len); + else if (opfunc == _paravirt_ident_64) + ret = paravirt_patch_ident_64(insnbuf, len); + + else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) || + type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64)) + /* If operation requires a jmp, then jmp */ + ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len); + else + /* Otherwise call the function; assume target could + clobber any caller-save reg */ + ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY, + addr, clobbers, len); + + return ret; +} + +unsigned paravirt_patch_insns(void *insnbuf, unsigned len, + const char *start, const char *end) +{ + unsigned insn_len = end - start; + + if (insn_len > len || start == NULL) + insn_len = len; + else + memcpy(insnbuf, start, insn_len); + + return insn_len; +} + +static void native_flush_tlb(void) +{ + __native_flush_tlb(); +} + +/* + * Global pages have to be flushed a bit differently. Not a real + * performance problem because this does not happen often. + */ +static void native_flush_tlb_global(void) +{ + __native_flush_tlb_global(); +} + +static void native_flush_tlb_one_user(unsigned long addr) +{ + __native_flush_tlb_one_user(addr); +} + +struct static_key paravirt_steal_enabled; +struct static_key paravirt_steal_rq_enabled; + +static u64 native_steal_clock(int cpu) +{ + return 0; +} + +/* These are in entry.S */ +extern void native_iret(void); +extern void native_usergs_sysret64(void); + +static struct resource reserve_ioports = { + .start = 0, + .end = IO_SPACE_LIMIT, + .name = "paravirt-ioport", + .flags = IORESOURCE_IO | IORESOURCE_BUSY, +}; + +/* + * Reserve the whole legacy IO space to prevent any legacy drivers + * from wasting time probing for their hardware. This is a fairly + * brute-force approach to disabling all non-virtual drivers. + * + * Note that this must be called very early to have any effect. + */ +int paravirt_disable_iospace(void) +{ + return request_resource(&ioport_resource, &reserve_ioports); +} + +static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE; + +static inline void enter_lazy(enum paravirt_lazy_mode mode) +{ + BUG_ON(this_cpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE); + + this_cpu_write(paravirt_lazy_mode, mode); +} + +static void leave_lazy(enum paravirt_lazy_mode mode) +{ + BUG_ON(this_cpu_read(paravirt_lazy_mode) != mode); + + this_cpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE); +} + +void paravirt_enter_lazy_mmu(void) +{ + enter_lazy(PARAVIRT_LAZY_MMU); +} + +void paravirt_leave_lazy_mmu(void) +{ + leave_lazy(PARAVIRT_LAZY_MMU); +} + +void paravirt_flush_lazy_mmu(void) +{ + preempt_disable(); + + if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) { + arch_leave_lazy_mmu_mode(); + arch_enter_lazy_mmu_mode(); + } + + preempt_enable(); +} + +void paravirt_start_context_switch(struct task_struct *prev) +{ + BUG_ON(preemptible()); + + if (this_cpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) { + arch_leave_lazy_mmu_mode(); + set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES); + } + enter_lazy(PARAVIRT_LAZY_CPU); +} + +void paravirt_end_context_switch(struct task_struct *next) +{ + BUG_ON(preemptible()); + + leave_lazy(PARAVIRT_LAZY_CPU); + + if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES)) + arch_enter_lazy_mmu_mode(); +} + +enum paravirt_lazy_mode paravirt_get_lazy_mode(void) +{ + if (in_interrupt()) + return PARAVIRT_LAZY_NONE; + + return this_cpu_read(paravirt_lazy_mode); +} + +struct pv_info pv_info = { + .name = "bare hardware", + .kernel_rpl = 0, + .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */ + +#ifdef CONFIG_X86_64 + .extra_user_64bit_cs = __USER_CS, +#endif +}; + +struct pv_init_ops pv_init_ops = { + .patch = native_patch, +}; + +struct pv_time_ops pv_time_ops = { + .sched_clock = native_sched_clock, + .steal_clock = native_steal_clock, +}; + +__visible struct pv_irq_ops pv_irq_ops = { + .save_fl = __PV_IS_CALLEE_SAVE(native_save_fl), + .restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl), + .irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable), + .irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable), + .safe_halt = native_safe_halt, + .halt = native_halt, +}; + +__visible struct pv_cpu_ops pv_cpu_ops = { + .cpuid = native_cpuid, + .get_debugreg = native_get_debugreg, + .set_debugreg = native_set_debugreg, + .read_cr0 = native_read_cr0, + .write_cr0 = native_write_cr0, + .write_cr4 = native_write_cr4, +#ifdef CONFIG_X86_64 + .read_cr8 = native_read_cr8, + .write_cr8 = native_write_cr8, +#endif + .wbinvd = native_wbinvd, + .read_msr = native_read_msr, + .write_msr = native_write_msr, + .read_msr_safe = native_read_msr_safe, + .write_msr_safe = native_write_msr_safe, + .read_pmc = native_read_pmc, + .load_tr_desc = native_load_tr_desc, + .set_ldt = native_set_ldt, + .load_gdt = native_load_gdt, + .load_idt = native_load_idt, + .store_tr = native_store_tr, + .load_tls = native_load_tls, +#ifdef CONFIG_X86_64 + .load_gs_index = native_load_gs_index, +#endif + .write_ldt_entry = native_write_ldt_entry, + .write_gdt_entry = native_write_gdt_entry, + .write_idt_entry = native_write_idt_entry, + + .alloc_ldt = paravirt_nop, + .free_ldt = paravirt_nop, + + .load_sp0 = native_load_sp0, + +#ifdef CONFIG_X86_64 + .usergs_sysret64 = native_usergs_sysret64, +#endif + .iret = native_iret, + .swapgs = native_swapgs, + + .set_iopl_mask = native_set_iopl_mask, + .io_delay = native_io_delay, + + .start_context_switch = paravirt_nop, + .end_context_switch = paravirt_nop, +}; + +/* At this point, native_get/set_debugreg has real function entries */ +NOKPROBE_SYMBOL(native_get_debugreg); +NOKPROBE_SYMBOL(native_set_debugreg); +NOKPROBE_SYMBOL(native_load_idt); + +#if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE) +/* 32-bit pagetable entries */ +#define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_32) +#else +/* 64-bit pagetable entries */ +#define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64) +#endif + +struct pv_mmu_ops pv_mmu_ops __ro_after_init = { + + .read_cr2 = native_read_cr2, + .write_cr2 = native_write_cr2, + .read_cr3 = __native_read_cr3, + .write_cr3 = native_write_cr3, + + .flush_tlb_user = native_flush_tlb, + .flush_tlb_kernel = native_flush_tlb_global, + .flush_tlb_one_user = native_flush_tlb_one_user, + .flush_tlb_others = native_flush_tlb_others, + .tlb_remove_table = (void (*)(struct mmu_gather *, void *))tlb_remove_page, + + .pgd_alloc = __paravirt_pgd_alloc, + .pgd_free = paravirt_nop, + + .alloc_pte = paravirt_nop, + .alloc_pmd = paravirt_nop, + .alloc_pud = paravirt_nop, + .alloc_p4d = paravirt_nop, + .release_pte = paravirt_nop, + .release_pmd = paravirt_nop, + .release_pud = paravirt_nop, + .release_p4d = paravirt_nop, + + .set_pte = native_set_pte, + .set_pte_at = native_set_pte_at, + .set_pmd = native_set_pmd, + + .ptep_modify_prot_start = __ptep_modify_prot_start, + .ptep_modify_prot_commit = __ptep_modify_prot_commit, + +#if CONFIG_PGTABLE_LEVELS >= 3 +#ifdef CONFIG_X86_PAE + .set_pte_atomic = native_set_pte_atomic, + .pte_clear = native_pte_clear, + .pmd_clear = native_pmd_clear, +#endif + .set_pud = native_set_pud, + + .pmd_val = PTE_IDENT, + .make_pmd = PTE_IDENT, + +#if CONFIG_PGTABLE_LEVELS >= 4 + .pud_val = PTE_IDENT, + .make_pud = PTE_IDENT, + + .set_p4d = native_set_p4d, + +#if CONFIG_PGTABLE_LEVELS >= 5 + .p4d_val = PTE_IDENT, + .make_p4d = PTE_IDENT, + + .set_pgd = native_set_pgd, +#endif /* CONFIG_PGTABLE_LEVELS >= 5 */ +#endif /* CONFIG_PGTABLE_LEVELS >= 4 */ +#endif /* CONFIG_PGTABLE_LEVELS >= 3 */ + + .pte_val = PTE_IDENT, + .pgd_val = PTE_IDENT, + + .make_pte = PTE_IDENT, + .make_pgd = PTE_IDENT, + + .dup_mmap = paravirt_nop, + .exit_mmap = paravirt_nop, + .activate_mm = paravirt_nop, + + .lazy_mode = { + .enter = paravirt_nop, + .leave = paravirt_nop, + .flush = paravirt_nop, + }, + + .set_fixmap = native_set_fixmap, +}; + +EXPORT_SYMBOL_GPL(pv_time_ops); +EXPORT_SYMBOL (pv_cpu_ops); +EXPORT_SYMBOL (pv_mmu_ops); +EXPORT_SYMBOL_GPL(pv_info); +EXPORT_SYMBOL (pv_irq_ops); |