1/* SPDX-License-Identifier: GPL-2.0 */ 2/* 3 * Asm versions of Xen pv-ops, suitable for direct use. 4 * 5 * We only bother with direct forms (ie, vcpu in percpu data) of the 6 * operations here; the indirect forms are better handled in C. 7 */ 8 9#include <asm/errno.h> 10#include <asm/asm-offsets.h> 11#include <asm/percpu.h> 12#include <asm/processor-flags.h> 13#include <asm/segment.h> 14#include <asm/thread_info.h> 15#include <asm/asm.h> 16#include <asm/frame.h> 17#include <asm/unwind_hints.h> 18 19#include <xen/interface/xen.h> 20 21#include <linux/init.h> 22#include <linux/linkage.h> 23 24.pushsection .noinstr.text, "ax" 25/* 26 * Disabling events is simply a matter of making the event mask 27 * non-zero. 28 */ 29SYM_FUNC_START(xen_irq_disable_direct) 30 movb $1, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask 31 ret 32SYM_FUNC_END(xen_irq_disable_direct) 33 34/* 35 * Force an event check by making a hypercall, but preserve regs 36 * before making the call. 37 */ 38SYM_FUNC_START(check_events) 39 FRAME_BEGIN 40 push %rax 41 push %rcx 42 push %rdx 43 push %rsi 44 push %rdi 45 push %r8 46 push %r9 47 push %r10 48 push %r11 49 call xen_force_evtchn_callback 50 pop %r11 51 pop %r10 52 pop %r9 53 pop %r8 54 pop %rdi 55 pop %rsi 56 pop %rdx 57 pop %rcx 58 pop %rax 59 FRAME_END 60 ret 61SYM_FUNC_END(check_events) 62 63/* 64 * Enable events. This clears the event mask and tests the pending 65 * event status with one and operation. If there are pending events, 66 * then enter the hypervisor to get them handled. 67 */ 68SYM_FUNC_START(xen_irq_enable_direct) 69 FRAME_BEGIN 70 /* Unmask events */ 71 movb $0, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask 72 73 /* 74 * Preempt here doesn't matter because that will deal with any 75 * pending interrupts. The pending check may end up being run 76 * on the wrong CPU, but that doesn't hurt. 77 */ 78 79 /* Test for pending */ 80 testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_pending 81 jz 1f 82 83 call check_events 841: 85 FRAME_END 86 ret 87SYM_FUNC_END(xen_irq_enable_direct) 88 89/* 90 * (xen_)save_fl is used to get the current interrupt enable status. 91 * Callers expect the status to be in X86_EFLAGS_IF, and other bits 92 * may be set in the return value. We take advantage of this by 93 * making sure that X86_EFLAGS_IF has the right value (and other bits 94 * in that byte are 0), but other bits in the return value are 95 * undefined. We need to toggle the state of the bit, because Xen and 96 * x86 use opposite senses (mask vs enable). 97 */ 98SYM_FUNC_START(xen_save_fl_direct) 99 testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask 100 setz %ah 101 addb %ah, %ah 102 ret 103SYM_FUNC_END(xen_save_fl_direct) 104 105SYM_FUNC_START(xen_read_cr2) 106 FRAME_BEGIN 107 _ASM_MOV PER_CPU_VAR(xen_vcpu), %_ASM_AX 108 _ASM_MOV XEN_vcpu_info_arch_cr2(%_ASM_AX), %_ASM_AX 109 FRAME_END 110 ret 111SYM_FUNC_END(xen_read_cr2); 112 113SYM_FUNC_START(xen_read_cr2_direct) 114 FRAME_BEGIN 115 _ASM_MOV PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_arch_cr2, %_ASM_AX 116 FRAME_END 117 ret 118SYM_FUNC_END(xen_read_cr2_direct); 119.popsection 120 121.macro xen_pv_trap name 122SYM_CODE_START(xen_\name) 123 UNWIND_HINT_EMPTY 124 pop %rcx 125 pop %r11 126 jmp \name 127SYM_CODE_END(xen_\name) 128_ASM_NOKPROBE(xen_\name) 129.endm 130 131xen_pv_trap asm_exc_divide_error 132xen_pv_trap asm_xenpv_exc_debug 133xen_pv_trap asm_exc_int3 134xen_pv_trap asm_xenpv_exc_nmi 135xen_pv_trap asm_exc_overflow 136xen_pv_trap asm_exc_bounds 137xen_pv_trap asm_exc_invalid_op 138xen_pv_trap asm_exc_device_not_available 139xen_pv_trap asm_xenpv_exc_double_fault 140xen_pv_trap asm_exc_coproc_segment_overrun 141xen_pv_trap asm_exc_invalid_tss 142xen_pv_trap asm_exc_segment_not_present 143xen_pv_trap asm_exc_stack_segment 144xen_pv_trap asm_exc_general_protection 145xen_pv_trap asm_exc_page_fault 146xen_pv_trap asm_exc_spurious_interrupt_bug 147xen_pv_trap asm_exc_coprocessor_error 148xen_pv_trap asm_exc_alignment_check 149#ifdef CONFIG_X86_MCE 150xen_pv_trap asm_xenpv_exc_machine_check 151#endif /* CONFIG_X86_MCE */ 152xen_pv_trap asm_exc_simd_coprocessor_error 153#ifdef CONFIG_IA32_EMULATION 154xen_pv_trap entry_INT80_compat 155#endif 156xen_pv_trap asm_exc_xen_unknown_trap 157xen_pv_trap asm_exc_xen_hypervisor_callback 158 159 __INIT 160SYM_CODE_START(xen_early_idt_handler_array) 161 i = 0 162 .rept NUM_EXCEPTION_VECTORS 163 UNWIND_HINT_EMPTY 164 pop %rcx 165 pop %r11 166 jmp early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE 167 i = i + 1 168 .fill xen_early_idt_handler_array + i*XEN_EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc 169 .endr 170SYM_CODE_END(xen_early_idt_handler_array) 171 __FINIT 172 173hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32 174/* 175 * Xen64 iret frame: 176 * 177 * ss 178 * rsp 179 * rflags 180 * cs 181 * rip <-- standard iret frame 182 * 183 * flags 184 * 185 * rcx } 186 * r11 }<-- pushed by hypercall page 187 * rsp->rax } 188 */ 189SYM_CODE_START(xen_iret) 190 UNWIND_HINT_EMPTY 191 pushq $0 192 jmp hypercall_iret 193SYM_CODE_END(xen_iret) 194 195/* 196 * Xen handles syscall callbacks much like ordinary exceptions, which 197 * means we have: 198 * - kernel gs 199 * - kernel rsp 200 * - an iret-like stack frame on the stack (including rcx and r11): 201 * ss 202 * rsp 203 * rflags 204 * cs 205 * rip 206 * r11 207 * rsp->rcx 208 */ 209 210/* Normal 64-bit system call target */ 211SYM_CODE_START(xen_syscall_target) 212 UNWIND_HINT_EMPTY 213 popq %rcx 214 popq %r11 215 216 /* 217 * Neither Xen nor the kernel really knows what the old SS and 218 * CS were. The kernel expects __USER_DS and __USER_CS, so 219 * report those values even though Xen will guess its own values. 220 */ 221 movq $__USER_DS, 4*8(%rsp) 222 movq $__USER_CS, 1*8(%rsp) 223 224 jmp entry_SYSCALL_64_after_hwframe 225SYM_CODE_END(xen_syscall_target) 226 227#ifdef CONFIG_IA32_EMULATION 228 229/* 32-bit compat syscall target */ 230SYM_CODE_START(xen_syscall32_target) 231 UNWIND_HINT_EMPTY 232 popq %rcx 233 popq %r11 234 235 /* 236 * Neither Xen nor the kernel really knows what the old SS and 237 * CS were. The kernel expects __USER32_DS and __USER32_CS, so 238 * report those values even though Xen will guess its own values. 239 */ 240 movq $__USER32_DS, 4*8(%rsp) 241 movq $__USER32_CS, 1*8(%rsp) 242 243 jmp entry_SYSCALL_compat_after_hwframe 244SYM_CODE_END(xen_syscall32_target) 245 246/* 32-bit compat sysenter target */ 247SYM_CODE_START(xen_sysenter_target) 248 UNWIND_HINT_EMPTY 249 /* 250 * NB: Xen is polite and clears TF from EFLAGS for us. This means 251 * that we don't need to guard against single step exceptions here. 252 */ 253 popq %rcx 254 popq %r11 255 256 /* 257 * Neither Xen nor the kernel really knows what the old SS and 258 * CS were. The kernel expects __USER32_DS and __USER32_CS, so 259 * report those values even though Xen will guess its own values. 260 */ 261 movq $__USER32_DS, 4*8(%rsp) 262 movq $__USER32_CS, 1*8(%rsp) 263 264 jmp entry_SYSENTER_compat_after_hwframe 265SYM_CODE_END(xen_sysenter_target) 266 267#else /* !CONFIG_IA32_EMULATION */ 268 269SYM_CODE_START(xen_syscall32_target) 270SYM_CODE_START(xen_sysenter_target) 271 UNWIND_HINT_EMPTY 272 lea 16(%rsp), %rsp /* strip %rcx, %r11 */ 273 mov $-ENOSYS, %rax 274 pushq $0 275 jmp hypercall_iret 276SYM_CODE_END(xen_sysenter_target) 277SYM_CODE_END(xen_syscall32_target) 278 279#endif /* CONFIG_IA32_EMULATION */ 280