1 /* SPDX-License-Identifier: GPL-2.0 */
3 * Asm versions of Xen pv-ops, suitable for direct use.
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.
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>
16 #include <asm/frame.h>
17 #include <asm/unwind_hints.h>
19 #include <xen/interface/xen.h>
21 #include <linux/init.h>
22 #include <linux/linkage.h>
23 #include <../entry/calling.h>
25 .pushsection .noinstr.text, "ax"
27 * Disabling events is simply a matter of making the event mask
30 SYM_FUNC_START(xen_irq_disable_direct)
31 movb $1, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
33 SYM_FUNC_END(xen_irq_disable_direct)
36 * Force an event check by making a hypercall, but preserve regs
37 * before making the call.
39 SYM_FUNC_START(check_events)
50 call xen_force_evtchn_callback
62 SYM_FUNC_END(check_events)
65 * Enable events. This clears the event mask and tests the pending
66 * event status with one and operation. If there are pending events,
67 * then enter the hypervisor to get them handled.
69 SYM_FUNC_START(xen_irq_enable_direct)
72 movb $0, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
75 * Preempt here doesn't matter because that will deal with any
76 * pending interrupts. The pending check may end up being run
77 * on the wrong CPU, but that doesn't hurt.
80 /* Test for pending */
81 testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_pending
88 SYM_FUNC_END(xen_irq_enable_direct)
91 * (xen_)save_fl is used to get the current interrupt enable status.
92 * Callers expect the status to be in X86_EFLAGS_IF, and other bits
93 * may be set in the return value. We take advantage of this by
94 * making sure that X86_EFLAGS_IF has the right value (and other bits
95 * in that byte are 0), but other bits in the return value are
96 * undefined. We need to toggle the state of the bit, because Xen and
97 * x86 use opposite senses (mask vs enable).
99 SYM_FUNC_START(xen_save_fl_direct)
100 testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
104 SYM_FUNC_END(xen_save_fl_direct)
106 SYM_FUNC_START(xen_read_cr2)
108 _ASM_MOV PER_CPU_VAR(xen_vcpu), %_ASM_AX
109 _ASM_MOV XEN_vcpu_info_arch_cr2(%_ASM_AX), %_ASM_AX
112 SYM_FUNC_END(xen_read_cr2);
114 SYM_FUNC_START(xen_read_cr2_direct)
116 _ASM_MOV PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_arch_cr2, %_ASM_AX
119 SYM_FUNC_END(xen_read_cr2_direct);
122 .macro xen_pv_trap name
123 SYM_CODE_START(xen_\name)
128 SYM_CODE_END(xen_\name)
129 _ASM_NOKPROBE(xen_\name)
132 xen_pv_trap asm_exc_divide_error
133 xen_pv_trap asm_xenpv_exc_debug
134 xen_pv_trap asm_exc_int3
135 xen_pv_trap asm_xenpv_exc_nmi
136 xen_pv_trap asm_exc_overflow
137 xen_pv_trap asm_exc_bounds
138 xen_pv_trap asm_exc_invalid_op
139 xen_pv_trap asm_exc_device_not_available
140 xen_pv_trap asm_xenpv_exc_double_fault
141 xen_pv_trap asm_exc_coproc_segment_overrun
142 xen_pv_trap asm_exc_invalid_tss
143 xen_pv_trap asm_exc_segment_not_present
144 xen_pv_trap asm_exc_stack_segment
145 xen_pv_trap asm_exc_general_protection
146 xen_pv_trap asm_exc_page_fault
147 xen_pv_trap asm_exc_spurious_interrupt_bug
148 xen_pv_trap asm_exc_coprocessor_error
149 xen_pv_trap asm_exc_alignment_check
150 #ifdef CONFIG_X86_MCE
151 xen_pv_trap asm_xenpv_exc_machine_check
152 #endif /* CONFIG_X86_MCE */
153 xen_pv_trap asm_exc_simd_coprocessor_error
154 #ifdef CONFIG_IA32_EMULATION
155 xen_pv_trap entry_INT80_compat
157 xen_pv_trap asm_exc_xen_unknown_trap
158 xen_pv_trap asm_exc_xen_hypervisor_callback
161 SYM_CODE_START(xen_early_idt_handler_array)
163 .rept NUM_EXCEPTION_VECTORS
167 jmp early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE
169 .fill xen_early_idt_handler_array + i*XEN_EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc
171 SYM_CODE_END(xen_early_idt_handler_array)
174 hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32
182 * rip <-- standard iret frame
187 * r11 }<-- pushed by hypercall page
190 SYM_CODE_START(xen_iret)
194 SYM_CODE_END(xen_iret)
197 * XEN pv doesn't use trampoline stack, PER_CPU_VAR(cpu_tss_rw + TSS_sp0) is
198 * also the kernel stack. Reusing swapgs_restore_regs_and_return_to_usermode()
199 * in XEN pv would cause %rsp to move up to the top of the kernel stack and
200 * leave the IRET frame below %rsp, which is dangerous to be corrupted if #NMI
201 * interrupts. And swapgs_restore_regs_and_return_to_usermode() pushing the IRET
202 * frame at the same address is useless.
204 SYM_CODE_START(xenpv_restore_regs_and_return_to_usermode)
208 /* stackleak_erase() can work safely on the kernel stack. */
209 STACKLEAK_ERASE_NOCLOBBER
211 addq $8, %rsp /* skip regs->orig_ax */
213 SYM_CODE_END(xenpv_restore_regs_and_return_to_usermode)
216 * Xen handles syscall callbacks much like ordinary exceptions, which
220 * - an iret-like stack frame on the stack (including rcx and r11):
230 /* Normal 64-bit system call target */
231 SYM_CODE_START(xen_syscall_target)
237 * Neither Xen nor the kernel really knows what the old SS and
238 * CS were. The kernel expects __USER_DS and __USER_CS, so
239 * report those values even though Xen will guess its own values.
241 movq $__USER_DS, 4*8(%rsp)
242 movq $__USER_CS, 1*8(%rsp)
244 jmp entry_SYSCALL_64_after_hwframe
245 SYM_CODE_END(xen_syscall_target)
247 #ifdef CONFIG_IA32_EMULATION
249 /* 32-bit compat syscall target */
250 SYM_CODE_START(xen_syscall32_target)
256 * Neither Xen nor the kernel really knows what the old SS and
257 * CS were. The kernel expects __USER32_DS and __USER32_CS, so
258 * report those values even though Xen will guess its own values.
260 movq $__USER32_DS, 4*8(%rsp)
261 movq $__USER32_CS, 1*8(%rsp)
263 jmp entry_SYSCALL_compat_after_hwframe
264 SYM_CODE_END(xen_syscall32_target)
266 /* 32-bit compat sysenter target */
267 SYM_CODE_START(xen_sysenter_target)
270 * NB: Xen is polite and clears TF from EFLAGS for us. This means
271 * that we don't need to guard against single step exceptions here.
277 * Neither Xen nor the kernel really knows what the old SS and
278 * CS were. The kernel expects __USER32_DS and __USER32_CS, so
279 * report those values even though Xen will guess its own values.
281 movq $__USER32_DS, 4*8(%rsp)
282 movq $__USER32_CS, 1*8(%rsp)
284 jmp entry_SYSENTER_compat_after_hwframe
285 SYM_CODE_END(xen_sysenter_target)
287 #else /* !CONFIG_IA32_EMULATION */
289 SYM_CODE_START(xen_syscall32_target)
290 SYM_CODE_START(xen_sysenter_target)
292 lea 16(%rsp), %rsp /* strip %rcx, %r11 */
296 SYM_CODE_END(xen_sysenter_target)
297 SYM_CODE_END(xen_syscall32_target)
299 #endif /* CONFIG_IA32_EMULATION */