xen-head.S

  1/* SPDX-License-Identifier: GPL-2.0 */
  2/* Xen-specific pieces of head.S, intended to be included in the right
  3	place in head.S */
  4
  5#ifdef CONFIG_XEN
  6
  7#include <linux/elfnote.h>
  8#include <linux/init.h>
  9#include <linux/instrumentation.h>
 10
 11#include <asm/boot.h>
 12#include <asm/asm.h>
 13#include <asm/frame.h>
 14#include <asm/msr.h>
 15#include <asm/page_types.h>
 16#include <asm/percpu.h>
 17#include <asm/unwind_hints.h>
 18
 19#include <xen/interface/elfnote.h>
 20#include <xen/interface/features.h>
 21#include <xen/interface/xen.h>
 22#include <xen/interface/xen-mca.h>
 23#include <asm/xen/interface.h>
 24
 25#ifdef CONFIG_XEN_PV
 26	__INIT
 27SYM_CODE_START(startup_xen)
 28	UNWIND_HINT_END_OF_STACK
 29	ANNOTATE_NOENDBR
 30	cld
 31
 32	leaq	__top_init_kernel_stack(%rip), %rsp
 33
 34	/*
 35	 * Set up GSBASE.
 36	 * Note that, on SMP, the boot cpu uses init data section until
 37	 * the per cpu areas are set up.
 38	 */
 39	movl	$MSR_GS_BASE,%ecx
 40	xorl	%eax, %eax
 41	xorl	%edx, %edx
 42	wrmsr
 43
 44	mov	%rsi, %rdi
 45	call xen_start_kernel
 46SYM_CODE_END(startup_xen)
 47	__FINIT
 48
 49#ifdef CONFIG_XEN_PV_SMP
 50.pushsection .text
 51SYM_CODE_START(asm_cpu_bringup_and_idle)
 52	UNWIND_HINT_END_OF_STACK
 53	ENDBR
 54
 55	call cpu_bringup_and_idle
 56SYM_CODE_END(asm_cpu_bringup_and_idle)
 57
 58SYM_CODE_START(xen_cpu_bringup_again)
 59	UNWIND_HINT_FUNC
 60	mov	%rdi, %rsp
 61	UNWIND_HINT_REGS
 62	call	cpu_bringup_and_idle
 63SYM_CODE_END(xen_cpu_bringup_again)
 64.popsection
 65#endif
 66#endif
 67
 68	.pushsection .noinstr.text, "ax"
 69/*
 70 * Xen hypercall interface to the hypervisor.
 71 *
 72 * Input:
 73 *     %eax: hypercall number
 74 *   32-bit:
 75 *     %ebx, %ecx, %edx, %esi, %edi: args 1..5 for the hypercall
 76 *   64-bit:
 77 *     %rdi, %rsi, %rdx, %r10, %r8: args 1..5 for the hypercall
 78 * Output: %[er]ax
 79 */
 80SYM_FUNC_START(xen_hypercall_hvm)
 81	ENDBR
 82	FRAME_BEGIN
 83	/* Save all relevant registers (caller save and arguments). */
 84#ifdef CONFIG_X86_32
 85	push %eax
 86	push %ebx
 87	push %ecx
 88	push %edx
 89	push %esi
 90	push %edi
 91#else
 92	push %rax
 93	push %rcx
 94	push %rdx
 95	push %rdi
 96	push %rsi
 97	push %r11
 98	push %r10
 99	push %r9
100	push %r8
101#endif
102	/* Set the vendor specific function. */
103	call __xen_hypercall_setfunc
104	/* Set ZF = 1 if AMD, Restore saved registers. */
105#ifdef CONFIG_X86_32
106	lea xen_hypercall_amd, %ebx
107	cmp %eax, %ebx
108	pop %edi
109	pop %esi
110	pop %edx
111	pop %ecx
112	pop %ebx
113	pop %eax
114#else
115	lea xen_hypercall_amd(%rip), %rcx
116	cmp %rax, %rcx
117	pop %r8
118	pop %r9
119	pop %r10
120	pop %r11
121	pop %rsi
122	pop %rdi
123	pop %rdx
124	pop %rcx
125	pop %rax
126#endif
127	FRAME_END
128	/* Use correct hypercall function. */
129	jz xen_hypercall_amd
130	jmp xen_hypercall_intel
131SYM_FUNC_END(xen_hypercall_hvm)
132
133SYM_FUNC_START(xen_hypercall_amd)
134	ANNOTATE_NOENDBR
135	vmmcall
136	RET
137SYM_FUNC_END(xen_hypercall_amd)
138
139SYM_FUNC_START(xen_hypercall_intel)
140	ANNOTATE_NOENDBR
141	vmcall
142	RET
143SYM_FUNC_END(xen_hypercall_intel)
144	.popsection
145
146	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS,       .asciz "linux")
147	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION,  .asciz "2.6")
148	ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION,    .asciz "xen-3.0")
149#ifdef CONFIG_XEN_PV
150	ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE,      _ASM_PTR __START_KERNEL_map)
151	/* Map the p2m table to a 512GB-aligned user address. */
152	ELFNOTE(Xen, XEN_ELFNOTE_INIT_P2M,       .quad (PUD_SIZE * PTRS_PER_PUD))
153	ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          .globl xen_elfnote_entry;
154		xen_elfnote_entry: _ASM_PTR xen_elfnote_entry_value - .)
155	ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .ascii "!writable_page_tables")
156	ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE,       .asciz "yes")
157	ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,
158		.quad _PAGE_PRESENT; .quad _PAGE_PRESENT)
159	ELFNOTE(Xen, XEN_ELFNOTE_MOD_START_PFN,  .long 1)
160	ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET,   _ASM_PTR 0)
161# define FEATURES_PV (1 << XENFEAT_writable_page_tables)
162#else
163# define FEATURES_PV 0
164#endif
165#ifdef CONFIG_XEN_PVH
166# define FEATURES_PVH (1 << XENFEAT_linux_rsdp_unrestricted)
167#else
168# define FEATURES_PVH 0
169#endif
170#ifdef CONFIG_XEN_DOM0
171# define FEATURES_DOM0 (1 << XENFEAT_dom0)
172#else
173# define FEATURES_DOM0 0
174#endif
175	ELFNOTE(Xen, XEN_ELFNOTE_SUPPORTED_FEATURES,
176		.long FEATURES_PV | FEATURES_PVH | FEATURES_DOM0)
177	ELFNOTE(Xen, XEN_ELFNOTE_LOADER,         .asciz "generic")
178	ELFNOTE(Xen, XEN_ELFNOTE_SUSPEND_CANCEL, .long 1)
179
180#endif /*CONFIG_XEN */