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
10#include <asm/boot.h>
11#include <asm/asm.h>
12#include <asm/msr.h>
13#include <asm/page_types.h>
14#include <asm/percpu.h>
15#include <asm/unwind_hints.h>
16
17#include <xen/interface/elfnote.h>
18#include <xen/interface/features.h>
19#include <xen/interface/xen.h>
20#include <xen/interface/xen-mca.h>
21#include <asm/xen/interface.h>
22
23.pushsection .noinstr.text, "ax"
24 .balign PAGE_SIZE
25SYM_CODE_START(hypercall_page)
26 .rept (PAGE_SIZE / 32)
27 UNWIND_HINT_FUNC
28 ANNOTATE_NOENDBR
29 ANNOTATE_UNRET_SAFE
30 ret
31 /*
32 * Xen will write the hypercall page, and sort out ENDBR.
33 */
34 .skip 31, 0xcc
35 .endr
36
37#define HYPERCALL(n) \
38 .equ xen_hypercall_##n, hypercall_page + __HYPERVISOR_##n * 32; \
39 .type xen_hypercall_##n, @function; .size xen_hypercall_##n, 32
40#include <asm/xen-hypercalls.h>
41#undef HYPERCALL
42SYM_CODE_END(hypercall_page)
43.popsection
44
45#ifdef CONFIG_XEN_PV
46 __INIT
47SYM_CODE_START(startup_xen)
48 UNWIND_HINT_END_OF_STACK
49 ANNOTATE_NOENDBR
50 cld
51
52 leaq (__end_init_task - PTREGS_SIZE)(%rip), %rsp
53
54 /* Set up %gs.
55 *
56 * The base of %gs always points to fixed_percpu_data. If the
57 * stack protector canary is enabled, it is located at %gs:40.
58 * Note that, on SMP, the boot cpu uses init data section until
59 * the per cpu areas are set up.
60 */
61 movl $MSR_GS_BASE,%ecx
62 movq $INIT_PER_CPU_VAR(fixed_percpu_data),%rax
63 cdq
64 wrmsr
65
66 mov %rsi, %rdi
67 call xen_start_kernel
68SYM_CODE_END(startup_xen)
69 __FINIT
70
71#ifdef CONFIG_XEN_PV_SMP
72.pushsection .text
73SYM_CODE_START(asm_cpu_bringup_and_idle)
74 UNWIND_HINT_END_OF_STACK
75 ENDBR
76
77 call cpu_bringup_and_idle
78SYM_CODE_END(asm_cpu_bringup_and_idle)
79
80SYM_CODE_START(xen_cpu_bringup_again)
81 UNWIND_HINT_FUNC
82 mov %rdi, %rsp
83 UNWIND_HINT_REGS
84 call cpu_bringup_and_idle
85SYM_CODE_END(xen_cpu_bringup_again)
86.popsection
87#endif
88#endif
89
90 ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS, .asciz "linux")
91 ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION, .asciz "2.6")
92 ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION, .asciz "xen-3.0")
93#ifdef CONFIG_XEN_PV
94 ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE, _ASM_PTR __START_KERNEL_map)
95 /* Map the p2m table to a 512GB-aligned user address. */
96 ELFNOTE(Xen, XEN_ELFNOTE_INIT_P2M, .quad (PUD_SIZE * PTRS_PER_PUD))
97 ELFNOTE(Xen, XEN_ELFNOTE_ENTRY, _ASM_PTR startup_xen)
98 ELFNOTE(Xen, XEN_ELFNOTE_FEATURES, .ascii "!writable_page_tables")
99 ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE, .asciz "yes")
100 ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,
101 .quad _PAGE_PRESENT; .quad _PAGE_PRESENT)
102 ELFNOTE(Xen, XEN_ELFNOTE_MOD_START_PFN, .long 1)
103 ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET, _ASM_PTR 0)
104# define FEATURES_PV (1 << XENFEAT_writable_page_tables)
105#else
106# define FEATURES_PV 0
107#endif
108#ifdef CONFIG_XEN_PVH
109# define FEATURES_PVH (1 << XENFEAT_linux_rsdp_unrestricted)
110#else
111# define FEATURES_PVH 0
112#endif
113#ifdef CONFIG_XEN_DOM0
114# define FEATURES_DOM0 (1 << XENFEAT_dom0)
115#else
116# define FEATURES_DOM0 0
117#endif
118 ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, _ASM_PTR hypercall_page)
119 ELFNOTE(Xen, XEN_ELFNOTE_SUPPORTED_FEATURES,
120 .long FEATURES_PV | FEATURES_PVH | FEATURES_DOM0)
121 ELFNOTE(Xen, XEN_ELFNOTE_LOADER, .asciz "generic")
122 ELFNOTE(Xen, XEN_ELFNOTE_SUSPEND_CANCEL, .long 1)
123
124#endif /*CONFIG_XEN */
125

source code of linux/arch/x86/xen/xen-head.S