xref: /openbmc/linux/arch/x86/xen/xen-head.S (revision a9a08845)
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#ifdef CONFIG_XEN_PV
24	__INIT
25ENTRY(startup_xen)
26	UNWIND_HINT_EMPTY
27	cld
28
29	/* Clear .bss */
30	xor %eax,%eax
31	mov $__bss_start, %_ASM_DI
32	mov $__bss_stop, %_ASM_CX
33	sub %_ASM_DI, %_ASM_CX
34	shr $__ASM_SEL(2, 3), %_ASM_CX
35	rep __ASM_SIZE(stos)
36
37	mov %_ASM_SI, xen_start_info
38	mov $init_thread_union+THREAD_SIZE, %_ASM_SP
39
40#ifdef CONFIG_X86_64
41	/* Set up %gs.
42	 *
43	 * The base of %gs always points to the bottom of the irqstack
44	 * union.  If the stack protector canary is enabled, it is
45	 * located at %gs:40.  Note that, on SMP, the boot cpu uses
46	 * init data section till per cpu areas are set up.
47	 */
48	movl	$MSR_GS_BASE,%ecx
49	movq	$INIT_PER_CPU_VAR(irq_stack_union),%rax
50	cdq
51	wrmsr
52#endif
53
54	jmp xen_start_kernel
55END(startup_xen)
56	__FINIT
57#endif
58
59.pushsection .text
60	.balign PAGE_SIZE
61ENTRY(hypercall_page)
62	.rept (PAGE_SIZE / 32)
63		UNWIND_HINT_EMPTY
64		.skip 32
65	.endr
66
67#define HYPERCALL(n) \
68	.equ xen_hypercall_##n, hypercall_page + __HYPERVISOR_##n * 32; \
69	.type xen_hypercall_##n, @function; .size xen_hypercall_##n, 32
70#include <asm/xen-hypercalls.h>
71#undef HYPERCALL
72END(hypercall_page)
73.popsection
74
75	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS,       .asciz "linux")
76	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION,  .asciz "2.6")
77	ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION,    .asciz "xen-3.0")
78#ifdef CONFIG_X86_32
79	ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE,      _ASM_PTR __PAGE_OFFSET)
80#else
81	ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE,      _ASM_PTR __START_KERNEL_map)
82	/* Map the p2m table to a 512GB-aligned user address. */
83	ELFNOTE(Xen, XEN_ELFNOTE_INIT_P2M,       .quad (PUD_SIZE * PTRS_PER_PUD))
84#endif
85#ifdef CONFIG_XEN_PV
86	ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          _ASM_PTR startup_xen)
87#endif
88	ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, _ASM_PTR hypercall_page)
89	ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,
90		.ascii "!writable_page_tables|pae_pgdir_above_4gb")
91	ELFNOTE(Xen, XEN_ELFNOTE_SUPPORTED_FEATURES,
92		.long (1 << XENFEAT_writable_page_tables) | (1 << XENFEAT_dom0))
93	ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE,       .asciz "yes")
94	ELFNOTE(Xen, XEN_ELFNOTE_LOADER,         .asciz "generic")
95	ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,
96		.quad _PAGE_PRESENT; .quad _PAGE_PRESENT)
97	ELFNOTE(Xen, XEN_ELFNOTE_SUSPEND_CANCEL, .long 1)
98	ELFNOTE(Xen, XEN_ELFNOTE_MOD_START_PFN,  .long 1)
99	ELFNOTE(Xen, XEN_ELFNOTE_HV_START_LOW,   _ASM_PTR __HYPERVISOR_VIRT_START)
100	ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET,   _ASM_PTR 0)
101
102#endif /*CONFIG_XEN */
103