xref: /openbmc/linux/arch/x86/xen/xen-head.S (revision 293d5b43)
1/* Xen-specific pieces of head.S, intended to be included in the right
2	place in head.S */
3
4#ifdef CONFIG_XEN
5
6#include <linux/elfnote.h>
7#include <linux/init.h>
8
9#include <asm/boot.h>
10#include <asm/asm.h>
11#include <asm/page_types.h>
12
13#include <xen/interface/elfnote.h>
14#include <xen/interface/features.h>
15#include <xen/interface/xen.h>
16#include <xen/interface/xen-mca.h>
17#include <asm/xen/interface.h>
18
19#ifdef CONFIG_XEN_PVH
20#define PVH_FEATURES_STR  "|writable_descriptor_tables|auto_translated_physmap|supervisor_mode_kernel"
21/* Note the lack of 'hvm_callback_vector'. Older hypervisor will
22 * balk at this being part of XEN_ELFNOTE_FEATURES, so we put it in
23 * XEN_ELFNOTE_SUPPORTED_FEATURES which older hypervisors will ignore.
24 */
25#define PVH_FEATURES ((1 << XENFEAT_writable_page_tables) | \
26		      (1 << XENFEAT_auto_translated_physmap) | \
27		      (1 << XENFEAT_supervisor_mode_kernel) | \
28		      (1 << XENFEAT_hvm_callback_vector))
29/* The XENFEAT_writable_page_tables is not stricly necessary as we set that
30 * up regardless whether this CONFIG option is enabled or not, but it
31 * clarifies what the right flags need to be.
32 */
33#else
34#define PVH_FEATURES_STR  ""
35#define PVH_FEATURES (0)
36#endif
37
38	__INIT
39ENTRY(startup_xen)
40	cld
41
42	/* Clear .bss */
43	xor %eax,%eax
44	mov $__bss_start, %_ASM_DI
45	mov $__bss_stop, %_ASM_CX
46	sub %_ASM_DI, %_ASM_CX
47	shr $__ASM_SEL(2, 3), %_ASM_CX
48	rep __ASM_SIZE(stos)
49
50	mov %_ASM_SI, xen_start_info
51	mov $init_thread_union+THREAD_SIZE, %_ASM_SP
52
53	jmp xen_start_kernel
54
55	__FINIT
56
57#ifdef CONFIG_XEN_PVH
58/*
59 * xen_pvh_early_cpu_init() - early PVH VCPU initialization
60 * @cpu:   this cpu number (%rdi)
61 * @entry: true if this is a secondary vcpu coming up on this entry
62 *         point, false if this is the boot CPU being initialized for
63 *         the first time (%rsi)
64 *
65 * Note: This is called as a function on the boot CPU, and is the entry point
66 *       on the secondary CPU.
67 */
68ENTRY(xen_pvh_early_cpu_init)
69	mov     %rsi, %r11
70
71	/* Gather features to see if NX implemented. */
72	mov     $0x80000001, %eax
73	cpuid
74	mov     %edx, %esi
75
76	mov     $MSR_EFER, %ecx
77	rdmsr
78	bts     $_EFER_SCE, %eax
79
80	bt      $20, %esi
81	jnc     1f      	/* No NX, skip setting it */
82	bts     $_EFER_NX, %eax
831:	wrmsr
84#ifdef CONFIG_SMP
85	cmp     $0, %r11b
86	jne     cpu_bringup_and_idle
87#endif
88	ret
89
90#endif /* CONFIG_XEN_PVH */
91
92.pushsection .text
93	.balign PAGE_SIZE
94ENTRY(hypercall_page)
95	.skip PAGE_SIZE
96
97#define HYPERCALL(n) \
98	.equ xen_hypercall_##n, hypercall_page + __HYPERVISOR_##n * 32; \
99	.type xen_hypercall_##n, @function; .size xen_hypercall_##n, 32
100#include <asm/xen-hypercalls.h>
101#undef HYPERCALL
102
103.popsection
104
105	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS,       .asciz "linux")
106	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION,  .asciz "2.6")
107	ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION,    .asciz "xen-3.0")
108#ifdef CONFIG_X86_32
109	ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE,      _ASM_PTR __PAGE_OFFSET)
110#else
111	ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE,      _ASM_PTR __START_KERNEL_map)
112	/* Map the p2m table to a 512GB-aligned user address. */
113	ELFNOTE(Xen, XEN_ELFNOTE_INIT_P2M,       .quad PGDIR_SIZE)
114#endif
115	ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          _ASM_PTR startup_xen)
116	ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, _ASM_PTR hypercall_page)
117	ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .ascii "!writable_page_tables|pae_pgdir_above_4gb"; .asciz PVH_FEATURES_STR)
118	ELFNOTE(Xen, XEN_ELFNOTE_SUPPORTED_FEATURES, .long (PVH_FEATURES) |
119						(1 << XENFEAT_writable_page_tables) |
120						(1 << XENFEAT_dom0))
121	ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE,       .asciz "yes")
122	ELFNOTE(Xen, XEN_ELFNOTE_LOADER,         .asciz "generic")
123	ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,
124		.quad _PAGE_PRESENT; .quad _PAGE_PRESENT)
125	ELFNOTE(Xen, XEN_ELFNOTE_SUSPEND_CANCEL, .long 1)
126	ELFNOTE(Xen, XEN_ELFNOTE_MOD_START_PFN,  .long 1)
127	ELFNOTE(Xen, XEN_ELFNOTE_HV_START_LOW,   _ASM_PTR __HYPERVISOR_VIRT_START)
128	ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET,   _ASM_PTR 0)
129
130#endif /*CONFIG_XEN */
131