1 /* SPDX-License-Identifier: GPL-2.0 */
4 * Copyright C 2016, Oracle and/or its affiliates. All rights reserved.
9 #define _pa(x) ((x) - __START_KERNEL_map)
11 #include <linux/elfnote.h>
12 #include <linux/init.h>
13 #include <linux/linkage.h>
14 #include <asm/segment.h>
17 #include <asm/processor-flags.h>
19 #include <asm/nospec-branch.h>
20 #include <xen/interface/elfnote.h>
25 * Entry point for PVH guests.
27 * Xen ABI specifies the following register state when we come here:
29 * - `ebx`: contains the physical memory address where the loader has placed
30 * the boot start info structure.
31 * - `cr0`: bit 0 (PE) must be set. All the other writeable bits are cleared.
32 * - `cr4`: all bits are cleared.
33 * - `cs `: must be a 32-bit read/execute code segment with a base of `0`
34 * and a limit of `0xFFFFFFFF`. The selector value is unspecified.
35 * - `ds`, `es`: must be a 32-bit read/write data segment with a base of
36 * `0` and a limit of `0xFFFFFFFF`. The selector values are all
38 * - `tr`: must be a 32-bit TSS (active) with a base of '0' and a limit
40 * - `eflags`: bit 17 (VM) must be cleared. Bit 9 (IF) must be cleared.
41 * Bit 8 (TF) must be cleared. Other bits are all unspecified.
43 * All other processor registers and flag bits are unspecified. The OS is in
44 * charge of setting up it's own stack, GDT and IDT.
47 #define PVH_GDT_ENTRY_CS 1
48 #define PVH_GDT_ENTRY_DS 2
49 #define PVH_CS_SEL (PVH_GDT_ENTRY_CS * 8)
50 #define PVH_DS_SEL (PVH_GDT_ENTRY_DS * 8)
52 SYM_CODE_START_LOCAL(pvh_start_xen)
53 UNWIND_HINT_END_OF_STACK
63 /* Stash hvm_start_info. */
64 mov $_pa(pvh_start_info), %edi
66 mov _pa(pvh_start_info_sz), %ecx
71 mov $_pa(early_stack_end), %esp
73 /* Enable PAE mode. */
75 orl $X86_CR4_PAE, %eax
79 /* Enable Long mode. */
85 /* Enable pre-constructed page tables. */
86 mov $_pa(init_top_pgt), %eax
88 mov $(X86_CR0_PG | X86_CR0_PE), %eax
91 /* Jump to 64-bit mode. */
92 ljmp $PVH_CS_SEL, $_pa(1f)
94 /* 64-bit entry point. */
97 /* Set base address in stack canary descriptor. */
99 mov $_pa(canary), %eax
105 /* startup_64 expects boot_params in %rsi. */
106 mov $_pa(pvh_bootparams), %rsi
107 mov $_pa(startup_64), %rax
108 ANNOTATE_RETPOLINE_SAFE
111 #else /* CONFIG_X86_64 */
113 call mk_early_pgtbl_32
115 mov $_pa(initial_page_table), %eax
119 or $(X86_CR0_PG | X86_CR0_PE), %eax
122 ljmp $PVH_CS_SEL, $1f
125 mov $_pa(pvh_bootparams), %esi
127 /* startup_32 doesn't expect paging and PAE to be on. */
128 ljmp $PVH_CS_SEL, $_pa(2f)
131 and $~X86_CR0_PG, %eax
134 and $~X86_CR4_PAE, %eax
137 ljmp $PVH_CS_SEL, $_pa(startup_32)
139 SYM_CODE_END(pvh_start_xen)
141 .section ".init.data","aw"
143 SYM_DATA_START_LOCAL(gdt)
144 .word gdt_end - gdt_start
148 SYM_DATA_START_LOCAL(gdt_start)
149 .quad 0x0000000000000000 /* NULL descriptor */
151 .quad GDT_ENTRY(0xa09a, 0, 0xfffff) /* PVH_CS_SEL */
153 .quad GDT_ENTRY(0xc09a, 0, 0xfffff) /* PVH_CS_SEL */
155 .quad GDT_ENTRY(0xc092, 0, 0xfffff) /* PVH_DS_SEL */
156 SYM_DATA_END_LABEL(gdt_start, SYM_L_LOCAL, gdt_end)
159 SYM_DATA_LOCAL(canary, .fill 48, 1, 0)
161 SYM_DATA_START_LOCAL(early_stack)
162 .fill BOOT_STACK_SIZE, 1, 0
163 SYM_DATA_END_LABEL(early_stack, SYM_L_LOCAL, early_stack_end)
165 ELFNOTE(Xen, XEN_ELFNOTE_PHYS32_ENTRY,
166 _ASM_PTR (pvh_start_xen - __START_KERNEL_map))