arch/x86/xen/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
  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
  25 SYM_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
  42 SYM_CODE_END(hypercall_page)
  43 .popsection
  44
  45 #ifdef CONFIG_XEN_PV
  46         __INIT
  47 SYM_CODE_START(startup_xen)
  48         UNWIND_HINT_END_OF_STACK
  49         ANNOTATE_NOENDBR
  50         cld
  51
  52         leaq    __top_init_kernel_stack(%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
  68 SYM_CODE_END(startup_xen)
  69         __FINIT
  70
  71 #ifdef CONFIG_XEN_PV_SMP
  72 .pushsection .text
  73 SYM_CODE_START(asm_cpu_bringup_and_idle)
  74         UNWIND_HINT_END_OF_STACK
  75         ENDBR
  76
  77         call cpu_bringup_and_idle
  78 SYM_CODE_END(asm_cpu_bringup_and_idle)
  79
  80 SYM_CODE_START(xen_cpu_bringup_again)
  81         UNWIND_HINT_FUNC
  82         mov     %rdi, %rsp
  83         UNWIND_HINT_REGS
  84         call    cpu_bringup_and_idle
  85 SYM_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,          .globl xen_elfnote_entry;
  98                 xen_elfnote_entry: _ASM_PTR xen_elfnote_entry_value - .)
  99         ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .ascii "!writable_page_tables")
 100         ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE,       .asciz "yes")
 101         ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,
 102                 .quad _PAGE_PRESENT; .quad _PAGE_PRESENT)
 103         ELFNOTE(Xen, XEN_ELFNOTE_MOD_START_PFN,  .long 1)
 104         ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET,   _ASM_PTR 0)
 105 # define FEATURES_PV (1 << XENFEAT_writable_page_tables)
 106 #else
 107 # define FEATURES_PV 0
 108 #endif
 109 #ifdef CONFIG_XEN_PVH
 110 # define FEATURES_PVH (1 << XENFEAT_linux_rsdp_unrestricted)
 111 #else
 112 # define FEATURES_PVH 0
 113 #endif
 114 #ifdef CONFIG_XEN_DOM0
 115 # define FEATURES_DOM0 (1 << XENFEAT_dom0)
 116 #else
 117 # define FEATURES_DOM0 0
 118 #endif
 119         ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, .globl xen_elfnote_hypercall_page;
 120                 xen_elfnote_hypercall_page: _ASM_PTR xen_elfnote_hypercall_page_value - .)
 121         ELFNOTE(Xen, XEN_ELFNOTE_SUPPORTED_FEATURES,
 122                 .long FEATURES_PV | FEATURES_PVH | FEATURES_DOM0)
 123         ELFNOTE(Xen, XEN_ELFNOTE_LOADER,         .asciz "generic")
 124         ELFNOTE(Xen, XEN_ELFNOTE_SUSPEND_CANCEL, .long 1)
 125
 126 #endif /*CONFIG_XEN */