1 files changed, 124 insertions, 0 deletions
diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
new file mode 100644
index 0000000000..a0ea285878
--- /dev/null
+++ b/arch/x86/xen/xen-head.S
@@ -0,0 +1,124 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Xen-specific pieces of head.S, intended to be included in the right
+	place in head.S */
+
+#ifdef CONFIG_XEN
+
+#include <linux/elfnote.h>
+#include <linux/init.h>
+
+#include <asm/boot.h>
+#include <asm/asm.h>
+#include <asm/msr.h>
+#include <asm/page_types.h>
+#include <asm/percpu.h>
+#include <asm/unwind_hints.h>
+
+#include <xen/interface/elfnote.h>
+#include <xen/interface/features.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/xen-mca.h>
+#include <asm/xen/interface.h>
+
+.pushsection .noinstr.text, "ax"
+	.balign PAGE_SIZE
+SYM_CODE_START(hypercall_page)
+	.rept (PAGE_SIZE / 32)
+		UNWIND_HINT_FUNC
+		ANNOTATE_NOENDBR
+		ANNOTATE_UNRET_SAFE
+		ret
+		/*
+		 * Xen will write the hypercall page, and sort out ENDBR.
+		 */
+		.skip 31, 0xcc
+	.endr
+
+#define HYPERCALL(n) \
+	.equ xen_hypercall_##n, hypercall_page + __HYPERVISOR_##n * 32; \
+	.type xen_hypercall_##n, @function; .size xen_hypercall_##n, 32
+#include <asm/xen-hypercalls.h>
+#undef HYPERCALL
+SYM_CODE_END(hypercall_page)
+.popsection
+
+#ifdef CONFIG_XEN_PV
+	__INIT
+SYM_CODE_START(startup_xen)
+	UNWIND_HINT_END_OF_STACK
+	ANNOTATE_NOENDBR
+	cld
+
+	leaq	(__end_init_task - PTREGS_SIZE)(%rip), %rsp
+
+	/* Set up %gs.
+	 *
+	 * The base of %gs always points to fixed_percpu_data.  If the
+	 * stack protector canary is enabled, it is located at %gs:40.
+	 * Note that, on SMP, the boot cpu uses init data section until
+	 * the per cpu areas are set up.
+	 */
+	movl	$MSR_GS_BASE,%ecx
+	movq	$INIT_PER_CPU_VAR(fixed_percpu_data),%rax
+	cdq
+	wrmsr
+
+	mov	%rsi, %rdi
+	call xen_start_kernel
+SYM_CODE_END(startup_xen)
+	__FINIT
+
+#ifdef CONFIG_XEN_PV_SMP
+.pushsection .text
+SYM_CODE_START(asm_cpu_bringup_and_idle)
+	UNWIND_HINT_END_OF_STACK
+	ENDBR
+
+	call cpu_bringup_and_idle
+SYM_CODE_END(asm_cpu_bringup_and_idle)
+
+SYM_CODE_START(xen_cpu_bringup_again)
+	UNWIND_HINT_FUNC
+	mov	%rdi, %rsp
+	UNWIND_HINT_REGS
+	call	cpu_bringup_and_idle
+SYM_CODE_END(xen_cpu_bringup_again)
+.popsection
+#endif
+#endif
+
+	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS,       .asciz "linux")
+	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION,  .asciz "2.6")
+	ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION,    .asciz "xen-3.0")
+#ifdef CONFIG_XEN_PV
+	ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE,      _ASM_PTR __START_KERNEL_map)
+	/* Map the p2m table to a 512GB-aligned user address. */
+	ELFNOTE(Xen, XEN_ELFNOTE_INIT_P2M,       .quad (PUD_SIZE * PTRS_PER_PUD))
+	ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          _ASM_PTR startup_xen)
+	ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .ascii "!writable_page_tables")
+	ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE,       .asciz "yes")
+	ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,
+		.quad _PAGE_PRESENT; .quad _PAGE_PRESENT)
+	ELFNOTE(Xen, XEN_ELFNOTE_MOD_START_PFN,  .long 1)
+	ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET,   _ASM_PTR 0)
+# define FEATURES_PV (1 << XENFEAT_writable_page_tables)
+#else
+# define FEATURES_PV 0
+#endif
+#ifdef CONFIG_XEN_PVH
+# define FEATURES_PVH (1 << XENFEAT_linux_rsdp_unrestricted)
+#else
+# define FEATURES_PVH 0
+#endif
+#ifdef CONFIG_XEN_DOM0
+# define FEATURES_DOM0 (1 << XENFEAT_dom0)
+#else
+# define FEATURES_DOM0 0
+#endif
+	ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, _ASM_PTR hypercall_page)
+	ELFNOTE(Xen, XEN_ELFNOTE_SUPPORTED_FEATURES,
+		.long FEATURES_PV | FEATURES_PVH | FEATURES_DOM0)
+	ELFNOTE(Xen, XEN_ELFNOTE_LOADER,         .asciz "generic")
+	ELFNOTE(Xen, XEN_ELFNOTE_SUSPEND_CANCEL, .long 1)
+
+#endif /*CONFIG_XEN */