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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/x86/xen/xen-head.S
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/* SPDX-License-Identifier: GPL-2.0 */

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/* Xen-specific pieces of head.S, intended to be included in the right

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	place in head.S */

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#ifdef CONFIG_XEN

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#include <linux/elfnote.h>

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#include <linux/init.h>

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#include <linux/instrumentation.h>

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#include <asm/boot.h>

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#include <asm/asm.h>

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#include <asm/frame.h>

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#include <asm/msr.h>

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#include <asm/page_types.h>

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#include <asm/percpu.h>

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#include <asm/unwind_hints.h>

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#include <xen/interface/elfnote.h>

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#include <xen/interface/features.h>

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#include <xen/interface/xen.h>

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#include <xen/interface/xen-mca.h>

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#include <asm/xen/interface.h>

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#ifdef CONFIG_XEN_PV

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	__INIT

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SYM_CODE_START(startup_xen)

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	UNWIND_HINT_END_OF_STACK

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	ANNOTATE_NOENDBR

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	cld

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	leaq	__top_init_kernel_stack(%rip), %rsp

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	/*

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	 * Set up GSBASE.

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	 * Note that, on SMP, the boot cpu uses init data section until

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	 * the per cpu areas are set up.

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	 */

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	movl	$MSR_GS_BASE,%ecx

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	xorl	%eax, %eax

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	xorl	%edx, %edx

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	wrmsr

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	mov	%rsi, %rdi

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	call xen_start_kernel

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SYM_CODE_END(startup_xen)

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	__FINIT

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#ifdef CONFIG_XEN_PV_SMP

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.pushsection .text

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SYM_CODE_START(asm_cpu_bringup_and_idle)

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	UNWIND_HINT_END_OF_STACK

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	ENDBR

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	call cpu_bringup_and_idle

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SYM_CODE_END(asm_cpu_bringup_and_idle)

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SYM_CODE_START(xen_cpu_bringup_again)

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	UNWIND_HINT_FUNC

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	mov	%rdi, %rsp

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	UNWIND_HINT_REGS

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	call	cpu_bringup_and_idle

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SYM_CODE_END(xen_cpu_bringup_again)

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.popsection

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#endif

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#endif

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	.pushsection .noinstr.text, "ax"

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/*

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 * Xen hypercall interface to the hypervisor.

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 *

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 * Input:

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 *     %eax: hypercall number

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 *   32-bit:

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 *     %ebx, %ecx, %edx, %esi, %edi: args 1..5 for the hypercall

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 *   64-bit:

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 *     %rdi, %rsi, %rdx, %r10, %r8: args 1..5 for the hypercall

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 * Output: %[er]ax

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 */

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SYM_FUNC_START(xen_hypercall_hvm)

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	ENDBR

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	FRAME_BEGIN

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	/* Save all relevant registers (caller save and arguments). */

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#ifdef CONFIG_X86_32

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	push %eax

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	push %ebx

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	push %ecx

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	push %edx

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	push %esi

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	push %edi

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#else

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	push %rax

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	push %rcx

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	push %rdx

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	push %rdi

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	push %rsi

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	push %r11

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	push %r10

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	push %r9

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	push %r8

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#endif

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	/* Set the vendor specific function. */

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	call __xen_hypercall_setfunc

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	/* Set ZF = 1 if AMD, Restore saved registers. */

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#ifdef CONFIG_X86_32

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	lea xen_hypercall_amd, %ebx

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	cmp %eax, %ebx

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	pop %edi

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	pop %esi

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	pop %edx

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	pop %ecx

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	pop %ebx

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	pop %eax

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#else

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	lea xen_hypercall_amd(%rip), %rcx

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	cmp %rax, %rcx

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	pop %r8

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	pop %r9

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	pop %r10

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	pop %r11

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	pop %rsi

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	pop %rdi

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	pop %rdx

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	pop %rcx

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	pop %rax

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#endif

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	FRAME_END

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	/* Use correct hypercall function. */

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	jz xen_hypercall_amd

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	jmp xen_hypercall_intel

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SYM_FUNC_END(xen_hypercall_hvm)

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SYM_FUNC_START(xen_hypercall_amd)

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	ANNOTATE_NOENDBR

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	vmmcall

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	RET

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SYM_FUNC_END(xen_hypercall_amd)

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SYM_FUNC_START(xen_hypercall_intel)

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	ANNOTATE_NOENDBR

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	vmcall

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	RET

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SYM_FUNC_END(xen_hypercall_intel)

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	.popsection

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	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS,       .asciz "linux")

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	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION,  .asciz "2.6")

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	ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION,    .asciz "xen-3.0")

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#ifdef CONFIG_XEN_PV

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	ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE,      _ASM_PTR __START_KERNEL_map)

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	/* Map the p2m table to a 512GB-aligned user address. */

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	ELFNOTE(Xen, XEN_ELFNOTE_INIT_P2M,       .quad (PUD_SIZE * PTRS_PER_PUD))

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	ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          .globl xen_elfnote_entry;

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		xen_elfnote_entry: _ASM_PTR xen_elfnote_entry_value - .)

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	ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .ascii "!writable_page_tables")

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	ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE,       .asciz "yes")

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	ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,

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		.quad _PAGE_PRESENT; .quad _PAGE_PRESENT)

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	ELFNOTE(Xen, XEN_ELFNOTE_MOD_START_PFN,  .long 1)

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	ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET,   _ASM_PTR 0)

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# define FEATURES_PV (1 << XENFEAT_writable_page_tables)

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#else

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# define FEATURES_PV 0

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#endif

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#ifdef CONFIG_XEN_PVH

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# define FEATURES_PVH (1 << XENFEAT_linux_rsdp_unrestricted)

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#else

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# define FEATURES_PVH 0

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#endif

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#ifdef CONFIG_XEN_DOM0

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# define FEATURES_DOM0 (1 << XENFEAT_dom0)

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#else

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# define FEATURES_DOM0 0

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#endif

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	ELFNOTE(Xen, XEN_ELFNOTE_SUPPORTED_FEATURES,

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		.long FEATURES_PV | FEATURES_PVH | FEATURES_DOM0)

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	ELFNOTE(Xen, XEN_ELFNOTE_LOADER,         .asciz "generic")

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	ELFNOTE(Xen, XEN_ELFNOTE_SUSPEND_CANCEL, .long 1)

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#endif /*CONFIG_XEN */

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