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linux-next/arch/x86/xen/xen-head.S
Boris Ostrovsky a5a18ae73b xen/pvh: Indicate XENFEAT_linux_rsdp_unrestricted to Xen
Pre-4.17 kernels ignored start_info's rsdp_paddr pointer and instead
relied on finding RSDP in standard location in BIOS RO memory. This
has worked since that's where Xen used to place it.

However, with recent Xen change (commit 4a5733771e6f ("libxl: put RSDP
for PVH guest near 4GB")) it prefers to keep RSDP at a "non-standard"
address. Even though as of commit b17d9d1df3 ("x86/xen: Add pvh
specific rsdp address retrieval function") Linux is able to find RSDP,
for back-compatibility reasons we need to indicate to Xen that we can
handle this, an we do so by setting XENFEAT_linux_rsdp_unrestricted
flag in ELF notes.

(Also take this opportunity and sync features.h header file with Xen)

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
2018-04-10 09:22:22 -04:00

105 lines
2.9 KiB
ArmAsm

/* 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>
#ifdef CONFIG_XEN_PV
__INIT
ENTRY(startup_xen)
UNWIND_HINT_EMPTY
cld
/* Clear .bss */
xor %eax,%eax
mov $__bss_start, %_ASM_DI
mov $__bss_stop, %_ASM_CX
sub %_ASM_DI, %_ASM_CX
shr $__ASM_SEL(2, 3), %_ASM_CX
rep __ASM_SIZE(stos)
mov %_ASM_SI, xen_start_info
mov $init_thread_union+THREAD_SIZE, %_ASM_SP
#ifdef CONFIG_X86_64
/* Set up %gs.
*
* The base of %gs always points to the bottom of the irqstack
* union. If the stack protector canary is enabled, it is
* located at %gs:40. Note that, on SMP, the boot cpu uses
* init data section till per cpu areas are set up.
*/
movl $MSR_GS_BASE,%ecx
movq $INIT_PER_CPU_VAR(irq_stack_union),%rax
cdq
wrmsr
#endif
jmp xen_start_kernel
END(startup_xen)
__FINIT
#endif
.pushsection .text
.balign PAGE_SIZE
ENTRY(hypercall_page)
.rept (PAGE_SIZE / 32)
UNWIND_HINT_EMPTY
.skip 32
.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
END(hypercall_page)
.popsection
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_X86_32
ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE, _ASM_PTR __PAGE_OFFSET)
#else
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))
#endif
#ifdef CONFIG_XEN_PV
ELFNOTE(Xen, XEN_ELFNOTE_ENTRY, _ASM_PTR startup_xen)
#endif
ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, _ASM_PTR hypercall_page)
ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,
.ascii "!writable_page_tables|pae_pgdir_above_4gb")
ELFNOTE(Xen, XEN_ELFNOTE_SUPPORTED_FEATURES,
.long (1 << XENFEAT_writable_page_tables) | \
(1 << XENFEAT_dom0) | \
(1 << XENFEAT_linux_rsdp_unrestricted))
ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE, .asciz "yes")
ELFNOTE(Xen, XEN_ELFNOTE_LOADER, .asciz "generic")
ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,
.quad _PAGE_PRESENT; .quad _PAGE_PRESENT)
ELFNOTE(Xen, XEN_ELFNOTE_SUSPEND_CANCEL, .long 1)
ELFNOTE(Xen, XEN_ELFNOTE_MOD_START_PFN, .long 1)
ELFNOTE(Xen, XEN_ELFNOTE_HV_START_LOW, _ASM_PTR __HYPERVISOR_VIRT_START)
ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET, _ASM_PTR 0)
#endif /*CONFIG_XEN */