linux/arch/x86/xen/xen-head.S
Jan Beulich 1cfd4ccb30 x86/Xen: tidy xen-head.S
First of all move PV-only ELF notes inside the XEN_PV conditional; note
that
- HV_START_LOW is dropped altogether, as it was meaningful for 32-bit PV
  only,
- the 32-bit instance of VIRT_BASE is dropped, as it would be dead code
  once inside the conditional,
- while PADDR_OFFSET is not exactly unused for PVH, it defaults to zero
  there, and the hypervisor (or tool stack) complains if it is present
  but VIRT_BASE isn't.
Then have the "supported features" note actually report reality: All
three of the features there are supported and/or applicable only in
certain cases.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/f99bacc6-2a2f-41b0-5c0b-e01b7051cb07@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
2023-07-04 06:57:38 +02:00

125 lines
3.3 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>
.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 */