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336f560a89
A function called via the paravirt play_dead() hook should not return to the caller. xen_pv_play_dead() has a problem in this regard, as it currently will return in case an offlined cpu is brought to life again. This can be changed only by doing basically a longjmp() to cpu_bringup_and_idle(), as the hypercall for bringing down the cpu will just return when the cpu is coming up again. Just re-initializing the cpu isn't possible, as the Xen hypervisor will deny that operation. So introduce xen_cpu_bringup_again() resetting the stack and calling cpu_bringup_and_idle(), which can be called after HYPERVISOR_vcpu_op() in xen_pv_play_dead(). Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20221125063248.30256-2-jgross@suse.com Signed-off-by: Juergen Gross <jgross@suse.com>
120 lines
3.2 KiB
ArmAsm
120 lines
3.2 KiB
ArmAsm
/* 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 <asm/boot.h>
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#include <asm/asm.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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.pushsection .noinstr.text, "ax"
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.balign PAGE_SIZE
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SYM_CODE_START(hypercall_page)
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.rept (PAGE_SIZE / 32)
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UNWIND_HINT_FUNC
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ANNOTATE_NOENDBR
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ANNOTATE_UNRET_SAFE
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ret
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/*
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* Xen will write the hypercall page, and sort out ENDBR.
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*/
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.skip 31, 0xcc
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.endr
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#define HYPERCALL(n) \
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.equ xen_hypercall_##n, hypercall_page + __HYPERVISOR_##n * 32; \
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.type xen_hypercall_##n, @function; .size xen_hypercall_##n, 32
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#include <asm/xen-hypercalls.h>
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#undef HYPERCALL
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SYM_CODE_END(hypercall_page)
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.popsection
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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_EMPTY
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ANNOTATE_NOENDBR
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cld
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mov initial_stack(%rip), %rsp
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/* Set up %gs.
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*
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* The base of %gs always points to fixed_percpu_data. If the
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* stack protector canary is enabled, it is located at %gs:40.
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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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movq $INIT_PER_CPU_VAR(fixed_percpu_data),%rax
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cdq
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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_EMPTY
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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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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_X86_32
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ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE, _ASM_PTR __PAGE_OFFSET)
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#else
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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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#endif
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#ifdef CONFIG_XEN_PV
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ELFNOTE(Xen, XEN_ELFNOTE_ENTRY, _ASM_PTR startup_xen)
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#endif
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ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, _ASM_PTR hypercall_page)
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ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,
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.ascii "!writable_page_tables|pae_pgdir_above_4gb")
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ELFNOTE(Xen, XEN_ELFNOTE_SUPPORTED_FEATURES,
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.long (1 << XENFEAT_writable_page_tables) | \
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(1 << XENFEAT_dom0) | \
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(1 << XENFEAT_linux_rsdp_unrestricted))
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ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE, .asciz "yes")
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ELFNOTE(Xen, XEN_ELFNOTE_LOADER, .asciz "generic")
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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_SUSPEND_CANCEL, .long 1)
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ELFNOTE(Xen, XEN_ELFNOTE_MOD_START_PFN, .long 1)
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ELFNOTE(Xen, XEN_ELFNOTE_HV_START_LOW, _ASM_PTR __HYPERVISOR_VIRT_START)
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ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET, _ASM_PTR 0)
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#endif /*CONFIG_XEN */
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