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98f05b5138
In the non-trampoline SYSCALL64 path, a percpu variable is used to temporarily store the user RSP value. Instead of a separate variable, use the otherwise unused sp2 slot in the TSS. This will improve cache locality, as the sp1 slot is already used in the same code to find the kernel stack. It will also simplify a future change to make the non-trampoline path work in PTI mode. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lkml.kernel.org/r/08e769a0023dbad4bac6f34f3631dbaf8ad59f4f.1536015544.git.luto@kernel.org
179 lines
3.8 KiB
ArmAsm
179 lines
3.8 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Asm versions of Xen pv-ops, suitable for direct use.
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*
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* We only bother with direct forms (ie, vcpu in pda) of the
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* operations here; the indirect forms are better handled in C.
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*/
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#include <asm/errno.h>
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#include <asm/percpu.h>
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#include <asm/processor-flags.h>
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#include <asm/segment.h>
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#include <asm/asm-offsets.h>
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#include <asm/thread_info.h>
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#include <xen/interface/xen.h>
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#include <linux/init.h>
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#include <linux/linkage.h>
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.macro xen_pv_trap name
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ENTRY(xen_\name)
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pop %rcx
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pop %r11
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jmp \name
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END(xen_\name)
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.endm
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xen_pv_trap divide_error
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xen_pv_trap debug
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xen_pv_trap xendebug
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xen_pv_trap int3
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xen_pv_trap xenint3
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xen_pv_trap xennmi
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xen_pv_trap overflow
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xen_pv_trap bounds
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xen_pv_trap invalid_op
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xen_pv_trap device_not_available
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xen_pv_trap double_fault
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xen_pv_trap coprocessor_segment_overrun
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xen_pv_trap invalid_TSS
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xen_pv_trap segment_not_present
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xen_pv_trap stack_segment
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xen_pv_trap general_protection
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xen_pv_trap page_fault
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xen_pv_trap spurious_interrupt_bug
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xen_pv_trap coprocessor_error
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xen_pv_trap alignment_check
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#ifdef CONFIG_X86_MCE
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xen_pv_trap machine_check
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#endif /* CONFIG_X86_MCE */
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xen_pv_trap simd_coprocessor_error
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#ifdef CONFIG_IA32_EMULATION
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xen_pv_trap entry_INT80_compat
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#endif
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xen_pv_trap hypervisor_callback
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__INIT
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ENTRY(xen_early_idt_handler_array)
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i = 0
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.rept NUM_EXCEPTION_VECTORS
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pop %rcx
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pop %r11
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jmp early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE
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i = i + 1
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.fill xen_early_idt_handler_array + i*XEN_EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc
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.endr
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END(xen_early_idt_handler_array)
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__FINIT
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hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32
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/*
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* Xen64 iret frame:
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*
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* ss
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* rsp
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* rflags
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* cs
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* rip <-- standard iret frame
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*
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* flags
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*
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* rcx }
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* r11 }<-- pushed by hypercall page
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* rsp->rax }
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*/
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ENTRY(xen_iret)
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pushq $0
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jmp hypercall_iret
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ENTRY(xen_sysret64)
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/*
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* We're already on the usermode stack at this point, but
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* still with the kernel gs, so we can easily switch back.
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*
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* tss.sp2 is scratch space.
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*/
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movq %rsp, PER_CPU_VAR(cpu_tss_rw + TSS_sp2)
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movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
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pushq $__USER_DS
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pushq PER_CPU_VAR(cpu_tss_rw + TSS_sp2)
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pushq %r11
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pushq $__USER_CS
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pushq %rcx
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pushq $VGCF_in_syscall
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jmp hypercall_iret
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/*
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* Xen handles syscall callbacks much like ordinary exceptions, which
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* means we have:
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* - kernel gs
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* - kernel rsp
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* - an iret-like stack frame on the stack (including rcx and r11):
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* ss
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* rsp
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* rflags
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* cs
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* rip
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* r11
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* rsp->rcx
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*/
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/* Normal 64-bit system call target */
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ENTRY(xen_syscall_target)
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popq %rcx
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popq %r11
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/*
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* Neither Xen nor the kernel really knows what the old SS and
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* CS were. The kernel expects __USER_DS and __USER_CS, so
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* report those values even though Xen will guess its own values.
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*/
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movq $__USER_DS, 4*8(%rsp)
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movq $__USER_CS, 1*8(%rsp)
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jmp entry_SYSCALL_64_after_hwframe
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ENDPROC(xen_syscall_target)
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#ifdef CONFIG_IA32_EMULATION
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/* 32-bit compat syscall target */
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ENTRY(xen_syscall32_target)
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popq %rcx
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popq %r11
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/*
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* Neither Xen nor the kernel really knows what the old SS and
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* CS were. The kernel expects __USER32_DS and __USER32_CS, so
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* report those values even though Xen will guess its own values.
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*/
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movq $__USER32_DS, 4*8(%rsp)
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movq $__USER32_CS, 1*8(%rsp)
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jmp entry_SYSCALL_compat_after_hwframe
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ENDPROC(xen_syscall32_target)
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/* 32-bit compat sysenter target */
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ENTRY(xen_sysenter_target)
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mov 0*8(%rsp), %rcx
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mov 1*8(%rsp), %r11
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mov 5*8(%rsp), %rsp
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jmp entry_SYSENTER_compat
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ENDPROC(xen_sysenter_target)
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#else /* !CONFIG_IA32_EMULATION */
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ENTRY(xen_syscall32_target)
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ENTRY(xen_sysenter_target)
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lea 16(%rsp), %rsp /* strip %rcx, %r11 */
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mov $-ENOSYS, %rax
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pushq $0
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jmp hypercall_iret
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ENDPROC(xen_syscall32_target)
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ENDPROC(xen_sysenter_target)
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#endif /* CONFIG_IA32_EMULATION */
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