b2502b418e
The 'system_call' entry points differ starkly between native 32-bit and 64-bit kernels: on 32-bit kernels it defines the INT 0x80 entry point, while on 64-bit it's the SYSCALL entry point. This is pretty confusing when looking at generic code, and it also obscures the nature of the entry point at the assembly level. So unangle this by splitting the name into its two uses: system_call (32) -> entry_INT80_32 system_call (64) -> entry_SYSCALL_64 As per the generic naming scheme for x86 system call entry points: entry_MNEMONIC_qualifier where 'qualifier' is one of _32, _64 or _compat. Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
146 lines
3.1 KiB
ArmAsm
146 lines
3.1 KiB
ArmAsm
/*
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* Asm versions of Xen pv-ops, suitable for either direct use or
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* inlining. The inline versions are the same as the direct-use
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* versions, with the pre- and post-amble chopped off.
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*
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* This code is encoded for size rather than absolute efficiency, with
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* a view to being able to inline as much as possible.
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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, since
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* they're generally too large to inline anyway.
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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 "xen-asm.h"
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ENTRY(xen_adjust_exception_frame)
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mov 8+0(%rsp), %rcx
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mov 8+8(%rsp), %r11
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ret $16
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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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1: jmp hypercall_iret
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ENDPATCH(xen_iret)
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RELOC(xen_iret, 1b+1)
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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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movq %rsp, PER_CPU_VAR(rsp_scratch)
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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(rsp_scratch)
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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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1: jmp hypercall_iret
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ENDPATCH(xen_sysret64)
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RELOC(xen_sysret64, 1b+1)
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ENTRY(xen_sysret32)
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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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movq %rsp, PER_CPU_VAR(rsp_scratch)
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movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
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pushq $__USER32_DS
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pushq PER_CPU_VAR(rsp_scratch)
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pushq %r11
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pushq $__USER32_CS
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pushq %rcx
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pushq $0
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1: jmp hypercall_iret
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ENDPATCH(xen_sysret32)
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RELOC(xen_sysret32, 1b+1)
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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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* In all the entrypoints, we undo all that to make it look like a
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* CPU-generated syscall/sysenter and jump to the normal entrypoint.
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*/
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.macro undo_xen_syscall
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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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.endm
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/* Normal 64-bit system call target */
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ENTRY(xen_syscall_target)
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undo_xen_syscall
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jmp entry_SYSCALL_64_after_swapgs
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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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undo_xen_syscall
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jmp entry_SYSCALL_compat
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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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undo_xen_syscall
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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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