root/arch/arm/kvm/interrupts.S

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2012 - Virtual Open Systems and Columbia University
   4  * Author: Christoffer Dall <c.dall@virtualopensystems.com>
   5  */
   6 
   7 #include <linux/linkage.h>
   8 
   9         .text
  10 
  11 /********************************************************************
  12  *  Call function in Hyp mode
  13  *
  14  *
  15  * unsigned long kvm_call_hyp(void *hypfn, ...);
  16  *
  17  * This is not really a variadic function in the classic C-way and care must
  18  * be taken when calling this to ensure parameters are passed in registers
  19  * only, since the stack will change between the caller and the callee.
  20  *
  21  * Call the function with the first argument containing a pointer to the
  22  * function you wish to call in Hyp mode, and subsequent arguments will be
  23  * passed as r0, r1, and r2 (a maximum of 3 arguments in addition to the
  24  * function pointer can be passed).  The function being called must be mapped
  25  * in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c).  Return values are
  26  * passed in r0 (strictly 32bit).
  27  *
  28  * The calling convention follows the standard AAPCS:
  29  *   r0 - r3: caller save
  30  *   r12:     caller save
  31  *   rest:    callee save
  32  */
  33 ENTRY(__kvm_call_hyp)
  34         hvc     #0
  35         bx      lr
  36 ENDPROC(__kvm_call_hyp)