root/arch/arm/vfp/entry.S

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  *  linux/arch/arm/vfp/entry.S
   4  *
   5  *  Copyright (C) 2004 ARM Limited.
   6  *  Written by Deep Blue Solutions Limited.
   7  */
   8 #include <linux/init.h>
   9 #include <linux/linkage.h>
  10 #include <asm/thread_info.h>
  11 #include <asm/vfpmacros.h>
  12 #include <asm/assembler.h>
  13 #include <asm/asm-offsets.h>
  14 
  15 @ VFP entry point.
  16 @
  17 @  r0  = instruction opcode (32-bit ARM or two 16-bit Thumb)
  18 @  r2  = PC value to resume execution after successful emulation
  19 @  r9  = normal "successful" return address
  20 @  r10 = this threads thread_info structure
  21 @  lr  = unrecognised instruction return address
  22 @  IRQs enabled.
  23 @
  24 ENTRY(do_vfp)
  25         inc_preempt_count r10, r4
  26         ldr     r4, .LCvfp
  27         ldr     r11, [r10, #TI_CPU]     @ CPU number
  28         add     r10, r10, #TI_VFPSTATE  @ r10 = workspace
  29         ldr     pc, [r4]                @ call VFP entry point
  30 ENDPROC(do_vfp)
  31 
  32 ENTRY(vfp_null_entry)
  33         dec_preempt_count_ti r10, r4
  34         ret     lr
  35 ENDPROC(vfp_null_entry)
  36 
  37         .align  2
  38 .LCvfp:
  39         .word   vfp_vector
  40 
  41 @ This code is called if the VFP does not exist. It needs to flag the
  42 @ failure to the VFP initialisation code.
  43 
  44         __INIT
  45 ENTRY(vfp_testing_entry)
  46         dec_preempt_count_ti r10, r4
  47         ldr     r0, VFP_arch_address
  48         str     r0, [r0]                @ set to non-zero value
  49         ret     r9                      @ we have handled the fault
  50 ENDPROC(vfp_testing_entry)
  51 
  52         .align  2
  53 VFP_arch_address:
  54         .word   VFP_arch
  55 
  56         __FINIT