arch/arm/vfp/entry.S

   1 /*
   2  *  linux/arch/arm/vfp/entry.S
   3  *
   4  *  Copyright (C) 2004 ARM Limited.
   5  *  Written by Deep Blue Solutions Limited.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <asm/thread_info.h>
  12 #include <asm/vfpmacros.h>
  13 #include "../kernel/entry-header.S"
  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 disabled.
  23 @
  24 ENTRY(do_vfp)
  25 #ifdef CONFIG_PREEMPT
  26         ldr     r4, [r10, #TI_PREEMPT]  @ get preempt count
  27         add     r11, r4, #1             @ increment it
  28         str     r11, [r10, #TI_PREEMPT]
  29 #endif
  30         enable_irq
  31         ldr     r4, .LCvfp
  32         ldr     r11, [r10, #TI_CPU]     @ CPU number
  33         add     r10, r10, #TI_VFPSTATE  @ r10 = workspace
  34         ldr     pc, [r4]                @ call VFP entry point
  35 ENDPROC(do_vfp)
  36
  37 ENTRY(vfp_null_entry)
  38 #ifdef CONFIG_PREEMPT
  39         get_thread_info r10
  40         ldr     r4, [r10, #TI_PREEMPT]  @ get preempt count
  41         sub     r11, r4, #1             @ decrement it
  42         str     r11, [r10, #TI_PREEMPT]
  43 #endif
  44         mov     pc, lr
  45 ENDPROC(vfp_null_entry)
  46
  47         .align  2
  48 .LCvfp:
  49         .word   vfp_vector
  50
  51 @ This code is called if the VFP does not exist. It needs to flag the
  52 @ failure to the VFP initialisation code.
  53
  54         __INIT
  55 ENTRY(vfp_testing_entry)
  56 #ifdef CONFIG_PREEMPT
  57         get_thread_info r10
  58         ldr     r4, [r10, #TI_PREEMPT]  @ get preempt count
  59         sub     r11, r4, #1             @ decrement it
  60         str     r11, [r10, #TI_PREEMPT]
  61 #endif
  62         ldr     r0, VFP_arch_address
  63         str     r5, [r0]                @ known non-zero value
  64         mov     pc, r9                  @ we have handled the fault
  65 ENDPROC(vfp_testing_entry)
  66
  67         .align  2
  68 VFP_arch_address:
  69         .word   VFP_arch
  70
  71         __FINIT