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 <linux/init.h>
  12 #include <linux/linkage.h>
  13 #include <asm/thread_info.h>
  14 #include <asm/vfpmacros.h>
  15 #include <asm/assembler.h>
  16 #include <asm/asm-offsets.h>
  17
  18 @ VFP entry point.
  19 @
  20 @  r0  = instruction opcode (32-bit ARM or two 16-bit Thumb)
  21 @  r2  = PC value to resume execution after successful emulation
  22 @  r9  = normal "successful" return address
  23 @  r10 = this threads thread_info structure
  24 @  lr  = unrecognised instruction return address
  25 @  IRQs disabled.
  26 @
  27 ENTRY(do_vfp)
  28 #ifdef CONFIG_PREEMPT_COUNT
  29         ldr     r4, [r10, #TI_PREEMPT]  @ get preempt count
  30         add     r11, r4, #1             @ increment it
  31         str     r11, [r10, #TI_PREEMPT]
  32 #endif
  33         enable_irq
  34         ldr     r4, .LCvfp
  35         ldr     r11, [r10, #TI_CPU]     @ CPU number
  36         add     r10, r10, #TI_VFPSTATE  @ r10 = workspace
  37         ldr     pc, [r4]                @ call VFP entry point
  38 ENDPROC(do_vfp)
  39
  40 ENTRY(vfp_null_entry)
  41 #ifdef CONFIG_PREEMPT_COUNT
  42         get_thread_info r10
  43         ldr     r4, [r10, #TI_PREEMPT]  @ get preempt count
  44         sub     r11, r4, #1             @ decrement it
  45         str     r11, [r10, #TI_PREEMPT]
  46 #endif
  47         mov     pc, lr
  48 ENDPROC(vfp_null_entry)
  49
  50         .align  2
  51 .LCvfp:
  52         .word   vfp_vector
  53
  54 @ This code is called if the VFP does not exist. It needs to flag the
  55 @ failure to the VFP initialisation code.
  56
  57         __INIT
  58 ENTRY(vfp_testing_entry)
  59 #ifdef CONFIG_PREEMPT_COUNT
  60         get_thread_info r10
  61         ldr     r4, [r10, #TI_PREEMPT]  @ get preempt count
  62         sub     r11, r4, #1             @ decrement it
  63         str     r11, [r10, #TI_PREEMPT]
  64 #endif
  65         ldr     r0, VFP_arch_address
  66         str     r0, [r0]                @ set to non-zero value
  67         mov     pc, r9                  @ we have handled the fault
  68 ENDPROC(vfp_testing_entry)
  69
  70         .align  2
  71 VFP_arch_address:
  72         .word   VFP_arch
  73
  74         __FINIT