head-nommu.S 2.1 KB

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  1. /*
  2. * linux/arch/arm/kernel/head-nommu.S
  3. *
  4. * Copyright (C) 1994-2002 Russell King
  5. * Copyright (C) 2003-2006 Hyok S. Choi
  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. * Common kernel startup code (non-paged MM)
  12. * for 32-bit CPUs which has a process ID register(CP15).
  13. *
  14. */
  15. #include <linux/config.h>
  16. #include <linux/linkage.h>
  17. #include <linux/init.h>
  18. #include <asm/assembler.h>
  19. #include <asm/mach-types.h>
  20. #include <asm/procinfo.h>
  21. #include <asm/ptrace.h>
  22. #include <asm/constants.h>
  23. #include <asm/system.h>
  24. #define PROCINFO_INITFUNC 12
  25. /*
  26. * Kernel startup entry point.
  27. * ---------------------------
  28. *
  29. * This is normally called from the decompressor code. The requirements
  30. * are: MMU = off, D-cache = off, I-cache = dont care, r0 = 0,
  31. * r1 = machine nr.
  32. *
  33. * See linux/arch/arm/tools/mach-types for the complete list of machine
  34. * numbers for r1.
  35. *
  36. */
  37. __INIT
  38. .type stext, %function
  39. ENTRY(stext)
  40. msr cpsr_c, #PSR_F_BIT | PSR_I_BIT | MODE_SVC @ ensure svc mode
  41. @ and irqs disabled
  42. mrc p15, 0, r9, c0, c0 @ get processor id
  43. bl __lookup_processor_type @ r5=procinfo r9=cpuid
  44. movs r10, r5 @ invalid processor (r5=0)?
  45. beq __error_p @ yes, error 'p'
  46. bl __lookup_machine_type @ r5=machinfo
  47. movs r8, r5 @ invalid machine (r5=0)?
  48. beq __error_a @ yes, error 'a'
  49. ldr r13, __switch_data @ address to jump to after
  50. @ the initialization is done
  51. adr lr, __after_proc_init @ return (PIC) address
  52. add pc, r10, #PROCINFO_INITFUNC
  53. /*
  54. * Set the Control Register and Read the process ID.
  55. */
  56. .type __after_proc_init, %function
  57. __after_proc_init:
  58. mrc p15, 0, r0, c1, c0, 0 @ read control reg
  59. #ifdef CONFIG_ALIGNMENT_TRAP
  60. orr r0, r0, #CR_A
  61. #else
  62. bic r0, r0, #CR_A
  63. #endif
  64. #ifdef CONFIG_CPU_DCACHE_DISABLE
  65. bic r0, r0, #CR_C
  66. #endif
  67. #ifdef CONFIG_CPU_BPREDICT_DISABLE
  68. bic r0, r0, #CR_Z
  69. #endif
  70. #ifdef CONFIG_CPU_ICACHE_DISABLE
  71. bic r0, r0, #CR_I
  72. #endif
  73. mcr p15, 0, r0, c1, c0, 0 @ write control reg
  74. mov pc, r13 @ clear the BSS and jump
  75. @ to start_kernel
  76. #include "head-common.S"