kernel/fiasco/src/kern/arm/kern_lib_page.cpp

   1 INTERFACE [arm]:
   2
   3 class Kern_lib_page
   4 {
   5 public:
   6   static void init();
   7 };
   8
   9
  10 //---------------------------------------------------------------------------
  11 IMPLEMENTATION [arm]:
  12
  13 #include <panic.h>
  14
  15 #include "kmem_alloc.h"
  16 #include "kmem_space.h"
  17 #include "ram_quota.h"
  18 #include "paging.h"
  19
  20 IMPLEMENT
  21 void Kern_lib_page::init()
  22 {
  23   extern char kern_lib_start;
  24   auto pte = Kmem_space::kdir()->walk(Virt_addr(Kmem_space::Kern_lib_base),
  25       Pdir::Depth, true,
  26       Kmem_alloc::q_allocator(Ram_quota::root));
  27
  28   if (pte.level == 0) // allocation of second level faild
  29     panic("FATAL: Error mapping kernel-lib page to %p\n",
  30           (void *)Kmem_space::Kern_lib_base);
  31
  32   pte.create_page(Phys_mem_addr((Address)&kern_lib_start - Mem_layout::Map_base
  33           + Mem_layout::Sdram_phys_base), Page::Attr(Page::Rights::URX(), Page::Type::Normal(), Page::Kern::Global()));
  34   pte.write_back_if(true, Mem_unit::Asid_kernel);
  35 }
  36
  37 //---------------------------------------------------------------------------
  38 IMPLEMENTATION [arm && !armv6plus]:
  39
  40 asm (
  41     ".p2align(12)                        \n"
  42     "kern_lib_start:                     \n"
  43
  44     // atomic add
  45     // r0: memory reference
  46     // r1: delta value
  47     "  ldr r2, [r0]                      \n"
  48     "  add r2, r2, r1                    \n"
  49     "  nop                               \n"
  50     "  str r2, [r0]                      \n"
  51     // forward point
  52     "  mov r0, r2                        \n"
  53     "  mov pc, lr                        \n"
  54     // return: always succeeds, new value
  55
  56     // compare exchange
  57     // r0: memory reference
  58     // r1: cmp value
  59     // r2: new value
  60     // r3: tmp
  61     ".p2align(8)                         \n"
  62     "  ldr r3, [r0]                      \n"
  63     "  cmp r3, r1                        \n"
  64     "  nop                               \n"
  65     "  streq r2, [r0]                    \n"
  66     // forward point
  67     "  moveq r0, #1                      \n"
  68     "  movne r0, #0                      \n"
  69     "  mov pc, lr                        \n"
  70     // return result: 1 success, 0 failure
  71
  72     // exchange
  73     //  in-r0: memory reference
  74     //  in-r1: new value
  75     // out-r0: old value
  76     // tmp-r2
  77     ".p2align(8)                         \n"
  78     "  ldr r2, [r0]                      \n"
  79     "  nop                               \n"
  80     "  nop                               \n"
  81     "  str r1, [r0]                      \n"
  82     // forward point
  83     "  mov r0, r2                        \n"
  84     "  mov pc, lr                        \n"
  85     // return: always succeeds, old value
  86     );
  87
  88 //---------------------------------------------------------------------------
  89 IMPLEMENTATION [arm && armv6plus]:
  90
  91 asm (
  92     ".p2align(12)                        \n"
  93     ".global kern_lib_start              \n" // need this for mem_space.cpp
  94     "kern_lib_start:                     \n"
  95
  96     // no restart through kernel entry code
  97
  98     // atomic add
  99     // r0: memory reference
 100     // r1: delta value
 101     // r2: temp register
 102     // r3: temp register
 103     " 1:                                 \n"
 104     " ldrex r2, [r0]                     \n"
 105     " add   r2, r2, r1                   \n"
 106     " strex r3, r2, [r0]                 \n"
 107     " teq r3, #0                         \n"
 108     " bne 1b                             \n"
 109     " mov r0, r2                         \n"
 110     " mov pc, lr                         \n"
 111     // return: always succeeds, new value
 112
 113
 114     // compare exchange
 115     // r0: memory reference
 116     // r1: cmp value
 117     // r2: new value
 118     // r3: tmp reg
 119     ".p2align(8)                         \n"
 120     "  1: ldrex r3, [r0]                 \n"
 121     "  cmp r3, r1                        \n"
 122     "  movne r0, #0                      \n"
 123     "  movne pc, lr                      \n"
 124     "  strex r3, r2, [r0]                \n"
 125     "  teq r3, #0                        \n"
 126     "  bne 1b                            \n"
 127     "  mov r0, #1                        \n"
 128     "  mov pc, lr                        \n"
 129     // return result: 1 success, 0 failure
 130
 131
 132     // exchange
 133     //  in-r0: memory reference
 134     //  in-r1: new value
 135     // out-r0: old value
 136     ".p2align(8)                         \n"
 137     "  1:                                \n"
 138     "  ldrex r2, [r0]                    \n"
 139     "  strex r3, r1, [r0]                \n"
 140     "  cmp r3, #0                        \n"
 141     "  bne 1b                            \n"
 142     "  mov r0, r2                        \n"
 143     "  mov pc, lr                        \n"
 144     // return: always succeeds, old value
 145     );