arch/ia64/kernel/patch.c

   1 /*
   2  * Instruction-patching support.
   3  *
   4  * Copyright (C) 2003 Hewlett-Packard Co
   5  *      David Mosberger-Tang <davidm@hpl.hp.com>
   6  */
   7 #include <linux/init.h>
   8 #include <linux/string.h>
   9
  10 #include <asm/patch.h>
  11 #include <asm/processor.h>
  12 #include <asm/sections.h>
  13 #include <asm/system.h>
  14 #include <asm/unistd.h>
  15
  16 /*
  17  * This was adapted from code written by Tony Luck:
  18  *
  19  * The 64-bit value in a "movl reg=value" is scattered between the two words of the bundle
  20  * like this:
  21  *
  22  * 6  6         5         4         3         2         1
  23  * 3210987654321098765432109876543210987654321098765432109876543210
  24  * ABBBBBBBBBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCCCDEEEEEFFFFFFFFFGGGGGGG
  25  *
  26  * CCCCCCCCCCCCCCCCCCxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
  27  * xxxxAFFFFFFFFFEEEEEDxGGGGGGGxxxxxxxxxxxxxBBBBBBBBBBBBBBBBBBBBBBB
  28  */
  29 static u64
  30 get_imm64 (u64 insn_addr)
  31 {
  32         u64 *p = (u64 *) (insn_addr & -16);     /* mask out slot number */
  33
  34         return ( (p[1] & 0x0800000000000000UL) << 4)  | /*A*/
  35                 ((p[1] & 0x00000000007fffffUL) << 40) | /*B*/
  36                 ((p[0] & 0xffffc00000000000UL) >> 24) | /*C*/
  37                 ((p[1] & 0x0000100000000000UL) >> 23) | /*D*/
  38                 ((p[1] & 0x0003e00000000000UL) >> 29) | /*E*/
  39                 ((p[1] & 0x07fc000000000000UL) >> 43) | /*F*/
  40                 ((p[1] & 0x000007f000000000UL) >> 36);  /*G*/
  41 }
  42
  43 /* Patch instruction with "val" where "mask" has 1 bits. */
  44 void
  45 ia64_patch (u64 insn_addr, u64 mask, u64 val)
  46 {
  47         u64 m0, m1, v0, v1, b0, b1, *b = (u64 *) (insn_addr & -16);
  48 #       define insn_mask ((1UL << 41) - 1)
  49         unsigned long shift;
  50
  51         b0 = b[0]; b1 = b[1];
  52         shift = 5 + 41 * (insn_addr % 16); /* 5 bits of template, then 3 x 41-bit instructions */
  53         if (shift >= 64) {
  54                 m1 = mask << (shift - 64);
  55                 v1 = val << (shift - 64);
  56         } else {
  57                 m0 = mask << shift; m1 = mask >> (64 - shift);
  58                 v0 = val  << shift; v1 = val >> (64 - shift);
  59                 b[0] = (b0 & ~m0) | (v0 & m0);
  60         }
  61         b[1] = (b1 & ~m1) | (v1 & m1);
  62 }
  63
  64 void
  65 ia64_patch_imm64 (u64 insn_addr, u64 val)
  66 {
  67         /* The assembler may generate offset pointing to either slot 1
  68            or slot 2 for a long (2-slot) instruction, occupying slots 1
  69            and 2.  */
  70         insn_addr &= -16UL;
  71         ia64_patch(insn_addr + 2,
  72                    0x01fffefe000UL, (  ((val & 0x8000000000000000UL) >> 27) /* bit 63 -> 36 */
  73                                      | ((val & 0x0000000000200000UL) <<  0) /* bit 21 -> 21 */
  74                                      | ((val & 0x00000000001f0000UL) <<  6) /* bit 16 -> 22 */
  75                                      | ((val & 0x000000000000ff80UL) << 20) /* bit  7 -> 27 */
  76                                      | ((val & 0x000000000000007fUL) << 13) /* bit  0 -> 13 */));
  77         ia64_patch(insn_addr + 1, 0x1ffffffffffUL, val >> 22);
  78 }
  79
  80 void
  81 ia64_patch_imm60 (u64 insn_addr, u64 val)
  82 {
  83         /* The assembler may generate offset pointing to either slot 1
  84            or slot 2 for a long (2-slot) instruction, occupying slots 1
  85            and 2.  */
  86         insn_addr &= -16UL;
  87         ia64_patch(insn_addr + 2,
  88                    0x011ffffe000UL, (  ((val & 0x0800000000000000UL) >> 23) /* bit 59 -> 36 */
  89                                      | ((val & 0x00000000000fffffUL) << 13) /* bit  0 -> 13 */));
  90         ia64_patch(insn_addr + 1, 0x1fffffffffcUL, val >> 18);
  91 }
  92
  93 /*
  94  * We need sometimes to load the physical address of a kernel
  95  * object.  Often we can convert the virtual address to physical
  96  * at execution time, but sometimes (either for performance reasons
  97  * or during error recovery) we cannot to this.  Patch the marked
  98  * bundles to load the physical address.
  99  */
 100 void __init
 101 ia64_patch_vtop (unsigned long start, unsigned long end)
 102 {
 103         s32 *offp = (s32 *) start;
 104         u64 ip;
 105
 106         while (offp < (s32 *) end) {
 107                 ip = (u64) offp + *offp;
 108
 109                 /* replace virtual address with corresponding physical address: */
 110                 ia64_patch_imm64(ip, ia64_tpa(get_imm64(ip)));
 111                 ia64_fc((void *) ip);
 112                 ++offp;
 113         }
 114         ia64_sync_i();
 115         ia64_srlz_i();
 116 }
 117
 118 void __init
 119 ia64_patch_mckinley_e9 (unsigned long start, unsigned long end)
 120 {
 121         static int first_time = 1;
 122         int need_workaround;
 123         s32 *offp = (s32 *) start;
 124         u64 *wp;
 125
 126         need_workaround = (local_cpu_data->family == 0x1f && local_cpu_data->model == 0);
 127
 128         if (first_time) {
 129                 first_time = 0;
 130                 if (need_workaround)
 131                         printk(KERN_INFO "Leaving McKinley Errata 9 workaround enabled\n");
 132         }
 133         if (need_workaround)
 134                 return;
 135
 136         while (offp < (s32 *) end) {
 137                 wp = (u64 *) ia64_imva((char *) offp + *offp);
 138                 wp[0] = 0x0000000100000000UL; /* nop.m 0; nop.i 0; nop.i 0 */
 139                 wp[1] = 0x0004000000000200UL;
 140                 wp[2] = 0x0000000100000011UL; /* nop.m 0; nop.i 0; br.ret.sptk.many b6 */
 141                 wp[3] = 0x0084006880000200UL;
 142                 ia64_fc(wp); ia64_fc(wp + 2);
 143                 ++offp;
 144         }
 145         ia64_sync_i();
 146         ia64_srlz_i();
 147 }
 148
 149 static void __init
 150 patch_fsyscall_table (unsigned long start, unsigned long end)
 151 {
 152         extern unsigned long fsyscall_table[NR_syscalls];
 153         s32 *offp = (s32 *) start;
 154         u64 ip;
 155
 156         while (offp < (s32 *) end) {
 157                 ip = (u64) ia64_imva((char *) offp + *offp);
 158                 ia64_patch_imm64(ip, (u64) fsyscall_table);
 159                 ia64_fc((void *) ip);
 160                 ++offp;
 161         }
 162         ia64_sync_i();
 163         ia64_srlz_i();
 164 }
 165
 166 static void __init
 167 patch_brl_fsys_bubble_down (unsigned long start, unsigned long end)
 168 {
 169         extern char fsys_bubble_down[];
 170         s32 *offp = (s32 *) start;
 171         u64 ip;
 172
 173         while (offp < (s32 *) end) {
 174                 ip = (u64) offp + *offp;
 175                 ia64_patch_imm60((u64) ia64_imva((void *) ip),
 176                                  (u64) (fsys_bubble_down - (ip & -16)) / 16);
 177                 ia64_fc((void *) ip);
 178                 ++offp;
 179         }
 180         ia64_sync_i();
 181         ia64_srlz_i();
 182 }
 183
 184 void __init
 185 ia64_patch_gate (void)
 186 {
 187 #       define START(name)      ((unsigned long) __start_gate_##name##_patchlist)
 188 #       define END(name)        ((unsigned long)__end_gate_##name##_patchlist)
 189
 190         patch_fsyscall_table(START(fsyscall), END(fsyscall));
 191         patch_brl_fsys_bubble_down(START(brl_fsys_bubble_down), END(brl_fsys_bubble_down));
 192         ia64_patch_vtop(START(vtop), END(vtop));
 193         ia64_patch_mckinley_e9(START(mckinley_e9), END(mckinley_e9));
 194 }
 195
 196 void ia64_patch_phys_stack_reg(unsigned long val)
 197 {
 198         s32 * offp = (s32 *) __start___phys_stack_reg_patchlist;
 199         s32 * end = (s32 *) __end___phys_stack_reg_patchlist;
 200         u64 ip, mask, imm;
 201
 202         /* see instruction format A4: adds r1 = imm13, r3 */
 203         mask = (0x3fUL << 27) | (0x7f << 13);
 204         imm = (((val >> 7) & 0x3f) << 27) | (val & 0x7f) << 13;
 205
 206         while (offp < end) {
 207                 ip = (u64) offp + *offp;
 208                 ia64_patch(ip, mask, imm);
 209                 ia64_fc(ip);
 210                 ++offp;
 211         }
 212         ia64_sync_i();
 213         ia64_srlz_i();
 214 }