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/paravirt.h>
  11 #include <asm/patch.h>
  12 #include <asm/processor.h>
  13 #include <asm/sections.h>
  14 #include <asm/system.h>
  15 #include <asm/unistd.h>
  16
  17 /*
  18  * This was adapted from code written by Tony Luck:
  19  *
  20  * The 64-bit value in a "movl reg=value" is scattered between the two words of the bundle
  21  * like this:
  22  *
  23  * 6  6         5         4         3         2         1
  24  * 3210987654321098765432109876543210987654321098765432109876543210
  25  * ABBBBBBBBBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCCCDEEEEEFFFFFFFFFGGGGGGG
  26  *
  27  * CCCCCCCCCCCCCCCCCCxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
  28  * xxxxAFFFFFFFFFEEEEEDxGGGGGGGxxxxxxxxxxxxxBBBBBBBBBBBBBBBBBBBBBBB
  29  */
  30 static u64
  31 get_imm64 (u64 insn_addr)
  32 {
  33         u64 *p = (u64 *) (insn_addr & -16);     /* mask out slot number */
  34
  35         return ( (p[1] & 0x0800000000000000UL) << 4)  | /*A*/
  36                 ((p[1] & 0x00000000007fffffUL) << 40) | /*B*/
  37                 ((p[0] & 0xffffc00000000000UL) >> 24) | /*C*/
  38                 ((p[1] & 0x0000100000000000UL) >> 23) | /*D*/
  39                 ((p[1] & 0x0003e00000000000UL) >> 29) | /*E*/
  40                 ((p[1] & 0x07fc000000000000UL) >> 43) | /*F*/
  41                 ((p[1] & 0x000007f000000000UL) >> 36);  /*G*/
  42 }
  43
  44 /* Patch instruction with "val" where "mask" has 1 bits. */
  45 void
  46 ia64_patch (u64 insn_addr, u64 mask, u64 val)
  47 {
  48         u64 m0, m1, v0, v1, b0, b1, *b = (u64 *) (insn_addr & -16);
  49 #       define insn_mask ((1UL << 41) - 1)
  50         unsigned long shift;
  51
  52         b0 = b[0]; b1 = b[1];
  53         shift = 5 + 41 * (insn_addr % 16); /* 5 bits of template, then 3 x 41-bit instructions */
  54         if (shift >= 64) {
  55                 m1 = mask << (shift - 64);
  56                 v1 = val << (shift - 64);
  57         } else {
  58                 m0 = mask << shift; m1 = mask >> (64 - shift);
  59                 v0 = val  << shift; v1 = val >> (64 - shift);
  60                 b[0] = (b0 & ~m0) | (v0 & m0);
  61         }
  62         b[1] = (b1 & ~m1) | (v1 & m1);
  63 }
  64
  65 void
  66 ia64_patch_imm64 (u64 insn_addr, u64 val)
  67 {
  68         /* The assembler may generate offset pointing to either slot 1
  69            or slot 2 for a long (2-slot) instruction, occupying slots 1
  70            and 2.  */
  71         insn_addr &= -16UL;
  72         ia64_patch(insn_addr + 2,
  73                    0x01fffefe000UL, (  ((val & 0x8000000000000000UL) >> 27) /* bit 63 -> 36 */
  74                                      | ((val & 0x0000000000200000UL) <<  0) /* bit 21 -> 21 */
  75                                      | ((val & 0x00000000001f0000UL) <<  6) /* bit 16 -> 22 */
  76                                      | ((val & 0x000000000000ff80UL) << 20) /* bit  7 -> 27 */
  77                                      | ((val & 0x000000000000007fUL) << 13) /* bit  0 -> 13 */));
  78         ia64_patch(insn_addr + 1, 0x1ffffffffffUL, val >> 22);
  79 }
  80
  81 void
  82 ia64_patch_imm60 (u64 insn_addr, u64 val)
  83 {
  84         /* The assembler may generate offset pointing to either slot 1
  85            or slot 2 for a long (2-slot) instruction, occupying slots 1
  86            and 2.  */
  87         insn_addr &= -16UL;
  88         ia64_patch(insn_addr + 2,
  89                    0x011ffffe000UL, (  ((val & 0x0800000000000000UL) >> 23) /* bit 59 -> 36 */
  90                                      | ((val & 0x00000000000fffffUL) << 13) /* bit  0 -> 13 */));
  91         ia64_patch(insn_addr + 1, 0x1fffffffffcUL, val >> 18);
  92 }
  93
  94 /*
  95  * We need sometimes to load the physical address of a kernel
  96  * object.  Often we can convert the virtual address to physical
  97  * at execution time, but sometimes (either for performance reasons
  98  * or during error recovery) we cannot to this.  Patch the marked
  99  * bundles to load the physical address.
 100  */
 101 void __init
 102 ia64_patch_vtop (unsigned long start, unsigned long end)
 103 {
 104         s32 *offp = (s32 *) start;
 105         u64 ip;
 106
 107         while (offp < (s32 *) end) {
 108                 ip = (u64) offp + *offp;
 109
 110                 /* replace virtual address with corresponding physical address: */
 111                 ia64_patch_imm64(ip, ia64_tpa(get_imm64(ip)));
 112                 ia64_fc((void *) ip);
 113                 ++offp;
 114         }
 115         ia64_sync_i();
 116         ia64_srlz_i();
 117 }
 118
 119 /*
 120  * Disable the RSE workaround by turning the conditional branch
 121  * that we tagged in each place the workaround was used into an
 122  * unconditional branch.
 123  */
 124 void __init
 125 ia64_patch_rse (unsigned long start, unsigned long end)
 126 {
 127         s32 *offp = (s32 *) start;
 128         u64 ip, *b;
 129
 130         while (offp < (s32 *) end) {
 131                 ip = (u64) offp + *offp;
 132
 133                 b = (u64 *)(ip & -16);
 134                 b[1] &= ~0xf800000L;
 135                 ia64_fc((void *) ip);
 136                 ++offp;
 137         }
 138         ia64_sync_i();
 139         ia64_srlz_i();
 140 }
 141
 142 void __init
 143 ia64_patch_mckinley_e9 (unsigned long start, unsigned long end)
 144 {
 145         static int first_time = 1;
 146         int need_workaround;
 147         s32 *offp = (s32 *) start;
 148         u64 *wp;
 149
 150         need_workaround = (local_cpu_data->family == 0x1f && local_cpu_data->model == 0);
 151
 152         if (first_time) {
 153                 first_time = 0;
 154                 if (need_workaround)
 155                         printk(KERN_INFO "Leaving McKinley Errata 9 workaround enabled\n");
 156         }
 157         if (need_workaround)
 158                 return;
 159
 160         while (offp < (s32 *) end) {
 161                 wp = (u64 *) ia64_imva((char *) offp + *offp);
 162                 wp[0] = 0x0000000100000011UL; /* nop.m 0; nop.i 0; br.ret.sptk.many b6 */
 163                 wp[1] = 0x0084006880000200UL;
 164                 wp[2] = 0x0000000100000000UL; /* nop.m 0; nop.i 0; nop.i 0 */
 165                 wp[3] = 0x0004000000000200UL;
 166                 ia64_fc(wp); ia64_fc(wp + 2);
 167                 ++offp;
 168         }
 169         ia64_sync_i();
 170         ia64_srlz_i();
 171 }
 172
 173 extern unsigned long ia64_native_fsyscall_table[NR_syscalls];
 174 extern char ia64_native_fsys_bubble_down[];
 175 struct pv_fsys_data pv_fsys_data __initdata = {
 176         .fsyscall_table = (unsigned long *)ia64_native_fsyscall_table,
 177         .fsys_bubble_down = (void *)ia64_native_fsys_bubble_down,
 178 };
 179
 180 unsigned long * __init
 181 paravirt_get_fsyscall_table(void)
 182 {
 183         return pv_fsys_data.fsyscall_table;
 184 }
 185
 186 char * __init
 187 paravirt_get_fsys_bubble_down(void)
 188 {
 189         return pv_fsys_data.fsys_bubble_down;
 190 }
 191
 192 static void __init
 193 patch_fsyscall_table (unsigned long start, unsigned long end)
 194 {
 195         u64 fsyscall_table = (u64)paravirt_get_fsyscall_table();
 196         s32 *offp = (s32 *) start;
 197         u64 ip;
 198
 199         while (offp < (s32 *) end) {
 200                 ip = (u64) ia64_imva((char *) offp + *offp);
 201                 ia64_patch_imm64(ip, fsyscall_table);
 202                 ia64_fc((void *) ip);
 203                 ++offp;
 204         }
 205         ia64_sync_i();
 206         ia64_srlz_i();
 207 }
 208
 209 static void __init
 210 patch_brl_fsys_bubble_down (unsigned long start, unsigned long end)
 211 {
 212         u64 fsys_bubble_down = (u64)paravirt_get_fsys_bubble_down();
 213         s32 *offp = (s32 *) start;
 214         u64 ip;
 215
 216         while (offp < (s32 *) end) {
 217                 ip = (u64) offp + *offp;
 218                 ia64_patch_imm60((u64) ia64_imva((void *) ip),
 219                                  (u64) (fsys_bubble_down - (ip & -16)) / 16);
 220                 ia64_fc((void *) ip);
 221                 ++offp;
 222         }
 223         ia64_sync_i();
 224         ia64_srlz_i();
 225 }
 226
 227 void __init
 228 ia64_patch_gate (void)
 229 {
 230 #       define START(name)      paravirt_get_gate_patchlist(PV_GATE_START_##name)
 231 #       define END(name)        paravirt_get_gate_patchlist(PV_GATE_END_##name)
 232
 233         patch_fsyscall_table(START(FSYSCALL), END(FSYSCALL));
 234         patch_brl_fsys_bubble_down(START(BRL_FSYS_BUBBLE_DOWN), END(BRL_FSYS_BUBBLE_DOWN));
 235         ia64_patch_vtop(START(VTOP), END(VTOP));
 236         ia64_patch_mckinley_e9(START(MCKINLEY_E9), END(MCKINLEY_E9));
 237 }
 238
 239 void ia64_patch_phys_stack_reg(unsigned long val)
 240 {
 241         s32 * offp = (s32 *) __start___phys_stack_reg_patchlist;
 242         s32 * end = (s32 *) __end___phys_stack_reg_patchlist;
 243         u64 ip, mask, imm;
 244
 245         /* see instruction format A4: adds r1 = imm13, r3 */
 246         mask = (0x3fUL << 27) | (0x7f << 13);
 247         imm = (((val >> 7) & 0x3f) << 27) | (val & 0x7f) << 13;
 248
 249         while (offp < end) {
 250                 ip = (u64) offp + *offp;
 251                 ia64_patch(ip, mask, imm);
 252                 ia64_fc((void *)ip);
 253                 ++offp;
 254         }
 255         ia64_sync_i();
 256         ia64_srlz_i();
 257 }