gdbserver/linux-ppc-ipa.cc

   1 /* GNU/Linux/PowerPC specific low level interface, for the in-process
   2    agent library for GDB.
   3
   4    Copyright (C) 2016-2023 Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "server.h"
  22 #include <sys/mman.h>
  23 #include "tracepoint.h"
  24 #include "arch/ppc-linux-tdesc.h"
  25 #include "linux-ppc-tdesc-init.h"
  26 #include <elf.h>
  27 #ifdef HAVE_GETAUXVAL
  28 #include <sys/auxv.h>
  29 #endif
  30
  31 /* These macros define the position of registers in the buffer collected
  32    by the fast tracepoint jump pad.  */
  33 #define FT_CR_R0        0
  34 #define FT_CR_CR        32
  35 #define FT_CR_XER       33
  36 #define FT_CR_LR        34
  37 #define FT_CR_CTR       35
  38 #define FT_CR_PC        36
  39 #define FT_CR_GPR(n)    (FT_CR_R0 + (n))
  40
  41 static const int ppc_ft_collect_regmap[] = {
  42   /* GPRs */
  43   FT_CR_GPR (0), FT_CR_GPR (1), FT_CR_GPR (2),
  44   FT_CR_GPR (3), FT_CR_GPR (4), FT_CR_GPR (5),
  45   FT_CR_GPR (6), FT_CR_GPR (7), FT_CR_GPR (8),
  46   FT_CR_GPR (9), FT_CR_GPR (10), FT_CR_GPR (11),
  47   FT_CR_GPR (12), FT_CR_GPR (13), FT_CR_GPR (14),
  48   FT_CR_GPR (15), FT_CR_GPR (16), FT_CR_GPR (17),
  49   FT_CR_GPR (18), FT_CR_GPR (19), FT_CR_GPR (20),
  50   FT_CR_GPR (21), FT_CR_GPR (22), FT_CR_GPR (23),
  51   FT_CR_GPR (24), FT_CR_GPR (25), FT_CR_GPR (26),
  52   FT_CR_GPR (27), FT_CR_GPR (28), FT_CR_GPR (29),
  53   FT_CR_GPR (30), FT_CR_GPR (31),
  54   /* FPRs - not collected.  */
  55   -1, -1, -1, -1, -1, -1, -1, -1,
  56   -1, -1, -1, -1, -1, -1, -1, -1,
  57   -1, -1, -1, -1, -1, -1, -1, -1,
  58   -1, -1, -1, -1, -1, -1, -1, -1,
  59   FT_CR_PC, /* PC */
  60   -1, /* MSR */
  61   FT_CR_CR, /* CR */
  62   FT_CR_LR, /* LR */
  63   FT_CR_CTR, /* CTR */
  64   FT_CR_XER, /* XER */
  65   -1, /* FPSCR */
  66 };
  67
  68 #define PPC_NUM_FT_COLLECT_GREGS \
  69   (sizeof (ppc_ft_collect_regmap) / sizeof(ppc_ft_collect_regmap[0]))
  70
  71 /* Supply registers collected by the fast tracepoint jump pad.
  72    BUF is the second argument we pass to gdb_collect in jump pad.  */
  73
  74 void
  75 supply_fast_tracepoint_registers (struct regcache *regcache,
  76                                   const unsigned char *buf)
  77 {
  78   int i;
  79
  80   for (i = 0; i < PPC_NUM_FT_COLLECT_GREGS; i++)
  81     {
  82       if (ppc_ft_collect_regmap[i] == -1)
  83         continue;
  84       supply_register (regcache, i,
  85                        ((char *) buf)
  86                         + ppc_ft_collect_regmap[i] * sizeof (long));
  87     }
  88 }
  89
  90 /* Return the value of register REGNUM.  RAW_REGS is collected buffer
  91    by jump pad.  This function is called by emit_reg.  */
  92
  93 ULONGEST
  94 get_raw_reg (const unsigned char *raw_regs, int regnum)
  95 {
  96   if (regnum >= PPC_NUM_FT_COLLECT_GREGS)
  97     return 0;
  98   if (ppc_ft_collect_regmap[regnum] == -1)
  99     return 0;
 100
 101   return *(unsigned long *) (raw_regs
 102                              + ppc_ft_collect_regmap[regnum] * sizeof (long));
 103 }
 104
 105 /* Allocate buffer for the jump pads.  The branch instruction has a reach
 106    of +/- 32MiB, and the executable is loaded at 0x10000000 (256MiB).
 107
 108    64-bit: To maximize the area of executable that can use tracepoints,
 109    try allocating at 0x10000000 - size initially, decreasing until we hit
 110    a free area.
 111
 112    32-bit: ld.so loads dynamic libraries right below the executable, so
 113    we cannot depend on that area (dynamic libraries can be quite large).
 114    Instead, aim right after the executable - at sbrk(0).  This will
 115    cause future brk to fail, and malloc will fallback to mmap.  */
 116
 117 void *
 118 alloc_jump_pad_buffer (size_t size)
 119 {
 120 #ifdef __powerpc64__
 121   uintptr_t addr;
 122   uintptr_t exec_base = getauxval (AT_PHDR);
 123   int pagesize;
 124   void *res;
 125
 126   if (exec_base == 0)
 127     exec_base = 0x10000000;
 128
 129   pagesize = sysconf (_SC_PAGE_SIZE);
 130   if (pagesize == -1)
 131     perror_with_name ("sysconf");
 132
 133   addr = exec_base - size;
 134
 135   /* size should already be page-aligned, but this can't hurt.  */
 136   addr &= ~(pagesize - 1);
 137
 138   /* Search for a free area.  If we hit 0, we're out of luck.  */
 139   for (; addr; addr -= pagesize)
 140     {
 141       /* No MAP_FIXED - we don't want to zap someone's mapping.  */
 142       res = mmap ((void *) addr, size,
 143                   PROT_READ | PROT_WRITE | PROT_EXEC,
 144                   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 145
 146       /* If we got what we wanted, return.  */
 147       if ((uintptr_t) res == addr)
 148         return res;
 149
 150       /* If we got a mapping, but at a wrong address, undo it.  */
 151       if (res != MAP_FAILED)
 152         munmap (res, size);
 153     }
 154
 155   return NULL;
 156 #else
 157   void *target = sbrk (0);
 158   void *res = mmap (target, size, PROT_READ | PROT_WRITE | PROT_EXEC,
 159                     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 160
 161   if (res == target)
 162     return res;
 163
 164   if (res != MAP_FAILED)
 165     munmap (res, size);
 166
 167   return NULL;
 168 #endif
 169 }
 170
 171 /* Return target_desc to use for IPA, given the tdesc index passed by
 172    gdbserver.  */
 173
 174 const struct target_desc *
 175 get_ipa_tdesc (int idx)
 176 {
 177   switch (idx)
 178     {
 179 #ifdef __powerpc64__
 180     case PPC_TDESC_BASE:
 181       return tdesc_powerpc_64l;
 182     case PPC_TDESC_ALTIVEC:
 183       return tdesc_powerpc_altivec64l;
 184     case PPC_TDESC_VSX:
 185       return tdesc_powerpc_vsx64l;
 186     case PPC_TDESC_ISA205:
 187       return tdesc_powerpc_isa205_64l;
 188     case PPC_TDESC_ISA205_ALTIVEC:
 189       return tdesc_powerpc_isa205_altivec64l;
 190     case PPC_TDESC_ISA205_VSX:
 191       return tdesc_powerpc_isa205_vsx64l;
 192     case PPC_TDESC_ISA205_PPR_DSCR_VSX:
 193       return tdesc_powerpc_isa205_ppr_dscr_vsx64l;
 194     case PPC_TDESC_ISA207_VSX:
 195       return tdesc_powerpc_isa207_vsx64l;
 196     case PPC_TDESC_ISA207_HTM_VSX:
 197       return tdesc_powerpc_isa207_htm_vsx64l;
 198 #else
 199     case PPC_TDESC_BASE:
 200       return tdesc_powerpc_32l;
 201     case PPC_TDESC_ALTIVEC:
 202       return tdesc_powerpc_altivec32l;
 203     case PPC_TDESC_VSX:
 204       return tdesc_powerpc_vsx32l;
 205     case PPC_TDESC_ISA205:
 206       return tdesc_powerpc_isa205_32l;
 207     case PPC_TDESC_ISA205_ALTIVEC:
 208       return tdesc_powerpc_isa205_altivec32l;
 209     case PPC_TDESC_ISA205_VSX:
 210       return tdesc_powerpc_isa205_vsx32l;
 211     case PPC_TDESC_ISA205_PPR_DSCR_VSX:
 212       return tdesc_powerpc_isa205_ppr_dscr_vsx32l;
 213     case PPC_TDESC_ISA207_VSX:
 214       return tdesc_powerpc_isa207_vsx32l;
 215     case PPC_TDESC_ISA207_HTM_VSX:
 216       return tdesc_powerpc_isa207_htm_vsx32l;
 217     case PPC_TDESC_E500:
 218       return tdesc_powerpc_e500l;
 219 #endif
 220     default:
 221       internal_error ("unknown ipa tdesc index: %d", idx);
 222 #ifdef __powerpc64__
 223       return tdesc_powerpc_64l;
 224 #else
 225       return tdesc_powerpc_32l;
 226 #endif
 227     }
 228 }
 229
 230
 231 /* Initialize ipa_tdesc and others.  */
 232
 233 void
 234 initialize_low_tracepoint (void)
 235 {
 236 #ifdef __powerpc64__
 237   init_registers_powerpc_64l ();
 238   init_registers_powerpc_altivec64l ();
 239   init_registers_powerpc_vsx64l ();
 240   init_registers_powerpc_isa205_64l ();
 241   init_registers_powerpc_isa205_altivec64l ();
 242   init_registers_powerpc_isa205_vsx64l ();
 243   init_registers_powerpc_isa205_ppr_dscr_vsx64l ();
 244   init_registers_powerpc_isa207_vsx64l ();
 245   init_registers_powerpc_isa207_htm_vsx64l ();
 246 #else
 247   init_registers_powerpc_32l ();
 248   init_registers_powerpc_altivec32l ();
 249   init_registers_powerpc_vsx32l ();
 250   init_registers_powerpc_isa205_32l ();
 251   init_registers_powerpc_isa205_altivec32l ();
 252   init_registers_powerpc_isa205_vsx32l ();
 253   init_registers_powerpc_isa205_ppr_dscr_vsx32l ();
 254   init_registers_powerpc_isa207_vsx32l ();
 255   init_registers_powerpc_isa207_htm_vsx32l ();
 256   init_registers_powerpc_e500l ();
 257 #endif
 258 }