arch/sparc/kernel/kgdb_32.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* kgdb.c: KGDB support for 32-bit sparc.
   3  *
   4  * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
   5  */
   6
   7 #include <linux/kgdb.h>
   8 #include <linux/kdebug.h>
   9 #include <linux/sched.h>
  10
  11 #include <asm/kdebug.h>
  12 #include <asm/ptrace.h>
  13 #include <asm/irq.h>
  14 #include <asm/cacheflush.h>
  15
  16 #include "kernel.h"
  17 #include "entry.h"
  18
  19 void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
  20 {
  21         struct reg_window32 *win;
  22         int i;
  23
  24         gdb_regs[GDB_G0] = 0;
  25         for (i = 0; i < 15; i++)
  26                 gdb_regs[GDB_G1 + i] = regs->u_regs[UREG_G1 + i];
  27
  28         win = (struct reg_window32 *) regs->u_regs[UREG_FP];
  29         for (i = 0; i < 8; i++)
  30                 gdb_regs[GDB_L0 + i] = win->locals[i];
  31         for (i = 0; i < 8; i++)
  32                 gdb_regs[GDB_I0 + i] = win->ins[i];
  33
  34         for (i = GDB_F0; i <= GDB_F31; i++)
  35                 gdb_regs[i] = 0;
  36
  37         gdb_regs[GDB_Y] = regs->y;
  38         gdb_regs[GDB_PSR] = regs->psr;
  39         gdb_regs[GDB_WIM] = 0;
  40         gdb_regs[GDB_TBR] = (unsigned long) &trapbase;
  41         gdb_regs[GDB_PC] = regs->pc;
  42         gdb_regs[GDB_NPC] = regs->npc;
  43         gdb_regs[GDB_FSR] = 0;
  44         gdb_regs[GDB_CSR] = 0;
  45 }
  46
  47 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
  48 {
  49         struct thread_info *t = task_thread_info(p);
  50         struct reg_window32 *win;
  51         int i;
  52
  53         for (i = GDB_G0; i < GDB_G6; i++)
  54                 gdb_regs[i] = 0;
  55         gdb_regs[GDB_G6] = (unsigned long) t;
  56         gdb_regs[GDB_G7] = 0;
  57         for (i = GDB_O0; i < GDB_SP; i++)
  58                 gdb_regs[i] = 0;
  59         gdb_regs[GDB_SP] = t->ksp;
  60         gdb_regs[GDB_O7] = 0;
  61
  62         win = (struct reg_window32 *) t->ksp;
  63         for (i = 0; i < 8; i++)
  64                 gdb_regs[GDB_L0 + i] = win->locals[i];
  65         for (i = 0; i < 8; i++)
  66                 gdb_regs[GDB_I0 + i] = win->ins[i];
  67
  68         for (i = GDB_F0; i <= GDB_F31; i++)
  69                 gdb_regs[i] = 0;
  70
  71         gdb_regs[GDB_Y] = 0;
  72
  73         gdb_regs[GDB_PSR] = t->kpsr;
  74         gdb_regs[GDB_WIM] = t->kwim;
  75         gdb_regs[GDB_TBR] = (unsigned long) &trapbase;
  76         gdb_regs[GDB_PC] = t->kpc;
  77         gdb_regs[GDB_NPC] = t->kpc + 4;
  78         gdb_regs[GDB_FSR] = 0;
  79         gdb_regs[GDB_CSR] = 0;
  80 }
  81
  82 void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
  83 {
  84         struct reg_window32 *win;
  85         int i;
  86
  87         for (i = 0; i < 15; i++)
  88                 regs->u_regs[UREG_G1 + i] = gdb_regs[GDB_G1 + i];
  89
  90         /* If the PSR register is changing, we have to preserve
  91          * the CWP field, otherwise window save/restore explodes.
  92          */
  93         if (regs->psr != gdb_regs[GDB_PSR]) {
  94                 unsigned long cwp = regs->psr & PSR_CWP;
  95
  96                 regs->psr = (gdb_regs[GDB_PSR] & ~PSR_CWP) | cwp;
  97         }
  98
  99         regs->pc = gdb_regs[GDB_PC];
 100         regs->npc = gdb_regs[GDB_NPC];
 101         regs->y = gdb_regs[GDB_Y];
 102
 103         win = (struct reg_window32 *) regs->u_regs[UREG_FP];
 104         for (i = 0; i < 8; i++)
 105                 win->locals[i] = gdb_regs[GDB_L0 + i];
 106         for (i = 0; i < 8; i++)
 107                 win->ins[i] = gdb_regs[GDB_I0 + i];
 108 }
 109
 110 int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
 111                                char *remcomInBuffer, char *remcomOutBuffer,
 112                                struct pt_regs *linux_regs)
 113 {
 114         unsigned long addr;
 115         char *ptr;
 116
 117         switch (remcomInBuffer[0]) {
 118         case 'c':
 119                 /* try to read optional parameter, pc unchanged if no parm */
 120                 ptr = &remcomInBuffer[1];
 121                 if (kgdb_hex2long(&ptr, &addr)) {
 122                         linux_regs->pc = addr;
 123                         linux_regs->npc = addr + 4;
 124                 }
 125                 /* fallthru */
 126
 127         case 'D':
 128         case 'k':
 129                 if (linux_regs->pc == (unsigned long) arch_kgdb_breakpoint) {
 130                         linux_regs->pc = linux_regs->npc;
 131                         linux_regs->npc += 4;
 132                 }
 133                 return 0;
 134         }
 135         return -1;
 136 }
 137
 138 asmlinkage void kgdb_trap(unsigned long trap_level, struct pt_regs *regs)
 139 {
 140         unsigned long flags;
 141
 142         if (user_mode(regs)) {
 143                 do_hw_interrupt(regs, trap_level);
 144                 return;
 145         }
 146
 147         flushw_all();
 148
 149         local_irq_save(flags);
 150         kgdb_handle_exception(trap_level, SIGTRAP, 0, regs);
 151         local_irq_restore(flags);
 152 }
 153
 154 int kgdb_arch_init(void)
 155 {
 156         return 0;
 157 }
 158
 159 void kgdb_arch_exit(void)
 160 {
 161 }
 162
 163 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
 164 {
 165         regs->pc = ip;
 166         regs->npc = regs->pc + 4;
 167 }
 168
 169 struct kgdb_arch arch_kgdb_ops = {
 170         /* Breakpoint instruction: ta 0x7d */
 171         .gdb_bpt_instr          = { 0x91, 0xd0, 0x20, 0x7d },
 172 };