arch/microblaze/kernel/kgdb.c

   1 /*
   2  * Microblaze KGDB support
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License.  See the file "COPYING" in the main directory of this archive
   6  * for more details.
   7  */
   8
   9 #include <linux/kgdb.h>
  10 #include <linux/kdebug.h>
  11 #include <linux/irq.h>
  12 #include <linux/io.h>
  13 #include <asm/cacheflush.h>
  14 #include <asm/asm-offsets.h>
  15 #include <asm/kgdb.h>
  16 #include <asm/pvr.h>
  17
  18 #define GDB_REG         0
  19 #define GDB_PC          32
  20 #define GDB_MSR         33
  21 #define GDB_EAR         34
  22 #define GDB_ESR         35
  23 #define GDB_FSR         36
  24 #define GDB_BTR         37
  25 #define GDB_PVR         38
  26 #define GDB_REDR        50
  27 #define GDB_RPID        51
  28 #define GDB_RZPR        52
  29 #define GDB_RTLBX       53
  30 #define GDB_RTLBSX      54 /* mfs can't read it */
  31 #define GDB_RTLBLO      55
  32 #define GDB_RTLBHI      56
  33
  34 /* keep pvr separately because it is unchangeble */
  35 static struct pvr_s pvr;
  36
  37 void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
  38 {
  39         unsigned int i;
  40         unsigned long *pt_regb = (unsigned long *)regs;
  41         int temp;
  42
  43         /* registers r0 - r31, pc, msr, ear, esr, fsr + do not save pt_mode */
  44         for (i = 0; i < (sizeof(struct pt_regs) / 4) - 1; i++)
  45                 gdb_regs[i] = pt_regb[i];
  46
  47         /* Branch target register can't be changed */
  48         __asm__ __volatile__ ("mfs %0, rbtr;" : "=r"(temp) : );
  49         gdb_regs[GDB_BTR] = temp;
  50
  51         /* pvr part  - we have 11 pvr regs */
  52         for (i = 0; i < sizeof(struct pvr_s)/4; i++)
  53                 gdb_regs[GDB_PVR + i] = pvr.pvr[i];
  54
  55         /* read special registers - can't be changed */
  56         __asm__ __volatile__ ("mfs %0, redr;" : "=r"(temp) : );
  57         gdb_regs[GDB_REDR] = temp;
  58         __asm__ __volatile__ ("mfs %0, rpid;" : "=r"(temp) : );
  59         gdb_regs[GDB_RPID] = temp;
  60         __asm__ __volatile__ ("mfs %0, rzpr;" : "=r"(temp) : );
  61         gdb_regs[GDB_RZPR] = temp;
  62         __asm__ __volatile__ ("mfs %0, rtlbx;" : "=r"(temp) : );
  63         gdb_regs[GDB_RTLBX] = temp;
  64         __asm__ __volatile__ ("mfs %0, rtlblo;" : "=r"(temp) : );
  65         gdb_regs[GDB_RTLBLO] = temp;
  66         __asm__ __volatile__ ("mfs %0, rtlbhi;" : "=r"(temp) : );
  67         gdb_regs[GDB_RTLBHI] = temp;
  68 }
  69
  70 void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
  71 {
  72         unsigned int i;
  73         unsigned long *pt_regb = (unsigned long *)regs;
  74
  75         /* pt_regs and gdb_regs have the same 37 values.
  76          * The rest of gdb_regs are unused and can't be changed.
  77          * r0 register value can't be changed too. */
  78         for (i = 1; i < (sizeof(struct pt_regs) / 4) - 1; i++)
  79                 pt_regb[i] = gdb_regs[i];
  80 }
  81
  82 asmlinkage void microblaze_kgdb_break(struct pt_regs *regs)
  83 {
  84         if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0)
  85                 return;
  86
  87         /* Jump over the first arch_kgdb_breakpoint which is barrier to
  88          * get kgdb work. The same solution is used for powerpc */
  89         if (*(u32 *) (regs->pc) == *(u32 *) (&arch_kgdb_ops.gdb_bpt_instr))
  90                 regs->pc += BREAK_INSTR_SIZE;
  91 }
  92
  93 /* untested */
  94 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
  95 {
  96         unsigned int i;
  97         unsigned long *pt_regb = (unsigned long *)(p->thread.regs);
  98
  99         /* registers r0 - r31, pc, msr, ear, esr, fsr + do not save pt_mode */
 100         for (i = 0; i < (sizeof(struct pt_regs) / 4) - 1; i++)
 101                 gdb_regs[i] = pt_regb[i];
 102
 103         /* pvr part  - we have 11 pvr regs */
 104         for (i = 0; i < sizeof(struct pvr_s)/4; i++)
 105                 gdb_regs[GDB_PVR + i] = pvr.pvr[i];
 106 }
 107
 108 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
 109 {
 110         regs->pc = ip;
 111 }
 112
 113 int kgdb_arch_handle_exception(int vector, int signo, int err_code,
 114                                char *remcom_in_buffer, char *remcom_out_buffer,
 115                                struct pt_regs *regs)
 116 {
 117         char *ptr;
 118         unsigned long address;
 119
 120         switch (remcom_in_buffer[0]) {
 121         case 'c':
 122                 /* handle the optional parameter */
 123                 ptr = &remcom_in_buffer[1];
 124                 if (kgdb_hex2long(&ptr, &address))
 125                         regs->pc = address;
 126
 127                 return 0;
 128         }
 129         return -1; /* this means that we do not want to exit from the handler */
 130 }
 131
 132 int kgdb_arch_init(void)
 133 {
 134         get_pvr(&pvr); /* Fill PVR structure */
 135         return 0;
 136 }
 137
 138 void kgdb_arch_exit(void)
 139 {
 140         /* Nothing to do */
 141 }
 142
 143 /*
 144  * Global data
 145  */
 146 struct kgdb_arch arch_kgdb_ops = {
 147 #ifdef __MICROBLAZEEL__
 148         .gdb_bpt_instr = {0x18, 0x00, 0x0c, 0xba}, /* brki r16, 0x18 */
 149 #else
 150         .gdb_bpt_instr = {0xba, 0x0c, 0x00, 0x18}, /* brki r16, 0x18 */
 151 #endif
 152 };