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