kgdb.c

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/*
 * Microblaze KGDB support
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */

#include <linux/kgdb.h>
#include <linux/kdebug.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <asm/cacheflush.h>
#include <asm/asm-offsets.h>
#include <asm/pvr.h>

#define GDB_REG     0
#define GDB_PC      32
#define GDB_MSR     33
#define GDB_EAR     34
#define GDB_ESR     35
#define GDB_FSR     36
#define GDB_BTR     37
#define GDB_PVR     38
#define GDB_REDR    50
#define GDB_RPID    51
#define GDB_RZPR    52
#define GDB_RTLBX   53
#define GDB_RTLBSX  54 /* mfs can't read it */
#define GDB_RTLBLO  55
#define GDB_RTLBHI  56

/* keep pvr separately because it is unchangeble */
struct pvr_s pvr;

void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
{
    int i;
    unsigned long *pt_regb = (unsigned long *)regs;
    int temp;
    /* registers r0 - r31, pc, msr, ear, esr, fsr + do not save pt_mode */
    for (i = 0; i < (sizeof(struct pt_regs) / 4) - 1; i++)
        gdb_regs[i] = pt_regb[i];

    /* Branch target register can't be changed */
    __asm__ __volatile__ ("mfs %0, rbtr;" : "=r"(temp) : );
    gdb_regs[GDB_BTR] = temp;

    /* pvr part  - we have 11 pvr regs */
    for (i = 0; i < sizeof(struct pvr_s)/4; i++)
        gdb_regs[GDB_PVR + i] = pvr.pvr[i];

    /* read special registers - can't be changed */
    __asm__ __volatile__ ("mfs %0, redr;" : "=r"(temp) : );
    gdb_regs[GDB_REDR] = temp;
    __asm__ __volatile__ ("mfs %0, rpid;" : "=r"(temp) : );
    gdb_regs[GDB_RPID] = temp;
    __asm__ __volatile__ ("mfs %0, rzpr;" : "=r"(temp) : );
    gdb_regs[GDB_RZPR] = temp;
    __asm__ __volatile__ ("mfs %0, rtlbx;" : "=r"(temp) : );
    gdb_regs[GDB_RTLBX] = temp;
    __asm__ __volatile__ ("mfs %0, rtlblo;" : "=r"(temp) : );
    gdb_regs[GDB_RTLBLO] = temp;
    __asm__ __volatile__ ("mfs %0, rtlbhi;" : "=r"(temp) : );
    gdb_regs[GDB_RTLBHI] = temp;
}

void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
{
    int i;
    unsigned long *pt_regb = (unsigned long *)regs;

    /* pt_regs and gdb_regs have the same 37 values.
     * The rest of gdb_regs are unused and can't be changed.
     * r0 register value can't be changed too. */
    for (i = 1; i < (sizeof(struct pt_regs) / 4) - 1; i++)
        pt_regb[i] = gdb_regs[i];
}

void microblaze_kgdb_break(struct pt_regs *regs)
{
    if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0)
        return;

    /* Jump over the first arch_kgdb_breakpoint which is barrier to
     * get kgdb work. The same solution is used for powerpc */
    if (*(u32 *) (regs->pc) == *(u32 *) (&arch_kgdb_ops.gdb_bpt_instr))
        regs->pc += BREAK_INSTR_SIZE;
}

/* untested */
void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
{
    int i;
    unsigned long *pt_regb = (unsigned long *)(p->thread.regs);

    /* registers r0 - r31, pc, msr, ear, esr, fsr + do not save pt_mode */
    for (i = 0; i < (sizeof(struct pt_regs) / 4) - 1; i++)
        gdb_regs[i] = pt_regb[i];

    /* pvr part  - we have 11 pvr regs */
    for (i = 0; i < sizeof(struct pvr_s)/4; i++)
        gdb_regs[GDB_PVR + i] = pvr.pvr[i];
}

void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
{
    regs->pc = ip;
}

int kgdb_arch_handle_exception(int vector, int signo, int err_code,
                   char *remcom_in_buffer, char *remcom_out_buffer,
                   struct pt_regs *regs)
{
    char *ptr;
    unsigned long address;

    switch (remcom_in_buffer[0]) {
    case 'c':
        /* handle the optional parameter */
        ptr = &remcom_in_buffer[1];
        if (kgdb_hex2long(&ptr, &address))
            regs->pc = address;

        return 0;
    }
    return -1; /* this means that we do not want to exit from the handler */
}

int kgdb_arch_init(void)
{
    get_pvr(&pvr); /* Fill PVR structure */
    return 0;
}

void kgdb_arch_exit(void)
{
    /* Nothing to do */
}

/*
 * Global data
 */
struct kgdb_arch arch_kgdb_ops = {
#ifdef __MICROBLAZEEL__
    .gdb_bpt_instr = {0x18, 0x00, 0x0c, 0xba}, /* brki r16, 0x18 */
#else
    .gdb_bpt_instr = {0xba, 0x0c, 0x00, 0x18}, /* brki r16, 0x18 */
#endif
};