kgdb_64.c

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/* kgdb.c: KGDB support for 64-bit sparc.
 *
 * Copyright (C) 2008 David S. Miller <[email protected]>
 */

#include <linux/kgdb.h>
#include <linux/kdebug.h>
#include <linux/ftrace.h>

#include <asm/cacheflush.h>
#include <asm/kdebug.h>
#include <asm/ptrace.h>
#include <asm/irq.h>

void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
{
    struct reg_window *win;
    int i;

    gdb_regs[GDB_G0] = 0;
    for (i = 0; i < 15; i++)
        gdb_regs[GDB_G1 + i] = regs->u_regs[UREG_G1 + i];

    win = (struct reg_window *) (regs->u_regs[UREG_FP] + STACK_BIAS);
    for (i = 0; i < 8; i++)
        gdb_regs[GDB_L0 + i] = win->locals[i];
    for (i = 0; i < 8; i++)
        gdb_regs[GDB_I0 + i] = win->ins[i];

    for (i = GDB_F0; i <= GDB_F62; i++)
        gdb_regs[i] = 0;

    gdb_regs[GDB_PC] = regs->tpc;
    gdb_regs[GDB_NPC] = regs->tnpc;
    gdb_regs[GDB_STATE] = regs->tstate;
    gdb_regs[GDB_FSR] = 0;
    gdb_regs[GDB_FPRS] = 0;
    gdb_regs[GDB_Y] = regs->y;
}

void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
{
    struct thread_info *t = task_thread_info(p);
    extern unsigned int switch_to_pc;
    extern unsigned int ret_from_syscall;
    struct reg_window *win;
    unsigned long pc, cwp;
    int i;

    for (i = GDB_G0; i < GDB_G6; i++)
        gdb_regs[i] = 0;
    gdb_regs[GDB_G6] = (unsigned long) t;
    gdb_regs[GDB_G7] = (unsigned long) p;
    for (i = GDB_O0; i < GDB_SP; i++)
        gdb_regs[i] = 0;
    gdb_regs[GDB_SP] = t->ksp;
    gdb_regs[GDB_O7] = 0;

    win = (struct reg_window *) (t->ksp + STACK_BIAS);
    for (i = 0; i < 8; i++)
        gdb_regs[GDB_L0 + i] = win->locals[i];
    for (i = 0; i < 8; i++)
        gdb_regs[GDB_I0 + i] = win->ins[i];

    for (i = GDB_F0; i <= GDB_F62; i++)
        gdb_regs[i] = 0;

    if (t->new_child)
        pc = (unsigned long) &ret_from_syscall;
    else
        pc = (unsigned long) &switch_to_pc;

    gdb_regs[GDB_PC] = pc;
    gdb_regs[GDB_NPC] = pc + 4;

    cwp = __thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP];

    gdb_regs[GDB_STATE] = (TSTATE_PRIV | TSTATE_IE | cwp);
    gdb_regs[GDB_FSR] = 0;
    gdb_regs[GDB_FPRS] = 0;
    gdb_regs[GDB_Y] = 0;
}

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

    for (i = 0; i < 15; i++)
        regs->u_regs[UREG_G1 + i] = gdb_regs[GDB_G1 + i];

    /* If the TSTATE register is changing, we have to preserve
     * the CWP field, otherwise window save/restore explodes.
     */
    if (regs->tstate != gdb_regs[GDB_STATE]) {
        unsigned long cwp = regs->tstate & TSTATE_CWP;

        regs->tstate = (gdb_regs[GDB_STATE] & ~TSTATE_CWP) | cwp;
    }

    regs->tpc = gdb_regs[GDB_PC];
    regs->tnpc = gdb_regs[GDB_NPC];
    regs->y = gdb_regs[GDB_Y];

    win = (struct reg_window *) (regs->u_regs[UREG_FP] + STACK_BIAS);
    for (i = 0; i < 8; i++)
        win->locals[i] = gdb_regs[GDB_L0 + i];
    for (i = 0; i < 8; i++)
        win->ins[i] = gdb_regs[GDB_I0 + i];
}

#ifdef CONFIG_SMP
void __irq_entry smp_kgdb_capture_client(int irq, struct pt_regs *regs)
{
    unsigned long flags;

    __asm__ __volatile__("rdpr      %%pstate, %0\n\t"
                 "wrpr      %0, %1, %%pstate"
                 : "=r" (flags)
                 : "i" (PSTATE_IE));

    flushw_all();

    if (atomic_read(&kgdb_active) != -1)
        kgdb_nmicallback(raw_smp_processor_id(), regs);

    __asm__ __volatile__("wrpr  %0, 0, %%pstate"
                 : : "r" (flags));
}
#endif

int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
                   char *remcomInBuffer, char *remcomOutBuffer,
                   struct pt_regs *linux_regs)
{
    unsigned long addr;
    char *ptr;

    switch (remcomInBuffer[0]) {
    case 'c':
        /* try to read optional parameter, pc unchanged if no parm */
        ptr = &remcomInBuffer[1];
        if (kgdb_hex2long(&ptr, &addr)) {
            linux_regs->tpc = addr;
            linux_regs->tnpc = addr + 4;
        }
        /* fallthru */

    case 'D':
    case 'k':
        if (linux_regs->tpc == (unsigned long) arch_kgdb_breakpoint) {
            linux_regs->tpc = linux_regs->tnpc;
            linux_regs->tnpc += 4;
        }
        return 0;
    }
    return -1;
}

asmlinkage void kgdb_trap(unsigned long trap_level, struct pt_regs *regs)
{
    unsigned long flags;

    if (user_mode(regs)) {
        bad_trap(regs, trap_level);
        return;
    }

    flushw_all();

    local_irq_save(flags);
    kgdb_handle_exception(0x172, SIGTRAP, 0, regs);
    local_irq_restore(flags);
}

int kgdb_arch_init(void)
{
    return 0;
}

void kgdb_arch_exit(void)
{
}

void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
{
    regs->tpc = ip;
    regs->tnpc = regs->tpc + 4;
}

struct kgdb_arch arch_kgdb_ops = {
    /* Breakpoint instruction: ta 0x72 */
    .gdb_bpt_instr      = { 0x91, 0xd0, 0x20, 0x72 },
};