// SPDX-License-Identifier: GPL-2.0-only
/*
 * PowerPC backend to the KGDB stub.
 *
 * 1998 (c) Michael AK Tesch (tesch@cs.wisc.edu)
 * Copyright (C) 2003 Timesys Corporation.
 * Copyright (C) 2004-2006 MontaVista Software, Inc.
 * PPC64 Mods (C) 2005 Frank Rowand (frowand@mvista.com)
 * PPC32 support restored by Vitaly Wool <vwool@ru.mvista.com> and
 * Sergei Shtylyov <sshtylyov@ru.mvista.com>
 * Copyright (C) 2007-2008 Wind River Systems, Inc.
 */

#include <linux/kernel.h>
#include <linux/kgdb.h>
#include <linux/smp.h>
#include <linux/signal.h>
#include <linux/ptrace.h>
#include <linux/kdebug.h>
#include <asm/current.h>
#include <asm/processor.h>
#include <asm/machdep.h>
#include <asm/debug.h>
#include <asm/text-patching.h>
#include <linux/slab.h>
#include <asm/inst.h>

/*
 * This table contains the mapping between PowerPC hardware trap types, and
 * signals, which are primarily what GDB understands.  GDB and the kernel
 * don't always agree on values, so we use constants taken from gdb-6.2.
 */
static struct hard_trap_info
{
        unsigned int tt;                /* Trap type code for powerpc */
        unsigned char signo;            /* Signal that we map this trap into */
} hard_trap_info[] = {
        { 0x0100, 0x02 /* SIGINT */  },         /* system reset */
        { 0x0200, 0x0b /* SIGSEGV */ },         /* machine check */
        { 0x0300, 0x0b /* SIGSEGV */ },         /* data access */
        { 0x0400, 0x0b /* SIGSEGV */ },         /* instruction access */
        { 0x0500, 0x02 /* SIGINT */  },         /* external interrupt */
        { 0x0600, 0x0a /* SIGBUS */  },         /* alignment */
        { 0x0700, 0x05 /* SIGTRAP */ },         /* program check */
        { 0x0800, 0x08 /* SIGFPE */  },         /* fp unavailable */
        { 0x0900, 0x0e /* SIGALRM */ },         /* decrementer */
        { 0x0c00, 0x14 /* SIGCHLD */ },         /* system call */
#ifdef CONFIG_BOOKE
        { 0x2002, 0x05 /* SIGTRAP */ },         /* debug */
#if defined(CONFIG_PPC_85xx)
        { 0x2010, 0x08 /* SIGFPE */  },         /* spe unavailable */
        { 0x2020, 0x08 /* SIGFPE */  },         /* spe unavailable */
        { 0x2030, 0x08 /* SIGFPE */  },         /* spe fp data */
        { 0x2040, 0x08 /* SIGFPE */  },         /* spe fp data */
        { 0x2050, 0x08 /* SIGFPE */  },         /* spe fp round */
        { 0x2060, 0x0e /* SIGILL */  },         /* performance monitor */
        { 0x2900, 0x08 /* SIGFPE */  },         /* apu unavailable */
        { 0x3100, 0x0e /* SIGALRM */ },         /* fixed interval timer */
        { 0x3200, 0x02 /* SIGINT */  },         /* watchdog */
#else /* ! CONFIG_PPC_85xx */
        { 0x1000, 0x0e /* SIGALRM */ },         /* prog interval timer */
        { 0x1010, 0x0e /* SIGALRM */ },         /* fixed interval timer */
        { 0x1020, 0x02 /* SIGINT */  },         /* watchdog */
        { 0x2010, 0x08 /* SIGFPE */  },         /* fp unavailable */
        { 0x2020, 0x08 /* SIGFPE */  },         /* ap unavailable */
#endif
#else /* !CONFIG_BOOKE */
        { 0x0d00, 0x05 /* SIGTRAP */ },         /* single-step */
#if defined(CONFIG_PPC_8xx)
        { 0x1000, 0x04 /* SIGILL */  },         /* software emulation */
#else /* ! CONFIG_PPC_8xx */
        { 0x0f00, 0x04 /* SIGILL */  },         /* performance monitor */
        { 0x0f20, 0x08 /* SIGFPE */  },         /* altivec unavailable */
        { 0x1300, 0x05 /* SIGTRAP */ },         /* instruction address break */
#if defined(CONFIG_PPC64)
        { 0x1200, 0x05 /* SIGILL */  },         /* system error */
        { 0x1500, 0x04 /* SIGILL */  },         /* soft patch */
        { 0x1600, 0x04 /* SIGILL */  },         /* maintenance */
        { 0x1700, 0x08 /* SIGFPE */  },         /* altivec assist */
        { 0x1800, 0x04 /* SIGILL */  },         /* thermal */
#else /* ! CONFIG_PPC64 */
        { 0x1400, 0x02 /* SIGINT */  },         /* SMI */
        { 0x1600, 0x08 /* SIGFPE */  },         /* altivec assist */
        { 0x1700, 0x04 /* SIGILL */  },         /* TAU */
        { 0x2000, 0x05 /* SIGTRAP */ },         /* run mode */
#endif
#endif
#endif
        { 0x0000, 0x00 }                        /* Must be last */
};

static int computeSignal(unsigned int tt)
{
        struct hard_trap_info *ht;

        for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
                if (ht->tt == tt)
                        return ht->signo;

        return SIGHUP;          /* default for things we don't know about */
}

/**
 *
 *      kgdb_skipexception - Bail out of KGDB when we've been triggered.
 *      @exception: Exception vector number
 *      @regs: Current &struct pt_regs.
 *
 *      On some architectures we need to skip a breakpoint exception when
 *      it occurs after a breakpoint has been removed.
 *
 */
int kgdb_skipexception(int exception, struct pt_regs *regs)
{
        return kgdb_isremovedbreak(regs->nip);
}

static int kgdb_debugger_ipi(struct pt_regs *regs)
{
        kgdb_nmicallback(raw_smp_processor_id(), regs);
        return 0;
}

#ifdef CONFIG_SMP
void kgdb_roundup_cpus(void)
{
        smp_send_debugger_break();
}
#endif

/* KGDB functions to use existing PowerPC64 hooks. */
static int kgdb_debugger(struct pt_regs *regs)
{
        return !kgdb_handle_exception(1, computeSignal(TRAP(regs)),
                                      DIE_OOPS, regs);
}

static int kgdb_handle_breakpoint(struct pt_regs *regs)
{
        if (user_mode(regs))
                return 0;

        if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0)
                return 0;

        if (*(u32 *)regs->nip == BREAK_INSTR)
                regs_add_return_ip(regs, BREAK_INSTR_SIZE);

        return 1;
}

static int kgdb_singlestep(struct pt_regs *regs)
{
        if (user_mode(regs))
                return 0;

        kgdb_handle_exception(0, SIGTRAP, 0, regs);

        return 1;
}

static int kgdb_iabr_match(struct pt_regs *regs)
{
        if (user_mode(regs))
                return 0;

        if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
                return 0;
        return 1;
}

static int kgdb_break_match(struct pt_regs *regs)
{
        if (user_mode(regs))
                return 0;

        if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
                return 0;
        return 1;
}

#define PACK64(ptr, src) do { *(ptr++) = (src); } while (0)

#define PACK32(ptr, src) do {          \
        u32 *ptr32;                   \
        ptr32 = (u32 *)ptr;           \
        *(ptr32++) = (src);           \
        ptr = (unsigned long *)ptr32; \
        } while (0)

void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
{
        struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp +
                                                  STACK_INT_FRAME_REGS);
        unsigned long *ptr = gdb_regs;
        int reg;

        memset(gdb_regs, 0, NUMREGBYTES);

        /* Regs GPR0-2 */
        for (reg = 0; reg < 3; reg++)
                PACK64(ptr, regs->gpr[reg]);

        /* Regs GPR3-13 are caller saved, not in regs->gpr[] */
        ptr += 11;

        /* Regs GPR14-31 */
        for (reg = 14; reg < 32; reg++)
                PACK64(ptr, regs->gpr[reg]);

#ifdef CONFIG_PPC_85xx
#ifdef CONFIG_SPE
        for (reg = 0; reg < 32; reg++)
                PACK64(ptr, p->thread.evr[reg]);
#else
        ptr += 32;
#endif
#else
        /* fp registers not used by kernel, leave zero */
        ptr += 32 * 8 / sizeof(long);
#endif

        PACK64(ptr, regs->nip);
        PACK64(ptr, regs->msr);
        PACK32(ptr, regs->ccr);
        PACK64(ptr, regs->link);
        PACK64(ptr, regs->ctr);
        PACK32(ptr, regs->xer);

        BUG_ON((unsigned long)ptr >
               (unsigned long)(((void *)gdb_regs) + NUMREGBYTES));
}

#define GDB_SIZEOF_REG sizeof(unsigned long)
#define GDB_SIZEOF_REG_U32 sizeof(u32)

#ifdef CONFIG_PPC_85xx
#define GDB_SIZEOF_FLOAT_REG sizeof(unsigned long)
#else
#define GDB_SIZEOF_FLOAT_REG sizeof(u64)
#endif

struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
{
        { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[0]) },
        { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[1]) },
        { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[2]) },
        { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[3]) },
        { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[4]) },
        { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[5]) },
        { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[6]) },
        { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[7]) },
        { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[8]) },
        { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[9]) },
        { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[10]) },
        { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[11]) },
        { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[12]) },
        { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[13]) },
        { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[14]) },
        { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[15]) },
        { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[16]) },
        { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[17]) },
        { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[18]) },
        { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[19]) },
        { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[20]) },
        { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[21]) },
        { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[22]) },
        { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[23]) },
        { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[24]) },
        { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[25]) },
        { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[26]) },
        { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[27]) },
        { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[28]) },
        { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[29]) },
        { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[30]) },
        { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[31]) },

        { "f0", GDB_SIZEOF_FLOAT_REG, 0 },
        { "f1", GDB_SIZEOF_FLOAT_REG, 1 },
        { "f2", GDB_SIZEOF_FLOAT_REG, 2 },
        { "f3", GDB_SIZEOF_FLOAT_REG, 3 },
        { "f4", GDB_SIZEOF_FLOAT_REG, 4 },
        { "f5", GDB_SIZEOF_FLOAT_REG, 5 },
        { "f6", GDB_SIZEOF_FLOAT_REG, 6 },
        { "f7", GDB_SIZEOF_FLOAT_REG, 7 },
        { "f8", GDB_SIZEOF_FLOAT_REG, 8 },
        { "f9", GDB_SIZEOF_FLOAT_REG, 9 },
        { "f10", GDB_SIZEOF_FLOAT_REG, 10 },
        { "f11", GDB_SIZEOF_FLOAT_REG, 11 },
        { "f12", GDB_SIZEOF_FLOAT_REG, 12 },
        { "f13", GDB_SIZEOF_FLOAT_REG, 13 },
        { "f14", GDB_SIZEOF_FLOAT_REG, 14 },
        { "f15", GDB_SIZEOF_FLOAT_REG, 15 },
        { "f16", GDB_SIZEOF_FLOAT_REG, 16 },
        { "f17", GDB_SIZEOF_FLOAT_REG, 17 },
        { "f18", GDB_SIZEOF_FLOAT_REG, 18 },
        { "f19", GDB_SIZEOF_FLOAT_REG, 19 },
        { "f20", GDB_SIZEOF_FLOAT_REG, 20 },
        { "f21", GDB_SIZEOF_FLOAT_REG, 21 },
        { "f22", GDB_SIZEOF_FLOAT_REG, 22 },
        { "f23", GDB_SIZEOF_FLOAT_REG, 23 },
        { "f24", GDB_SIZEOF_FLOAT_REG, 24 },
        { "f25", GDB_SIZEOF_FLOAT_REG, 25 },
        { "f26", GDB_SIZEOF_FLOAT_REG, 26 },
        { "f27", GDB_SIZEOF_FLOAT_REG, 27 },
        { "f28", GDB_SIZEOF_FLOAT_REG, 28 },
        { "f29", GDB_SIZEOF_FLOAT_REG, 29 },
        { "f30", GDB_SIZEOF_FLOAT_REG, 30 },
        { "f31", GDB_SIZEOF_FLOAT_REG, 31 },

        { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, nip) },
        { "msr", GDB_SIZEOF_REG, offsetof(struct pt_regs, msr) },
        { "cr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ccr) },
        { "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, link) },
        { "ctr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ctr) },
        { "xer", GDB_SIZEOF_REG, offsetof(struct pt_regs, xer) },
};

char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
{
        if (regno >= DBG_MAX_REG_NUM || regno < 0)
                return NULL;

        if (regno < 32 || regno >= 64)
                /* First 0 -> 31 gpr registers*/
                /* pc, msr, ls... registers 64 -> 69 */
                memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
                                dbg_reg_def[regno].size);

        if (regno >= 32 && regno < 64) {
                /* FP registers 32 -> 63 */
#if defined(CONFIG_PPC_85xx) && defined(CONFIG_SPE)
                if (current)
                        memcpy(mem, &current->thread.evr[regno-32],
                                        dbg_reg_def[regno].size);
#else
                /* fp registers not used by kernel, leave zero */
                memset(mem, 0, dbg_reg_def[regno].size);
#endif
        }

        return dbg_reg_def[regno].name;
}

int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
{
        if (regno >= DBG_MAX_REG_NUM || regno < 0)
                return -EINVAL;

        if (regno < 32 || regno >= 64)
                /* First 0 -> 31 gpr registers*/
                /* pc, msr, ls... registers 64 -> 69 */
                memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
                                dbg_reg_def[regno].size);

        if (regno >= 32 && regno < 64) {
                /* FP registers 32 -> 63 */
#if defined(CONFIG_PPC_85xx) && defined(CONFIG_SPE)
                memcpy(&current->thread.evr[regno-32], mem,
                                dbg_reg_def[regno].size);
#else
                /* fp registers not used by kernel, leave zero */
                return 0;
#endif
        }

        return 0;
}

void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
{
        regs_set_return_ip(regs, pc);
}

/*
 * This function does PowerPC specific processing for interfacing to gdb.
 */
int kgdb_arch_handle_exception(int vector, int signo, int err_code,
                               char *remcom_in_buffer, char *remcom_out_buffer,
                               struct pt_regs *linux_regs)
{
        char *ptr = &remcom_in_buffer[1];
        unsigned long addr;

        switch (remcom_in_buffer[0]) {
                /*
                 * sAA..AA   Step one instruction from AA..AA
                 * This will return an error to gdb ..
                 */
        case 's':
        case 'c':
                /* handle the optional parameter */
                if (kgdb_hex2long(&ptr, &addr))
                        regs_set_return_ip(linux_regs, addr);

                atomic_set(&kgdb_cpu_doing_single_step, -1);
                /* set the trace bit if we're stepping */
                if (remcom_in_buffer[0] == 's') {
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
                        mtspr(SPRN_DBCR0,
                              mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
                        regs_set_return_msr(linux_regs, linux_regs->msr | MSR_DE);
#else
                        regs_set_return_msr(linux_regs, linux_regs->msr | MSR_SE);
#endif
                        atomic_set(&kgdb_cpu_doing_single_step,
                                   raw_smp_processor_id());
                }
                return 0;
        }

        return -1;
}

int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
{
        u32 instr, *addr = (u32 *)bpt->bpt_addr;
        int err;

        err = get_kernel_nofault(instr, addr);
        if (err)
                return err;

        err = patch_instruction(addr, ppc_inst(BREAK_INSTR));
        if (err)
                return -EFAULT;

        *(u32 *)bpt->saved_instr = instr;

        return 0;
}

int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
{
        int err;
        unsigned int instr = *(unsigned int *)bpt->saved_instr;
        u32 *addr = (u32 *)bpt->bpt_addr;

        err = patch_instruction(addr, ppc_inst(instr));
        if (err)
                return -EFAULT;

        return 0;
}

/*
 * Global data
 */
const struct kgdb_arch arch_kgdb_ops;

static int kgdb_not_implemented(struct pt_regs *regs)
{
        return 0;
}

static void *old__debugger_ipi;
static void *old__debugger;
static void *old__debugger_bpt;
static void *old__debugger_sstep;
static void *old__debugger_iabr_match;
static void *old__debugger_break_match;
static void *old__debugger_fault_handler;

int kgdb_arch_init(void)
{
        old__debugger_ipi = __debugger_ipi;
        old__debugger = __debugger;
        old__debugger_bpt = __debugger_bpt;
        old__debugger_sstep = __debugger_sstep;
        old__debugger_iabr_match = __debugger_iabr_match;
        old__debugger_break_match = __debugger_break_match;
        old__debugger_fault_handler = __debugger_fault_handler;

        __debugger_ipi = kgdb_debugger_ipi;
        __debugger = kgdb_debugger;
        __debugger_bpt = kgdb_handle_breakpoint;
        __debugger_sstep = kgdb_singlestep;
        __debugger_iabr_match = kgdb_iabr_match;
        __debugger_break_match = kgdb_break_match;
        __debugger_fault_handler = kgdb_not_implemented;

        return 0;
}

void kgdb_arch_exit(void)
{
        __debugger_ipi = old__debugger_ipi;
        __debugger = old__debugger;
        __debugger_bpt = old__debugger_bpt;
        __debugger_sstep = old__debugger_sstep;
        __debugger_iabr_match = old__debugger_iabr_match;
        __debugger_break_match = old__debugger_break_match;
        __debugger_fault_handler = old__debugger_fault_handler;
}