// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright 2018, Michael Ellerman, IBM Corp.
 *
 * Test that an out-of-bounds branch to counter behaves as expected.
 */

#include <setjmp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <ucontext.h>
#include <unistd.h>

#include "utils.h"


#define BAD_NIP 0x788c545a18000000ull

static struct pt_regs signal_regs;
static jmp_buf setjmp_env;

static void save_regs(ucontext_t *ctxt)
{
        struct pt_regs *regs = ctxt->uc_mcontext.regs;

        memcpy(&signal_regs, regs, sizeof(signal_regs));
}

static void segv_handler(int signum, siginfo_t *info, void *ctxt_v)
{
        save_regs(ctxt_v);
        longjmp(setjmp_env, 1);
}

static void usr2_handler(int signum, siginfo_t *info, void *ctxt_v)
{
        save_regs(ctxt_v);
}

static int ok(void)
{
        printf("Everything is OK in here.\n");
        return 0;
}

#define REG_POISON      0x5a5a
#define POISONED_REG(n) ((((unsigned long)REG_POISON) << 48) | ((n) << 32) | \
                         (((unsigned long)REG_POISON) << 16) | (n))

static inline void poison_regs(void)
{
        #define POISON_REG(n)   \
          "lis  " __stringify(n) "," __stringify(REG_POISON) ";" \
          "addi " __stringify(n) "," __stringify(n) "," __stringify(n) ";" \
          "sldi " __stringify(n) "," __stringify(n) ", 32 ;" \
          "oris " __stringify(n) "," __stringify(n) "," __stringify(REG_POISON) ";" \
          "addi " __stringify(n) "," __stringify(n) "," __stringify(n) ";"

        asm (POISON_REG(15)
             POISON_REG(16)
             POISON_REG(17)
             POISON_REG(18)
             POISON_REG(19)
             POISON_REG(20)
             POISON_REG(21)
             POISON_REG(22)
             POISON_REG(23)
             POISON_REG(24)
             POISON_REG(25)
             POISON_REG(26)
             POISON_REG(27)
             POISON_REG(28)
             POISON_REG(29)
             : // inputs
             : // outputs
             : "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25",
               "26", "27", "28", "29"
        );
        #undef POISON_REG
}

static int check_regs(void)
{
        unsigned long i;

        for (i = 15; i <= 29; i++)
                FAIL_IF(signal_regs.gpr[i] != POISONED_REG(i));

        printf("Regs OK\n");
        return 0;
}

static void dump_regs(void)
{
        for (int i = 0; i < 32; i += 4) {
                printf("r%02d 0x%016lx  r%02d 0x%016lx  " \
                       "r%02d 0x%016lx  r%02d 0x%016lx\n",
                       i, signal_regs.gpr[i],
                       i+1, signal_regs.gpr[i+1],
                       i+2, signal_regs.gpr[i+2],
                       i+3, signal_regs.gpr[i+3]);
        }
}

#ifdef _CALL_AIXDESC
struct opd {
        unsigned long ip;
        unsigned long toc;
        unsigned long env;
};
static struct opd bad_opd = {
        .ip = BAD_NIP,
};
#define BAD_FUNC (&bad_opd)
#else
#define BAD_FUNC BAD_NIP
#endif

int test_wild_bctr(void)
{
        int (*func_ptr)(void);
        struct sigaction segv = {
                .sa_sigaction = segv_handler,
                .sa_flags = SA_SIGINFO
        };
        struct sigaction usr2 = {
                .sa_sigaction = usr2_handler,
                .sa_flags = SA_SIGINFO
        };

        FAIL_IF(sigaction(SIGSEGV, &segv, NULL));
        FAIL_IF(sigaction(SIGUSR2, &usr2, NULL));

        bzero(&signal_regs, sizeof(signal_regs));

        if (setjmp(setjmp_env) == 0) {
                func_ptr = ok;
                func_ptr();

                kill(getpid(), SIGUSR2);
                printf("Regs before:\n");
                dump_regs();
                bzero(&signal_regs, sizeof(signal_regs));

                poison_regs();

                func_ptr = (int (*)(void))BAD_FUNC;
                func_ptr();

                FAIL_IF(1); /* we didn't segv? */
        }

        FAIL_IF(signal_regs.nip != BAD_NIP);

        printf("All good - took SEGV as expected branching to 0x%llx\n", BAD_NIP);

        dump_regs();
        FAIL_IF(check_regs());

        return 0;
}

int main(void)
{
        return test_harness(test_wild_bctr, "wild_bctr");
}