/*
 * Copyright 2009-2016 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <setjmp.h>
#include <signal.h>
#include <unistd.h>
#if defined(__linux) || defined(_AIX)
# include <sys/utsname.h>
#endif
#if defined(_AIX53)     /* defined even on post-5.3 */
# include <sys/systemcfg.h>
# if !defined(__power_set)
#  define __power_set(a) (_system_configuration.implementation & (a))
# endif
#endif
#include <openssl/crypto.h>

#include "ppc_arch.h"

unsigned int OPENSSL_ppccap_P = 0;

static sigset_t all_masked;

static sigjmp_buf ill_jmp;
static void ill_handler(int sig)
{
    siglongjmp(ill_jmp, sig);
}

void OPENSSL_fpu_probe(void);
void OPENSSL_ppc64_probe(void);
void OPENSSL_altivec_probe(void);
void OPENSSL_crypto207_probe(void);
void OPENSSL_madd300_probe(void);

/*
 * Use a weak reference to getauxval() so we can use it if it is available
 * but don't break the build if it is not. Note that this is *link-time*
 * feature detection, not *run-time*. In other words if we link with
 * symbol present, it's expected to be present even at run-time.
 */
#if defined(__GNUC__) && __GNUC__>=2 && defined(__ELF__)
extern unsigned long getauxval(unsigned long type) __attribute__ ((weak));
#else
static unsigned long (*getauxval) (unsigned long) = NULL;
#endif

/* I wish <sys/auxv.h> was universally available */
#define HWCAP                   16      /* AT_HWCAP */
#define HWCAP_PPC64             (1U << 30)
#define HWCAP_ALTIVEC           (1U << 28)
#define HWCAP_FPU               (1U << 27)
#define HWCAP_POWER6_EXT        (1U << 9)
#define HWCAP_VSX               (1U << 7)

#define HWCAP2                  26      /* AT_HWCAP2 */
#define HWCAP_VEC_CRYPTO        (1U << 25)
#define HWCAP_ARCH_3_00         (1U << 23)

# if defined(__GNUC__) && __GNUC__>=2
__attribute__ ((constructor))
# endif
void OPENSSL_cpuid_setup(void)
{
    char *e;
    struct sigaction ill_oact, ill_act;
    sigset_t oset;
    static int trigger = 0;

    if (trigger)
        return;
    trigger = 1;

    if ((e = getenv("OPENSSL_ppccap"))) {
        OPENSSL_ppccap_P = strtoul(e, NULL, 0);
        return;
    }

    OPENSSL_ppccap_P = 0;

#if defined(_AIX)
    OPENSSL_ppccap_P |= PPC_FPU;

    if (sizeof(size_t) == 4) {
        struct utsname uts;
# if defined(_SC_AIX_KERNEL_BITMODE)
        if (sysconf(_SC_AIX_KERNEL_BITMODE) != 64)
            return;
# endif
        if (uname(&uts) != 0 || atoi(uts.version) < 6)
            return;
    }

# if defined(__power_set)
    /*
     * Value used in __power_set is a single-bit 1<<n one denoting
     * specific processor class. Incidentally 0xffffffff<<n can be
     * used to denote specific processor and its successors.
     */
    if (sizeof(size_t) == 4) {
        /* In 32-bit case PPC_FPU64 is always fastest [if option] */
        if (__power_set(0xffffffffU<<13))       /* POWER5 and later */
            OPENSSL_ppccap_P |= PPC_FPU64;
    } else {
        /* In 64-bit case PPC_FPU64 is fastest only on POWER6 */
        if (__power_set(0x1U<<14))              /* POWER6 */
            OPENSSL_ppccap_P |= PPC_FPU64;
    }

    if (__power_set(0xffffffffU<<14))           /* POWER6 and later */
        OPENSSL_ppccap_P |= PPC_ALTIVEC;

    if (__power_set(0xffffffffU<<16))           /* POWER8 and later */
        OPENSSL_ppccap_P |= PPC_CRYPTO207;

    if (__power_set(0xffffffffU<<17))           /* POWER9 and later */
        OPENSSL_ppccap_P |= PPC_MADD300;

    return;
# endif
#endif

    if (getauxval != NULL) {
        unsigned long hwcap = getauxval(HWCAP);

        if (hwcap & HWCAP_FPU) {
            OPENSSL_ppccap_P |= PPC_FPU;

            if (sizeof(size_t) == 4) {
                /* In 32-bit case PPC_FPU64 is always fastest [if option] */
                if (hwcap & HWCAP_PPC64)
                    OPENSSL_ppccap_P |= PPC_FPU64;
            } else {
                /* In 64-bit case PPC_FPU64 is fastest only on POWER6 */
                if (hwcap & HWCAP_POWER6_EXT)
                    OPENSSL_ppccap_P |= PPC_FPU64;
            }
        }

        if (hwcap & HWCAP_ALTIVEC) {
            OPENSSL_ppccap_P |= PPC_ALTIVEC;

            if ((hwcap & HWCAP_VSX) && (getauxval(HWCAP2) & HWCAP_VEC_CRYPTO))
                OPENSSL_ppccap_P |= PPC_CRYPTO207;
        }

        if (hwcap & HWCAP_ARCH_3_00) {
            OPENSSL_ppccap_P |= PPC_MADD300;
        }

        return;
    }

    sigfillset(&all_masked);
    sigdelset(&all_masked, SIGILL);
    sigdelset(&all_masked, SIGTRAP);
#ifdef SIGEMT
    sigdelset(&all_masked, SIGEMT);
#endif
    sigdelset(&all_masked, SIGFPE);
    sigdelset(&all_masked, SIGBUS);
    sigdelset(&all_masked, SIGSEGV);

    memset(&ill_act, 0, sizeof(ill_act));
    ill_act.sa_handler = ill_handler;
    ill_act.sa_mask = all_masked;

    sigprocmask(SIG_SETMASK, &ill_act.sa_mask, &oset);
    sigaction(SIGILL, &ill_act, &ill_oact);

    if (sigsetjmp(ill_jmp,1) == 0) {
        OPENSSL_fpu_probe();
        OPENSSL_ppccap_P |= PPC_FPU;

        if (sizeof(size_t) == 4) {
#ifdef __linux
            struct utsname uts;
            if (uname(&uts) == 0 && strcmp(uts.machine, "ppc64") == 0)
#endif
                if (sigsetjmp(ill_jmp, 1) == 0) {
                    OPENSSL_ppc64_probe();
                    OPENSSL_ppccap_P |= PPC_FPU64;
                }
        } else {
            /*
             * Wanted code detecting POWER6 CPU and setting PPC_FPU64
             */
        }
    }

    if (sigsetjmp(ill_jmp, 1) == 0) {
        OPENSSL_altivec_probe();
        OPENSSL_ppccap_P |= PPC_ALTIVEC;
        if (sigsetjmp(ill_jmp, 1) == 0) {
            OPENSSL_crypto207_probe();
            OPENSSL_ppccap_P |= PPC_CRYPTO207;
        }
    }

    if (sigsetjmp(ill_jmp, 1) == 0) {
        OPENSSL_madd300_probe();
        OPENSSL_ppccap_P |= PPC_MADD300;
    }

    sigaction(SIGILL, &ill_oact, NULL);
    sigprocmask(SIG_SETMASK, &oset, NULL);
}