Refactor the first prime index.
[oweals/openssl.git] / crypto / bn / bn_exp.c
index 8441994e9b733ccbb5742563283fff27ecf6e94b..ea2bd0a8984bb29a4ef537817ccf0361d9c5102a 100644 (file)
 # ifndef alloca
 #  define alloca(s) __builtin_alloca((s))
 # endif
+#elif defined(__sun)
+# include <alloca.h>
 #endif
 
-#if defined(OPENSSL_BN_ASM_MONT) && defined(__sparc__)
+#undef RSAZ_ENABLED
+#if defined(OPENSSL_BN_ASM_MONT) && \
+       (defined(__x86_64) || defined(__x86_64__) || \
+        defined(_M_AMD64) || defined(_M_X64))
+# include "rsaz_exp.h"
+# define RSAZ_ENABLED
+#endif
+
+#undef SPARC_T4_MONT
+#if defined(OPENSSL_BN_ASM_MONT) && (defined(__sparc__) || defined(__sparc))
 # include "sparc_arch.h"
 extern unsigned int OPENSSL_sparcv9cap_P[];
+# define SPARC_T4_MONT
 #endif
 
 /* maximum precomputation table size for *variable* sliding windows */
@@ -473,6 +485,21 @@ int BN_mod_exp_mont(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
        wstart=bits-1;  /* The top bit of the window */
        wend=0;         /* The bottom bit of the window */
 
+#if 1  /* by Shay Gueron's suggestion */
+       j = m->top;     /* borrow j */
+       if (m->d[j-1] & (((BN_ULONG)1)<<(BN_BITS2-1)))
+               {
+               if (bn_wexpand(r,j) == NULL) goto err;
+               /* 2^(top*BN_BITS2) - m */
+               r->d[0] = (0-m->d[0])&BN_MASK2;
+               for(i=1;i<j;i++) r->d[i] = (~m->d[i])&BN_MASK2;
+               r->top = j;
+               /* Upper words will be zero if the corresponding words of 'm'
+                * were 0xfff[...], so decrement r->top accordingly. */
+               bn_correct_top(r);
+               }
+       else
+#endif
        if (!BN_to_montgomery(r,BN_value_one(),mont,ctx)) goto err;
        for (;;)
                {
@@ -525,6 +552,17 @@ int BN_mod_exp_mont(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
                start=0;
                if (wstart < 0) break;
                }
+#if defined(SPARC_T4_MONT)
+       if (OPENSSL_sparcv9cap_P[0]&(SPARCV9_VIS3|SPARCV9_PREFER_FPU))
+               {
+               j = mont->N.top;        /* borrow j */
+               val[0]->d[0] = 1;       /* borrow val[0] */
+               for (i=1;i<j;i++) val[0]->d[i] = 0;
+               val[0]->top = j;
+               if (!BN_mod_mul_montgomery(rr,r,val[0],mont,ctx)) goto err;
+               }
+       else
+#endif
        if (!BN_from_montgomery(rr,r,mont,ctx)) goto err;
        ret=1;
 err:
@@ -534,6 +572,28 @@ err:
        return(ret);
        }
 
+#if defined(SPARC_T4_MONT)
+static BN_ULONG bn_get_bits(const BIGNUM *a, int bitpos)
+       {
+       BN_ULONG ret=0;
+       int wordpos;
+
+       wordpos = bitpos/BN_BITS2;
+       bitpos %= BN_BITS2;
+       if (wordpos>=0 && wordpos < a->top)
+               {
+               ret = a->d[wordpos]&BN_MASK2;
+               if (bitpos)
+                       {
+                       ret >>= bitpos;
+                       if (++wordpos < a->top)
+                               ret |= a->d[wordpos]<<(BN_BITS2-bitpos);
+                       }
+               }
+
+       return ret&BN_MASK2;
+}
+#endif
 
 /* BN_mod_exp_mont_consttime() stores the precomputed powers in a specific layout
  * so that accessing any of these table values shows the same access pattern as far
@@ -593,7 +653,7 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
        int powerbufLen = 0;
        unsigned char *powerbuf=NULL;
        BIGNUM tmp, am;
-#if defined(OPENSSL_BN_ASM_MONT) && defined(__sparc__)
+#if defined(SPARC_T4_MONT)
        unsigned int t4=0;
 #endif
 
@@ -628,9 +688,39 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
                if (!BN_MONT_CTX_set(mont,m,ctx)) goto err;
                }
 
+#ifdef RSAZ_ENABLED
+       /*
+        * If the size of the operands allow it, perform the optimized
+        * RSAZ exponentiation. For further information see
+        * crypto/bn/rsaz_exp.c and accompanying assembly modules.
+        */
+       if (((OPENSSL_ia32cap_P[2]&0x80100) != 0x80100) /* check for MULX/AD*X */
+           && (16 == a->top) && (16 == p->top) && (BN_num_bits(m) == 1024)
+           && rsaz_avx2_eligible())
+               {
+               if (NULL == bn_wexpand(rr, 16)) goto err;
+               RSAZ_1024_mod_exp_avx2(rr->d, a->d, p->d, m->d, mont->RR.d, mont->n0[0]);
+               rr->top = 16;
+               rr->neg = 0;
+               bn_correct_top(rr);
+               ret = 1;
+               goto err;
+               }
+       else if ((8 == a->top) && (8 == p->top) && (BN_num_bits(m) == 512))
+               {
+               if (NULL == bn_wexpand(rr,8)) goto err;
+               RSAZ_512_mod_exp(rr->d, a->d, p->d, m->d, mont->n0[0], mont->RR.d);
+               rr->top = 8;
+               rr->neg = 0;
+               bn_correct_top(rr);
+               ret = 1;
+               goto err;
+               }
+#endif
+
        /* Get the window size to use with size of p. */
        window = BN_window_bits_for_ctime_exponent_size(bits);
-#if defined(OPENSSL_BN_ASM_MONT) && defined(__sparc__)
+#if defined(SPARC_T4_MONT)
        if (window>=5 && (top&15)==0 && top<=64 &&
            (OPENSSL_sparcv9cap_P[1]&(CFR_MONTMUL|CFR_MONTSQR))==
                                     (CFR_MONTMUL|CFR_MONTSQR) &&
@@ -639,7 +729,11 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
        else
 #endif
 #if defined(OPENSSL_BN_ASM_MONT5)
-       if (window==6 && bits<=1024) window=5;  /* ~5% improvement of 2048-bit RSA sign */
+       if (window>=5)
+               {
+               window=5;       /* ~5% improvement for RSA2048 sign, and even for RSA4096 */
+               if ((top&7)==0) powerbufLen += 2*top*sizeof(m->d[0]);
+               }
 #endif
        (void)0;
 
@@ -647,7 +741,7 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
         * powers of am, am itself and tmp.
         */
        numPowers = 1 << window;
-       powerbufLen = sizeof(m->d[0])*(top*numPowers +
+       powerbufLen += sizeof(m->d[0])*(top*numPowers +
                                ((2*top)>numPowers?(2*top):numPowers));
 #ifdef alloca
        if (powerbufLen < 3072)
@@ -674,14 +768,17 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
        tmp.flags = am.flags = BN_FLG_STATIC_DATA;
 
        /* prepare a^0 in Montgomery domain */
-#if 1
-       if (!BN_to_montgomery(&tmp,BN_value_one(),mont,ctx))    goto err;
-#else
-       tmp.d[0] = (0-m->d[0])&BN_MASK2;        /* 2^(top*BN_BITS2) - m */
-       for (i=1;i<top;i++)
-               tmp.d[i] = (~m->d[i])&BN_MASK2;
-       tmp.top = top;
+#if 1  /* by Shay Gueron's suggestion */
+       if (m->d[top-1] & (((BN_ULONG)1)<<(BN_BITS2-1)))
+               {
+               /* 2^(top*BN_BITS2) - m */
+               tmp.d[0] = (0-m->d[0])&BN_MASK2;
+               for (i=1;i<top;i++) tmp.d[i] = (~m->d[i])&BN_MASK2;
+               tmp.top = top;
+               }
+       else
 #endif
+       if (!BN_to_montgomery(&tmp,BN_value_one(),mont,ctx))    goto err;
 
        /* prepare a^1 in Montgomery domain */
        if (a->neg || BN_ucmp(a,m) >= 0)
@@ -691,61 +788,83 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
                }
        else    if (!BN_to_montgomery(&am,a,mont,ctx))          goto err;
 
-#if defined(OPENSSL_BN_ASM_MONT) && defined(__sparc__)
+#if defined(SPARC_T4_MONT)
     if (t4)
        {
        typedef int (*bn_pwr5_mont_f)(BN_ULONG *tp,const BN_ULONG *np,
-                       const BN_ULONG *n0,const void *table,int power);
+                       const BN_ULONG *n0,const void *table,int power,int bits);
        int bn_pwr5_mont_t4_8(BN_ULONG *tp,const BN_ULONG *np,
-                       const BN_ULONG *n0,const void *table,int power);
+                       const BN_ULONG *n0,const void *table,int power,int bits);
        int bn_pwr5_mont_t4_16(BN_ULONG *tp,const BN_ULONG *np,
-                       const BN_ULONG *n0,const void *table,int power);
+                       const BN_ULONG *n0,const void *table,int power,int bits);
        int bn_pwr5_mont_t4_24(BN_ULONG *tp,const BN_ULONG *np,
-                       const BN_ULONG *n0,const void *table,int power);
+                       const BN_ULONG *n0,const void *table,int power,int bits);
        int bn_pwr5_mont_t4_32(BN_ULONG *tp,const BN_ULONG *np,
-                       const BN_ULONG *n0,const void *table,int power);
-       static const bn_pwr5_mont_f funcs[4] = {
+                       const BN_ULONG *n0,const void *table,int power,int bits);
+       static const bn_pwr5_mont_f pwr5_funcs[4] = {
                        bn_pwr5_mont_t4_8,      bn_pwr5_mont_t4_16,
                        bn_pwr5_mont_t4_24,     bn_pwr5_mont_t4_32 };
-       bn_pwr5_mont_f worker = funcs[top/16-1];
-
+       bn_pwr5_mont_f pwr5_worker = pwr5_funcs[top/16-1];
+
+       typedef int (*bn_mul_mont_f)(BN_ULONG *rp,const BN_ULONG *ap,
+                       const void *bp,const BN_ULONG *np,const BN_ULONG *n0);
+       int bn_mul_mont_t4_8(BN_ULONG *rp,const BN_ULONG *ap,
+                       const void *bp,const BN_ULONG *np,const BN_ULONG *n0);
+       int bn_mul_mont_t4_16(BN_ULONG *rp,const BN_ULONG *ap,
+                       const void *bp,const BN_ULONG *np,const BN_ULONG *n0);
+       int bn_mul_mont_t4_24(BN_ULONG *rp,const BN_ULONG *ap,
+                       const void *bp,const BN_ULONG *np,const BN_ULONG *n0);
+       int bn_mul_mont_t4_32(BN_ULONG *rp,const BN_ULONG *ap,
+                       const void *bp,const BN_ULONG *np,const BN_ULONG *n0);
+       static const bn_mul_mont_f mul_funcs[4] = {
+                       bn_mul_mont_t4_8,       bn_mul_mont_t4_16,
+                       bn_mul_mont_t4_24,      bn_mul_mont_t4_32 };
+       bn_mul_mont_f mul_worker = mul_funcs[top/16-1];
+
+       void bn_mul_mont_vis3(BN_ULONG *rp,const BN_ULONG *ap,
+                       const void *bp,const BN_ULONG *np,
+                       const BN_ULONG *n0,int num);
        void bn_mul_mont_t4(BN_ULONG *rp,const BN_ULONG *ap,
                        const void *bp,const BN_ULONG *np,
                        const BN_ULONG *n0,int num);
        void bn_mul_mont_gather5_t4(BN_ULONG *rp,const BN_ULONG *ap,
                        const void *table,const BN_ULONG *np,
                        const BN_ULONG *n0,int num,int power);
-       void bn_scatter5_t4(const BN_ULONG *inp,size_t num,
+       void bn_flip_n_scatter5_t4(const BN_ULONG *inp,size_t num,
                        void *table,size_t power);
        void bn_gather5_t4(BN_ULONG *out,size_t num,
                        void *table,size_t power);
        void bn_flip_t4(BN_ULONG *dst,BN_ULONG *src,size_t num);
 
-       BN_ULONG *np=alloca(top*sizeof(BN_ULONG)), *n0=mont->n0;
+       BN_ULONG *np=mont->N.d, *n0=mont->n0;
+       int stride = 5*(6-(top/16-1));  /* multiple of 5, but less than 32 */
 
        /* BN_to_montgomery can contaminate words above .top
         * [in BN_DEBUG[_DEBUG] build]... */
        for (i=am.top; i<top; i++)      am.d[i]=0;
        for (i=tmp.top; i<top; i++)     tmp.d[i]=0;
 
-       /* switch to 64-bit domain */ 
-       top /= 2;
-       bn_flip_t4(np,mont->N.d,top);
-       bn_flip_t4(tmp.d,tmp.d,top);
-       bn_flip_t4(am.d,am.d,top);
-
-       bn_scatter5_t4(tmp.d,top,powerbuf,0);
-       bn_scatter5_t4(am.d,top,powerbuf,1);
-       bn_mul_mont_t4(tmp.d,am.d,am.d,np,n0,top);
-       bn_scatter5_t4(tmp.d,top,powerbuf,2);
+       bn_flip_n_scatter5_t4(tmp.d,top,powerbuf,0);
+       bn_flip_n_scatter5_t4(am.d,top,powerbuf,1);
+       if (!(*mul_worker)(tmp.d,am.d,am.d,np,n0) &&
+           !(*mul_worker)(tmp.d,am.d,am.d,np,n0))
+               bn_mul_mont_vis3(tmp.d,am.d,am.d,np,n0,top);
+       bn_flip_n_scatter5_t4(tmp.d,top,powerbuf,2);
 
        for (i=3; i<32; i++)
                {
                /* Calculate a^i = a^(i-1) * a */
-               bn_mul_mont_gather5_t4(tmp.d,am.d,powerbuf,np,n0,top,i-1);
-               bn_scatter5_t4(tmp.d,top,powerbuf,i);
+               if (!(*mul_worker)(tmp.d,tmp.d,am.d,np,n0) &&
+                   !(*mul_worker)(tmp.d,tmp.d,am.d,np,n0))
+                       bn_mul_mont_vis3(tmp.d,tmp.d,am.d,np,n0,top);
+               bn_flip_n_scatter5_t4(tmp.d,top,powerbuf,i);
                }
 
+       /* switch to 64-bit domain */ 
+       np = alloca(top*sizeof(BN_ULONG));
+       top /= 2;
+       bn_flip_t4(np,mont->N.d,top);
+
        bits--;
        for (wvalue=0, i=bits%5; i>=0; i--,bits--)
                wvalue = (wvalue<<1)+BN_is_bit_set(p,bits);
@@ -756,12 +875,17 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
         */
        while (bits >= 0)
                {
-               for (wvalue=0, i=0; i<5; i++,bits--)
-                       wvalue = (wvalue<<1)+BN_is_bit_set(p,bits);
+               if (bits < stride) stride = bits+1;
+               bits -= stride;
+               wvalue = bn_get_bits(p,bits+1);
 
-               if ((*worker)(tmp.d,np,n0,powerbuf,wvalue)) continue;
+               if ((*pwr5_worker)(tmp.d,np,n0,powerbuf,wvalue,stride)) continue;
                /* retry once and fall back */
-               if ((*worker)(tmp.d,np,n0,powerbuf,wvalue)) continue;
+               if ((*pwr5_worker)(tmp.d,np,n0,powerbuf,wvalue,stride)) continue;
+
+               bits += stride-5;
+               wvalue >>= stride-5;
+               wvalue &= 31;
                bn_mul_mont_t4(tmp.d,tmp.d,tmp.d,np,n0,top);
                bn_mul_mont_t4(tmp.d,tmp.d,tmp.d,np,n0,top);
                bn_mul_mont_t4(tmp.d,tmp.d,tmp.d,np,n0,top);
@@ -795,14 +919,26 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
                        void *table,size_t power);
        void bn_gather5(BN_ULONG *out,size_t num,
                        void *table,size_t power);
+       void bn_power5(BN_ULONG *rp,const BN_ULONG *ap,
+                       const void *table,const BN_ULONG *np,
+                       const BN_ULONG *n0,int num,int power);
+       int bn_get_bits5(const BN_ULONG *ap,int off);
+       int bn_from_montgomery(BN_ULONG *rp,const BN_ULONG *ap,
+                       const BN_ULONG *not_used,const BN_ULONG *np,
+                       const BN_ULONG *n0,int num);
 
-       BN_ULONG *np=mont->N.d, *n0=mont->n0;
+       BN_ULONG *np=mont->N.d, *n0=mont->n0, *np2;
 
        /* BN_to_montgomery can contaminate words above .top
         * [in BN_DEBUG[_DEBUG] build]... */
        for (i=am.top; i<top; i++)      am.d[i]=0;
        for (i=tmp.top; i<top; i++)     tmp.d[i]=0;
 
+       if (top&7)
+               np2 = np;
+       else
+               for (np2=am.d+top,i=0; i<top; i++) np2[2*i]=np[i];
+
        bn_scatter5(tmp.d,top,powerbuf,0);
        bn_scatter5(am.d,am.top,powerbuf,1);
        bn_mul_mont(tmp.d,am.d,am.d,np,n0,top);
@@ -812,7 +948,7 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
        for (i=3; i<32; i++)
                {
                /* Calculate a^i = a^(i-1) * a */
-               bn_mul_mont_gather5(tmp.d,am.d,powerbuf,np,n0,top,i-1);
+               bn_mul_mont_gather5(tmp.d,am.d,powerbuf,np2,n0,top,i-1);
                bn_scatter5(tmp.d,top,powerbuf,i);
                }
 #else
@@ -825,7 +961,7 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
        for (i=3; i<8; i+=2)
                {
                int j;
-               bn_mul_mont_gather5(tmp.d,am.d,powerbuf,np,n0,top,i-1);
+               bn_mul_mont_gather5(tmp.d,am.d,powerbuf,np2,n0,top,i-1);
                bn_scatter5(tmp.d,top,powerbuf,i);
                for (j=2*i; j<32; j*=2)
                        {
@@ -835,14 +971,14 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
                }
        for (; i<16; i+=2)
                {
-               bn_mul_mont_gather5(tmp.d,am.d,powerbuf,np,n0,top,i-1);
+               bn_mul_mont_gather5(tmp.d,am.d,powerbuf,np2,n0,top,i-1);
                bn_scatter5(tmp.d,top,powerbuf,i);
                bn_mul_mont(tmp.d,tmp.d,tmp.d,np,n0,top);
                bn_scatter5(tmp.d,top,powerbuf,2*i);
                }
        for (; i<32; i+=2)
                {
-               bn_mul_mont_gather5(tmp.d,am.d,powerbuf,np,n0,top,i-1);
+               bn_mul_mont_gather5(tmp.d,am.d,powerbuf,np2,n0,top,i-1);
                bn_scatter5(tmp.d,top,powerbuf,i);
                }
 #endif
@@ -854,7 +990,8 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
        /* Scan the exponent one window at a time starting from the most
         * significant bits.
         */
-       while (bits >= 0)
+       if (top&7)
+           while (bits >= 0)
                {
                for (wvalue=0, i=0; i<5; i++,bits--)
                        wvalue = (wvalue<<1)+BN_is_bit_set(p,bits);
@@ -866,9 +1003,24 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
                bn_mul_mont(tmp.d,tmp.d,tmp.d,np,n0,top);
                bn_mul_mont_gather5(tmp.d,tmp.d,powerbuf,np,n0,top,wvalue);
                }
+       else
+           {
+           while (bits >= 0)
+               {
+               wvalue = bn_get_bits5(p->d,bits-4);
+               bits-=5;
+               bn_power5(tmp.d,tmp.d,powerbuf,np2,n0,top,wvalue);
+               }
+           }
 
+       ret=bn_from_montgomery(tmp.d,tmp.d,NULL,np2,n0,top);
        tmp.top=top;
        bn_correct_top(&tmp);
+       if (ret)
+               {
+               if (!BN_copy(rr,&tmp)) ret=0;
+               goto err; /* non-zero ret means it's not error */
+               }
        }
     else
 #endif
@@ -922,6 +1074,15 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
        }
 
        /* Convert the final result from montgomery to standard format */
+#if defined(SPARC_T4_MONT)
+       if (OPENSSL_sparcv9cap_P[0]&(SPARCV9_VIS3|SPARCV9_PREFER_FPU))
+               {
+               am.d[0] = 1;    /* borrow am */
+               for (i=1;i<top;i++) am.d[i] = 0;
+               if (!BN_mod_mul_montgomery(rr,&tmp,&am,mont,ctx)) goto err;
+               }
+       else
+#endif
        if (!BN_from_montgomery(rr,&tmp,mont,ctx)) goto err;
        ret=1;
 err:
@@ -980,7 +1141,14 @@ int BN_mod_exp_mont_word(BIGNUM *rr, BN_ULONG a, const BIGNUM *p,
        bits = BN_num_bits(p);
        if (bits == 0)
                {
-               ret = BN_one(rr);
+               /* x**0 mod 1 is still zero. */
+               if (BN_is_one(m))
+                       {
+                       ret = 1;
+                       BN_zero(rr);
+                       }
+               else
+                       ret = BN_one(rr);
                return ret;
                }
        if (a == 0)