cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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muldi3.c (1709B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 */
      4
      5#include <linux/export.h>
      6#include <linux/libgcc.h>
      7
      8#define W_TYPE_SIZE 32
      9
     10#define __ll_B ((unsigned long) 1 << (W_TYPE_SIZE / 2))
     11#define __ll_lowpart(t) ((unsigned long) (t) & (__ll_B - 1))
     12#define __ll_highpart(t) ((unsigned long) (t) >> (W_TYPE_SIZE / 2))
     13
     14/* If we still don't have umul_ppmm, define it using plain C.  */
     15#if !defined(umul_ppmm)
     16#define umul_ppmm(w1, w0, u, v)						\
     17	do {								\
     18		unsigned long __x0, __x1, __x2, __x3;			\
     19		unsigned short __ul, __vl, __uh, __vh;			\
     20									\
     21		__ul = __ll_lowpart(u);					\
     22		__uh = __ll_highpart(u);				\
     23		__vl = __ll_lowpart(v);					\
     24		__vh = __ll_highpart(v);				\
     25									\
     26		__x0 = (unsigned long) __ul * __vl;			\
     27		__x1 = (unsigned long) __ul * __vh;			\
     28		__x2 = (unsigned long) __uh * __vl;			\
     29		__x3 = (unsigned long) __uh * __vh;			\
     30									\
     31		__x1 += __ll_highpart(__x0); /* this can't give carry */\
     32		__x1 += __x2; /* but this indeed can */			\
     33		if (__x1 < __x2) /* did we get it? */			\
     34		__x3 += __ll_B; /* yes, add it in the proper pos */	\
     35									\
     36		(w1) = __x3 + __ll_highpart(__x1);			\
     37		(w0) = __ll_lowpart(__x1) * __ll_B + __ll_lowpart(__x0);\
     38	} while (0)
     39#endif
     40
     41#if !defined(__umulsidi3)
     42#define __umulsidi3(u, v) ({				\
     43	DWunion __w;					\
     44	umul_ppmm(__w.s.high, __w.s.low, u, v);		\
     45	__w.ll;						\
     46	})
     47#endif
     48
     49long long notrace __muldi3(long long u, long long v)
     50{
     51	const DWunion uu = {.ll = u};
     52	const DWunion vv = {.ll = v};
     53	DWunion w = {.ll = __umulsidi3(uu.s.low, vv.s.low)};
     54
     55	w.s.high += ((unsigned long) uu.s.low * (unsigned long) vv.s.high
     56		+ (unsigned long) uu.s.high * (unsigned long) vv.s.low);
     57
     58	return w.ll;
     59}
     60EXPORT_SYMBOL(__muldi3);