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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fcmpo.c (1010B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <linux/types.h>
      3#include <linux/errno.h>
      4#include <linux/uaccess.h>
      5
      6#include <asm/sfp-machine.h>
      7#include <math-emu/soft-fp.h>
      8#include <math-emu/double.h>
      9
     10int
     11fcmpo(u32 *ccr, int crfD, void *frA, void *frB)
     12{
     13	FP_DECL_D(A);
     14	FP_DECL_D(B);
     15	FP_DECL_EX;
     16	int code[4] = { (1 << 3), (1 << 1), (1 << 2), (1 << 0) };
     17	long cmp;
     18
     19#ifdef DEBUG
     20	printk("%s: %p (%08x) %d %p %p\n", __func__, ccr, *ccr, crfD, frA, frB);
     21#endif
     22
     23	FP_UNPACK_DP(A, frA);
     24	FP_UNPACK_DP(B, frB);
     25
     26#ifdef DEBUG
     27	printk("A: %ld %lu %lu %ld (%ld)\n", A_s, A_f1, A_f0, A_e, A_c);
     28	printk("B: %ld %lu %lu %ld (%ld)\n", B_s, B_f1, B_f0, B_e, B_c);
     29#endif
     30
     31	if (A_c == FP_CLS_NAN || B_c == FP_CLS_NAN)
     32		FP_SET_EXCEPTION(EFLAG_VXVC);
     33
     34	FP_CMP_D(cmp, A, B, 2);
     35	cmp = code[(cmp + 1) & 3];
     36
     37	__FPU_FPSCR &= ~(0x1f000);
     38	__FPU_FPSCR |= (cmp << 12);
     39
     40	*ccr &= ~(15 << ((7 - crfD) << 2));
     41	*ccr |= (cmp << ((7 - crfD) << 2));
     42
     43#ifdef DEBUG
     44	printk("CR: %08x\n", *ccr);
     45#endif
     46
     47	return FP_CUR_EXCEPTIONS;
     48}