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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jump_label.c (1062B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <linux/kernel.h>
      3#include <linux/types.h>
      4#include <linux/mutex.h>
      5#include <linux/cpu.h>
      6
      7#include <linux/jump_label.h>
      8#include <linux/memory.h>
      9
     10#include <asm/cacheflush.h>
     11
     12void arch_jump_label_transform(struct jump_entry *entry,
     13			       enum jump_label_type type)
     14{
     15	u32 *insn = (u32 *) (unsigned long) entry->code;
     16	u32 val;
     17
     18	if (type == JUMP_LABEL_JMP) {
     19		s32 off = (s32)entry->target - (s32)entry->code;
     20		bool use_v9_branch = false;
     21
     22		BUG_ON(off & 3);
     23
     24#ifdef CONFIG_SPARC64
     25		if (off <= 0xfffff && off >= -0x100000)
     26			use_v9_branch = true;
     27#endif
     28		if (use_v9_branch) {
     29			/* WDISP19 - target is . + immed << 2 */
     30			/* ba,pt %xcc, . + off */
     31			val = 0x10680000 | (((u32) off >> 2) & 0x7ffff);
     32		} else {
     33			/* WDISP22 - target is . + immed << 2 */
     34			BUG_ON(off > 0x7fffff);
     35			BUG_ON(off < -0x800000);
     36			/* ba . + off */
     37			val = 0x10800000 | (((u32) off >> 2) & 0x3fffff);
     38		}
     39	} else {
     40		val = 0x01000000;
     41	}
     42
     43	mutex_lock(&text_mutex);
     44	*insn = val;
     45	flushi(insn);
     46	mutex_unlock(&text_mutex);
     47}