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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pai.h (1723B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2/*
      3 * Processor Activity Instrumentation support for cryptography counters
      4 *
      5 *  Copyright IBM Corp. 2022
      6 *  Author(s): Thomas Richter <tmricht@linux.ibm.com>
      7 */
      8#ifndef _ASM_S390_PAI_H
      9#define _ASM_S390_PAI_H
     10
     11#include <linux/jump_label.h>
     12#include <asm/lowcore.h>
     13#include <asm/ptrace.h>
     14
     15struct qpaci_info_block {
     16	u64 header;
     17	struct {
     18		u64 : 8;
     19		u64 num_cc : 8;	/* # of supported crypto counters */
     20		u64 : 48;
     21	};
     22};
     23
     24static inline int qpaci(struct qpaci_info_block *info)
     25{
     26	/* Size of info (in double words minus one) */
     27	size_t size = sizeof(*info) / sizeof(u64) - 1;
     28	int cc;
     29
     30	asm volatile(
     31		"	lgr	0,%[size]\n"
     32		"	.insn	s,0xb28f0000,%[info]\n"
     33		"	lgr	%[size],0\n"
     34		"	ipm	%[cc]\n"
     35		"	srl	%[cc],28\n"
     36		: [cc] "=d" (cc), [info] "=Q" (*info), [size] "+&d" (size)
     37		:
     38		: "0", "cc", "memory");
     39	return cc ? (size + 1) * sizeof(u64) : 0;
     40}
     41
     42#define PAI_CRYPTO_BASE			0x1000	/* First event number */
     43#define PAI_CRYPTO_MAXCTR		256	/* Max # of event counters */
     44#define PAI_CRYPTO_KERNEL_OFFSET	2048
     45
     46DECLARE_STATIC_KEY_FALSE(pai_key);
     47
     48static __always_inline void pai_kernel_enter(struct pt_regs *regs)
     49{
     50	if (!IS_ENABLED(CONFIG_PERF_EVENTS))
     51		return;
     52	if (!static_branch_unlikely(&pai_key))
     53		return;
     54	if (!S390_lowcore.ccd)
     55		return;
     56	if (!user_mode(regs))
     57		return;
     58	WRITE_ONCE(S390_lowcore.ccd, S390_lowcore.ccd | PAI_CRYPTO_KERNEL_OFFSET);
     59}
     60
     61static __always_inline void pai_kernel_exit(struct pt_regs *regs)
     62{
     63	if (!IS_ENABLED(CONFIG_PERF_EVENTS))
     64		return;
     65	if (!static_branch_unlikely(&pai_key))
     66		return;
     67	if (!S390_lowcore.ccd)
     68		return;
     69	if (!user_mode(regs))
     70		return;
     71	WRITE_ONCE(S390_lowcore.ccd, S390_lowcore.ccd & ~PAI_CRYPTO_KERNEL_OFFSET);
     72}
     73
     74#endif