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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spectre.c (1577B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2#include <linux/bpf.h>
      3#include <linux/cpu.h>
      4#include <linux/device.h>
      5
      6#include <asm/spectre.h>
      7
      8static bool _unprivileged_ebpf_enabled(void)
      9{
     10#ifdef CONFIG_BPF_SYSCALL
     11	return !sysctl_unprivileged_bpf_disabled;
     12#else
     13	return false;
     14#endif
     15}
     16
     17ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr,
     18			    char *buf)
     19{
     20	return sprintf(buf, "Mitigation: __user pointer sanitization\n");
     21}
     22
     23static unsigned int spectre_v2_state;
     24static unsigned int spectre_v2_methods;
     25
     26void spectre_v2_update_state(unsigned int state, unsigned int method)
     27{
     28	if (state > spectre_v2_state)
     29		spectre_v2_state = state;
     30	spectre_v2_methods |= method;
     31}
     32
     33ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr,
     34			    char *buf)
     35{
     36	const char *method;
     37
     38	if (spectre_v2_state == SPECTRE_UNAFFECTED)
     39		return sprintf(buf, "%s\n", "Not affected");
     40
     41	if (spectre_v2_state != SPECTRE_MITIGATED)
     42		return sprintf(buf, "%s\n", "Vulnerable");
     43
     44	if (_unprivileged_ebpf_enabled())
     45		return sprintf(buf, "Vulnerable: Unprivileged eBPF enabled\n");
     46
     47	switch (spectre_v2_methods) {
     48	case SPECTRE_V2_METHOD_BPIALL:
     49		method = "Branch predictor hardening";
     50		break;
     51
     52	case SPECTRE_V2_METHOD_ICIALLU:
     53		method = "I-cache invalidation";
     54		break;
     55
     56	case SPECTRE_V2_METHOD_SMC:
     57	case SPECTRE_V2_METHOD_HVC:
     58		method = "Firmware call";
     59		break;
     60
     61	case SPECTRE_V2_METHOD_LOOP8:
     62		method = "History overwrite";
     63		break;
     64
     65	default:
     66		method = "Multiple mitigations";
     67		break;
     68	}
     69
     70	return sprintf(buf, "Mitigation: %s\n", method);
     71}