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, fmt: "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, fmt: "%s\n", "Not affected");
40
41 if (spectre_v2_state != SPECTRE_MITIGATED)
42 return sprintf(buf, fmt: "%s\n", "Vulnerable");
43
44 if (_unprivileged_ebpf_enabled())
45 return sprintf(buf, fmt: "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, fmt: "Mitigation: %s\n", method);
71}
72

source code of linux/arch/arm/kernel/spectre.c