[PATCH 5.4 003/215] x86/bugs: Use sysfs_emit()

Greg Kroah-Hartman
2024-04-11T10:14:59Z

From: Borislav Petkov <bp@suse.de>

commit 1d30800c0c0ae1d086ffad2bdf0ba4403370f132 upstream.

Those mitigations are very talkative; use the printing helper which pays
attention to the buffer size.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220809153419.10182-1-bp@alien8.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/cpu/bugs.c | 82 ++++++++++++++++++++++-----------------------
1 file changed, 41 insertions(+), 41 deletions(-)

--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -2148,69 +2148,69 @@ static const char * const l1tf_vmx_state
static ssize_t l1tf_show_state(char *buf)
{
if (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_AUTO)
- return sprintf(buf, "%s\n", L1TF_DEFAULT_MSG);
+ return sysfs_emit(buf, "%s\n", L1TF_DEFAULT_MSG);

if (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_EPT_DISABLED ||
(l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_NEVER &&
sched_smt_active())) {
- return sprintf(buf, "%s; VMX: %s\n", L1TF_DEFAULT_MSG,
- l1tf_vmx_states[l1tf_vmx_mitigation]);
+ return sysfs_emit(buf, "%s; VMX: %s\n", L1TF_DEFAULT_MSG,
+ l1tf_vmx_states[l1tf_vmx_mitigation]);
}

- return sprintf(buf, "%s; VMX: %s, SMT %s\n", L1TF_DEFAULT_MSG,
- l1tf_vmx_states[l1tf_vmx_mitigation],
- sched_smt_active() ? "vulnerable" : "disabled");
+ return sysfs_emit(buf, "%s; VMX: %s, SMT %s\n", L1TF_DEFAULT_MSG,
+ l1tf_vmx_states[l1tf_vmx_mitigation],
+ sched_smt_active() ? "vulnerable" : "disabled");
}

static ssize_t itlb_multihit_show_state(char *buf)
{
if (itlb_multihit_kvm_mitigation)
- return sprintf(buf, "KVM: Mitigation: Split huge pages\n");
+ return sysfs_emit(buf, "KVM: Mitigation: Split huge pages\n");
else
- return sprintf(buf, "KVM: Vulnerable\n");
+ return sysfs_emit(buf, "KVM: Vulnerable\n");
}
#else
static ssize_t l1tf_show_state(char *buf)
{
- return sprintf(buf, "%s\n", L1TF_DEFAULT_MSG);
+ return sysfs_emit(buf, "%s\n", L1TF_DEFAULT_MSG);
}

static ssize_t itlb_multihit_show_state(char *buf)
{
- return sprintf(buf, "Processor vulnerable\n");
+ return sysfs_emit(buf, "Processor vulnerable\n");
}
#endif

static ssize_t mds_show_state(char *buf)
{
if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
- return sprintf(buf, "%s; SMT Host state unknown\n",
- mds_strings[mds_mitigation]);
+ return sysfs_emit(buf, "%s; SMT Host state unknown\n",
+ mds_strings[mds_mitigation]);
}

if (boot_cpu_has(X86_BUG_MSBDS_ONLY)) {
- return sprintf(buf, "%s; SMT %s\n", mds_strings[mds_mitigation],
- (mds_mitigation == MDS_MITIGATION_OFF ? "vulnerable" :
- sched_smt_active() ? "mitigated" : "disabled"));
+ return sysfs_emit(buf, "%s; SMT %s\n", mds_strings[mds_mitigation],
+ (mds_mitigation == MDS_MITIGATION_OFF ? "vulnerable" :
+ sched_smt_active() ? "mitigated" : "disabled"));
}

- return sprintf(buf, "%s; SMT %s\n", mds_strings[mds_mitigation],
- sched_smt_active() ? "vulnerable" : "disabled");
+ return sysfs_emit(buf, "%s; SMT %s\n", mds_strings[mds_mitigation],
+ sched_smt_active() ? "vulnerable" : "disabled");
}

static ssize_t tsx_async_abort_show_state(char *buf)
{
if ((taa_mitigation == TAA_MITIGATION_TSX_DISABLED) ||
(taa_mitigation == TAA_MITIGATION_OFF))
- return sprintf(buf, "%s\n", taa_strings[taa_mitigation]);
+ return sysfs_emit(buf, "%s\n", taa_strings[taa_mitigation]);

if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
- return sprintf(buf, "%s; SMT Host state unknown\n",
- taa_strings[taa_mitigation]);
+ return sysfs_emit(buf, "%s; SMT Host state unknown\n",
+ taa_strings[taa_mitigation]);
}

- return sprintf(buf, "%s; SMT %s\n", taa_strings[taa_mitigation],
- sched_smt_active() ? "vulnerable" : "disabled");
+ return sysfs_emit(buf, "%s; SMT %s\n", taa_strings[taa_mitigation],
+ sched_smt_active() ? "vulnerable" : "disabled");
}

static ssize_t mmio_stale_data_show_state(char *buf)
@@ -2278,33 +2278,33 @@ static char *pbrsb_eibrs_state(void)
static ssize_t spectre_v2_show_state(char *buf)
{
if (spectre_v2_enabled == SPECTRE_V2_LFENCE)
- return sprintf(buf, "Vulnerable: LFENCE\n");
+ return sysfs_emit(buf, "Vulnerable: LFENCE\n");

if (spectre_v2_enabled == SPECTRE_V2_EIBRS && unprivileged_ebpf_enabled())
- return sprintf(buf, "Vulnerable: eIBRS with unprivileged eBPF\n");
+ return sysfs_emit(buf, "Vulnerable: eIBRS with unprivileged eBPF\n");

if (sched_smt_active() && unprivileged_ebpf_enabled() &&
spectre_v2_enabled == SPECTRE_V2_EIBRS_LFENCE)
- return sprintf(buf, "Vulnerable: eIBRS+LFENCE with unprivileged eBPF and SMT\n");
+ return sysfs_emit(buf, "Vulnerable: eIBRS+LFENCE with unprivileged eBPF and SMT\n");

- return sprintf(buf, "%s%s%s%s%s%s%s\n",
- spectre_v2_strings[spectre_v2_enabled],
- ibpb_state(),
- boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "",
- stibp_state(),
- boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "",
- pbrsb_eibrs_state(),
- spectre_v2_module_string());
+ return sysfs_emit(buf, "%s%s%s%s%s%s%s\n",
+ spectre_v2_strings[spectre_v2_enabled],
+ ibpb_state(),
+ boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "",
+ stibp_state(),
+ boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "",
+ pbrsb_eibrs_state(),
+ spectre_v2_module_string());
}

static ssize_t srbds_show_state(char *buf)
{
- return sprintf(buf, "%s\n", srbds_strings[srbds_mitigation]);
+ return sysfs_emit(buf, "%s\n", srbds_strings[srbds_mitigation]);
}

static ssize_t retbleed_show_state(char *buf)
{
- return sprintf(buf, "%s\n", retbleed_strings[retbleed_mitigation]);
+ return sysfs_emit(buf, "%s\n", retbleed_strings[retbleed_mitigation]);
}

static ssize_t gds_show_state(char *buf)
@@ -2316,26 +2316,26 @@ static ssize_t cpu_show_common(struct de
char *buf, unsigned int bug)
{
if (!boot_cpu_has_bug(bug))
- return sprintf(buf, "Not affected\n");
+ return sysfs_emit(buf, "Not affected\n");

switch (bug) {
case X86_BUG_CPU_MELTDOWN:
if (boot_cpu_has(X86_FEATURE_PTI))
- return sprintf(buf, "Mitigation: PTI\n");
+ return sysfs_emit(buf, "Mitigation: PTI\n");

if (hypervisor_is_type(X86_HYPER_XEN_PV))
- return sprintf(buf, "Unknown (XEN PV detected, hypervisor mitigation required)\n");
+ return sysfs_emit(buf, "Unknown (XEN PV detected, hypervisor mitigation required)\n");

break;

case X86_BUG_SPECTRE_V1:
- return sprintf(buf, "%s\n", spectre_v1_strings[spectre_v1_mitigation]);
+ return sysfs_emit(buf, "%s\n", spectre_v1_strings[spectre_v1_mitigation]);

case X86_BUG_SPECTRE_V2:
return spectre_v2_show_state(buf);

case X86_BUG_SPEC_STORE_BYPASS:
- return sprintf(buf, "%s\n", ssb_strings[ssb_mode]);
+ return sysfs_emit(buf, "%s\n", ssb_strings[ssb_mode]);

case X86_BUG_L1TF:
if (boot_cpu_has(X86_FEATURE_L1TF_PTEINV))
@@ -2368,7 +2368,7 @@ static ssize_t cpu_show_common(struct de
break;
}

- return sprintf(buf, "Vulnerable\n");
+ return sysfs_emit(buf, "Vulnerable\n");
}

ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)