This is a note to let you know that I've just added the patch titled
x86/bugs: Use sysfs_emit()
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-bugs-use-sysfs_emit.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 1d30800c0c0ae1d086ffad2bdf0ba4403370f132 Mon Sep 17 00:00:00 2001
From: Borislav Petkov <bp@xxxxxxx>
Date: Tue, 9 Aug 2022 17:32:02 +0200
Subject: x86/bugs: Use sysfs_emit()
From: Borislav Petkov <bp@xxxxxxx>
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@xxxxxxx>
Link: https://lore.kernel.org/r/20220809153419.10182-1-bp@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/bugs.c | 105 ++++++++++++++++++++++-----------------------
1 file changed, 52 insertions(+), 53 deletions(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -2436,74 +2436,74 @@ 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 (!boot_cpu_has(X86_FEATURE_MSR_IA32_FEAT_CTL) ||
!boot_cpu_has(X86_FEATURE_VMX))
- return sprintf(buf, "KVM: Mitigation: VMX unsupported\n");
+ return sysfs_emit(buf, "KVM: Mitigation: VMX unsupported\n");
else if (!(cr4_read_shadow() & X86_CR4_VMXE))
- return sprintf(buf, "KVM: Mitigation: VMX disabled\n");
+ return sysfs_emit(buf, "KVM: Mitigation: VMX disabled\n");
else 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)
@@ -2571,47 +2571,46 @@ 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)
{
if (retbleed_mitigation == RETBLEED_MITIGATION_UNRET ||
retbleed_mitigation == RETBLEED_MITIGATION_IBPB) {
- if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
- boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
- return sprintf(buf, "Vulnerable: untrained return thunk / IBPB on non-AMD based uarch\n");
-
- return sprintf(buf, "%s; SMT %s\n",
- retbleed_strings[retbleed_mitigation],
- !sched_smt_active() ? "disabled" :
- spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT ||
- spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED ?
- "enabled with STIBP protection" : "vulnerable");
+ if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
+ boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
+ return sysfs_emit(buf, "Vulnerable: untrained return thunk / IBPB on non-AMD based uarch\n");
+
+ return sysfs_emit(buf, "%s; SMT %s\n", retbleed_strings[retbleed_mitigation],
+ !sched_smt_active() ? "disabled" :
+ spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT ||
+ spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED ?
+ "enabled with STIBP protection" : "vulnerable");
}
- 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)
@@ -2633,26 +2632,26 @@ 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))
@@ -2688,7 +2687,7 @@ 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)
Patches currently in stable-queue which might be from bp@xxxxxxx are
queue-5.10/x86-bugs-use-sysfs_emit.patch
