Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
index f6f469f..bd91dce 100644
--- a/arch/powerpc/kernel/security.c
+++ b/arch/powerpc/kernel/security.c
@@ -4,6 +4,7 @@
//
// Copyright 2018, Michael Ellerman, IBM Corporation.
+#include <linux/cpu.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/seq_buf.h>
@@ -22,10 +23,15 @@
COUNT_CACHE_FLUSH_SW = 0x2,
COUNT_CACHE_FLUSH_HW = 0x4,
};
-static enum count_cache_flush_type count_cache_flush_type;
+static enum count_cache_flush_type count_cache_flush_type = COUNT_CACHE_FLUSH_NONE;
+static bool link_stack_flush_enabled;
bool barrier_nospec_enabled;
static bool no_nospec;
+static bool btb_flush_enabled;
+#if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_BOOK3S_64)
+static bool no_spectrev2;
+#endif
static void enable_barrier_nospec(bool enable)
{
@@ -52,7 +58,7 @@
enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR);
- if (!no_nospec)
+ if (!no_nospec && !cpu_mitigations_off())
enable_barrier_nospec(enable);
}
@@ -99,8 +105,36 @@
return 0;
}
device_initcall(barrier_nospec_debugfs_init);
+
+static __init int security_feature_debugfs_init(void)
+{
+ debugfs_create_x64("security_features", 0400, powerpc_debugfs_root,
+ (u64 *)&powerpc_security_features);
+ return 0;
+}
+device_initcall(security_feature_debugfs_init);
#endif /* CONFIG_DEBUG_FS */
+#if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_BOOK3S_64)
+static int __init handle_nospectre_v2(char *p)
+{
+ no_spectrev2 = true;
+
+ return 0;
+}
+early_param("nospectre_v2", handle_nospectre_v2);
+#endif /* CONFIG_PPC_FSL_BOOK3E || CONFIG_PPC_BOOK3S_64 */
+
+#ifdef CONFIG_PPC_FSL_BOOK3E
+void setup_spectre_v2(void)
+{
+ if (no_spectrev2 || cpu_mitigations_off())
+ do_btb_flush_fixups();
+ else
+ btb_flush_enabled = true;
+}
+#endif /* CONFIG_PPC_FSL_BOOK3E */
+
#ifdef CONFIG_PPC_BOOK3S_64
ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
{
@@ -168,31 +202,35 @@
bcs = security_ftr_enabled(SEC_FTR_BCCTRL_SERIALISED);
ccd = security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED);
- if (bcs || ccd || count_cache_flush_type != COUNT_CACHE_FLUSH_NONE) {
- bool comma = false;
+ if (bcs || ccd) {
seq_buf_printf(&s, "Mitigation: ");
- if (bcs) {
+ if (bcs)
seq_buf_printf(&s, "Indirect branch serialisation (kernel only)");
- comma = true;
- }
- if (ccd) {
- if (comma)
- seq_buf_printf(&s, ", ");
- seq_buf_printf(&s, "Indirect branch cache disabled");
- comma = true;
- }
-
- if (comma)
+ if (bcs && ccd)
seq_buf_printf(&s, ", ");
- seq_buf_printf(&s, "Software count cache flush");
+ if (ccd)
+ seq_buf_printf(&s, "Indirect branch cache disabled");
+
+ if (link_stack_flush_enabled)
+ seq_buf_printf(&s, ", Software link stack flush");
+
+ } else if (count_cache_flush_type != COUNT_CACHE_FLUSH_NONE) {
+ seq_buf_printf(&s, "Mitigation: Software count cache flush");
if (count_cache_flush_type == COUNT_CACHE_FLUSH_HW)
- seq_buf_printf(&s, "(hardware accelerated)");
- } else
+ seq_buf_printf(&s, " (hardware accelerated)");
+
+ if (link_stack_flush_enabled)
+ seq_buf_printf(&s, ", Software link stack flush");
+
+ } else if (btb_flush_enabled) {
+ seq_buf_printf(&s, "Mitigation: Branch predictor state flush");
+ } else {
seq_buf_printf(&s, "Vulnerable");
+ }
seq_buf_printf(&s, "\n");
@@ -282,7 +320,7 @@
stf_enabled_flush_types = type;
- if (!no_stf_barrier)
+ if (!no_stf_barrier && !cpu_mitigations_off())
stf_barrier_enable(enable);
}
@@ -348,18 +386,49 @@
device_initcall(stf_barrier_debugfs_init);
#endif /* CONFIG_DEBUG_FS */
+static void no_count_cache_flush(void)
+{
+ count_cache_flush_type = COUNT_CACHE_FLUSH_NONE;
+ pr_info("count-cache-flush: software flush disabled.\n");
+}
+
static void toggle_count_cache_flush(bool enable)
{
- if (!enable || !security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE)) {
+ if (!security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE) &&
+ !security_ftr_enabled(SEC_FTR_FLUSH_LINK_STACK))
+ enable = false;
+
+ if (!enable) {
patch_instruction_site(&patch__call_flush_count_cache, PPC_INST_NOP);
- count_cache_flush_type = COUNT_CACHE_FLUSH_NONE;
- pr_info("count-cache-flush: software flush disabled.\n");
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+ patch_instruction_site(&patch__call_kvm_flush_link_stack, PPC_INST_NOP);
+#endif
+ pr_info("link-stack-flush: software flush disabled.\n");
+ link_stack_flush_enabled = false;
+ no_count_cache_flush();
return;
}
+ // This enables the branch from _switch to flush_count_cache
patch_branch_site(&patch__call_flush_count_cache,
(u64)&flush_count_cache, BRANCH_SET_LINK);
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+ // This enables the branch from guest_exit_cont to kvm_flush_link_stack
+ patch_branch_site(&patch__call_kvm_flush_link_stack,
+ (u64)&kvm_flush_link_stack, BRANCH_SET_LINK);
+#endif
+
+ pr_info("link-stack-flush: software flush enabled.\n");
+ link_stack_flush_enabled = true;
+
+ // If we just need to flush the link stack, patch an early return
+ if (!security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE)) {
+ patch_instruction_site(&patch__flush_link_stack_return, PPC_INST_BLR);
+ no_count_cache_flush();
+ return;
+ }
+
if (!security_ftr_enabled(SEC_FTR_BCCTR_FLUSH_ASSIST)) {
count_cache_flush_type = COUNT_CACHE_FLUSH_SW;
pr_info("count-cache-flush: full software flush sequence enabled.\n");
@@ -373,7 +442,26 @@
void setup_count_cache_flush(void)
{
- toggle_count_cache_flush(true);
+ bool enable = true;
+
+ if (no_spectrev2 || cpu_mitigations_off()) {
+ if (security_ftr_enabled(SEC_FTR_BCCTRL_SERIALISED) ||
+ security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED))
+ pr_warn("Spectre v2 mitigations not fully under software control, can't disable\n");
+
+ enable = false;
+ }
+
+ /*
+ * There's no firmware feature flag/hypervisor bit to tell us we need to
+ * flush the link stack on context switch. So we set it here if we see
+ * either of the Spectre v2 mitigations that aim to protect userspace.
+ */
+ if (security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED) ||
+ security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE))
+ security_ftr_set(SEC_FTR_FLUSH_LINK_STACK);
+
+ toggle_count_cache_flush(enable);
}
#ifdef CONFIG_DEBUG_FS