Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 866 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
new file mode 100644
index 000000000..4856e1a51
--- /dev/null
+++ b/arch/powerpc/kernel/security.c
@@ -0,0 +1,866 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Security related flags and so on.
+//
+// Copyright 2018, Michael Ellerman, IBM Corporation.
+
+#include <linux/cpu.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/memblock.h>
+#include <linux/nospec.h>
+#include <linux/prctl.h>
+#include <linux/seq_buf.h>
+#include <linux/debugfs.h>
+
+#include <asm/asm-prototypes.h>
+#include <asm/code-patching.h>
+#include <asm/security_features.h>
+#include <asm/sections.h>
+#include <asm/setup.h>
+#include <asm/inst.h>
+
+#include "setup.h"
+
+u64 powerpc_security_features __read_mostly = SEC_FTR_DEFAULT;
+
+enum branch_cache_flush_type {
+	BRANCH_CACHE_FLUSH_NONE	= 0x1,
+	BRANCH_CACHE_FLUSH_SW	= 0x2,
+	BRANCH_CACHE_FLUSH_HW	= 0x4,
+};
+static enum branch_cache_flush_type count_cache_flush_type = BRANCH_CACHE_FLUSH_NONE;
+static enum branch_cache_flush_type link_stack_flush_type = BRANCH_CACHE_FLUSH_NONE;
+
+bool barrier_nospec_enabled;
+static bool no_nospec;
+static bool btb_flush_enabled;
+#if defined(CONFIG_PPC_E500) || defined(CONFIG_PPC_BOOK3S_64)
+static bool no_spectrev2;
+#endif
+
+static void enable_barrier_nospec(bool enable)
+{
+	barrier_nospec_enabled = enable;
+	do_barrier_nospec_fixups(enable);
+}
+
+void __init setup_barrier_nospec(void)
+{
+	bool enable;
+
+	/*
+	 * It would make sense to check SEC_FTR_SPEC_BAR_ORI31 below as well.
+	 * But there's a good reason not to. The two flags we check below are
+	 * both are enabled by default in the kernel, so if the hcall is not
+	 * functional they will be enabled.
+	 * On a system where the host firmware has been updated (so the ori
+	 * functions as a barrier), but on which the hypervisor (KVM/Qemu) has
+	 * not been updated, we would like to enable the barrier. Dropping the
+	 * check for SEC_FTR_SPEC_BAR_ORI31 achieves that. The only downside is
+	 * we potentially enable the barrier on systems where the host firmware
+	 * is not updated, but that's harmless as it's a no-op.
+	 */
+	enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
+		 security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR);
+
+	if (!no_nospec && !cpu_mitigations_off())
+		enable_barrier_nospec(enable);
+}
+
+static int __init handle_nospectre_v1(char *p)
+{
+	no_nospec = true;
+
+	return 0;
+}
+early_param("nospectre_v1", handle_nospectre_v1);
+
+#ifdef CONFIG_DEBUG_FS
+static int barrier_nospec_set(void *data, u64 val)
+{
+	switch (val) {
+	case 0:
+	case 1:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (!!val == !!barrier_nospec_enabled)
+		return 0;
+
+	enable_barrier_nospec(!!val);
+
+	return 0;
+}
+
+static int barrier_nospec_get(void *data, u64 *val)
+{
+	*val = barrier_nospec_enabled ? 1 : 0;
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(fops_barrier_nospec, barrier_nospec_get,
+			 barrier_nospec_set, "%llu\n");
+
+static __init int barrier_nospec_debugfs_init(void)
+{
+	debugfs_create_file_unsafe("barrier_nospec", 0600,
+				   arch_debugfs_dir, NULL,
+				   &fops_barrier_nospec);
+	return 0;
+}
+device_initcall(barrier_nospec_debugfs_init);
+
+static __init int security_feature_debugfs_init(void)
+{
+	debugfs_create_x64("security_features", 0400, arch_debugfs_dir,
+			   &powerpc_security_features);
+	return 0;
+}
+device_initcall(security_feature_debugfs_init);
+#endif /* CONFIG_DEBUG_FS */
+
+#if defined(CONFIG_PPC_E500) || 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_E500 || CONFIG_PPC_BOOK3S_64 */
+
+#ifdef CONFIG_PPC_E500
+void __init setup_spectre_v2(void)
+{
+	if (no_spectrev2 || cpu_mitigations_off())
+		do_btb_flush_fixups();
+	else
+		btb_flush_enabled = true;
+}
+#endif /* CONFIG_PPC_E500 */
+
+#ifdef CONFIG_PPC_BOOK3S_64
+ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	bool thread_priv;
+
+	thread_priv = security_ftr_enabled(SEC_FTR_L1D_THREAD_PRIV);
+
+	if (rfi_flush) {
+		struct seq_buf s;
+		seq_buf_init(&s, buf, PAGE_SIZE - 1);
+
+		seq_buf_printf(&s, "Mitigation: RFI Flush");
+		if (thread_priv)
+			seq_buf_printf(&s, ", L1D private per thread");
+
+		seq_buf_printf(&s, "\n");
+
+		return s.len;
+	}
+
+	if (thread_priv)
+		return sprintf(buf, "Vulnerable: L1D private per thread\n");
+
+	if (!security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) &&
+	    !security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR))
+		return sprintf(buf, "Not affected\n");
+
+	return sprintf(buf, "Vulnerable\n");
+}
+
+ssize_t cpu_show_l1tf(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return cpu_show_meltdown(dev, attr, buf);
+}
+#endif
+
+ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct seq_buf s;
+
+	seq_buf_init(&s, buf, PAGE_SIZE - 1);
+
+	if (security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR)) {
+		if (barrier_nospec_enabled)
+			seq_buf_printf(&s, "Mitigation: __user pointer sanitization");
+		else
+			seq_buf_printf(&s, "Vulnerable");
+
+		if (security_ftr_enabled(SEC_FTR_SPEC_BAR_ORI31))
+			seq_buf_printf(&s, ", ori31 speculation barrier enabled");
+
+		seq_buf_printf(&s, "\n");
+	} else
+		seq_buf_printf(&s, "Not affected\n");
+
+	return s.len;
+}
+
+ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct seq_buf s;
+	bool bcs, ccd;
+
+	seq_buf_init(&s, buf, PAGE_SIZE - 1);
+
+	bcs = security_ftr_enabled(SEC_FTR_BCCTRL_SERIALISED);
+	ccd = security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED);
+
+	if (bcs || ccd) {
+		seq_buf_printf(&s, "Mitigation: ");
+
+		if (bcs)
+			seq_buf_printf(&s, "Indirect branch serialisation (kernel only)");
+
+		if (bcs && ccd)
+			seq_buf_printf(&s, ", ");
+
+		if (ccd)
+			seq_buf_printf(&s, "Indirect branch cache disabled");
+
+	} else if (count_cache_flush_type != BRANCH_CACHE_FLUSH_NONE) {
+		seq_buf_printf(&s, "Mitigation: Software count cache flush");
+
+		if (count_cache_flush_type == BRANCH_CACHE_FLUSH_HW)
+			seq_buf_printf(&s, " (hardware accelerated)");
+
+	} else if (btb_flush_enabled) {
+		seq_buf_printf(&s, "Mitigation: Branch predictor state flush");
+	} else {
+		seq_buf_printf(&s, "Vulnerable");
+	}
+
+	if (bcs || ccd || count_cache_flush_type != BRANCH_CACHE_FLUSH_NONE) {
+		if (link_stack_flush_type != BRANCH_CACHE_FLUSH_NONE)
+			seq_buf_printf(&s, ", Software link stack flush");
+		if (link_stack_flush_type == BRANCH_CACHE_FLUSH_HW)
+			seq_buf_printf(&s, " (hardware accelerated)");
+	}
+
+	seq_buf_printf(&s, "\n");
+
+	return s.len;
+}
+
+#ifdef CONFIG_PPC_BOOK3S_64
+/*
+ * Store-forwarding barrier support.
+ */
+
+static enum stf_barrier_type stf_enabled_flush_types;
+static bool no_stf_barrier;
+static bool stf_barrier;
+
+static int __init handle_no_stf_barrier(char *p)
+{
+	pr_info("stf-barrier: disabled on command line.");
+	no_stf_barrier = true;
+	return 0;
+}
+
+early_param("no_stf_barrier", handle_no_stf_barrier);
+
+enum stf_barrier_type stf_barrier_type_get(void)
+{
+	return stf_enabled_flush_types;
+}
+
+/* This is the generic flag used by other architectures */
+static int __init handle_ssbd(char *p)
+{
+	if (!p || strncmp(p, "auto", 5) == 0 || strncmp(p, "on", 2) == 0 ) {
+		/* Until firmware tells us, we have the barrier with auto */
+		return 0;
+	} else if (strncmp(p, "off", 3) == 0) {
+		handle_no_stf_barrier(NULL);
+		return 0;
+	} else
+		return 1;
+
+	return 0;
+}
+early_param("spec_store_bypass_disable", handle_ssbd);
+
+/* This is the generic flag used by other architectures */
+static int __init handle_no_ssbd(char *p)
+{
+	handle_no_stf_barrier(NULL);
+	return 0;
+}
+early_param("nospec_store_bypass_disable", handle_no_ssbd);
+
+static void stf_barrier_enable(bool enable)
+{
+	if (enable)
+		do_stf_barrier_fixups(stf_enabled_flush_types);
+	else
+		do_stf_barrier_fixups(STF_BARRIER_NONE);
+
+	stf_barrier = enable;
+}
+
+void setup_stf_barrier(void)
+{
+	enum stf_barrier_type type;
+	bool enable;
+
+	/* Default to fallback in case fw-features are not available */
+	if (cpu_has_feature(CPU_FTR_ARCH_300))
+		type = STF_BARRIER_EIEIO;
+	else if (cpu_has_feature(CPU_FTR_ARCH_207S))
+		type = STF_BARRIER_SYNC_ORI;
+	else if (cpu_has_feature(CPU_FTR_ARCH_206))
+		type = STF_BARRIER_FALLBACK;
+	else
+		type = STF_BARRIER_NONE;
+
+	enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
+		 security_ftr_enabled(SEC_FTR_STF_BARRIER);
+
+	if (type == STF_BARRIER_FALLBACK) {
+		pr_info("stf-barrier: fallback barrier available\n");
+	} else if (type == STF_BARRIER_SYNC_ORI) {
+		pr_info("stf-barrier: hwsync barrier available\n");
+	} else if (type == STF_BARRIER_EIEIO) {
+		pr_info("stf-barrier: eieio barrier available\n");
+	}
+
+	stf_enabled_flush_types = type;
+
+	if (!no_stf_barrier && !cpu_mitigations_off())
+		stf_barrier_enable(enable);
+}
+
+ssize_t cpu_show_spec_store_bypass(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	if (stf_barrier && stf_enabled_flush_types != STF_BARRIER_NONE) {
+		const char *type;
+		switch (stf_enabled_flush_types) {
+		case STF_BARRIER_EIEIO:
+			type = "eieio";
+			break;
+		case STF_BARRIER_SYNC_ORI:
+			type = "hwsync";
+			break;
+		case STF_BARRIER_FALLBACK:
+			type = "fallback";
+			break;
+		default:
+			type = "unknown";
+		}
+		return sprintf(buf, "Mitigation: Kernel entry/exit barrier (%s)\n", type);
+	}
+
+	if (!security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) &&
+	    !security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR))
+		return sprintf(buf, "Not affected\n");
+
+	return sprintf(buf, "Vulnerable\n");
+}
+
+static int ssb_prctl_get(struct task_struct *task)
+{
+	/*
+	 * The STF_BARRIER feature is on by default, so if it's off that means
+	 * firmware has explicitly said the CPU is not vulnerable via either
+	 * the hypercall or device tree.
+	 */
+	if (!security_ftr_enabled(SEC_FTR_STF_BARRIER))
+		return PR_SPEC_NOT_AFFECTED;
+
+	/*
+	 * If the system's CPU has no known barrier (see setup_stf_barrier())
+	 * then assume that the CPU is not vulnerable.
+	 */
+	if (stf_enabled_flush_types == STF_BARRIER_NONE)
+		return PR_SPEC_NOT_AFFECTED;
+
+	/*
+	 * Otherwise the CPU is vulnerable. The barrier is not a global or
+	 * per-process mitigation, so the only value that can be reported here
+	 * is PR_SPEC_ENABLE, which appears as "vulnerable" in /proc.
+	 */
+	return PR_SPEC_ENABLE;
+}
+
+int arch_prctl_spec_ctrl_get(struct task_struct *task, unsigned long which)
+{
+	switch (which) {
+	case PR_SPEC_STORE_BYPASS:
+		return ssb_prctl_get(task);
+	default:
+		return -ENODEV;
+	}
+}
+
+#ifdef CONFIG_DEBUG_FS
+static int stf_barrier_set(void *data, u64 val)
+{
+	bool enable;
+
+	if (val == 1)
+		enable = true;
+	else if (val == 0)
+		enable = false;
+	else
+		return -EINVAL;
+
+	/* Only do anything if we're changing state */
+	if (enable != stf_barrier)
+		stf_barrier_enable(enable);
+
+	return 0;
+}
+
+static int stf_barrier_get(void *data, u64 *val)
+{
+	*val = stf_barrier ? 1 : 0;
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(fops_stf_barrier, stf_barrier_get, stf_barrier_set,
+			 "%llu\n");
+
+static __init int stf_barrier_debugfs_init(void)
+{
+	debugfs_create_file_unsafe("stf_barrier", 0600, arch_debugfs_dir,
+				   NULL, &fops_stf_barrier);
+	return 0;
+}
+device_initcall(stf_barrier_debugfs_init);
+#endif /* CONFIG_DEBUG_FS */
+
+static void update_branch_cache_flush(void)
+{
+	u32 *site, __maybe_unused *site2;
+
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+	site = &patch__call_kvm_flush_link_stack;
+	site2 = &patch__call_kvm_flush_link_stack_p9;
+	// This controls the branch from guest_exit_cont to kvm_flush_link_stack
+	if (link_stack_flush_type == BRANCH_CACHE_FLUSH_NONE) {
+		patch_instruction_site(site, ppc_inst(PPC_RAW_NOP()));
+		patch_instruction_site(site2, ppc_inst(PPC_RAW_NOP()));
+	} else {
+		// Could use HW flush, but that could also flush count cache
+		patch_branch_site(site, (u64)&kvm_flush_link_stack, BRANCH_SET_LINK);
+		patch_branch_site(site2, (u64)&kvm_flush_link_stack, BRANCH_SET_LINK);
+	}
+#endif
+
+	// Patch out the bcctr first, then nop the rest
+	site = &patch__call_flush_branch_caches3;
+	patch_instruction_site(site, ppc_inst(PPC_RAW_NOP()));
+	site = &patch__call_flush_branch_caches2;
+	patch_instruction_site(site, ppc_inst(PPC_RAW_NOP()));
+	site = &patch__call_flush_branch_caches1;
+	patch_instruction_site(site, ppc_inst(PPC_RAW_NOP()));
+
+	// This controls the branch from _switch to flush_branch_caches
+	if (count_cache_flush_type == BRANCH_CACHE_FLUSH_NONE &&
+	    link_stack_flush_type == BRANCH_CACHE_FLUSH_NONE) {
+		// Nothing to be done
+
+	} else if (count_cache_flush_type == BRANCH_CACHE_FLUSH_HW &&
+		   link_stack_flush_type == BRANCH_CACHE_FLUSH_HW) {
+		// Patch in the bcctr last
+		site = &patch__call_flush_branch_caches1;
+		patch_instruction_site(site, ppc_inst(0x39207fff)); // li r9,0x7fff
+		site = &patch__call_flush_branch_caches2;
+		patch_instruction_site(site, ppc_inst(0x7d2903a6)); // mtctr r9
+		site = &patch__call_flush_branch_caches3;
+		patch_instruction_site(site, ppc_inst(PPC_INST_BCCTR_FLUSH));
+
+	} else {
+		patch_branch_site(site, (u64)&flush_branch_caches, BRANCH_SET_LINK);
+
+		// If we just need to flush the link stack, early return
+		if (count_cache_flush_type == BRANCH_CACHE_FLUSH_NONE) {
+			patch_instruction_site(&patch__flush_link_stack_return,
+					       ppc_inst(PPC_RAW_BLR()));
+
+		// If we have flush instruction, early return
+		} else if (count_cache_flush_type == BRANCH_CACHE_FLUSH_HW) {
+			patch_instruction_site(&patch__flush_count_cache_return,
+					       ppc_inst(PPC_RAW_BLR()));
+		}
+	}
+}
+
+static void toggle_branch_cache_flush(bool enable)
+{
+	if (!enable || !security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE)) {
+		if (count_cache_flush_type != BRANCH_CACHE_FLUSH_NONE)
+			count_cache_flush_type = BRANCH_CACHE_FLUSH_NONE;
+
+		pr_info("count-cache-flush: flush disabled.\n");
+	} else {
+		if (security_ftr_enabled(SEC_FTR_BCCTR_FLUSH_ASSIST)) {
+			count_cache_flush_type = BRANCH_CACHE_FLUSH_HW;
+			pr_info("count-cache-flush: hardware flush enabled.\n");
+		} else {
+			count_cache_flush_type = BRANCH_CACHE_FLUSH_SW;
+			pr_info("count-cache-flush: software flush enabled.\n");
+		}
+	}
+
+	if (!enable || !security_ftr_enabled(SEC_FTR_FLUSH_LINK_STACK)) {
+		if (link_stack_flush_type != BRANCH_CACHE_FLUSH_NONE)
+			link_stack_flush_type = BRANCH_CACHE_FLUSH_NONE;
+
+		pr_info("link-stack-flush: flush disabled.\n");
+	} else {
+		if (security_ftr_enabled(SEC_FTR_BCCTR_LINK_FLUSH_ASSIST)) {
+			link_stack_flush_type = BRANCH_CACHE_FLUSH_HW;
+			pr_info("link-stack-flush: hardware flush enabled.\n");
+		} else {
+			link_stack_flush_type = BRANCH_CACHE_FLUSH_SW;
+			pr_info("link-stack-flush: software flush enabled.\n");
+		}
+	}
+
+	update_branch_cache_flush();
+}
+
+void setup_count_cache_flush(void)
+{
+	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_branch_cache_flush(enable);
+}
+
+static enum l1d_flush_type enabled_flush_types;
+static void *l1d_flush_fallback_area;
+static bool no_rfi_flush;
+static bool no_entry_flush;
+static bool no_uaccess_flush;
+bool rfi_flush;
+static bool entry_flush;
+static bool uaccess_flush;
+DEFINE_STATIC_KEY_FALSE(uaccess_flush_key);
+EXPORT_SYMBOL(uaccess_flush_key);
+
+static int __init handle_no_rfi_flush(char *p)
+{
+	pr_info("rfi-flush: disabled on command line.");
+	no_rfi_flush = true;
+	return 0;
+}
+early_param("no_rfi_flush", handle_no_rfi_flush);
+
+static int __init handle_no_entry_flush(char *p)
+{
+	pr_info("entry-flush: disabled on command line.");
+	no_entry_flush = true;
+	return 0;
+}
+early_param("no_entry_flush", handle_no_entry_flush);
+
+static int __init handle_no_uaccess_flush(char *p)
+{
+	pr_info("uaccess-flush: disabled on command line.");
+	no_uaccess_flush = true;
+	return 0;
+}
+early_param("no_uaccess_flush", handle_no_uaccess_flush);
+
+/*
+ * The RFI flush is not KPTI, but because users will see doco that says to use
+ * nopti we hijack that option here to also disable the RFI flush.
+ */
+static int __init handle_no_pti(char *p)
+{
+	pr_info("rfi-flush: disabling due to 'nopti' on command line.\n");
+	handle_no_rfi_flush(NULL);
+	return 0;
+}
+early_param("nopti", handle_no_pti);
+
+static void do_nothing(void *unused)
+{
+	/*
+	 * We don't need to do the flush explicitly, just enter+exit kernel is
+	 * sufficient, the RFI exit handlers will do the right thing.
+	 */
+}
+
+void rfi_flush_enable(bool enable)
+{
+	if (enable) {
+		do_rfi_flush_fixups(enabled_flush_types);
+		on_each_cpu(do_nothing, NULL, 1);
+	} else
+		do_rfi_flush_fixups(L1D_FLUSH_NONE);
+
+	rfi_flush = enable;
+}
+
+static void entry_flush_enable(bool enable)
+{
+	if (enable) {
+		do_entry_flush_fixups(enabled_flush_types);
+		on_each_cpu(do_nothing, NULL, 1);
+	} else {
+		do_entry_flush_fixups(L1D_FLUSH_NONE);
+	}
+
+	entry_flush = enable;
+}
+
+static void uaccess_flush_enable(bool enable)
+{
+	if (enable) {
+		do_uaccess_flush_fixups(enabled_flush_types);
+		static_branch_enable(&uaccess_flush_key);
+		on_each_cpu(do_nothing, NULL, 1);
+	} else {
+		static_branch_disable(&uaccess_flush_key);
+		do_uaccess_flush_fixups(L1D_FLUSH_NONE);
+	}
+
+	uaccess_flush = enable;
+}
+
+static void __ref init_fallback_flush(void)
+{
+	u64 l1d_size, limit;
+	int cpu;
+
+	/* Only allocate the fallback flush area once (at boot time). */
+	if (l1d_flush_fallback_area)
+		return;
+
+	l1d_size = ppc64_caches.l1d.size;
+
+	/*
+	 * If there is no d-cache-size property in the device tree, l1d_size
+	 * could be zero. That leads to the loop in the asm wrapping around to
+	 * 2^64-1, and then walking off the end of the fallback area and
+	 * eventually causing a page fault which is fatal. Just default to
+	 * something vaguely sane.
+	 */
+	if (!l1d_size)
+		l1d_size = (64 * 1024);
+
+	limit = min(ppc64_bolted_size(), ppc64_rma_size);
+
+	/*
+	 * Align to L1d size, and size it at 2x L1d size, to catch possible
+	 * hardware prefetch runoff. We don't have a recipe for load patterns to
+	 * reliably avoid the prefetcher.
+	 */
+	l1d_flush_fallback_area = memblock_alloc_try_nid(l1d_size * 2,
+						l1d_size, MEMBLOCK_LOW_LIMIT,
+						limit, NUMA_NO_NODE);
+	if (!l1d_flush_fallback_area)
+		panic("%s: Failed to allocate %llu bytes align=0x%llx max_addr=%pa\n",
+		      __func__, l1d_size * 2, l1d_size, &limit);
+
+
+	for_each_possible_cpu(cpu) {
+		struct paca_struct *paca = paca_ptrs[cpu];
+		paca->rfi_flush_fallback_area = l1d_flush_fallback_area;
+		paca->l1d_flush_size = l1d_size;
+	}
+}
+
+void setup_rfi_flush(enum l1d_flush_type types, bool enable)
+{
+	if (types & L1D_FLUSH_FALLBACK) {
+		pr_info("rfi-flush: fallback displacement flush available\n");
+		init_fallback_flush();
+	}
+
+	if (types & L1D_FLUSH_ORI)
+		pr_info("rfi-flush: ori type flush available\n");
+
+	if (types & L1D_FLUSH_MTTRIG)
+		pr_info("rfi-flush: mttrig type flush available\n");
+
+	enabled_flush_types = types;
+
+	if (!cpu_mitigations_off() && !no_rfi_flush)
+		rfi_flush_enable(enable);
+}
+
+void setup_entry_flush(bool enable)
+{
+	if (cpu_mitigations_off())
+		return;
+
+	if (!no_entry_flush)
+		entry_flush_enable(enable);
+}
+
+void setup_uaccess_flush(bool enable)
+{
+	if (cpu_mitigations_off())
+		return;
+
+	if (!no_uaccess_flush)
+		uaccess_flush_enable(enable);
+}
+
+#ifdef CONFIG_DEBUG_FS
+static int count_cache_flush_set(void *data, u64 val)
+{
+	bool enable;
+
+	if (val == 1)
+		enable = true;
+	else if (val == 0)
+		enable = false;
+	else
+		return -EINVAL;
+
+	toggle_branch_cache_flush(enable);
+
+	return 0;
+}
+
+static int count_cache_flush_get(void *data, u64 *val)
+{
+	if (count_cache_flush_type == BRANCH_CACHE_FLUSH_NONE)
+		*val = 0;
+	else
+		*val = 1;
+
+	return 0;
+}
+
+static int link_stack_flush_get(void *data, u64 *val)
+{
+	if (link_stack_flush_type == BRANCH_CACHE_FLUSH_NONE)
+		*val = 0;
+	else
+		*val = 1;
+
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(fops_count_cache_flush, count_cache_flush_get,
+			 count_cache_flush_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_link_stack_flush, link_stack_flush_get,
+			 count_cache_flush_set, "%llu\n");
+
+static __init int count_cache_flush_debugfs_init(void)
+{
+	debugfs_create_file_unsafe("count_cache_flush", 0600,
+				   arch_debugfs_dir, NULL,
+				   &fops_count_cache_flush);
+	debugfs_create_file_unsafe("link_stack_flush", 0600,
+				   arch_debugfs_dir, NULL,
+				   &fops_link_stack_flush);
+	return 0;
+}
+device_initcall(count_cache_flush_debugfs_init);
+
+static int rfi_flush_set(void *data, u64 val)
+{
+	bool enable;
+
+	if (val == 1)
+		enable = true;
+	else if (val == 0)
+		enable = false;
+	else
+		return -EINVAL;
+
+	/* Only do anything if we're changing state */
+	if (enable != rfi_flush)
+		rfi_flush_enable(enable);
+
+	return 0;
+}
+
+static int rfi_flush_get(void *data, u64 *val)
+{
+	*val = rfi_flush ? 1 : 0;
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(fops_rfi_flush, rfi_flush_get, rfi_flush_set, "%llu\n");
+
+static int entry_flush_set(void *data, u64 val)
+{
+	bool enable;
+
+	if (val == 1)
+		enable = true;
+	else if (val == 0)
+		enable = false;
+	else
+		return -EINVAL;
+
+	/* Only do anything if we're changing state */
+	if (enable != entry_flush)
+		entry_flush_enable(enable);
+
+	return 0;
+}
+
+static int entry_flush_get(void *data, u64 *val)
+{
+	*val = entry_flush ? 1 : 0;
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(fops_entry_flush, entry_flush_get, entry_flush_set, "%llu\n");
+
+static int uaccess_flush_set(void *data, u64 val)
+{
+	bool enable;
+
+	if (val == 1)
+		enable = true;
+	else if (val == 0)
+		enable = false;
+	else
+		return -EINVAL;
+
+	/* Only do anything if we're changing state */
+	if (enable != uaccess_flush)
+		uaccess_flush_enable(enable);
+
+	return 0;
+}
+
+static int uaccess_flush_get(void *data, u64 *val)
+{
+	*val = uaccess_flush ? 1 : 0;
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(fops_uaccess_flush, uaccess_flush_get, uaccess_flush_set, "%llu\n");
+
+static __init int rfi_flush_debugfs_init(void)
+{
+	debugfs_create_file("rfi_flush", 0600, arch_debugfs_dir, NULL, &fops_rfi_flush);
+	debugfs_create_file("entry_flush", 0600, arch_debugfs_dir, NULL, &fops_entry_flush);
+	debugfs_create_file("uaccess_flush", 0600, arch_debugfs_dir, NULL, &fops_uaccess_flush);
+	return 0;
+}
+device_initcall(rfi_flush_debugfs_init);
+#endif /* CONFIG_DEBUG_FS */
+#endif /* CONFIG_PPC_BOOK3S_64 */