Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 1020 insertions, 0 deletions

diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c
new file mode 100644
index 000000000..587c8cf12
--- /dev/null
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -0,0 +1,1020 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright (C) 2001 Ben. Herrenschmidt (benh@kernel.crashing.org)
+ *
+ *  Modifications for ppc64:
+ *      Copyright (C) 2003 Dave Engebretsen <engebret@us.ibm.com>
+ *
+ *  Copyright 2008 Michael Ellerman, IBM Corporation.
+ */
+
+#include <linux/types.h>
+#include <linux/jump_label.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/sched/mm.h>
+#include <linux/stop_machine.h>
+#include <asm/cputable.h>
+#include <asm/text-patching.h>
+#include <asm/interrupt.h>
+#include <asm/page.h>
+#include <asm/sections.h>
+#include <asm/setup.h>
+#include <asm/security_features.h>
+#include <asm/firmware.h>
+#include <asm/inst.h>
+
+/*
+ * Used to generate warnings if mmu or cpu feature check functions that
+ * use static keys before they are initialized.
+ */
+bool static_key_feature_checks_initialized __read_mostly;
+EXPORT_SYMBOL_GPL(static_key_feature_checks_initialized);
+
+struct fixup_entry {
+	unsigned long	mask;
+	unsigned long	value;
+	long		start_off;
+	long		end_off;
+	long		alt_start_off;
+	long		alt_end_off;
+};
+
+static u32 *calc_addr(struct fixup_entry *fcur, long offset)
+{
+	/*
+	 * We store the offset to the code as a negative offset from
+	 * the start of the alt_entry, to support the VDSO. This
+	 * routine converts that back into an actual address.
+	 */
+	return (u32 *)((unsigned long)fcur + offset);
+}
+
+static int patch_alt_instruction(u32 *src, u32 *dest, u32 *alt_start, u32 *alt_end)
+{
+	int err;
+	ppc_inst_t instr;
+
+	instr = ppc_inst_read(src);
+
+	if (instr_is_relative_branch(ppc_inst_read(src))) {
+		u32 *target = (u32 *)branch_target(src);
+
+		/* Branch within the section doesn't need translating */
+		if (target < alt_start || target > alt_end) {
+			err = translate_branch(&instr, dest, src);
+			if (err)
+				return 1;
+		}
+	}
+
+	raw_patch_instruction(dest, instr);
+
+	return 0;
+}
+
+static int patch_feature_section_mask(unsigned long value, unsigned long mask,
+				      struct fixup_entry *fcur)
+{
+	u32 *start, *end, *alt_start, *alt_end, *src, *dest;
+
+	start = calc_addr(fcur, fcur->start_off);
+	end = calc_addr(fcur, fcur->end_off);
+	alt_start = calc_addr(fcur, fcur->alt_start_off);
+	alt_end = calc_addr(fcur, fcur->alt_end_off);
+
+	if ((alt_end - alt_start) > (end - start))
+		return 1;
+
+	if ((value & fcur->mask & mask) == (fcur->value & mask))
+		return 0;
+
+	src = alt_start;
+	dest = start;
+
+	for (; src < alt_end; src = ppc_inst_next(src, src),
+			      dest = ppc_inst_next(dest, dest)) {
+		if (patch_alt_instruction(src, dest, alt_start, alt_end))
+			return 1;
+	}
+
+	for (; dest < end; dest++)
+		raw_patch_instruction(dest, ppc_inst(PPC_RAW_NOP()));
+
+	return 0;
+}
+
+static void do_feature_fixups_mask(unsigned long value, unsigned long mask,
+				   void *fixup_start, void *fixup_end)
+{
+	struct fixup_entry *fcur, *fend;
+
+	fcur = fixup_start;
+	fend = fixup_end;
+
+	for (; fcur < fend; fcur++) {
+		if (patch_feature_section_mask(value, mask, fcur)) {
+			WARN_ON(1);
+			printk("Unable to patch feature section at %p - %p" \
+				" with %p - %p\n",
+				calc_addr(fcur, fcur->start_off),
+				calc_addr(fcur, fcur->end_off),
+				calc_addr(fcur, fcur->alt_start_off),
+				calc_addr(fcur, fcur->alt_end_off));
+		}
+	}
+}
+
+void do_feature_fixups(unsigned long value, void *fixup_start, void *fixup_end)
+{
+	do_feature_fixups_mask(value, ~0, fixup_start, fixup_end);
+}
+
+#ifdef CONFIG_PPC_BARRIER_NOSPEC
+static bool is_fixup_addr_valid(void *dest, size_t size)
+{
+	return system_state < SYSTEM_FREEING_INITMEM ||
+	       !init_section_contains(dest, size);
+}
+
+static int do_patch_fixups(long *start, long *end, unsigned int *instrs, int num)
+{
+	int i;
+
+	for (i = 0; start < end; start++, i++) {
+		int j;
+		unsigned int *dest = (void *)start + *start;
+
+		if (!is_fixup_addr_valid(dest, sizeof(*instrs) * num))
+			continue;
+
+		pr_devel("patching dest %lx\n", (unsigned long)dest);
+
+		for (j = 0; j < num; j++)
+			patch_instruction(dest + j, ppc_inst(instrs[j]));
+	}
+	return i;
+}
+#endif
+
+#ifdef CONFIG_PPC_BOOK3S_64
+static int do_patch_entry_fixups(long *start, long *end, unsigned int *instrs,
+				 bool do_fallback, void *fallback)
+{
+	int i;
+
+	for (i = 0; start < end; start++, i++) {
+		unsigned int *dest = (void *)start + *start;
+
+		if (!is_fixup_addr_valid(dest, sizeof(*instrs) * 3))
+			continue;
+
+		pr_devel("patching dest %lx\n", (unsigned long)dest);
+
+		// See comment in do_entry_flush_fixups() RE order of patching
+		if (do_fallback) {
+			patch_instruction(dest, ppc_inst(instrs[0]));
+			patch_instruction(dest + 2, ppc_inst(instrs[2]));
+			patch_branch(dest + 1, (unsigned long)fallback, BRANCH_SET_LINK);
+		} else {
+			patch_instruction(dest + 1, ppc_inst(instrs[1]));
+			patch_instruction(dest + 2, ppc_inst(instrs[2]));
+			patch_instruction(dest, ppc_inst(instrs[0]));
+		}
+	}
+	return i;
+}
+
+static void do_stf_entry_barrier_fixups(enum stf_barrier_type types)
+{
+	unsigned int instrs[3];
+	long *start, *end;
+	int i;
+
+	start = PTRRELOC(&__start___stf_entry_barrier_fixup);
+	end = PTRRELOC(&__stop___stf_entry_barrier_fixup);
+
+	instrs[0] = PPC_RAW_NOP();
+	instrs[1] = PPC_RAW_NOP();
+	instrs[2] = PPC_RAW_NOP();
+
+	i = 0;
+	if (types & STF_BARRIER_FALLBACK) {
+		instrs[i++] = PPC_RAW_MFLR(_R10);
+		instrs[i++] = PPC_RAW_NOP(); /* branch patched below */
+		instrs[i++] = PPC_RAW_MTLR(_R10);
+	} else if (types & STF_BARRIER_EIEIO) {
+		instrs[i++] = PPC_RAW_EIEIO() | 0x02000000; /* eieio + bit 6 hint */
+	} else if (types & STF_BARRIER_SYNC_ORI) {
+		instrs[i++] = PPC_RAW_SYNC();
+		instrs[i++] = PPC_RAW_LD(_R10, _R13, 0);
+		instrs[i++] = PPC_RAW_ORI(_R31, _R31, 0); /* speculation barrier */
+	}
+
+	i = do_patch_entry_fixups(start, end, instrs, types & STF_BARRIER_FALLBACK,
+				  &stf_barrier_fallback);
+
+	printk(KERN_DEBUG "stf-barrier: patched %d entry locations (%s barrier)\n", i,
+		(types == STF_BARRIER_NONE)                  ? "no" :
+		(types == STF_BARRIER_FALLBACK)              ? "fallback" :
+		(types == STF_BARRIER_EIEIO)                 ? "eieio" :
+		(types == (STF_BARRIER_SYNC_ORI))            ? "hwsync"
+		                                           : "unknown");
+}
+
+static void do_stf_exit_barrier_fixups(enum stf_barrier_type types)
+{
+	unsigned int instrs[6];
+	long *start, *end;
+	int i;
+
+	start = PTRRELOC(&__start___stf_exit_barrier_fixup);
+	end = PTRRELOC(&__stop___stf_exit_barrier_fixup);
+
+	instrs[0] = PPC_RAW_NOP();
+	instrs[1] = PPC_RAW_NOP();
+	instrs[2] = PPC_RAW_NOP();
+	instrs[3] = PPC_RAW_NOP();
+	instrs[4] = PPC_RAW_NOP();
+	instrs[5] = PPC_RAW_NOP();
+
+	i = 0;
+	if (types & STF_BARRIER_FALLBACK || types & STF_BARRIER_SYNC_ORI) {
+		if (cpu_has_feature(CPU_FTR_HVMODE)) {
+			instrs[i++] = PPC_RAW_MTSPR(SPRN_HSPRG1, _R13);
+			instrs[i++] = PPC_RAW_MFSPR(_R13, SPRN_HSPRG0);
+		} else {
+			instrs[i++] = PPC_RAW_MTSPR(SPRN_SPRG2, _R13);
+			instrs[i++] = PPC_RAW_MFSPR(_R13, SPRN_SPRG1);
+	        }
+		instrs[i++] = PPC_RAW_SYNC();
+		instrs[i++] = PPC_RAW_LD(_R13, _R13, 0);
+		instrs[i++] = PPC_RAW_ORI(_R31, _R31, 0); /* speculation barrier */
+		if (cpu_has_feature(CPU_FTR_HVMODE))
+			instrs[i++] = PPC_RAW_MFSPR(_R13, SPRN_HSPRG1);
+		else
+			instrs[i++] = PPC_RAW_MFSPR(_R13, SPRN_SPRG2);
+	} else if (types & STF_BARRIER_EIEIO) {
+		instrs[i++] = PPC_RAW_EIEIO() | 0x02000000; /* eieio + bit 6 hint */
+	}
+
+	i = do_patch_fixups(start, end, instrs, ARRAY_SIZE(instrs));
+
+	printk(KERN_DEBUG "stf-barrier: patched %d exit locations (%s barrier)\n", i,
+		(types == STF_BARRIER_NONE)                  ? "no" :
+		(types == STF_BARRIER_FALLBACK)              ? "fallback" :
+		(types == STF_BARRIER_EIEIO)                 ? "eieio" :
+		(types == (STF_BARRIER_SYNC_ORI))            ? "hwsync"
+		                                           : "unknown");
+}
+
+static bool stf_exit_reentrant = false;
+static bool rfi_exit_reentrant = false;
+static DEFINE_MUTEX(exit_flush_lock);
+
+static int __do_stf_barrier_fixups(void *data)
+{
+	enum stf_barrier_type *types = data;
+
+	do_stf_entry_barrier_fixups(*types);
+	do_stf_exit_barrier_fixups(*types);
+
+	return 0;
+}
+
+void do_stf_barrier_fixups(enum stf_barrier_type types)
+{
+	/*
+	 * The call to the fallback entry flush, and the fallback/sync-ori exit
+	 * flush can not be safely patched in/out while other CPUs are
+	 * executing them. So call __do_stf_barrier_fixups() on one CPU while
+	 * all other CPUs spin in the stop machine core with interrupts hard
+	 * disabled.
+	 *
+	 * The branch to mark interrupt exits non-reentrant is enabled first,
+	 * then stop_machine runs which will ensure all CPUs are out of the
+	 * low level interrupt exit code before patching. After the patching,
+	 * if allowed, then flip the branch to allow fast exits.
+	 */
+
+	// Prevent static key update races with do_rfi_flush_fixups()
+	mutex_lock(&exit_flush_lock);
+	static_branch_enable(&interrupt_exit_not_reentrant);
+
+	stop_machine(__do_stf_barrier_fixups, &types, NULL);
+
+	if ((types & STF_BARRIER_FALLBACK) || (types & STF_BARRIER_SYNC_ORI))
+		stf_exit_reentrant = false;
+	else
+		stf_exit_reentrant = true;
+
+	if (stf_exit_reentrant && rfi_exit_reentrant)
+		static_branch_disable(&interrupt_exit_not_reentrant);
+
+	mutex_unlock(&exit_flush_lock);
+}
+
+void do_uaccess_flush_fixups(enum l1d_flush_type types)
+{
+	unsigned int instrs[4];
+	long *start, *end;
+	int i;
+
+	start = PTRRELOC(&__start___uaccess_flush_fixup);
+	end = PTRRELOC(&__stop___uaccess_flush_fixup);
+
+	instrs[0] = PPC_RAW_NOP();
+	instrs[1] = PPC_RAW_NOP();
+	instrs[2] = PPC_RAW_NOP();
+	instrs[3] = PPC_RAW_BLR();
+
+	i = 0;
+	if (types == L1D_FLUSH_FALLBACK) {
+		instrs[3] = PPC_RAW_NOP();
+		/* fallthrough to fallback flush */
+	}
+
+	if (types & L1D_FLUSH_ORI) {
+		instrs[i++] = PPC_RAW_ORI(_R31, _R31, 0); /* speculation barrier */
+		instrs[i++] = PPC_RAW_ORI(_R30, _R30, 0); /* L1d flush */
+	}
+
+	if (types & L1D_FLUSH_MTTRIG)
+		instrs[i++] = PPC_RAW_MTSPR(SPRN_TRIG2, _R0);
+
+	i = do_patch_fixups(start, end, instrs, ARRAY_SIZE(instrs));
+
+	printk(KERN_DEBUG "uaccess-flush: patched %d locations (%s flush)\n", i,
+		(types == L1D_FLUSH_NONE)       ? "no" :
+		(types == L1D_FLUSH_FALLBACK)   ? "fallback displacement" :
+		(types &  L1D_FLUSH_ORI)        ? (types & L1D_FLUSH_MTTRIG)
+							? "ori+mttrig type"
+							: "ori type" :
+		(types &  L1D_FLUSH_MTTRIG)     ? "mttrig type"
+						: "unknown");
+}
+
+static int __do_entry_flush_fixups(void *data)
+{
+	enum l1d_flush_type types = *(enum l1d_flush_type *)data;
+	unsigned int instrs[3];
+	long *start, *end;
+	int i;
+
+	instrs[0] = PPC_RAW_NOP();
+	instrs[1] = PPC_RAW_NOP();
+	instrs[2] = PPC_RAW_NOP();
+
+	i = 0;
+	if (types == L1D_FLUSH_FALLBACK) {
+		instrs[i++] = PPC_RAW_MFLR(_R10);
+		instrs[i++] = PPC_RAW_NOP(); /* branch patched below */
+		instrs[i++] = PPC_RAW_MTLR(_R10);
+	}
+
+	if (types & L1D_FLUSH_ORI) {
+		instrs[i++] = PPC_RAW_ORI(_R31, _R31, 0); /* speculation barrier */
+		instrs[i++] = PPC_RAW_ORI(_R30, _R30, 0); /* L1d flush */
+	}
+
+	if (types & L1D_FLUSH_MTTRIG)
+		instrs[i++] = PPC_RAW_MTSPR(SPRN_TRIG2, _R0);
+
+	/*
+	 * If we're patching in or out the fallback flush we need to be careful about the
+	 * order in which we patch instructions. That's because it's possible we could
+	 * take a page fault after patching one instruction, so the sequence of
+	 * instructions must be safe even in a half patched state.
+	 *
+	 * To make that work, when patching in the fallback flush we patch in this order:
+	 *  - the mflr		(dest)
+	 *  - the mtlr		(dest + 2)
+	 *  - the branch	(dest + 1)
+	 *
+	 * That ensures the sequence is safe to execute at any point. In contrast if we
+	 * patch the mtlr last, it's possible we could return from the branch and not
+	 * restore LR, leading to a crash later.
+	 *
+	 * When patching out the fallback flush (either with nops or another flush type),
+	 * we patch in this order:
+	 *  - the branch	(dest + 1)
+	 *  - the mtlr		(dest + 2)
+	 *  - the mflr		(dest)
+	 *
+	 * Note we are protected by stop_machine() from other CPUs executing the code in a
+	 * semi-patched state.
+	 */
+
+	start = PTRRELOC(&__start___entry_flush_fixup);
+	end = PTRRELOC(&__stop___entry_flush_fixup);
+	i = do_patch_entry_fixups(start, end, instrs, types == L1D_FLUSH_FALLBACK,
+				  &entry_flush_fallback);
+
+	start = PTRRELOC(&__start___scv_entry_flush_fixup);
+	end = PTRRELOC(&__stop___scv_entry_flush_fixup);
+	i += do_patch_entry_fixups(start, end, instrs, types == L1D_FLUSH_FALLBACK,
+				   &scv_entry_flush_fallback);
+
+	printk(KERN_DEBUG "entry-flush: patched %d locations (%s flush)\n", i,
+		(types == L1D_FLUSH_NONE)       ? "no" :
+		(types == L1D_FLUSH_FALLBACK)   ? "fallback displacement" :
+		(types &  L1D_FLUSH_ORI)        ? (types & L1D_FLUSH_MTTRIG)
+							? "ori+mttrig type"
+							: "ori type" :
+		(types &  L1D_FLUSH_MTTRIG)     ? "mttrig type"
+						: "unknown");
+
+	return 0;
+}
+
+void do_entry_flush_fixups(enum l1d_flush_type types)
+{
+	/*
+	 * The call to the fallback flush can not be safely patched in/out while
+	 * other CPUs are executing it. So call __do_entry_flush_fixups() on one
+	 * CPU while all other CPUs spin in the stop machine core with interrupts
+	 * hard disabled.
+	 */
+	stop_machine(__do_entry_flush_fixups, &types, NULL);
+}
+
+static int __do_rfi_flush_fixups(void *data)
+{
+	enum l1d_flush_type types = *(enum l1d_flush_type *)data;
+	unsigned int instrs[3];
+	long *start, *end;
+	int i;
+
+	start = PTRRELOC(&__start___rfi_flush_fixup);
+	end = PTRRELOC(&__stop___rfi_flush_fixup);
+
+	instrs[0] = PPC_RAW_NOP();
+	instrs[1] = PPC_RAW_NOP();
+	instrs[2] = PPC_RAW_NOP();
+
+	if (types & L1D_FLUSH_FALLBACK)
+		/* b .+16 to fallback flush */
+		instrs[0] = PPC_RAW_BRANCH(16);
+
+	i = 0;
+	if (types & L1D_FLUSH_ORI) {
+		instrs[i++] = PPC_RAW_ORI(_R31, _R31, 0); /* speculation barrier */
+		instrs[i++] = PPC_RAW_ORI(_R30, _R30, 0); /* L1d flush */
+	}
+
+	if (types & L1D_FLUSH_MTTRIG)
+		instrs[i++] = PPC_RAW_MTSPR(SPRN_TRIG2, _R0);
+
+	i = do_patch_fixups(start, end, instrs, ARRAY_SIZE(instrs));
+
+	printk(KERN_DEBUG "rfi-flush: patched %d locations (%s flush)\n", i,
+		(types == L1D_FLUSH_NONE)       ? "no" :
+		(types == L1D_FLUSH_FALLBACK)   ? "fallback displacement" :
+		(types &  L1D_FLUSH_ORI)        ? (types & L1D_FLUSH_MTTRIG)
+							? "ori+mttrig type"
+							: "ori type" :
+		(types &  L1D_FLUSH_MTTRIG)     ? "mttrig type"
+						: "unknown");
+
+	return 0;
+}
+
+void do_rfi_flush_fixups(enum l1d_flush_type types)
+{
+	/*
+	 * stop_machine gets all CPUs out of the interrupt exit handler same
+	 * as do_stf_barrier_fixups. do_rfi_flush_fixups patching can run
+	 * without stop_machine, so this could be achieved with a broadcast
+	 * IPI instead, but this matches the stf sequence.
+	 */
+
+	// Prevent static key update races with do_stf_barrier_fixups()
+	mutex_lock(&exit_flush_lock);
+	static_branch_enable(&interrupt_exit_not_reentrant);
+
+	stop_machine(__do_rfi_flush_fixups, &types, NULL);
+
+	if (types & L1D_FLUSH_FALLBACK)
+		rfi_exit_reentrant = false;
+	else
+		rfi_exit_reentrant = true;
+
+	if (stf_exit_reentrant && rfi_exit_reentrant)
+		static_branch_disable(&interrupt_exit_not_reentrant);
+
+	mutex_unlock(&exit_flush_lock);
+}
+
+void do_barrier_nospec_fixups_range(bool enable, void *fixup_start, void *fixup_end)
+{
+	unsigned int instr;
+	long *start, *end;
+	int i;
+
+	start = fixup_start;
+	end = fixup_end;
+
+	instr = PPC_RAW_NOP();
+
+	if (enable) {
+		pr_info("barrier-nospec: using ORI speculation barrier\n");
+		instr = PPC_RAW_ORI(_R31, _R31, 0); /* speculation barrier */
+	}
+
+	i = do_patch_fixups(start, end, &instr, 1);
+
+	printk(KERN_DEBUG "barrier-nospec: patched %d locations\n", i);
+}
+
+#endif /* CONFIG_PPC_BOOK3S_64 */
+
+#ifdef CONFIG_PPC_BARRIER_NOSPEC
+void do_barrier_nospec_fixups(bool enable)
+{
+	void *start, *end;
+
+	start = PTRRELOC(&__start___barrier_nospec_fixup);
+	end = PTRRELOC(&__stop___barrier_nospec_fixup);
+
+	do_barrier_nospec_fixups_range(enable, start, end);
+}
+#endif /* CONFIG_PPC_BARRIER_NOSPEC */
+
+#ifdef CONFIG_PPC_E500
+void do_barrier_nospec_fixups_range(bool enable, void *fixup_start, void *fixup_end)
+{
+	unsigned int instr[2];
+	long *start, *end;
+	int i;
+
+	start = fixup_start;
+	end = fixup_end;
+
+	instr[0] = PPC_RAW_NOP();
+	instr[1] = PPC_RAW_NOP();
+
+	if (enable) {
+		pr_info("barrier-nospec: using isync; sync as speculation barrier\n");
+		instr[0] = PPC_RAW_ISYNC();
+		instr[1] = PPC_RAW_SYNC();
+	}
+
+	i = do_patch_fixups(start, end, instr, ARRAY_SIZE(instr));
+
+	printk(KERN_DEBUG "barrier-nospec: patched %d locations\n", i);
+}
+
+static void __init patch_btb_flush_section(long *curr)
+{
+	unsigned int *start, *end;
+
+	start = (void *)curr + *curr;
+	end = (void *)curr + *(curr + 1);
+	for (; start < end; start++) {
+		pr_devel("patching dest %lx\n", (unsigned long)start);
+		patch_instruction(start, ppc_inst(PPC_RAW_NOP()));
+	}
+}
+
+void __init do_btb_flush_fixups(void)
+{
+	long *start, *end;
+
+	start = PTRRELOC(&__start__btb_flush_fixup);
+	end = PTRRELOC(&__stop__btb_flush_fixup);
+
+	for (; start < end; start += 2)
+		patch_btb_flush_section(start);
+}
+#endif /* CONFIG_PPC_E500 */
+
+void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end)
+{
+	long *start, *end;
+	u32 *dest;
+
+	if (!(value & CPU_FTR_LWSYNC))
+		return ;
+
+	start = fixup_start;
+	end = fixup_end;
+
+	for (; start < end; start++) {
+		dest = (void *)start + *start;
+		raw_patch_instruction(dest, ppc_inst(PPC_INST_LWSYNC));
+	}
+}
+
+static void __init do_final_fixups(void)
+{
+#if defined(CONFIG_PPC64) && defined(CONFIG_RELOCATABLE)
+	ppc_inst_t inst;
+	u32 *src, *dest, *end;
+
+	if (PHYSICAL_START == 0)
+		return;
+
+	src = (u32 *)(KERNELBASE + PHYSICAL_START);
+	dest = (u32 *)KERNELBASE;
+	end = (void *)src + (__end_interrupts - _stext);
+
+	while (src < end) {
+		inst = ppc_inst_read(src);
+		raw_patch_instruction(dest, inst);
+		src = ppc_inst_next(src, src);
+		dest = ppc_inst_next(dest, dest);
+	}
+#endif
+}
+
+static unsigned long __initdata saved_cpu_features;
+static unsigned int __initdata saved_mmu_features;
+#ifdef CONFIG_PPC64
+static unsigned long __initdata saved_firmware_features;
+#endif
+
+void __init apply_feature_fixups(void)
+{
+	struct cpu_spec *spec = PTRRELOC(*PTRRELOC(&cur_cpu_spec));
+
+	*PTRRELOC(&saved_cpu_features) = spec->cpu_features;
+	*PTRRELOC(&saved_mmu_features) = spec->mmu_features;
+
+	/*
+	 * Apply the CPU-specific and firmware specific fixups to kernel text
+	 * (nop out sections not relevant to this CPU or this firmware).
+	 */
+	do_feature_fixups(spec->cpu_features,
+			  PTRRELOC(&__start___ftr_fixup),
+			  PTRRELOC(&__stop___ftr_fixup));
+
+	do_feature_fixups(spec->mmu_features,
+			  PTRRELOC(&__start___mmu_ftr_fixup),
+			  PTRRELOC(&__stop___mmu_ftr_fixup));
+
+	do_lwsync_fixups(spec->cpu_features,
+			 PTRRELOC(&__start___lwsync_fixup),
+			 PTRRELOC(&__stop___lwsync_fixup));
+
+#ifdef CONFIG_PPC64
+	saved_firmware_features = powerpc_firmware_features;
+	do_feature_fixups(powerpc_firmware_features,
+			  &__start___fw_ftr_fixup, &__stop___fw_ftr_fixup);
+#endif
+	do_final_fixups();
+}
+
+void __init update_mmu_feature_fixups(unsigned long mask)
+{
+	saved_mmu_features &= ~mask;
+	saved_mmu_features |= cur_cpu_spec->mmu_features & mask;
+
+	do_feature_fixups_mask(cur_cpu_spec->mmu_features, mask,
+			       PTRRELOC(&__start___mmu_ftr_fixup),
+			       PTRRELOC(&__stop___mmu_ftr_fixup));
+	mmu_feature_keys_init();
+}
+
+void __init setup_feature_keys(void)
+{
+	/*
+	 * Initialise jump label. This causes all the cpu/mmu_has_feature()
+	 * checks to take on their correct polarity based on the current set of
+	 * CPU/MMU features.
+	 */
+	jump_label_init();
+	cpu_feature_keys_init();
+	mmu_feature_keys_init();
+	static_key_feature_checks_initialized = true;
+}
+
+static int __init check_features(void)
+{
+	WARN(saved_cpu_features != cur_cpu_spec->cpu_features,
+	     "CPU features changed after feature patching!\n");
+	WARN(saved_mmu_features != cur_cpu_spec->mmu_features,
+	     "MMU features changed after feature patching!\n");
+#ifdef CONFIG_PPC64
+	WARN(saved_firmware_features != powerpc_firmware_features,
+	     "Firmware features changed after feature patching!\n");
+#endif
+
+	return 0;
+}
+late_initcall(check_features);
+
+#ifdef CONFIG_FTR_FIXUP_SELFTEST
+
+#define check(x)	\
+	if (!(x)) printk("feature-fixups: test failed at line %d\n", __LINE__);
+
+static int patch_feature_section(unsigned long value, struct fixup_entry *fcur)
+{
+	return patch_feature_section_mask(value, ~0, fcur);
+}
+
+/* This must be after the text it fixes up, vmlinux.lds.S enforces that atm */
+static struct fixup_entry fixup;
+
+static long __init calc_offset(struct fixup_entry *entry, unsigned int *p)
+{
+	return (unsigned long)p - (unsigned long)entry;
+}
+
+static void __init test_basic_patching(void)
+{
+	extern unsigned int ftr_fixup_test1[];
+	extern unsigned int end_ftr_fixup_test1[];
+	extern unsigned int ftr_fixup_test1_orig[];
+	extern unsigned int ftr_fixup_test1_expected[];
+	int size = 4 * (end_ftr_fixup_test1 - ftr_fixup_test1);
+
+	fixup.value = fixup.mask = 8;
+	fixup.start_off = calc_offset(&fixup, ftr_fixup_test1 + 1);
+	fixup.end_off = calc_offset(&fixup, ftr_fixup_test1 + 2);
+	fixup.alt_start_off = fixup.alt_end_off = 0;
+
+	/* Sanity check */
+	check(memcmp(ftr_fixup_test1, ftr_fixup_test1_orig, size) == 0);
+
+	/* Check we don't patch if the value matches */
+	patch_feature_section(8, &fixup);
+	check(memcmp(ftr_fixup_test1, ftr_fixup_test1_orig, size) == 0);
+
+	/* Check we do patch if the value doesn't match */
+	patch_feature_section(0, &fixup);
+	check(memcmp(ftr_fixup_test1, ftr_fixup_test1_expected, size) == 0);
+
+	/* Check we do patch if the mask doesn't match */
+	memcpy(ftr_fixup_test1, ftr_fixup_test1_orig, size);
+	check(memcmp(ftr_fixup_test1, ftr_fixup_test1_orig, size) == 0);
+	patch_feature_section(~8, &fixup);
+	check(memcmp(ftr_fixup_test1, ftr_fixup_test1_expected, size) == 0);
+}
+
+static void __init test_alternative_patching(void)
+{
+	extern unsigned int ftr_fixup_test2[];
+	extern unsigned int end_ftr_fixup_test2[];
+	extern unsigned int ftr_fixup_test2_orig[];
+	extern unsigned int ftr_fixup_test2_alt[];
+	extern unsigned int ftr_fixup_test2_expected[];
+	int size = 4 * (end_ftr_fixup_test2 - ftr_fixup_test2);
+
+	fixup.value = fixup.mask = 0xF;
+	fixup.start_off = calc_offset(&fixup, ftr_fixup_test2 + 1);
+	fixup.end_off = calc_offset(&fixup, ftr_fixup_test2 + 2);
+	fixup.alt_start_off = calc_offset(&fixup, ftr_fixup_test2_alt);
+	fixup.alt_end_off = calc_offset(&fixup, ftr_fixup_test2_alt + 1);
+
+	/* Sanity check */
+	check(memcmp(ftr_fixup_test2, ftr_fixup_test2_orig, size) == 0);
+
+	/* Check we don't patch if the value matches */
+	patch_feature_section(0xF, &fixup);
+	check(memcmp(ftr_fixup_test2, ftr_fixup_test2_orig, size) == 0);
+
+	/* Check we do patch if the value doesn't match */
+	patch_feature_section(0, &fixup);
+	check(memcmp(ftr_fixup_test2, ftr_fixup_test2_expected, size) == 0);
+
+	/* Check we do patch if the mask doesn't match */
+	memcpy(ftr_fixup_test2, ftr_fixup_test2_orig, size);
+	check(memcmp(ftr_fixup_test2, ftr_fixup_test2_orig, size) == 0);
+	patch_feature_section(~0xF, &fixup);
+	check(memcmp(ftr_fixup_test2, ftr_fixup_test2_expected, size) == 0);
+}
+
+static void __init test_alternative_case_too_big(void)
+{
+	extern unsigned int ftr_fixup_test3[];
+	extern unsigned int end_ftr_fixup_test3[];
+	extern unsigned int ftr_fixup_test3_orig[];
+	extern unsigned int ftr_fixup_test3_alt[];
+	int size = 4 * (end_ftr_fixup_test3 - ftr_fixup_test3);
+
+	fixup.value = fixup.mask = 0xC;
+	fixup.start_off = calc_offset(&fixup, ftr_fixup_test3 + 1);
+	fixup.end_off = calc_offset(&fixup, ftr_fixup_test3 + 2);
+	fixup.alt_start_off = calc_offset(&fixup, ftr_fixup_test3_alt);
+	fixup.alt_end_off = calc_offset(&fixup, ftr_fixup_test3_alt + 2);
+
+	/* Sanity check */
+	check(memcmp(ftr_fixup_test3, ftr_fixup_test3_orig, size) == 0);
+
+	/* Expect nothing to be patched, and the error returned to us */
+	check(patch_feature_section(0xF, &fixup) == 1);
+	check(memcmp(ftr_fixup_test3, ftr_fixup_test3_orig, size) == 0);
+	check(patch_feature_section(0, &fixup) == 1);
+	check(memcmp(ftr_fixup_test3, ftr_fixup_test3_orig, size) == 0);
+	check(patch_feature_section(~0xF, &fixup) == 1);
+	check(memcmp(ftr_fixup_test3, ftr_fixup_test3_orig, size) == 0);
+}
+
+static void __init test_alternative_case_too_small(void)
+{
+	extern unsigned int ftr_fixup_test4[];
+	extern unsigned int end_ftr_fixup_test4[];
+	extern unsigned int ftr_fixup_test4_orig[];
+	extern unsigned int ftr_fixup_test4_alt[];
+	extern unsigned int ftr_fixup_test4_expected[];
+	int size = 4 * (end_ftr_fixup_test4 - ftr_fixup_test4);
+	unsigned long flag;
+
+	/* Check a high-bit flag */
+	flag = 1UL << ((sizeof(unsigned long) - 1) * 8);
+	fixup.value = fixup.mask = flag;
+	fixup.start_off = calc_offset(&fixup, ftr_fixup_test4 + 1);
+	fixup.end_off = calc_offset(&fixup, ftr_fixup_test4 + 5);
+	fixup.alt_start_off = calc_offset(&fixup, ftr_fixup_test4_alt);
+	fixup.alt_end_off = calc_offset(&fixup, ftr_fixup_test4_alt + 2);
+
+	/* Sanity check */
+	check(memcmp(ftr_fixup_test4, ftr_fixup_test4_orig, size) == 0);
+
+	/* Check we don't patch if the value matches */
+	patch_feature_section(flag, &fixup);
+	check(memcmp(ftr_fixup_test4, ftr_fixup_test4_orig, size) == 0);
+
+	/* Check we do patch if the value doesn't match */
+	patch_feature_section(0, &fixup);
+	check(memcmp(ftr_fixup_test4, ftr_fixup_test4_expected, size) == 0);
+
+	/* Check we do patch if the mask doesn't match */
+	memcpy(ftr_fixup_test4, ftr_fixup_test4_orig, size);
+	check(memcmp(ftr_fixup_test4, ftr_fixup_test4_orig, size) == 0);
+	patch_feature_section(~flag, &fixup);
+	check(memcmp(ftr_fixup_test4, ftr_fixup_test4_expected, size) == 0);
+}
+
+static void test_alternative_case_with_branch(void)
+{
+	extern unsigned int ftr_fixup_test5[];
+	extern unsigned int end_ftr_fixup_test5[];
+	extern unsigned int ftr_fixup_test5_expected[];
+	int size = 4 * (end_ftr_fixup_test5 - ftr_fixup_test5);
+
+	check(memcmp(ftr_fixup_test5, ftr_fixup_test5_expected, size) == 0);
+}
+
+static void __init test_alternative_case_with_external_branch(void)
+{
+	extern unsigned int ftr_fixup_test6[];
+	extern unsigned int end_ftr_fixup_test6[];
+	extern unsigned int ftr_fixup_test6_expected[];
+	int size = 4 * (end_ftr_fixup_test6 - ftr_fixup_test6);
+
+	check(memcmp(ftr_fixup_test6, ftr_fixup_test6_expected, size) == 0);
+}
+
+static void __init test_alternative_case_with_branch_to_end(void)
+{
+	extern unsigned int ftr_fixup_test7[];
+	extern unsigned int end_ftr_fixup_test7[];
+	extern unsigned int ftr_fixup_test7_expected[];
+	int size = 4 * (end_ftr_fixup_test7 - ftr_fixup_test7);
+
+	check(memcmp(ftr_fixup_test7, ftr_fixup_test7_expected, size) == 0);
+}
+
+static void __init test_cpu_macros(void)
+{
+	extern u8 ftr_fixup_test_FTR_macros[];
+	extern u8 ftr_fixup_test_FTR_macros_expected[];
+	unsigned long size = ftr_fixup_test_FTR_macros_expected -
+			     ftr_fixup_test_FTR_macros;
+
+	/* The fixups have already been done for us during boot */
+	check(memcmp(ftr_fixup_test_FTR_macros,
+		     ftr_fixup_test_FTR_macros_expected, size) == 0);
+}
+
+static void __init test_fw_macros(void)
+{
+#ifdef CONFIG_PPC64
+	extern u8 ftr_fixup_test_FW_FTR_macros[];
+	extern u8 ftr_fixup_test_FW_FTR_macros_expected[];
+	unsigned long size = ftr_fixup_test_FW_FTR_macros_expected -
+			     ftr_fixup_test_FW_FTR_macros;
+
+	/* The fixups have already been done for us during boot */
+	check(memcmp(ftr_fixup_test_FW_FTR_macros,
+		     ftr_fixup_test_FW_FTR_macros_expected, size) == 0);
+#endif
+}
+
+static void __init test_lwsync_macros(void)
+{
+	extern u8 lwsync_fixup_test[];
+	extern u8 end_lwsync_fixup_test[];
+	extern u8 lwsync_fixup_test_expected_LWSYNC[];
+	extern u8 lwsync_fixup_test_expected_SYNC[];
+	unsigned long size = end_lwsync_fixup_test -
+			     lwsync_fixup_test;
+
+	/* The fixups have already been done for us during boot */
+	if (cur_cpu_spec->cpu_features & CPU_FTR_LWSYNC) {
+		check(memcmp(lwsync_fixup_test,
+			     lwsync_fixup_test_expected_LWSYNC, size) == 0);
+	} else {
+		check(memcmp(lwsync_fixup_test,
+			     lwsync_fixup_test_expected_SYNC, size) == 0);
+	}
+}
+
+#ifdef CONFIG_PPC64
+static void __init test_prefix_patching(void)
+{
+	extern unsigned int ftr_fixup_prefix1[];
+	extern unsigned int end_ftr_fixup_prefix1[];
+	extern unsigned int ftr_fixup_prefix1_orig[];
+	extern unsigned int ftr_fixup_prefix1_expected[];
+	int size = sizeof(unsigned int) * (end_ftr_fixup_prefix1 - ftr_fixup_prefix1);
+
+	fixup.value = fixup.mask = 8;
+	fixup.start_off = calc_offset(&fixup, ftr_fixup_prefix1 + 1);
+	fixup.end_off = calc_offset(&fixup, ftr_fixup_prefix1 + 3);
+	fixup.alt_start_off = fixup.alt_end_off = 0;
+
+	/* Sanity check */
+	check(memcmp(ftr_fixup_prefix1, ftr_fixup_prefix1_orig, size) == 0);
+
+	patch_feature_section(0, &fixup);
+	check(memcmp(ftr_fixup_prefix1, ftr_fixup_prefix1_expected, size) == 0);
+	check(memcmp(ftr_fixup_prefix1, ftr_fixup_prefix1_orig, size) != 0);
+}
+
+static void __init test_prefix_alt_patching(void)
+{
+	extern unsigned int ftr_fixup_prefix2[];
+	extern unsigned int end_ftr_fixup_prefix2[];
+	extern unsigned int ftr_fixup_prefix2_orig[];
+	extern unsigned int ftr_fixup_prefix2_expected[];
+	extern unsigned int ftr_fixup_prefix2_alt[];
+	int size = sizeof(unsigned int) * (end_ftr_fixup_prefix2 - ftr_fixup_prefix2);
+
+	fixup.value = fixup.mask = 8;
+	fixup.start_off = calc_offset(&fixup, ftr_fixup_prefix2 + 1);
+	fixup.end_off = calc_offset(&fixup, ftr_fixup_prefix2 + 3);
+	fixup.alt_start_off = calc_offset(&fixup, ftr_fixup_prefix2_alt);
+	fixup.alt_end_off = calc_offset(&fixup, ftr_fixup_prefix2_alt + 2);
+	/* Sanity check */
+	check(memcmp(ftr_fixup_prefix2, ftr_fixup_prefix2_orig, size) == 0);
+
+	patch_feature_section(0, &fixup);
+	check(memcmp(ftr_fixup_prefix2, ftr_fixup_prefix2_expected, size) == 0);
+	check(memcmp(ftr_fixup_prefix2, ftr_fixup_prefix2_orig, size) != 0);
+}
+
+static void __init test_prefix_word_alt_patching(void)
+{
+	extern unsigned int ftr_fixup_prefix3[];
+	extern unsigned int end_ftr_fixup_prefix3[];
+	extern unsigned int ftr_fixup_prefix3_orig[];
+	extern unsigned int ftr_fixup_prefix3_expected[];
+	extern unsigned int ftr_fixup_prefix3_alt[];
+	int size = sizeof(unsigned int) * (end_ftr_fixup_prefix3 - ftr_fixup_prefix3);
+
+	fixup.value = fixup.mask = 8;
+	fixup.start_off = calc_offset(&fixup, ftr_fixup_prefix3 + 1);
+	fixup.end_off = calc_offset(&fixup, ftr_fixup_prefix3 + 4);
+	fixup.alt_start_off = calc_offset(&fixup, ftr_fixup_prefix3_alt);
+	fixup.alt_end_off = calc_offset(&fixup, ftr_fixup_prefix3_alt + 3);
+	/* Sanity check */
+	check(memcmp(ftr_fixup_prefix3, ftr_fixup_prefix3_orig, size) == 0);
+
+	patch_feature_section(0, &fixup);
+	check(memcmp(ftr_fixup_prefix3, ftr_fixup_prefix3_expected, size) == 0);
+	patch_feature_section(0, &fixup);
+	check(memcmp(ftr_fixup_prefix3, ftr_fixup_prefix3_orig, size) != 0);
+}
+#else
+static inline void test_prefix_patching(void) {}
+static inline void test_prefix_alt_patching(void) {}
+static inline void test_prefix_word_alt_patching(void) {}
+#endif /* CONFIG_PPC64 */
+
+static int __init test_feature_fixups(void)
+{
+	printk(KERN_DEBUG "Running feature fixup self-tests ...\n");
+
+	test_basic_patching();
+	test_alternative_patching();
+	test_alternative_case_too_big();
+	test_alternative_case_too_small();
+	test_alternative_case_with_branch();
+	test_alternative_case_with_external_branch();
+	test_alternative_case_with_branch_to_end();
+	test_cpu_macros();
+	test_fw_macros();
+	test_lwsync_macros();
+	test_prefix_patching();
+	test_prefix_alt_patching();
+	test_prefix_word_alt_patching();
+
+	return 0;
+}
+late_initcall(test_feature_fixups);
+
+#endif /* CONFIG_FTR_FIXUP_SELFTEST */