Adding upstream version 4.19.249.upstream/4.19.249upstream

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

1 files changed, 843 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..1561094ea
--- /dev/null
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -0,0 +1,843 @@
+/*
+ *  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.
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ */
+
+#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/code-patching.h>
+#include <asm/page.h>
+#include <asm/sections.h>
+#include <asm/setup.h>
+#include <asm/security_features.h>
+#include <asm/firmware.h>
+
+struct fixup_entry {
+	unsigned long	mask;
+	unsigned long	value;
+	long		start_off;
+	long		end_off;
+	long		alt_start_off;
+	long		alt_end_off;
+};
+
+static unsigned int *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 (unsigned int *)((unsigned long)fcur + offset);
+}
+
+static int patch_alt_instruction(unsigned int *src, unsigned int *dest,
+				 unsigned int *alt_start, unsigned int *alt_end)
+{
+	unsigned int instr;
+
+	instr = *src;
+
+	if (instr_is_relative_branch(*src)) {
+		unsigned int *target = (unsigned int *)branch_target(src);
+
+		/* Branch within the section doesn't need translating */
+		if (target < alt_start || target > alt_end) {
+			instr = translate_branch(dest, src);
+			if (!instr)
+				return 1;
+		}
+	}
+
+	raw_patch_instruction(dest, instr);
+
+	return 0;
+}
+
+static int patch_feature_section(unsigned long value, struct fixup_entry *fcur)
+{
+	unsigned int *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) == fcur->value)
+		return 0;
+
+	src = alt_start;
+	dest = start;
+
+	for (; src < alt_end; src++, dest++) {
+		if (patch_alt_instruction(src, dest, alt_start, alt_end))
+			return 1;
+	}
+
+	for (; dest < end; dest++)
+		raw_patch_instruction(dest, PPC_INST_NOP);
+
+	return 0;
+}
+
+void do_feature_fixups(unsigned long value, 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(value, 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));
+		}
+	}
+}
+
+#ifdef CONFIG_PPC_BOOK3S_64
+void do_stf_entry_barrier_fixups(enum stf_barrier_type types)
+{
+	unsigned int instrs[3], *dest;
+	long *start, *end;
+	int i;
+
+	start = PTRRELOC(&__start___stf_entry_barrier_fixup),
+	end = PTRRELOC(&__stop___stf_entry_barrier_fixup);
+
+	instrs[0] = 0x60000000; /* nop */
+	instrs[1] = 0x60000000; /* nop */
+	instrs[2] = 0x60000000; /* nop */
+
+	i = 0;
+	if (types & STF_BARRIER_FALLBACK) {
+		instrs[i++] = 0x7d4802a6; /* mflr r10		*/
+		instrs[i++] = 0x60000000; /* branch patched below */
+		instrs[i++] = 0x7d4803a6; /* mtlr r10		*/
+	} else if (types & STF_BARRIER_EIEIO) {
+		instrs[i++] = 0x7e0006ac; /* eieio + bit 6 hint */
+	} else if (types & STF_BARRIER_SYNC_ORI) {
+		instrs[i++] = 0x7c0004ac; /* hwsync		*/
+		instrs[i++] = 0xe94d0000; /* ld r10,0(r13)	*/
+		instrs[i++] = 0x63ff0000; /* ori 31,31,0 speculation barrier */
+	}
+
+	for (i = 0; start < end; start++, i++) {
+		dest = (void *)start + *start;
+
+		pr_devel("patching dest %lx\n", (unsigned long)dest);
+
+		patch_instruction(dest, instrs[0]);
+
+		if (types & STF_BARRIER_FALLBACK)
+			patch_branch(dest + 1, (unsigned long)&stf_barrier_fallback,
+				     BRANCH_SET_LINK);
+		else
+			patch_instruction(dest + 1, instrs[1]);
+
+		patch_instruction(dest + 2, instrs[2]);
+	}
+
+	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");
+}
+
+void do_stf_exit_barrier_fixups(enum stf_barrier_type types)
+{
+	unsigned int instrs[6], *dest;
+	long *start, *end;
+	int i;
+
+	start = PTRRELOC(&__start___stf_exit_barrier_fixup),
+	end = PTRRELOC(&__stop___stf_exit_barrier_fixup);
+
+	instrs[0] = 0x60000000; /* nop */
+	instrs[1] = 0x60000000; /* nop */
+	instrs[2] = 0x60000000; /* nop */
+	instrs[3] = 0x60000000; /* nop */
+	instrs[4] = 0x60000000; /* nop */
+	instrs[5] = 0x60000000; /* nop */
+
+	i = 0;
+	if (types & STF_BARRIER_FALLBACK || types & STF_BARRIER_SYNC_ORI) {
+		if (cpu_has_feature(CPU_FTR_HVMODE)) {
+			instrs[i++] = 0x7db14ba6; /* mtspr 0x131, r13 (HSPRG1) */
+			instrs[i++] = 0x7db04aa6; /* mfspr r13, 0x130 (HSPRG0) */
+		} else {
+			instrs[i++] = 0x7db243a6; /* mtsprg 2,r13	*/
+			instrs[i++] = 0x7db142a6; /* mfsprg r13,1    */
+	        }
+		instrs[i++] = 0x7c0004ac; /* hwsync		*/
+		instrs[i++] = 0xe9ad0000; /* ld r13,0(r13)	*/
+		instrs[i++] = 0x63ff0000; /* ori 31,31,0 speculation barrier */
+		if (cpu_has_feature(CPU_FTR_HVMODE)) {
+			instrs[i++] = 0x7db14aa6; /* mfspr r13, 0x131 (HSPRG1) */
+		} else {
+			instrs[i++] = 0x7db242a6; /* mfsprg r13,2 */
+		}
+	} else if (types & STF_BARRIER_EIEIO) {
+		instrs[i++] = 0x7e0006ac; /* eieio + bit 6 hint */
+	}
+
+	for (i = 0; start < end; start++, i++) {
+		dest = (void *)start + *start;
+
+		pr_devel("patching dest %lx\n", (unsigned long)dest);
+
+		patch_instruction(dest, instrs[0]);
+		patch_instruction(dest + 1, instrs[1]);
+		patch_instruction(dest + 2, instrs[2]);
+		patch_instruction(dest + 3, instrs[3]);
+		patch_instruction(dest + 4, instrs[4]);
+		patch_instruction(dest + 5, instrs[5]);
+	}
+	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 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.
+	 */
+	stop_machine(__do_stf_barrier_fixups, &types, NULL);
+}
+
+void do_uaccess_flush_fixups(enum l1d_flush_type types)
+{
+	unsigned int instrs[4], *dest;
+	long *start, *end;
+	int i;
+
+	start = PTRRELOC(&__start___uaccess_flush_fixup);
+	end = PTRRELOC(&__stop___uaccess_flush_fixup);
+
+	instrs[0] = 0x60000000; /* nop */
+	instrs[1] = 0x60000000; /* nop */
+	instrs[2] = 0x60000000; /* nop */
+	instrs[3] = 0x4e800020; /* blr */
+
+	i = 0;
+	if (types == L1D_FLUSH_FALLBACK) {
+		instrs[3] = 0x60000000; /* nop */
+		/* fallthrough to fallback flush */
+	}
+
+	if (types & L1D_FLUSH_ORI) {
+		instrs[i++] = 0x63ff0000; /* ori 31,31,0 speculation barrier */
+		instrs[i++] = 0x63de0000; /* ori 30,30,0 L1d flush*/
+	}
+
+	if (types & L1D_FLUSH_MTTRIG)
+		instrs[i++] = 0x7c12dba6; /* mtspr TRIG2,r0 (SPR #882) */
+
+	for (i = 0; start < end; start++, i++) {
+		dest = (void *)start + *start;
+
+		pr_devel("patching dest %lx\n", (unsigned long)dest);
+
+		patch_instruction(dest, instrs[0]);
+
+		patch_instruction((dest + 1), instrs[1]);
+		patch_instruction((dest + 2), instrs[2]);
+		patch_instruction((dest + 3), instrs[3]);
+	}
+
+	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], *dest;
+	long *start, *end;
+	int i;
+
+	start = PTRRELOC(&__start___entry_flush_fixup);
+	end = PTRRELOC(&__stop___entry_flush_fixup);
+
+	instrs[0] = 0x60000000; /* nop */
+	instrs[1] = 0x60000000; /* nop */
+	instrs[2] = 0x60000000; /* nop */
+
+	i = 0;
+	if (types == L1D_FLUSH_FALLBACK) {
+		instrs[i++] = 0x7d4802a6; /* mflr r10		*/
+		instrs[i++] = 0x60000000; /* branch patched below */
+		instrs[i++] = 0x7d4803a6; /* mtlr r10		*/
+	}
+
+	if (types & L1D_FLUSH_ORI) {
+		instrs[i++] = 0x63ff0000; /* ori 31,31,0 speculation barrier */
+		instrs[i++] = 0x63de0000; /* ori 30,30,0 L1d flush*/
+	}
+
+	if (types & L1D_FLUSH_MTTRIG)
+		instrs[i++] = 0x7c12dba6; /* mtspr TRIG2,r0 (SPR #882) */
+
+	for (i = 0; start < end; start++, i++) {
+		dest = (void *)start + *start;
+
+		pr_devel("patching dest %lx\n", (unsigned long)dest);
+
+		patch_instruction(dest, instrs[0]);
+
+		if (types == L1D_FLUSH_FALLBACK)
+			patch_branch((dest + 1), (unsigned long)&entry_flush_fallback,
+				     BRANCH_SET_LINK);
+		else
+			patch_instruction((dest + 1), instrs[1]);
+
+		patch_instruction((dest + 2), instrs[2]);
+	}
+
+	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);
+}
+
+void do_rfi_flush_fixups(enum l1d_flush_type types)
+{
+	unsigned int instrs[3], *dest;
+	long *start, *end;
+	int i;
+
+	start = PTRRELOC(&__start___rfi_flush_fixup),
+	end = PTRRELOC(&__stop___rfi_flush_fixup);
+
+	instrs[0] = 0x60000000; /* nop */
+	instrs[1] = 0x60000000; /* nop */
+	instrs[2] = 0x60000000; /* nop */
+
+	if (types & L1D_FLUSH_FALLBACK)
+		/* b .+16 to fallback flush */
+		instrs[0] = 0x48000010;
+
+	i = 0;
+	if (types & L1D_FLUSH_ORI) {
+		instrs[i++] = 0x63ff0000; /* ori 31,31,0 speculation barrier */
+		instrs[i++] = 0x63de0000; /* ori 30,30,0 L1d flush*/
+	}
+
+	if (types & L1D_FLUSH_MTTRIG)
+		instrs[i++] = 0x7c12dba6; /* mtspr TRIG2,r0 (SPR #882) */
+
+	for (i = 0; start < end; start++, i++) {
+		dest = (void *)start + *start;
+
+		pr_devel("patching dest %lx\n", (unsigned long)dest);
+
+		patch_instruction(dest, instrs[0]);
+		patch_instruction(dest + 1, instrs[1]);
+		patch_instruction(dest + 2, instrs[2]);
+	}
+
+	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");
+}
+
+void do_barrier_nospec_fixups_range(bool enable, void *fixup_start, void *fixup_end)
+{
+	unsigned int instr, *dest;
+	long *start, *end;
+	int i;
+
+	start = fixup_start;
+	end = fixup_end;
+
+	instr = 0x60000000; /* nop */
+
+	if (enable) {
+		pr_info("barrier-nospec: using ORI speculation barrier\n");
+		instr = 0x63ff0000; /* ori 31,31,0 speculation barrier */
+	}
+
+	for (i = 0; start < end; start++, i++) {
+		dest = (void *)start + *start;
+
+		pr_devel("patching dest %lx\n", (unsigned long)dest);
+		patch_instruction(dest, instr);
+	}
+
+	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_FSL_BOOK3E
+void do_barrier_nospec_fixups_range(bool enable, void *fixup_start, void *fixup_end)
+{
+	unsigned int instr[2], *dest;
+	long *start, *end;
+	int i;
+
+	start = fixup_start;
+	end = fixup_end;
+
+	instr[0] = PPC_INST_NOP;
+	instr[1] = PPC_INST_NOP;
+
+	if (enable) {
+		pr_info("barrier-nospec: using isync; sync as speculation barrier\n");
+		instr[0] = PPC_INST_ISYNC;
+		instr[1] = PPC_INST_SYNC;
+	}
+
+	for (i = 0; start < end; start++, i++) {
+		dest = (void *)start + *start;
+
+		pr_devel("patching dest %lx\n", (unsigned long)dest);
+		patch_instruction(dest, instr[0]);
+		patch_instruction(dest + 1, instr[1]);
+	}
+
+	printk(KERN_DEBUG "barrier-nospec: patched %d locations\n", i);
+}
+
+static void 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_NOP);
+	}
+}
+
+void 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_FSL_BOOK3E */
+
+void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end)
+{
+	long *start, *end;
+	unsigned int *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_LWSYNC);
+	}
+}
+
+static void do_final_fixups(void)
+{
+#if defined(CONFIG_PPC64) && defined(CONFIG_RELOCATABLE)
+	int *src, *dest;
+	unsigned long length;
+
+	if (PHYSICAL_START == 0)
+		return;
+
+	src = (int *)(KERNELBASE + PHYSICAL_START);
+	dest = (int *)KERNELBASE;
+	length = (__end_interrupts - _stext) / sizeof(int);
+
+	while (length--) {
+		raw_patch_instruction(dest, *src);
+		src++;
+		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 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 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__);
+
+/* This must be after the text it fixes up, vmlinux.lds.S enforces that atm */
+static struct fixup_entry fixup;
+
+static long calc_offset(struct fixup_entry *entry, unsigned int *p)
+{
+	return (unsigned long)p - (unsigned long)entry;
+}
+
+static void 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 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 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 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 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 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 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 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 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);
+	}
+}
+
+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();
+
+	return 0;
+}
+late_initcall(test_feature_fixups);
+
+#endif /* CONFIG_FTR_FIXUP_SELFTEST */