1 files changed, 376 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..7ce3870d7
--- /dev/null
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -0,0 +1,376 @@
+/*
+ *  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/kernel.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <asm/cputable.h>
+#include <asm/code-patching.h>
+#include <asm/page.h>
+#include <asm/sections.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;
+		}
+	}
+
+	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++)
+		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));
+		}
+	}
+}
+
+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;
+		patch_instruction(dest, PPC_INST_LWSYNC);
+	}
+}
+
+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--) {
+		patch_instruction(dest, *src);
+		src++;
+		dest++;
+	}
+#endif
+}
+
+#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 = &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 = &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 = &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 = &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 = &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 = &end_ftr_fixup_test6 - &ftr_fixup_test6;
+
+	check(memcmp(&ftr_fixup_test6, &ftr_fixup_test6_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_cpu_macros();
+	test_fw_macros();
+	test_lwsync_macros();
+
+	return 0;
+}
+late_initcall(test_feature_fixups);
+
+#endif /* CONFIG_FTR_FIXUP_SELFTEST */