WIP

This commit is still dirty, and is jumbling cut & pasted referring to dynup#1010 and dynup#1203.
keiya-nobuta · Oct 6, 2021 · d3ed70b · d3ed70b
1 parent 6ba8551
commit d3ed70b
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Showing 5 changed files with 122 additions and 25 deletions.
diff --git a/kpatch-build/Makefile b/kpatch-build/Makefile
@@ -22,6 +22,7 @@ GCC_PLUGINS_DIR := $(shell gcc -print-file-name=plugin)
 PLUGIN_CFLAGS := $(filter-out -Wconversion, $(CFLAGS))
 PLUGIN_CFLAGS += -shared -I$(GCC_PLUGINS_DIR)/include \
 		   -Igcc-plugins -fPIC -fno-rtti -O2 -Wall
+else ifeq ($(ARCH),aarch64)
 else
 $(error Unsupported architecture ${ARCH}, check https://github.com/dynup/kpatch/#supported-architectures)
 endif

diff --git a/kpatch-build/create-diff-object.c b/kpatch-build/create-diff-object.c
@@ -62,6 +62,8 @@
 
 #ifdef __powerpc64__
 #define ABSOLUTE_RELA_TYPE R_PPC64_ADDR64
+#elif __aarch64__
+#define ABSOLUTE_RELA_TYPE R_AARCH64_ABS64
 #else
 #define ABSOLUTE_RELA_TYPE R_X86_64_64
 #endif
@@ -367,6 +369,15 @@ static bool is_special_static(struct symbol *sym)
 	return false;
 }
 
+#ifdef __aarch64__
+static bool is_aarch64_mapping_symbol(struct symbol *sym)
+{
+	return (sym->name && sym->name[0] == '$' &&
+		sym->type == STT_NOTYPE &&
+		sym->bind == STB_LOCAL);
+}
+#endif
+
 static bool has_digit_tail(char *tail)
 {
 	if (*tail != '.')
@@ -563,6 +574,12 @@ static void kpatch_compare_correlated_section(struct section *sec)
 		goto out;
 	}
 
+	if (!strcmp(sec->name, ".rela__patchable_function_entries") ||
+	    !strcmp(sec->name, "__patchable_function_entries")) {
+		sec->status = SAME;
+		goto out;
+	}
+
 	if (sec1->sh.sh_size != sec2->sh.sh_size ||
 	    sec1->data->d_size != sec2->data->d_size) {
 		sec->status = CHANGED;
@@ -1033,6 +1050,10 @@ static void kpatch_correlate_symbols(struct list_head *symlist_orig,
 			    sym_orig->sec->twin != sym_patched->sec)
 				continue;
 
+#ifdef __aarch64__
+			if (is_aarch64_mapping_symbol(sym_orig))
+				continue;
+#endif
 			kpatch_correlate_symbol(sym_orig, sym_patched);
 			break;
 		}
@@ -1536,7 +1557,7 @@ static void kpatch_replace_sections_syms(struct kpatch_elf *kelf)
 				continue;
 			}
 
-#ifdef __powerpc64__
+#if defined(__powerpc64__) || defined(__aarch64__)
 			add_off = 0;
 #else
 			if (rela->type == R_X86_64_PC32 ||
@@ -1568,7 +1589,11 @@ static void kpatch_replace_sections_syms(struct kpatch_elf *kelf)
 				end = sym->sym.st_value + sym->sym.st_size;
 
 				if (!is_text_section(sym->sec) &&
+#if defined(__x86_64__)
 				    rela->type == R_X86_64_32S &&
+#elif defined(__aarch64__)
+				    rela->type == R_AARCH64_ABS64 &&
+#endif
 				    rela->addend == (long)sym->sec->sh.sh_size &&
 				    end == (long)sym->sec->sh.sh_size) {
 
@@ -1766,6 +1791,7 @@ static void kpatch_include_standard_elements(struct kpatch_elf *kelf)
 		    !strcmp(sec->name, ".symtab") ||
 		    !strcmp(sec->name, ".toc") ||
 		    !strcmp(sec->name, ".rodata") ||
+		    !strcmp(sec->name, ".rodata.str") ||
 		    (!strncmp(sec->name, ".rodata.", 8) &&
 		     strstr(sec->name, ".str1."))) {
 			kpatch_include_section(sec);
@@ -2044,35 +2070,36 @@ static int parainstructions_group_size(struct kpatch_elf *kelf, int offset)
 	return size;
 }
 
-static int altinstructions_group_size(struct kpatch_elf *kelf, int offset)
+static int smp_locks_group_size(struct kpatch_elf *kelf, int offset)
+{
+	return 4;
+}
+
+static int static_call_sites_group_size(struct kpatch_elf *kelf, int offset)
 {
 	static int size = 0;
 	char *str;
 
 	if (!size) {
-		str = getenv("ALT_STRUCT_SIZE");
+		str = getenv("STATIC_CALL_STRUCT_SIZE");
 		if (!str)
-			ERROR("ALT_STRUCT_SIZE not set");
+			ERROR("STATIC_CALL_STRUCT_SIZE not set");
 		size = atoi(str);
 	}
 
 	return size;
 }
-
-static int smp_locks_group_size(struct kpatch_elf *kelf, int offset)
-{
-	return 4;
-}
-
-static int static_call_sites_group_size(struct kpatch_elf *kelf, int offset)
+#endif
+#if defined(__s390__) || defined(__x86_64__) || defined(__aarch64__)
+static int altinstructions_group_size(struct kpatch_elf *kelf, int offset)
 {
 	static int size = 0;
 	char *str;
 
 	if (!size) {
-		str = getenv("STATIC_CALL_STRUCT_SIZE");
+		str = getenv("ALT_STRUCT_SIZE");
 		if (!str)
-			ERROR("STATIC_CALL_STRUCT_SIZE not set");
+			ERROR("ALT_STRUCT_SIZE not set");
 		size = atoi(str);
 	}
 
@@ -2216,6 +2243,12 @@ static struct special_section special_sections[] = {
 		.name		= "__barrier_nospec_fixup",
 		.group_size	= fixup_barrier_nospec_group_size,
 	},
+#endif
+#ifdef __aarch64__
+	{
+		.name		= ".altinstructions",
+		.group_size	= altinstructions_group_size,
+	},
 #endif
 	{},
 };
@@ -3404,7 +3437,7 @@ static void kpatch_create_mcount_sections(struct kpatch_elf *kelf)
 	int nr, index;
 	struct section *sec, *relasec;
 	struct symbol *sym;
-	struct rela *rela, *mcount_rela;
+	struct rela *mcount_rela;
 	void **funcs;
 	unsigned long insn_offset;
 
@@ -3415,7 +3448,7 @@ static void kpatch_create_mcount_sections(struct kpatch_elf *kelf)
 			nr++;
 
 	/* create text/rela section pair */
-	sec = create_section_pair(kelf, "__mcount_loc", sizeof(void*), nr);
+	sec = create_section_pair(kelf, MCOUNT_SECTION_NAME, sizeof(void*), nr);
 	relasec = sec->rela;
 
 	/* populate sections */
@@ -3430,7 +3463,8 @@ static void kpatch_create_mcount_sections(struct kpatch_elf *kelf)
 			continue;
 		}
 
-#ifdef __x86_64__
+#if defined(__x86_64__)
+		struct rela *rela;
 
 		rela = list_first_entry(&sym->sec->rela->relas, struct rela, list);
 
@@ -3473,8 +3507,9 @@ static void kpatch_create_mcount_sections(struct kpatch_elf *kelf)
 			rela->type = R_X86_64_PC32;
 		}
 
-#else /* __powerpc64__ */
+#elif defined(__powerpc64__)
 {
+		struct rela *rela;
 		bool found = false;
 
 		list_for_each_entry(rela, &sym->sec->rela->relas, list)
@@ -3488,6 +3523,8 @@ static void kpatch_create_mcount_sections(struct kpatch_elf *kelf)
 
 		insn_offset = rela->offset;
 }
+#else
+		insn_offset = sym->sym.st_value;
 #endif
 		/*
 		 * 'rela' points to the mcount/fentry call.

diff --git a/kpatch-build/kpatch-build b/kpatch-build/kpatch-build
@@ -376,11 +376,12 @@ find_special_section_data() {
 		return
 	fi
 
-	[[ "$CONFIG_PARAVIRT" -eq 0 ]] && AWK_OPTIONS="-vskip_p=1"
+	[[ "$CONFIG_PARAVIRT" -eq 0 || "$ARCH" == "aarch64" ]] && AWK_OPTIONS="-vskip_p=1"
 	[[ "$CONFIG_UNWINDER_ORC" -eq 0 ]] && AWK_OPTIONS="$AWK_OPTIONS -vskip_o=1"
 	[[ "$CONFIG_JUMP_LABEL" -eq 0 ]] && AWK_OPTIONS="$AWK_OPTIONS -vskip_j=1"
 	[[ "$CONFIG_PRINTK_INDEX" -eq 0 ]] && AWK_OPTIONS="$AWK_OPTIONS -vskip_i=1"
-	! kernel_version_gte 5.10.0 && AWK_OPTIONS="$AWK_OPTIONS -vskip_s=1"
+	(! kernel_version_gte 5.10.0 || [[ "CONFIG_HAVE_STATIC_CALL" -eq 0 ]]) \
+		&& AWK_OPTIONS="$AWK_OPTIONS -vskip_s=1"
 
 	# If $AWK_OPTIONS are blank gawk would treat "" as a blank script
 	# shellcheck disable=SC2086
@@ -426,11 +427,12 @@ find_special_section_data() {
 	[[ -z "$ALT_STRUCT_SIZE" ]] && die "can't find special struct alt_instr size"
 	[[ -z "$BUG_STRUCT_SIZE" ]] && die "can't find special struct bug_entry size"
 	[[ -z "$EX_STRUCT_SIZE" ]]  && die "can't find special struct paravirt_patch_site size"
-	[[ -z "$PARA_STRUCT_SIZE" && "$CONFIG_PARAVIRT" -ne 0 ]] && die "can't find special struct paravirt_patch_site size"
+	[[ -z "$PARA_STRUCT_SIZE" && "$CONFIG_PARAVIRT" -ne 0 && "$ARCH" != "aarch64" ]] \
+		&& die "can't find special struct paravirt_patch_site size"
 	[[ -z "$ORC_STRUCT_SIZE" && "$CONFIG_UNWINDER_ORC" -ne 0 ]] && die "can't find special struct orc_entry size"
 	[[ -z "$JUMP_STRUCT_SIZE" && "$CONFIG_JUMP_LABEL" -ne 0 ]] && die "can't find special struct jump_entry size"
 	[[ -z "$PRINTK_INDEX_STRUCT_SIZE" && "$CONFIG_PRINTK_INDEX" -ne 0 ]] && die "can't find special struct pi_entry size"
-	[[ -z "$STATIC_CALL_STRUCT_SIZE" ]] && kernel_version_gte 5.10.0 && die "can't find special struct static_call_site size"
+	[[ -z "$STATIC_CALL_STRUCT_SIZE" && "$CONFIG_HAVE_STATIC_CALL" -ne 0 ]] && kernel_version_gte 5.10.0 && die "can't find special struct static_call_site size"
 
 	return
 }
@@ -869,6 +871,7 @@ grep -q "CONFIG_JUMP_LABEL=y"   "$CONFIGFILE" && CONFIG_JUMP_LABEL=1
 grep -q "CONFIG_MODVERSIONS=y"  "$CONFIGFILE" && CONFIG_MODVERSIONS=1
 grep -q "CONFIG_CC_IS_CLANG=y"  "$CONFIGFILE" && CONFIG_CC_IS_CLANG=1
 grep -q "CONFIG_LD_IS_LLD=y"    "$CONFIGFILE" && CONFIG_LD_IS_LLD=1
+grep -q "CONFIG_HAVE_STATIC_CALL=y"    "$CONFIGFILE" && CONFIG_HAVE_STATIC_CALL=1
 
 # unsupported kernel option checking
 grep -q "CONFIG_DEBUG_INFO_SPLIT=y" "$CONFIGFILE" && die "kernel option 'CONFIG_DEBUG_INFO_SPLIT' not supported"

diff --git a/kpatch-build/kpatch-elf.c b/kpatch-build/kpatch-elf.c
@@ -151,6 +151,23 @@ int offset_of_string(struct list_head *list, char *name)
 	return index;
 }
 
+/*
+ * Check if the symbol name contains LC or L1^B.
+ *
+ * On s390x,
+ * .L1^B19 -> .rodata.str (bug_table)
+ * .LC0 -> .rodata.str1.2
+ *
+ *  In these cases, return true and rela->string should point to
+ *  rela->sym->sec->data->d_buf + value of the associated symbol.
+ */
+static bool lc_string(struct rela *rela) {
+	if (!strncmp(rela->sym->name, ".LC", 3) || !strncmp(rela->sym->name, ".L1", 3))
+		return true;
+	else
+		return false;
+}
+
 void kpatch_create_rela_list(struct kpatch_elf *kelf, struct section *sec)
 {
 	int index = 0, skip = 0;
@@ -193,7 +210,10 @@ void kpatch_create_rela_list(struct kpatch_elf *kelf, struct section *sec)
 			ERROR("could not find rela entry symbol\n");
 		if (rela->sym->sec &&
 		    (rela->sym->sec->sh.sh_flags & SHF_STRINGS)) {
-			rela->string = rela->sym->sec->data->d_buf + rela->addend;
+			if (lc_string(rela))
+				rela->string = rela->sym->sec->data->d_buf + rela->sym->sym.st_value;
+			else
+				rela->string = rela->sym->sec->data->d_buf + rela->addend;
 			if (!rela->string)
 				ERROR("could not lookup rela string for %s+%ld",
 				      rela->sym->name, rela->addend);
@@ -317,22 +337,37 @@ void kpatch_create_symbol_list(struct kpatch_elf *kelf)
 
 }
 
+#if !defined(__powerpc64__) && !defined(__x86_64__)
+static struct section *kpatch_find_profiling_section(struct list_head *seclist)
+{
+	struct section *sec;
+
+	list_for_each_entry(sec, seclist, list) {
+		if (!strcmp(sec->name, MCOUNT_SECTION_NAME))
+			return sec;
+	}
+	return NULL;
+}
+#endif
+
 /* Check which functions have fentry/mcount calls; save this info for later use. */
 static void kpatch_find_func_profiling_calls(struct kpatch_elf *kelf)
 {
 	struct symbol *sym;
-	struct rela *rela;
+
 	list_for_each_entry(sym, &kelf->symbols, list) {
 		if (sym->type != STT_FUNC || !sym->sec || !sym->sec->rela)
 			continue;
-#ifdef __powerpc64__
+#if defined(__powerpc64__)
+		struct rela *rela;
 		list_for_each_entry(rela, &sym->sec->rela->relas, list) {
 			if (!strcmp(rela->sym->name, "_mcount")) {
 				sym->has_func_profiling = 1;
 				break;
 			}
 		}
-#else
+#elif defined(__x86_64__)
+		struct rela *rela;
 		rela = list_first_entry(&sym->sec->rela->relas, struct rela,
 					list);
 		if ((rela->type != R_X86_64_NONE &&
@@ -342,6 +377,21 @@ static void kpatch_find_func_profiling_calls(struct kpatch_elf *kelf)
 			continue;
 
 		sym->has_func_profiling = 1;
+#else
+		struct section *prof_sec;
+
+		prof_sec = kpatch_find_profiling_section(&kelf->sections);
+		if (!prof_sec)
+			break;
+
+		struct rela *rela;
+		list_for_each_entry(rela, &prof_sec->rela->relas, list) {
+			if (!strncmp(rela->sym->name, ".text.", 6) &&
+			    !strcmp(rela->sym->name + 6, sym->name)) {
+				sym->has_func_profiling = 1;
+				break;
+			}
+		}
 #endif
 	}
 }

diff --git a/kpatch-build/kpatch-elf.h b/kpatch-build/kpatch-elf.h
@@ -31,6 +31,12 @@
 #define SHF_RELA_LIVEPATCH	0x00100000
 #define SHN_LIVEPATCH		0xff20
 
+#ifdef __aarch64__
+#define MCOUNT_SECTION_NAME "__patchable_function_entries"
+#else
+#define MCOUN_SECTION_NAME "__mcount_loc"
+#endif
+
 /*******************
  * Data structures
  * ****************/