From 6bea1dd7e4d7fe70d375f4eb65ade6774447cc37 Mon Sep 17 00:00:00 2001
From: Puranjay Mohan <pjy@amazon.com>
Date: Mon, 27 Jan 2025 12:39:56 +0000
Subject: [PATCH 01/11] kpatch-build: update version to 0.9.10

Signed-off-by: Puranjay Mohan <pjy@amazon.com>
---
 kpatch-build/kpatch-build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kpatch-build/kpatch-build b/kpatch-build/kpatch-build
index 7acf5bf5..99856321 100755
--- a/kpatch-build/kpatch-build
+++ b/kpatch-build/kpatch-build
@@ -33,7 +33,7 @@
 # - Builds the patched kernel/module and monitors changed objects
 # - Builds the patched objects with gcc flags -f[function|data]-sections
 # - Runs kpatch tools to create and link the patch kernel module
-VERSION=0.9.9
+VERSION=0.9.10
 
 set -o pipefail
 

From 2ed84b1bf67b261f356e35292c09246c9a1d6e5f Mon Sep 17 00:00:00 2001
From: Suraj Jitindar Singh <surajjs@amazon.com>
Date: Wed, 6 Oct 2021 12:41:16 -0700
Subject: [PATCH 02/11] kpatch-build: Add sym->has_func_profiling support for
 aarch64

The "has_function_profiling" support field in the symbol struct is used to show
that a function symbol is able to be patched. This is necessary to check that
functions which need to be patched are able to be.

On arm64 this means the presence of 2 NOP instructions at function entry
which are patched by ftrace to call the ftrace handling code. These 2 NOPs
are inserted by the compiler and the location of them is recorded in a
section called "__patchable_function_entries". Check whether a symbol has a
corresponding entry in the "__patchable_function_entries" section and if so
mark it as "has_func_profiling".

Signed-off-by: Suraj Jitindar Singh <surajjs@amazon.com>
[Modify to use __patchable_function_entries support added upstream]
Signed-off-by: Puranjay Mohan <pjy@amazon.com>
---
 kpatch-build/create-diff-object.c | 8 ++++++--
 kpatch-build/kpatch-elf.c         | 3 +++
 kpatch-build/kpatch-elf.h         | 1 +
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/kpatch-build/create-diff-object.c b/kpatch-build/create-diff-object.c
index 350a4591..a222a39d 100644
--- a/kpatch-build/create-diff-object.c
+++ b/kpatch-build/create-diff-object.c
@@ -1700,8 +1700,8 @@ static void kpatch_check_func_profiling_calls(struct kpatch_elf *kelf)
 		    (sym->parent && sym->parent->status == CHANGED))
 			continue;
 		if (!sym->twin->has_func_profiling) {
-			log_error("function %s has no fentry/mcount call, unable to patch\n",
-				  sym->name);
+			log_error("function %s doesn't have patchable function entry, unable to patch\n",
+				   sym->name);
 			errs++;
 		}
 	}
@@ -4180,6 +4180,10 @@ static void kpatch_find_func_profiling_calls(struct kpatch_elf *kelf)
 				insn[4] == 0x00 && insn[5] == 0x00)
 				sym->has_func_profiling = 1;
 			break;
+		case AARCH64:
+			if (kpatch_symbol_has_pfe_entry(kelf, sym))
+				sym->has_func_profiling = 1;
+			break;
 		default:
 			ERROR("unsupported arch");
 		}
diff --git a/kpatch-build/kpatch-elf.c b/kpatch-build/kpatch-elf.c
index 56819c8d..36f8b8ba 100755
--- a/kpatch-build/kpatch-elf.c
+++ b/kpatch-build/kpatch-elf.c
@@ -594,6 +594,9 @@ struct kpatch_elf *kpatch_elf_open(const char *name)
 	case EM_S390:
 		kelf->arch = S390;
 		break;
+	case EM_AARCH64:
+		kelf->arch = ARM64;
+		break;
 	default:
 		ERROR("Unsupported target architecture");
 	}
diff --git a/kpatch-build/kpatch-elf.h b/kpatch-build/kpatch-elf.h
index b574b019..fe5e0a6e 100644
--- a/kpatch-build/kpatch-elf.h
+++ b/kpatch-build/kpatch-elf.h
@@ -116,6 +116,7 @@ enum architecture {
 	PPC64  = 0x1 << 0,
 	X86_64 = 0x1 << 1,
 	S390   = 0x1 << 2,
+	AARCH64  = 0x1 << 3,
 };
 
 struct kpatch_elf {

From 062fd46ce1dbf3d5212de5796dcd9fe213ae0bc4 Mon Sep 17 00:00:00 2001
From: Pete Swain <swine@google.com>
Date: Fri, 24 Jan 2025 14:37:21 +0000
Subject: [PATCH 03/11] create-diff-object: Check __patchable_function_entries
 section for aarch64

Add aarch64 support to kpatch_create_ftrace_callsite_sections(). Check
for the 2 required NOP instructions on function entry, which may be
preceded by a BTI C instruction depending on whether the
function is a leaf function. This determines the offset of the
patch site.

Signed-off-by: Pete Swain <swine@google.com>
Signed-off-by: Puranjay Mohan <pjy@amazon.com>
---
 kpatch-build/create-diff-object.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/kpatch-build/create-diff-object.c b/kpatch-build/create-diff-object.c
index a222a39d..bbb2953b 100644
--- a/kpatch-build/create-diff-object.c
+++ b/kpatch-build/create-diff-object.c
@@ -3847,6 +3847,30 @@ static void kpatch_create_ftrace_callsite_sections(struct kpatch_elf *kelf)
 		}
 
 		switch(kelf->arch) {
+		case AARCH64: {
+			unsigned char *insn = sym->sec->data->d_buf;
+			int i;
+
+			/*
+			 * If BTI (Branch Target Identification) is enabled then there
+			 * might be an additional 'BTI C' instruction before the two
+			 * patchable function entry 'NOP's.
+			 * i.e. 0xd503245f (little endian)
+			 */
+			if (insn[0] == 0x5f) {
+				if (insn[1] != 0x24 || insn[2] != 0x03 || insn[3] != 0xd5)
+					ERROR("%s: unexpected instruction in patch section of function\n", sym->name);
+				insn_offset += 4;
+				insn += 4;
+			}
+			for (i = 0; i < 8; i += 4) {
+				/* We expect a NOP i.e. 0xd503201f (little endian) */
+				if (insn[i] != 0x1f || insn[i + 1] != 0x20 ||
+				    insn[i + 2] != 0x03 || insn [i + 3] != 0xd5)
+					ERROR("%s: unexpected instruction in patch section of function\n", sym->name);
+			}
+			break;
+		}
 		case PPC64: {
 			unsigned char *insn;
 

From c1034f5482b2fe8440555010a93ce24ef741b60b Mon Sep 17 00:00:00 2001
From: Suraj Jitindar Singh <surajjs@amazon.com>
Date: Wed, 6 Oct 2021 12:49:33 -0700
Subject: [PATCH 04/11] kpatch-build: Enable ARM64 support

Add the final support required for aarch64 and enable building on that arch.

Signed-off-by: Suraj Jitindar Singh <surajjs@amazon.com>
[kpatch_line_macro_change_only() fixes]
Signed-off-by: Puranjay Mohan <pjy@amazon.com>
---
 README.md                         |  2 +-
 kpatch-build/Makefile             |  2 +-
 kpatch-build/create-diff-object.c | 71 +++++++++++++++++++++++++------
 kpatch-build/kpatch-build         |  3 ++
 kpatch-build/kpatch-elf.c         |  7 ++-
 5 files changed, 69 insertions(+), 16 deletions(-)

diff --git a/README.md b/README.md
index 6cade1cf..5054ccdb 100644
--- a/README.md
+++ b/README.md
@@ -40,7 +40,7 @@ Supported Architectures
 
 - [x] x86-64
 - [x] ppc64le
-- [ ] arm64
+- [x] arm64
 - [x] s390 [upstream prerequisites](doc/s390-upstream-prerequisites.md)
 
 Installation
diff --git a/kpatch-build/Makefile b/kpatch-build/Makefile
index afd16f20..1f7ee4b1 100644
--- a/kpatch-build/Makefile
+++ b/kpatch-build/Makefile
@@ -21,7 +21,7 @@ PLUGIN_CFLAGS := $(filter-out -std=gnu11 -Wconversion, $(CFLAGS))
 PLUGIN_CFLAGS += -shared -I$(GCC_PLUGINS_DIR)/include \
 		   -Igcc-plugins -fPIC -fno-rtti -O2 -Wall
 endif
-ifeq ($(filter $(ARCH),s390x x86_64 ppc64le),)
+ifeq ($(filter $(ARCH),s390x x86_64 ppc64le aarch64),)
 $(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
index bbb2953b..c1d7575c 100644
--- a/kpatch-build/create-diff-object.c
+++ b/kpatch-build/create-diff-object.c
@@ -173,6 +173,8 @@ static bool is_gcc6_localentry_bundled_sym(struct kpatch_elf *kelf,
 					  struct symbol *sym)
 {
 	switch(kelf->arch) {
+	case AARCH64:
+		return false;
 	case PPC64:
 		return ((PPC64_LOCAL_ENTRY_OFFSET(sym->sym.st_other) != 0) &&
 			sym->sym.st_value == 8);
@@ -228,6 +230,31 @@ static struct rela *toc_rela(const struct rela *rela)
 				   (unsigned int)rela->addend);
 }
 
+/*
+ * Mapping symbols are used to mark and label the transitions between code and
+ * data in elf files. They begin with a "$" dollar symbol. Don't correlate them
+ * as they often all have the same name either "$x" to mark the start of code
+ * or "$d" to mark the start of data.
+ */
+static bool kpatch_is_mapping_symbol(struct kpatch_elf *kelf, struct symbol *sym)
+{
+	switch (kelf->arch) {
+	case AARCH64:
+		if (sym->name && sym->name[0] == '$'
+			&& sym->type == STT_NOTYPE \
+			&& sym->bind == STB_LOCAL)
+			return true;
+	case X86_64:
+	case PPC64:
+	case S390:
+		return false;
+	default:
+		ERROR("unsupported arch");
+	}
+
+	return false;
+}
+
 /*
  * When compiling with -ffunction-sections and -fdata-sections, almost every
  * symbol gets its own dedicated section.  We call such symbols "bundled"
@@ -706,6 +733,12 @@ static bool insn_is_load_immediate(struct kpatch_elf *kelf, void *addr)
 
 		break;
 
+	case AARCH64:
+		/* Verify mov w2 <line number> */
+		if ((insn[0] & 0b11111) == 0x2 && insn[3] == 0x52)
+			return true;
+		break;
+
 	default:
 		ERROR("unsupported arch");
 	}
@@ -746,6 +779,7 @@ static bool kpatch_line_macro_change_only(struct kpatch_elf *kelf,
 	void *data1, *data2, *insn1, *insn2;
 	struct rela *r, *rela;
 	bool found, found_any = false;
+	bool warn_printk_only = (kelf->arch == AARCH64);
 
 	if (sec->status != CHANGED ||
 	    is_rela_section(sec) ||
@@ -809,8 +843,15 @@ static bool kpatch_line_macro_change_only(struct kpatch_elf *kelf,
 			    !strncmp(rela->sym->name, "__func__.", 9))
 				continue;
 
+			if (!strcmp(rela->sym->name, "__warn_printk")) {
+				found = true;
+				break;
+			}
+
+			if (warn_printk_only)
+				return false;
+
 			if (!strncmp(rela->sym->name, "warn_slowpath_", 14) ||
-			    !strcmp(rela->sym->name, "__warn_printk") ||
 			    !strcmp(rela->sym->name, "__might_sleep") ||
 			    !strcmp(rela->sym->name, "___might_sleep") ||
 			    !strcmp(rela->sym->name, "__might_fault") ||
@@ -1075,15 +1116,15 @@ static void kpatch_correlate_sections(struct list_head *seclist_orig,
 	}
 }
 
-static void kpatch_correlate_symbols(struct list_head *symlist_orig,
-		struct list_head *symlist_patched)
+static void kpatch_correlate_symbols(struct kpatch_elf *kelf_orig,
+		struct kpatch_elf *kelf_patched)
 {
 	struct symbol *sym_orig, *sym_patched;
 
-	list_for_each_entry(sym_orig, symlist_orig, list) {
+	list_for_each_entry(sym_orig, &kelf_orig->symbols, list) {
 		if (sym_orig->twin)
 			continue;
-		list_for_each_entry(sym_patched, symlist_patched, list) {
+		list_for_each_entry(sym_patched, &kelf_patched->symbols, list) {
 			if (kpatch_mangled_strcmp(sym_orig->name, sym_patched->name) ||
 			    sym_orig->type != sym_patched->type || sym_patched->twin)
 				continue;
@@ -1103,6 +1144,9 @@ static void kpatch_correlate_symbols(struct list_head *symlist_orig,
 			    !strncmp(sym_orig->name, ".LC", 3))
 				continue;
 
+			if (kpatch_is_mapping_symbol(kelf_orig, sym_orig))
+				continue;
+
 			/* group section symbols must have correlated sections */
 			if (sym_orig->sec &&
 			    sym_orig->sec->sh.sh_type == SHT_GROUP &&
@@ -1508,7 +1552,7 @@ static void kpatch_correlate_elfs(struct kpatch_elf *kelf_orig,
 		struct kpatch_elf *kelf_patched)
 {
 	kpatch_correlate_sections(&kelf_orig->sections, &kelf_patched->sections);
-	kpatch_correlate_symbols(&kelf_orig->symbols, &kelf_patched->symbols);
+	kpatch_correlate_symbols(kelf_orig, kelf_patched);
 }
 
 static void kpatch_compare_correlated_elements(struct kpatch_elf *kelf)
@@ -1624,7 +1668,8 @@ static void kpatch_replace_sections_syms(struct kpatch_elf *kelf)
 
 				if (is_text_section(relasec->base) &&
 				    !is_text_section(sym->sec) &&
-				    rela->type == R_X86_64_32S &&
+				    (rela->type == R_X86_64_32S ||
+				     rela->type == R_AARCH64_ABS64) &&
 				    rela->addend == (long)sym->sec->sh.sh_size &&
 				    end == (long)sym->sec->sh.sh_size) {
 
@@ -2493,28 +2538,28 @@ static bool static_call_sites_group_filter(struct lookup_table *lookup,
 static struct special_section special_sections[] = {
 	{
 		.name		= "__bug_table",
-		.arch		= X86_64 | PPC64 | S390,
+		.arch		= AARCH64 | X86_64 | PPC64 | S390,
 		.group_size	= bug_table_group_size,
 	},
 	{
 		.name		= ".fixup",
-		.arch		= X86_64 | PPC64 | S390,
+		.arch		= AARCH64 | X86_64 | PPC64 | S390,
 		.group_size	= fixup_group_size,
 	},
 	{
 		.name		= "__ex_table", /* must come after .fixup */
-		.arch		= X86_64 | PPC64 | S390,
+		.arch		= AARCH64 | X86_64 | PPC64 | S390,
 		.group_size	= ex_table_group_size,
 	},
 	{
 		.name		= "__jump_table",
-		.arch		= X86_64 | PPC64 | S390,
+		.arch		= AARCH64 | X86_64 | PPC64 | S390,
 		.group_size	= jump_table_group_size,
 		.group_filter	= jump_table_group_filter,
 	},
 	{
 		.name		= ".printk_index",
-		.arch		= X86_64 | PPC64 | S390,
+		.arch		= AARCH64 | X86_64 | PPC64 | S390,
 		.group_size	= printk_index_group_size,
 	},
 	{
@@ -2529,7 +2574,7 @@ static struct special_section special_sections[] = {
 	},
 	{
 		.name		= ".altinstructions",
-		.arch		= X86_64 | S390,
+		.arch		= AARCH64 | X86_64 | S390,
 		.group_size	= altinstructions_group_size,
 	},
 	{
diff --git a/kpatch-build/kpatch-build b/kpatch-build/kpatch-build
index 99856321..3343f37d 100755
--- a/kpatch-build/kpatch-build
+++ b/kpatch-build/kpatch-build
@@ -402,6 +402,9 @@ find_special_section_data() {
 		"s390x")
 			check[a]=true					# alt_instr
 			;;
+		"aarch64")
+			check[a]=true					# alt_instr
+			;;
 	esac
 
 	# Kernel CONFIG_ features
diff --git a/kpatch-build/kpatch-elf.c b/kpatch-build/kpatch-elf.c
index 36f8b8ba..70a8d4ab 100755
--- a/kpatch-build/kpatch-elf.c
+++ b/kpatch-build/kpatch-elf.c
@@ -142,6 +142,8 @@ unsigned int absolute_rela_type(struct kpatch_elf *kelf)
 		return R_X86_64_64;
 	case S390:
 		return R_390_64;
+	case AARCH64:
+		return R_AARCH64_ABS64;
 	default:
 		ERROR("unsupported arch");
 	}
@@ -206,6 +208,7 @@ long rela_target_offset(struct kpatch_elf *kelf, struct section *relasec,
 
 	switch(kelf->arch) {
 	case PPC64:
+	case AARCH64:
 		add_off = 0;
 		break;
 	case X86_64:
@@ -255,6 +258,8 @@ unsigned int insn_length(struct kpatch_elf *kelf, void *addr)
 
 	switch(kelf->arch) {
 
+	case AARCH64:
+		return 4;
 	case X86_64:
 		insn_init(&decoded_insn, addr, 1);
 		insn_get_length(&decoded_insn);
@@ -595,7 +600,7 @@ struct kpatch_elf *kpatch_elf_open(const char *name)
 		kelf->arch = S390;
 		break;
 	case EM_AARCH64:
-		kelf->arch = ARM64;
+		kelf->arch = AARCH64;
 		break;
 	default:
 		ERROR("Unsupported target architecture");

From 72f6a887496e22b2cb6f8dc0ff4b7524d995e657 Mon Sep 17 00:00:00 2001
From: Suraj Jitindar Singh <surajjs@amazon.com>
Date: Thu, 2 Dec 2021 18:03:16 -0800
Subject: [PATCH 05/11] create-diff-object: Include .rodata.str section in
 output object

On arm64 when CONFIG_DEBUG_BUGVERBOSE is enabled debugging information about
bug sections is stored in the ".rodata.str" section of the object file. If this
isn't included then linking fails as labels in this section are referenced
by relocations in the bug table.

Include this section to enable building patches which contain this bug debug
information.

Signed-off-by: Suraj Jitindar Singh <surajjs@amazon.com>
---
 kpatch-build/create-diff-object.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kpatch-build/create-diff-object.c b/kpatch-build/create-diff-object.c
index c1d7575c..61e434b2 100644
--- a/kpatch-build/create-diff-object.c
+++ b/kpatch-build/create-diff-object.c
@@ -1950,6 +1950,7 @@ 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") ||
 		    is_string_literal_section(sec)) {
 			kpatch_include_section(sec);
 		}

From 8f292630dc73e537e0e1d42336c9cfc2263d3531 Mon Sep 17 00:00:00 2001
From: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Date: Wed, 7 Sep 2022 10:38:01 +0900
Subject: [PATCH 06/11] create-diff-object: Fix mapping symbol handling on
 aarch64

It seems mapping symbols in aarch64 elf has section size of 0.
So, exclude it in section symbol replacing code just like
kpatch_correlate_symbols().
This fixes the data-read-mostly unit test on aarch64.

Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Signed-off-by: Puranjay Mohan <pjy@amazon.com>
---
 kpatch-build/create-diff-object.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kpatch-build/create-diff-object.c b/kpatch-build/create-diff-object.c
index 61e434b2..85e881ac 100644
--- a/kpatch-build/create-diff-object.c
+++ b/kpatch-build/create-diff-object.c
@@ -1706,6 +1706,9 @@ static void kpatch_replace_sections_syms(struct kpatch_elf *kelf)
 					 */
 				} else if (target_off == start && target_off == end) {
 
+					if(kpatch_is_mapping_symbol(kelf, sym))
+						continue;
+
 					/*
 					 * Allow replacement for references to
 					 * empty symbols.

From 01db546ce83abbc76e5cd8217e1ebe52610490dc Mon Sep 17 00:00:00 2001
From: Pete Swain <swine@google.com>
Date: Fri, 28 Jul 2023 16:34:10 -0700
Subject: [PATCH 07/11] kpatch-syscall.h: add aarch64 helper

Copy from kernel source tree.

Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
---
 kmod/patch/kpatch-syscall.h | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/kmod/patch/kpatch-syscall.h b/kmod/patch/kpatch-syscall.h
index 8095bea2..16c5a0de 100644
--- a/kmod/patch/kpatch-syscall.h
+++ b/kmod/patch/kpatch-syscall.h
@@ -209,7 +209,34 @@
 
 # endif /* LINUX_VERSION_CODE */
 
-#endif /* CONFIG_X86_64 */
+#elif defined(CONFIG_ARM64)
+
+/* arm64/include/asm/syscall_wrapper.h versions */
+
+#define SC_ARM64_REGS_TO_ARGS(x, ...)       \
+  __MAP(x,__SC_ARGS         \
+        ,,regs->regs[0],,regs->regs[1],,regs->regs[2] \
+        ,,regs->regs[3],,regs->regs[4],,regs->regs[5])
+
+#define __KPATCH_SYSCALL_DEFINEx(x, name, ...)           \
+  asmlinkage long __arm64_sys##name(const struct pt_regs *regs);    \
+  ALLOW_ERROR_INJECTION(__arm64_sys##name, ERRNO);      \
+  static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__));   \
+  static inline long __kpatch_do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));  \
+  asmlinkage long __arm64_sys##name(const struct pt_regs *regs)   \
+  {                 \
+    return __se_sys##name(SC_ARM64_REGS_TO_ARGS(x,__VA_ARGS__));  \
+  }                 \
+  static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__))    \
+  {                 \
+    long ret = __kpatch_do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__));  \
+    __MAP(x,__SC_TEST,__VA_ARGS__);         \
+    __PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__));   \
+    return ret;             \
+  }                 \
+  static inline long __kpatch_do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
+
+#endif /* which arch */
 
 
 #ifndef __KPATCH_SYSCALL_DEFINEx

From 6f0ecd59b2845b4f5899db0b237e26d8431bf084 Mon Sep 17 00:00:00 2001
From: Dylan Hatch <dylanbhatch@google.com>
Date: Fri, 17 Jan 2025 20:28:11 +0000
Subject: [PATCH 08/11] create-diff-object: Add support for arm64
 DYNAMIC_FTRACE_WITH_CALL_OPS

For arm64 this option uses -fpatchable-function-entry=M,2, so 2 NOPs
are placed before the function entry point (in order to store a pointer
to ftrace_ops). When calculating function padding, check for the
presence of the two NOPs, and adjust the padding size by 8 if they are
found.

This was merged in the upstream kernel in v6.8 with:

      baaf553d3bc3 ("arm64: Implement HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS")

With this into the equation, the entry of a function can look like one
of:

1. Without DYNAMIC_FTRACE_WITH_CALL_OPS and CONFIG_ARM64_BTI_KERNEL
-------------------------------------------------------------------

Disassembly of section .text.cmdline_proc_show:

0000000000000008 <cmdline_proc_show>:
   8:   d503201f        nop
   c:   d503201f        nop

2. Without DYNAMIC_FTRACE_WITH_CALL_OPS and with CONFIG_ARM64_BTI_KERNEL
------------------------------------------------------------------------

Disassembly of section .text.cmdline_proc_show:

0000000000000008 <cmdline_proc_show>:
   0:   d503245f        bti     c
   4:   d503201f        nop
   8:   d503201f        nop

3. With DYNAMIC_FTRACE_WITH_CALL_OPS and without CONFIG_ARM64_BTI_KERNEL
------------------------------------------------------------------------

Disassembly of section .text.cmdline_proc_show:

0000000000000000 <cmdline_proc_show-0x8>:
   0:   d503201f        nop
   4:   d503201f        nop

0000000000000008 <cmdline_proc_show>:
   8:   d503201f        nop
   c:   d503201f        nop

4. With DYNAMIC_FTRACE_WITH_CALL_OPS and with CONFIG_ARM64_BTI_KERNEL
---------------------------------------------------------------------

Disassembly of section .text.cmdline_proc_show:

0000000000000000 <cmdline_proc_show-0x8>:
   0:   d503201f        nop
   4:   d503201f        nop

0000000000000008 <cmdline_proc_show>:
   8:   d503245f        bti     c
   c:   d503201f        nop
  10:   d503201f        nop

make create-diff-object aware of DYNAMIC_FTRACE_WITH_CALL_OPS and its
quirks.

Signed-off-by: Dylan Hatch <dylanbhatch@google.com>
Signed-off-by: Puranjay Mohan <pjy@amazon.com>
---
 kpatch-build/create-diff-object.c | 48 ++++++++++++++++++++++++++++++-
 1 file changed, 47 insertions(+), 1 deletion(-)

diff --git a/kpatch-build/create-diff-object.c b/kpatch-build/create-diff-object.c
index 85e881ac..d40c6ddd 100644
--- a/kpatch-build/create-diff-object.c
+++ b/kpatch-build/create-diff-object.c
@@ -255,6 +255,42 @@ static bool kpatch_is_mapping_symbol(struct kpatch_elf *kelf, struct symbol *sym
 	return false;
 }
 
+static unsigned int function_padding_size(struct kpatch_elf *kelf, struct symbol *sym)
+{
+	unsigned int size = 0;
+
+	switch (kelf->arch) {
+	case AARCH64:
+	{
+		uint8_t *insn = sym->sec->data->d_buf;
+		unsigned int i;
+		void *insn_end = sym->sec->data->d_buf + sym->sym.st_value;
+
+		/*
+		 * If the arm64 kernel is compiled with CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS
+		 * then there are two NOPs before the function and a `BTI C` + 2 NOPs at the
+		 * start of the function. Verify the presence of the two NOPs before the
+		 * function entry.
+		 */
+		for (i = 0; (void *)insn < insn_end; i++, insn += 4)
+			if (insn[0] != 0x1f || insn[1] != 0x20 ||
+			    insn[2] != 0x03 || insn[3] != 0xd5)
+				break;
+
+		if (i == 2)
+			size = 8;
+		else if (i != 0)
+			log_error("function %s within section %s has invalid padding\n", sym->name, sym->sec->name);
+			
+		break;
+	}
+	default:
+		break;
+	}
+
+	return size;
+}
+
 /*
  * When compiling with -ffunction-sections and -fdata-sections, almost every
  * symbol gets its own dedicated section.  We call such symbols "bundled"
@@ -271,6 +307,8 @@ static void kpatch_bundle_symbols(struct kpatch_elf *kelf)
 				expected_offset = sym->pfx->sym.st_size;
 			else if (is_gcc6_localentry_bundled_sym(kelf, sym))
 				expected_offset = 8;
+			else if (sym->type == STT_FUNC)
+				expected_offset = function_padding_size(kelf, sym);
 			else
 				expected_offset = 0;
 
@@ -3898,8 +3936,15 @@ static void kpatch_create_ftrace_callsite_sections(struct kpatch_elf *kelf)
 		switch(kelf->arch) {
 		case AARCH64: {
 			unsigned char *insn = sym->sec->data->d_buf;
+			int padding;
 			int i;
 
+			/*
+			 * Skip the padding NOPs added by CALL_OPS.
+			 */
+			padding = function_padding_size(kelf, sym);
+			insn += padding;
+
 			/*
 			 * If BTI (Branch Target Identification) is enabled then there
 			 * might be an additional 'BTI C' instruction before the two
@@ -3909,7 +3954,8 @@ static void kpatch_create_ftrace_callsite_sections(struct kpatch_elf *kelf)
 			if (insn[0] == 0x5f) {
 				if (insn[1] != 0x24 || insn[2] != 0x03 || insn[3] != 0xd5)
 					ERROR("%s: unexpected instruction in patch section of function\n", sym->name);
-				insn_offset += 4;
+				if (!padding)
+					insn_offset += 4;
 				insn += 4;
 			}
 			for (i = 0; i < 8; i += 4) {

From 197c679f3ced59985eefdd53fe38e48e8d5e5694 Mon Sep 17 00:00:00 2001
From: Puranjay Mohan <pjy@amazon.com>
Date: Thu, 6 Feb 2025 13:24:11 +0000
Subject: [PATCH 09/11] create-diff-object: skip sframe sections for now

The sframe sections can't be normally diffed and need to be created
separately. skip them for now.

Signed-off-by: Puranjay Mohan <pjy@amazon.com>
---
 kpatch-build/create-diff-object.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kpatch-build/create-diff-object.c b/kpatch-build/create-diff-object.c
index d40c6ddd..8ef07fef 100644
--- a/kpatch-build/create-diff-object.c
+++ b/kpatch-build/create-diff-object.c
@@ -687,6 +687,8 @@ static void kpatch_compare_correlated_section(struct section *sec)
 	 */
 	if (!strcmp(sec->name, ".rela__mcount_loc") ||
 	    !strcmp(sec->name, "__mcount_loc") ||
+	    !strcmp(sec->name, ".sframe") ||
+	    !strcmp(sec->name, ".rela.sframe") ||
 	    !strcmp(sec->name, ".rela__patchable_function_entries") ||
 	    !strcmp(sec->name, "__patchable_function_entries")) {
 		sec->status = SAME;

From 95d93a32f1d16a6717f54f30bd6acad83ca45814 Mon Sep 17 00:00:00 2001
From: Puranjay Mohan <pjy@amazon.com>
Date: Fri, 7 Feb 2025 17:30:05 +0000
Subject: [PATCH 10/11] create-diff-object: don't mangle
 .rela.__patchable_function_entries

kpatch_replace_sections_syms() substitutes the object/function symbols
for the section symbol in the relocation sections. But relocations in
.rela.__patchable_function_entries can point to an instruction ouside
the function. This is because with CALL_OPS enabled, two NOPs are added
before the function entry. __patchable_function_entries needs the
address of the first NOP above the function.

We anyway generate __patchable_function_entries again in
kpatch_create_ftrace_callsite_sections() so we can skip mangling these
relocations

Signed-off-by: Puranjay Mohan <pjy@amazon.com>
---
 kpatch-build/create-diff-object.c |  7 +++++++
 kpatch-build/kpatch-elf.c         | 12 ++++++++++++
 kpatch-build/kpatch-elf.h         |  1 +
 3 files changed, 20 insertions(+)

diff --git a/kpatch-build/create-diff-object.c b/kpatch-build/create-diff-object.c
index 8ef07fef..4bc6e4d5 100644
--- a/kpatch-build/create-diff-object.c
+++ b/kpatch-build/create-diff-object.c
@@ -1645,6 +1645,13 @@ static void kpatch_replace_sections_syms(struct kpatch_elf *kelf)
 		if (!is_rela_section(relasec) || is_debug_section(relasec))
 			continue;
 
+		/*
+		 * We regenerate __patchable_function_entries from scratch so
+		 * don't bother replacing section symbols in its relasec.
+		 */
+		if (is_patchable_function_entries_section(relasec))
+			continue;
+
 		list_for_each_entry(rela, &relasec->relas, list) {
 
 			if (rela->sym->type != STT_SECTION || !rela->sym->sec)
diff --git a/kpatch-build/kpatch-elf.c b/kpatch-build/kpatch-elf.c
index 70a8d4ab..11ce4554 100755
--- a/kpatch-build/kpatch-elf.c
+++ b/kpatch-build/kpatch-elf.c
@@ -65,6 +65,18 @@ bool is_text_section(struct section *sec)
 		(sec->sh.sh_flags & SHF_EXECINSTR));
 }
 
+bool is_patchable_function_entries_section(struct section *sec)
+{
+	char *name;
+
+	if (is_rela_section(sec))
+		name = sec->base->name;
+	else
+		name = sec->name;
+
+	return !strcmp(name, "__patchable_function_entries");
+}
+
 bool is_debug_section(struct section *sec)
 {
 	char *name;
diff --git a/kpatch-build/kpatch-elf.h b/kpatch-build/kpatch-elf.h
index fe5e0a6e..4a4c5a56 100644
--- a/kpatch-build/kpatch-elf.h
+++ b/kpatch-build/kpatch-elf.h
@@ -139,6 +139,7 @@ struct kpatch_elf {
 char *status_str(enum status status);
 bool is_rela_section(struct section *sec);
 bool is_text_section(struct section *sec);
+bool is_patchable_function_entries_section(struct section *sec);
 bool is_debug_section(struct section *sec);
 
 struct section *find_section_by_index(struct list_head *list, unsigned int index);

From f15eedf63f34c44a2c8239920e6368d2df9f7670 Mon Sep 17 00:00:00 2001
From: Puranjay Mohan <pjy@amazon.com>
Date: Thu, 11 Sep 2025 10:54:32 +0000
Subject: [PATCH 11/11] test/unit/objs: Update reference for arm64 objs

AArch64 test objects are now available in the kpatch-unit-test-objs
repository with commit 4ad64a06b6d0 ("Merge pull request #54 from
dynup/aarch64")

Update the submodule reference to the above commit so the objects are
available to the test suite. Add aarch64 to the unit Makefile so the
tests are run.

Signed-off-by: Puranjay Mohan <pjy@amazon.com>
---
 test/unit/Makefile | 2 +-
 test/unit/objs     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/unit/Makefile b/test/unit/Makefile
index fde1717d..e3ed7d71 100644
--- a/test/unit/Makefile
+++ b/test/unit/Makefile
@@ -1,4 +1,4 @@
-ARCHES ?= ppc64le x86_64
+ARCHES ?= aarch64 ppc64le x86_64
 
 .PHONY: all clean submodule-check
 
diff --git a/test/unit/objs b/test/unit/objs
index 956ebf60..4ad64a06 160000
--- a/test/unit/objs
+++ b/test/unit/objs
@@ -1 +1 @@
-Subproject commit 956ebf60b40cd13e66ea6d230479ea7ea109e6c9
+Subproject commit 4ad64a06b6d0a9b779348f04823f82b03e91942e