Arm64 support, including @surajjs95 & @t-msn changes

.gitmodules

@@ -1,3 +1,4 @@
 [submodule "test/unit/objs"]
 	path = test/unit/objs
-	url = https://github.com/dynup/kpatch-unit-test-objs.git
+	url = https://github.com/swine/kpatch-unit-test-objs.git
+	branch = remotes/github-swine/arm64

README.md

@@ -40,7 +40,7 @@ Supported Architectures
 
 - [x] x86-64
 - [x] ppc64le
-- [ ] arm64
+- [x] arm64 [upstream prerequisites](doc/arm64-upstream-prerequisites.md)
 - [x] s390 [upstream prerequisites](doc/s390-upstream-prerequisites.md)
 
 Installation

doc/arm64-upstream-prerequisites.md

@@ -0,0 +1,11 @@
+### arm64 backporting
+
+**Prerequisite kernel patches:**
+**v5.19:**
+- [Madhavan Venkataraman's [RFC PATCH v2 00/20] arm64: livepatch: Use ORC for dynamic frame pointer validation](https://lore.kernel.org/linux-arm-kernel/[email protected]/)
+- also tested against madvenka's earlier pre-objtool series up to v15
+
+**v5.15 and v5.10:**
+- under development, both known to work with backports of madvenka's v15,
+  but the objtool-using version above is likely to be the approach that
+  finally merges into upstream kernel

kmod/patch/kpatch-syscall.h

@@ -186,7 +186,34 @@
 
 # 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

kpatch-build/Makefile

@@ -22,7 +22,7 @@ PLUGIN_CFLAGS := $(filter-out -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),aarch64 s390x x86_64 ppc64le),)
 $(error Unsupported architecture ${ARCH}, check https://github.com/dynup/kpatch/#supported-architectures)
 endif