From baa9b7b4997e0f0445f059a54c31ea0874d4f31a Mon Sep 17 00:00:00 2001
From: Hayodea Hekol <hayodea@protonmail.com>
Date: Sun, 24 May 2026 16:43:24 -0400
Subject: [PATCH] Fix rseq ext detection on x86 and RPI

---
 buildmach/CMakeLists.txt     |  3 +++
 buildmach/rseqsliceprobe.cpp | 30 +++++++++++++++++++++---------
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/buildmach/CMakeLists.txt b/buildmach/CMakeLists.txt
index 4ef829c..c16eae0 100644
--- a/buildmach/CMakeLists.txt
+++ b/buildmach/CMakeLists.txt
@@ -1,3 +1,6 @@
+cmake_minimum_required(VERSION 3.16)
+project(buildmach CXX C)
+
 option(COMPILE_CL_CHECKS "Compile CL checks" OFF)
 option(COMPILE_PCL_TOOLS "Compile PCL-based validation tools" ON)
 
diff --git a/buildmach/rseqsliceprobe.cpp b/buildmach/rseqsliceprobe.cpp
index dda6ae7..d41c655 100644
--- a/buildmach/rseqsliceprobe.cpp
+++ b/buildmach/rseqsliceprobe.cpp
@@ -1,4 +1,3 @@
-#include <sys/prctl.h>
 #include <cerrno>
 #include <cinttypes>
 #include <cstddef>
@@ -14,6 +13,12 @@
 #include <sys/syscall.h>
 #include <unistd.h>
 
+#if defined(__x86_64__)
+#ifndef ARCH_GET_FS
+#define ARCH_GET_FS 0x1003
+#endif
+#endif
+
 #ifndef PR_RSEQ_SLICE_EXTENSION
 #define PR_RSEQ_SLICE_EXTENSION 79
 #define PR_RSEQ_SLICE_EXTENSION_GET 1
@@ -54,14 +59,16 @@ extern __attribute__((weak)) unsigned int __rseq_size;
 extern __attribute__((weak)) unsigned int __rseq_flags;
 }
 
+struct rseq_slice_ctrl_fields {
+	uint8_t request;
+	uint8_t granted;
+	uint16_t reserved;
+};
+
 struct rseq_slice_ctrl_compat {
 	union {
 		uint32_t all;
-		struct {
-			uint8_t request;
-			uint8_t granted;
-			uint16_t reserved;
-		};
+		rseq_slice_ctrl_fields parts;
 	};
 };
 
@@ -74,7 +81,6 @@ struct rseq_compat {
 	uint32_t mm_cid;
 	struct rseq_slice_ctrl_compat slice_ctrl;
 	uint8_t reserved;
-	char end[];
 } __attribute__((aligned(32)));
 
 alignas(32) static thread_local unsigned char local_rseq_storage[512];
@@ -95,6 +101,12 @@ static int get_thread_pointer(uintptr_t *tp_out)
 		return -1;
 	*tp_out = fsbase;
 	return 0;
+#elif defined(__aarch64__)
+	void *tp = nullptr;
+
+	__asm__ volatile("mrs %0, tpidr_el0" : "=r"(tp));
+	*tp_out = reinterpret_cast<uintptr_t>(tp);
+	return 0;
 #else
 	(void) tp_out;
 	errno = ENOTSUP;
@@ -268,8 +280,8 @@ static void probe_slice_extension(void)
 
 	if (has_slice_ctrl) {
 		std::printf("slice_ctrl.request=%u granted=%u raw=0x%x\n",
-			    g_registered_rseq_compat->slice_ctrl.request,
-			    g_registered_rseq_compat->slice_ctrl.granted,
+			    g_registered_rseq_compat->slice_ctrl.parts.request,
+			    g_registered_rseq_compat->slice_ctrl.parts.granted,
 			    g_registered_rseq_compat->slice_ctrl.all);
 	}