1 files changed, 17 insertions, 17 deletions
diff --git a/wasm2c/examples/fac/fac.c b/wasm2c/examples/fac/fac.c
index e253cc2a..38c5e823 100644
--- a/wasm2c/examples/fac/fac.c
+++ b/wasm2c/examples/fac/fac.c
@@ -51,11 +51,16 @@
 //     for accessing pointers, and supports memcpy on pointers with custom
 //     "address namespaces". GCC does not support the memcpy requirement, so
 //     this leaves only clang for now.
-// (5) The OS doesn't replace the segment register on context switch which
+// (5) The OS provides a way to query if (rd|wr)gsbase is allowed by the kernel
+// or the implementation has to use a syscall for this.
+// (6) The OS doesn't replace the segment register on context switch which
 //     eliminates windows for now
+//
+// While more OS can be supported in the future, we only support linux for now
 #if WASM_RT_ALLOW_SEGUE && !WABT_BIG_ENDIAN &&                               \
     (defined(__x86_64__) || defined(_M_X64)) && IS_SINGLE_UNSHARED_MEMORY && \
-    __clang__ && __has_builtin(__builtin_ia32_wrgsbase64) && !defined(_WIN32)
+    __clang__ && __has_builtin(__builtin_ia32_wrgsbase64) &&                 \
+    !defined(_WIN32) && defined(__linux__)
 #define WASM_RT_USE_SEGUE 1
 #else
 #define WASM_RT_USE_SEGUE 0
@@ -64,31 +69,26 @@
 
 #if WASM_RT_USE_SEGUE
 // POSIX uses FS for TLS, GS is free
-#include <asm/prctl.h>
-#include <stdio.h>
-#include <sys/syscall.h>
-#include <unistd.h>
-
 static inline void* wasm_rt_segue_read_base() {
   if (wasm_rt_fsgsbase_inst_supported) {
     return (void*)__builtin_ia32_rdgsbase64();
   } else {
-    void* base;
-    if (syscall(SYS_arch_prctl, ARCH_GET_GS, &base) != 0) {
-      perror("Syscall SYS_arch_prctl error");
-      abort();
-    }
-    return base;
+    return wasm_rt_syscall_get_segue_base();
   }
 }
 static inline void wasm_rt_segue_write_base(void* base) {
+#if WASM_RT_SEGUE_FREE_SEGMENT
+  if (wasm_rt_last_segment_val == base) {
+    return;
+  }
+
+  wasm_rt_last_segment_val = base;
+#endif
+
   if (wasm_rt_fsgsbase_inst_supported) {
     __builtin_ia32_wrgsbase64((uintptr_t)base);
   } else {
-    if (syscall(SYS_arch_prctl, ARCH_SET_GS, (uintptr_t)base) != 0) {
-      perror("Syscall SYS_arch_prctl error");
-      abort();
-    }
+    wasm_rt_syscall_set_segue_base(base);
   }
 }
 #define MEM_ADDR_MEMOP(mem, addr, n) ((uint8_t __seg_gs*)(uintptr_t)addr)