diff --git a/libc/bionic/bionic_elf_tls.cpp b/libc/bionic/bionic_elf_tls.cpp
index cce36c9f97cbeac5ab4d49a28957aa4dcc811206..8ab9a39eaed8df0d82f08a04f579bbf69050d831 100644
--- a/libc/bionic/bionic_elf_tls.cpp
+++ b/libc/bionic/bionic_elf_tls.cpp
@@ -140,7 +140,11 @@ size_t StaticTlsLayout::reserve_exe_segment_and_tcb(const TlsSegment* exe_segmen
 #elif __riscv_xlen == 64
   // FIXME: Align TCB block and EXE's segment more accurate. For current implementation,
   // alignment requirement is not considered carefully.
+
+  // First reserve enough space for the TCB before the executable segment.
   offset_bionic_tcb_ = reserve(sizeof(bionic_tcb), 1);
+
+  // Then reserve the segment itself.
   const size_t exe_size = round_up_with_overflow_check(exe_segment->size, exe_segment->alignment);
   return reserve(exe_size, 1);
 
diff --git a/libc/platform/bionic/tls_defines.h b/libc/platform/bionic/tls_defines.h
index 225e32301efd7411c22e8a9a7f251338c9824da6..c8e6b150ee1fcc5f7811f0923cd16ff109ee47aa 100644
--- a/libc/platform/bionic/tls_defines.h
+++ b/libc/platform/bionic/tls_defines.h
@@ -96,19 +96,19 @@
 
 #elif __riscv_xlen == 64
 
-#define MIN_TLS_SLOT              -10
-
-#define TLS_SLOT_SELF             -10
-#define TLS_SLOT_THREAD_ID        -9
-#define TLS_SLOT_APP              -8 // was historically used for errno
-#define TLS_SLOT_OPENGL           -7
-#define TLS_SLOT_OPENGL_API       -6
-#define TLS_SLOT_STACK_GUARD      -5
-#define TLS_SLOT_SANITIZER        -4 // was historically used for dlerror
-#define TLS_SLOT_ART_THREAD_SELF  -3
-#define TLS_SLOT_DTV              -2
-#define TLS_SLOT_BIONIC_TLS       -1
-#define MAX_TLS_SLOT              -1 // update this value when reserving a slot
+#define MIN_TLS_SLOT             (-9) // update this value when reserving a slot
+#define TLS_SLOT_BIONIC_TLS      (-9)
+#define TLS_SLOT_DTV             (-8)
+#define TLS_SLOT_THREAD_ID       (-7)
+#define TLS_SLOT_APP             (-6) // was historically used for errno
+#define TLS_SLOT_OPENGL          (-5)
+#define TLS_SLOT_OPENGL_API      (-4)
+#define TLS_SLOT_STACK_GUARD     (-3)
+#define TLS_SLOT_SANITIZER       (-2) // was historically used for dlerror
+#define TLS_SLOT_ART_THREAD_SELF (-1)
+
+// The maximum slot is fixed by the minimum TLS alignment in Bionic executables.
+#define MAX_TLS_SLOT             (-1)
 
 #elif defined(__i386__) || defined(__x86_64__)