aarch64: morello: elf: Return bounded pointer in __tls_get_addr

There is no traditional TLS support in morello that would explicitly
call __tls_get_addr, but the libc uses it internally and the returned
pointer escapes to user code.  So bound the pointers according to
the tls symbol size instead of doing so in each caller.

(Affects dlsym and dynamic TLSDESC.)

diff --git a/elf/dl-sym.c b/elf/dl-sym.c
index b1cf42f36df7cfafcc3d48f9d0611a08010cbd7a..cd7df7e6c706580476aa406f564d3332a0883207 100644 (file)
--- a/elf/dl-sym.c
+++ b/elf/dl-sym.c
@@ -49,6 +49,10 @@ _dl_tls_symaddr (struct link_map *map, const ElfW(Sym) *ref)
     {
       .ti_module = map->l_tls_modid,
       .ti_offset = ref->st_value
+#  ifdef __CHERI_PURE_CAPABILITY__
+       ,
+      .ti_size = ref->st_size
+#  endif
     };
 
   return __TLS_GET_ADDR (&tmp);

diff --git a/sysdeps/aarch64/morello/dl-tls.c b/sysdeps/aarch64/morello/dl-tls.c
new file mode 100644 (file)
index 0000000..6fadfe2
--- /dev/null
+++ b/sysdeps/aarch64/morello/dl-tls.c
@@ -0,0 +1,39 @@
+/* Thread-local storage handling in the ELF dynamic linker.  Morello version.
+   Copyright (C) 2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifdef SHARED
+/* Add a wrapper around the generic __tls_get_addr code to set the
+   bounds on the returned pointer.  */
+
+# define __tls_get_addr __tls_get_addr_unbounded
+# include <elf/dl-tls.c>
+# undef __tls_get_addr
+
+void *__tls_get_addr (tls_index *ti);
+rtld_hidden_proto (__tls_get_addr)
+rtld_hidden_def (__tls_get_addr)
+
+void *
+__tls_get_addr (tls_index *ti)
+{
+  void *p = __tls_get_addr_unbounded (ti);
+  return __builtin_cheri_bounds_set_exact (p, ti->ti_size);
+}
+#else
+# include <elf/dl-tls.c>
+#endif

diff --git a/sysdeps/aarch64/morello/dl-tls.h b/sysdeps/aarch64/morello/dl-tls.h
new file mode 100644 (file)
index 0000000..f47f89c
--- /dev/null
+++ b/sysdeps/aarch64/morello/dl-tls.h
@@ -0,0 +1,26 @@
+/* Copyright (C) 2022 Free Software Foundation, Inc.
+
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+typedef struct
+{
+  unsigned long int ti_module;
+  unsigned long int ti_offset;
+  unsigned long int ti_size;
+} tls_index;
+
+extern void *__tls_get_addr (tls_index *ti);

diff --git a/sysdeps/aarch64/morello/dl-tlsdesc.S b/sysdeps/aarch64/morello/dl-tlsdesc.S
index 6fced5373478c981561bfbf3eaec17cca34f7352..d11f5d5fa7c790c32e7d5dd6f493e503c47c2ae8 100644 (file)
--- a/sysdeps/aarch64/morello/dl-tlsdesc.S
+++ b/sysdeps/aarch64/morello/dl-tlsdesc.S
@@ -193,18 +193,9 @@ _dl_tlsdesc_dynamic:
 
        SAVE_Q_REGISTERS
 
-       /* TODO: remove once __tls_get_addr is fixed.  */
-       str     c1, [csp, #32*8]
-
        mov     c0, c1
        bl      __tls_get_addr
 
-       /* TODO: __tls_get_addr should return bounded pointer,
-          currently it does not so bound it here.  */
-       ldr     c1, [csp, #32*8]
-       ldr     x3, [c1, #TLSDESC_SIZE]
-       scbndse c0, c0, x3
-
        mrs     c2, ctpidr_el0 /* Restore c2.  */
 
        RESTORE_Q_REGISTERS