[glibc/arm/morello/main] cheri: Setup RX, RW capabilities for static linking

[Szabolcs Nagy <nsz@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=87dffcda136a7d1b0c0f81ccf9ac084178181321

commit 87dffcda136a7d1b0c0f81ccf9ac084178181321
Author: Szabolcs Nagy <szabolcs.nagy@arm.com>
Date:   Wed Sep 7 10:38:29 2022 +0100

    cheri: Setup RX, RW capabilities for static linking
    
    At least tls image access requires RX capability of the main link_map.

Diff:
---
 elf/dl-support.c                        | 5 +++++
 sysdeps/unix/sysv/linux/dl-parse_auxv.h | 9 +++++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/elf/dl-support.c b/elf/dl-support.c
index 599efb1d08..8551e18eb2 100644
--- a/elf/dl-support.c
+++ b/elf/dl-support.c
@@ -263,6 +263,11 @@ _dl_aux_init (ElfW(auxv_t) *av)
   for (int i = 0; i < array_length (auxv_values); ++i)
     auxv_values[i] = 0;
   _dl_parse_auxv (av, auxv_values);
+
+# ifdef __CHERI_PURE_CAPABILITY__
+  _dl_main_map.l_map_start = auxv_values[AT_CHERI_EXEC_RX_CAP];
+  _dl_main_map.l_rw_start = auxv_values[AT_CHERI_EXEC_RW_CAP];
+# endif
 }
 #endif
 
diff --git a/sysdeps/unix/sysv/linux/dl-parse_auxv.h b/sysdeps/unix/sysv/linux/dl-parse_auxv.h
index 48ca7736a0..a0770b4412 100644
--- a/sysdeps/unix/sysv/linux/dl-parse_auxv.h
+++ b/sysdeps/unix/sysv/linux/dl-parse_auxv.h
@@ -22,7 +22,12 @@
 #include <ldsodefs.h>
 #include <link.h>
 
-typedef elfptr_t dl_parse_auxv_t[AT_MINSIGSTKSZ + 1];
+#ifdef __CHERI_PURE_CAPABILITY__
+# define AT_MAX AT_ENVP
+#else
+# define AT_MAX AT_MINSIGSTKSZ
+#endif
+typedef elfptr_t dl_parse_auxv_t[AT_MAX + 1];
 
 /* Copy the auxiliary vector into AUXV_VALUES and set up GLRO
    variables.  */
@@ -39,7 +44,7 @@ void _dl_parse_auxv (ElfW(auxv_t) *av, dl_parse_auxv_t auxv_values)
   auxv_values[AT_MINSIGSTKSZ] = CONSTANT_MINSIGSTKSZ;
 
   for (; av->a_type != AT_NULL; av++)
-    if (av->a_type <= AT_MINSIGSTKSZ)
+    if (av->a_type <= AT_MAX)
       auxv_values[av->a_type] = av->a_un.a_val;
 
   GLRO(dl_pagesize) = auxv_values[AT_PAGESZ];