[PATCH v7 20/23] aarch64: Process gnu properties in static exe

[Yury Khrustalev]

From: Szabolcs Nagy <szabolcs.nagy@arm.com>

Unlike for BTI, the kernel does not process GCS properties so update
GL(dl_aarch64_gcs) before the GCS status is set.

Co-authored-by: Yury Khrustalev <yury.khrustalev@arm.com>
---
 csu/libc-start.c                             | 12 ++++++++++++
 sysdeps/generic/libc-start.h                 |  1 +
 sysdeps/unix/sysv/linux/aarch64/libc-start.h | 19 +++++++++++++++++++
 3 files changed, 32 insertions(+)

diff --git a/csu/libc-start.c b/csu/libc-start.c
index 6f3d52e223..325ef010d4 100644
--- a/csu/libc-start.c
+++ b/csu/libc-start.c
@@ -206,6 +206,10 @@ call_fini (void *unused)
 
 #include <libc-start.h>
 
+#ifndef ARCH_PROCESS_NOTES
+# define ARCH_PROCESS_NOTES()
+#endif
+
 STATIC int LIBC_START_MAIN (int (*main) (int, char **, char **
 					 MAIN_AUXVEC_DECL),
 			    int argc,
@@ -219,6 +223,11 @@ STATIC int LIBC_START_MAIN (int (*main) (int, char **, char **
 			    void *stack_end)
      __attribute__ ((noreturn));
 
+void
+__libc_process_notes (void)
+{
+
+}
 
 /* Note: The init and fini parameters are no longer used.  fini is
    completely unused, init is still called if not NULL, but the
@@ -276,6 +285,9 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
   /* Perform IREL{,A} relocations.  */
   ARCH_SETUP_IREL ();
 
+  /* Process notes: PT_NOTE / PT_GNU_PROPERTY.  */
+  ARCH_PROCESS_NOTES ();
+
   /* The stack guard goes into the TCB, so initialize it early.  */
   ARCH_SETUP_TLS ();
 
diff --git a/sysdeps/generic/libc-start.h b/sysdeps/generic/libc-start.h
index 0b107cf2a1..1a421626b5 100644
--- a/sysdeps/generic/libc-start.h
+++ b/sysdeps/generic/libc-start.h
@@ -24,6 +24,7 @@
    initialization, and this means you cannot, without machine
    knowledge, access TLS from an IFUNC resolver.  */
 #define ARCH_SETUP_IREL() apply_irel ()
+#define ARCH_PROCESS_NOTES() __libc_process_notes ()
 #define ARCH_SETUP_TLS() __libc_setup_tls ()
 #define ARCH_APPLY_IREL()
 #endif /* ! SHARED  */
diff --git a/sysdeps/unix/sysv/linux/aarch64/libc-start.h b/sysdeps/unix/sysv/linux/aarch64/libc-start.h
index 735076c086..0f80a8abe9 100644
--- a/sysdeps/unix/sysv/linux/aarch64/libc-start.h
+++ b/sysdeps/unix/sysv/linux/aarch64/libc-start.h
@@ -21,6 +21,24 @@
 
 #ifndef SHARED
 
+# include <dl-prop.h>
+
+/* Must be on a top-level stack frame that does not return.  */
+static inline void __attribute__((always_inline))
+aarch64_libc_process_notes (void)
+{
+  struct link_map *main_map = _dl_get_dl_main_map ();
+  const ElfW(Phdr) *phdr = GL(dl_phdr);
+  const ElfW(Phdr) *ph;
+  for (ph = phdr; ph < phdr + GL(dl_phnum); ph++)
+    if (ph->p_type == PT_GNU_PROPERTY)
+      {
+	_dl_process_pt_gnu_property (main_map, -1, ph);
+	_rtld_main_check (main_map, _dl_argv[0]);
+	break;
+      }
+}
+
 # ifndef PR_SET_SHADOW_STACK_STATUS
 #  define PR_SET_SHADOW_STACK_STATUS	75
 #  define PR_SHADOW_STACK_ENABLE	(1UL << 0)
@@ -39,6 +57,7 @@ aarch64_libc_setup_tls (void)
 }
 
 # define ARCH_SETUP_IREL() apply_irel ()
+# define ARCH_PROCESS_NOTES() aarch64_libc_process_notes ()
 # define ARCH_SETUP_TLS() aarch64_libc_setup_tls ()
 # define ARCH_APPLY_IREL()
 #endif /* ! SHARED  */
-- 
2.39.5