diff mbox series

[v2,1/4] Initial support for GNU_PROPERTY_1_NEEDED

Message ID 20210624134938.2025098-2-hjl.tools@gmail.com
State New
Headers show
Series Implement indirect external access marker | expand

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent

Commit Message

H.J. Lu June 24, 2021, 1:49 p.m. UTC
1. Add GNU_PROPERTY_1_NEEDED:

 #define GNU_PROPERTY_1_NEEDED      GNU_PROPERTY_UINT32_OR_LO

to indicate the needed properties by the object file.
2. Add GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS:

 #define GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS (1U << 0)

to indicate that the object file requires canonical function pointers and
cannot be used with copy relocation.
3. Scan GNU_PROPERTY_1_NEEDED property and store it in l_1_needed.
---
 elf/elf.h                  | 17 +++++++++++++++++
 sysdeps/generic/dl-prop.h  |  9 ++++++++-
 sysdeps/generic/link_map.h |  3 ++-
 sysdeps/x86/dl-prop.h      | 19 ++++++++++++++-----
 sysdeps/x86/link_map.h     |  2 ++
 5 files changed, 43 insertions(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/elf/elf.h b/elf/elf.h
index 2a62b98d4a..dd661a6a64 100644
--- a/elf/elf.h
+++ b/elf/elf.h
@@ -1310,6 +1310,23 @@  typedef struct
 /* No copy relocation on protected data symbol.  */
 #define GNU_PROPERTY_NO_COPY_ON_PROTECTED	2
 
+/* A 4-byte unsigned integer property: A bit is set if it is set in all
+   relocatable inputs.  */
+#define GNU_PROPERTY_UINT32_AND_LO	0xb0000000
+#define GNU_PROPERTY_UINT32_AND_HI	0xb0007fff
+
+/* A 4-byte unsigned integer property: A bit is set if it is set in any
+   relocatable inputs.  */
+#define GNU_PROPERTY_UINT32_OR_LO	0xb0008000
+#define GNU_PROPERTY_UINT32_OR_HI	0xb000ffff
+
+/* The needed properties by the object file.  */
+#define GNU_PROPERTY_1_NEEDED		GNU_PROPERTY_UINT32_OR_LO
+
+/* Set if the object file requires canonical function pointers and
+   cannot be used with copy relocation.  */
+#define GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS (1U << 0)
+
 /* Processor-specific semantics, lo */
 #define GNU_PROPERTY_LOPROC			0xc0000000
 /* Processor-specific semantics, hi */
diff --git a/sysdeps/generic/dl-prop.h b/sysdeps/generic/dl-prop.h
index eaee8052b6..207aadb35d 100644
--- a/sysdeps/generic/dl-prop.h
+++ b/sysdeps/generic/dl-prop.h
@@ -47,7 +47,14 @@  static inline int __attribute__ ((always_inline))
 _dl_process_gnu_property (struct link_map *l, int fd, uint32_t type,
 			  uint32_t datasz, void *data)
 {
-  return 0;
+  /* Continue until GNU_PROPERTY_1_NEEDED is found.  */
+  if (type == GNU_PROPERTY_1_NEEDED)
+    {
+      if (datasz == 4)
+	l->l_1_needed = *(unsigned int *) data;
+      return 0;
+    }
+  return 1;
 }
 
 #endif /* _DL_PROP_H */
diff --git a/sysdeps/generic/link_map.h b/sysdeps/generic/link_map.h
index a056184690..9f482b8c20 100644
--- a/sysdeps/generic/link_map.h
+++ b/sysdeps/generic/link_map.h
@@ -1 +1,2 @@ 
-/* No architecture specific definitions.  */
+/* GNU_PROPERTY_1_NEEDED of this object.  */
+unsigned int l_1_needed;
diff --git a/sysdeps/x86/dl-prop.h b/sysdeps/x86/dl-prop.h
index 56bd020b3c..385548fad3 100644
--- a/sysdeps/x86/dl-prop.h
+++ b/sysdeps/x86/dl-prop.h
@@ -97,6 +97,7 @@  _dl_process_property_note (struct link_map *l, const ElfW(Nhdr) *note,
 
   const ElfW(Addr) start = (ElfW(Addr)) note;
 
+  unsigned int needed_1 = 0;
   unsigned int feature_1_and = 0;
   unsigned int isa_1_needed = 0;
   unsigned int last_type = 0;
@@ -141,7 +142,8 @@  _dl_process_property_note (struct link_map *l, const ElfW(Nhdr) *note,
 	      last_type = type;
 
 	      if (type == GNU_PROPERTY_X86_FEATURE_1_AND
-		  || type == GNU_PROPERTY_X86_ISA_1_NEEDED)
+		  || type == GNU_PROPERTY_X86_ISA_1_NEEDED
+		  || type == GNU_PROPERTY_1_NEEDED)
 		{
 		  /* The sizes of types which we are searching for are
 		     4 bytes.  There is no point to continue if this
@@ -151,12 +153,18 @@  _dl_process_property_note (struct link_map *l, const ElfW(Nhdr) *note,
 
 		  /* NB: Stop the scan only after seeing all types which
 		     we are searching for.  */
-		  _Static_assert ((GNU_PROPERTY_X86_ISA_1_NEEDED >
-				   GNU_PROPERTY_X86_FEATURE_1_AND),
+		  _Static_assert (((GNU_PROPERTY_X86_ISA_1_NEEDED
+				    > GNU_PROPERTY_X86_FEATURE_1_AND)
+				   && (GNU_PROPERTY_X86_FEATURE_1_AND
+				       > GNU_PROPERTY_1_NEEDED)),
 				  "GNU_PROPERTY_X86_ISA_1_NEEDED > "
-				  "GNU_PROPERTY_X86_FEATURE_1_AND");
+				  "GNU_PROPERTY_X86_FEATURE_1_AND && "
+				  "GNU_PROPERTY_X86_FEATURE_1_AND > "
+				  "GNU_PROPERTY_1_NEEDED");
 		  if (type == GNU_PROPERTY_X86_FEATURE_1_AND)
 		    feature_1_and = *(unsigned int *) ptr;
+		  else if (type == GNU_PROPERTY_1_NEEDED)
+		    needed_1 = *(unsigned int *) ptr;
 		  else
 		    {
 		      isa_1_needed = *(unsigned int *) ptr;
@@ -187,9 +195,10 @@  _dl_process_property_note (struct link_map *l, const ElfW(Nhdr) *note,
     }
 
   /* We get here only if there is one or no GNU property note.  */
-  if (isa_1_needed != 0 || feature_1_and != 0)
+  if (needed_1 != 0 || isa_1_needed != 0 || feature_1_and != 0)
     {
       l->l_property = lc_property_valid;
+      l->l_1_needed = needed_1;
       l->l_x86_isa_1_needed = isa_1_needed;
       l->l_x86_feature_1_and = feature_1_and;
     }
diff --git a/sysdeps/x86/link_map.h b/sysdeps/x86/link_map.h
index 4c46a25f83..0c7e25dc96 100644
--- a/sysdeps/x86/link_map.h
+++ b/sysdeps/x86/link_map.h
@@ -29,3 +29,5 @@  unsigned int l_x86_feature_1_and;
 
 /* GNU_PROPERTY_X86_ISA_1_NEEDED of this object.  */
 unsigned int l_x86_isa_1_needed;
+
+#include <sysdeps/generic/link_map.h>