diff mbox series

[v7,01/14] Rewrite abi-note.S in C.

Message ID c1210543a60c2ba95f27ee94ae648f74e27b1ad7.1594209990.git.szabolcs.nagy@arm.com
State Committed
Commit dbfefbdc3aeec88868cb9d46267f91dc62461226
Headers show
Series aarch64: branch protection support | expand

Commit Message

Szabolcs Nagy July 8, 2020, 12:10 p.m. UTC
Using C code allows the compiler to add target specific object file
markings based on CFLAGS.

The arm specific abi-note.S is removed and similar object file fix
up will be avoided on AArch64 with standard branch protection.
---
 csu/{abi-note.S => abi-note.c} | 25 +++++++++++++++----------
 sysdeps/arm/abi-note.S         |  8 --------
 2 files changed, 15 insertions(+), 18 deletions(-)
 rename csu/{abi-note.S => abi-note.c} (89%)
 delete mode 100644 sysdeps/arm/abi-note.S

Comments

Florian Weimer July 8, 2020, 12:15 p.m. UTC | #1
* Szabolcs Nagy:

> Using C code allows the compiler to add target specific object file
> markings based on CFLAGS.
>
> The arm specific abi-note.S is removed and similar object file fix
> up will be avoided on AArch64 with standard branch protection.
> ---
>  csu/{abi-note.S => abi-note.c} | 25 +++++++++++++++----------
>  sysdeps/arm/abi-note.S         |  8 --------
>  2 files changed, 15 insertions(+), 18 deletions(-)
>  rename csu/{abi-note.S => abi-note.c} (89%)
>  delete mode 100644 sysdeps/arm/abi-note.S

This looks okay to me.

Thanks,
Florian
diff mbox series

Patch

diff --git a/csu/abi-note.S b/csu/abi-note.c
similarity index 89%
rename from csu/abi-note.S
rename to csu/abi-note.c
index 2b4b5f8824..8febf4cac0 100644
--- a/csu/abi-note.S
+++ b/csu/abi-note.c
@@ -53,6 +53,8 @@  offset	length	contents
    identify the earliest release of that OS that supports this ABI.
    See abi-tags (top level) for details. */
 
+#include <link.h>
+#include <stdint.h>
 #include <config.h>
 #include <abi-tag.h>		/* OS-specific ABI tag value */
 
@@ -60,13 +62,16 @@  offset	length	contents
    name begins with `.note' and creates a PT_NOTE program header entry
    pointing at it. */
 
-	.section ".note.ABI-tag", "a"
-	.p2align 2
-	.long 1f - 0f		/* name length */
-	.long 3f - 2f		/* data length */
-	.long  1		/* note type */
-0:	.asciz "GNU"		/* vendor name */
-1:	.p2align 2
-2:	.long __ABI_TAG_OS	/* note data: the ABI tag */
-	.long __ABI_TAG_VERSION
-3:	.p2align 2		/* pad out section */
+__attribute__ ((used, aligned (4), section (".note.ABI-tag")))
+static const struct
+{
+  ElfW(Nhdr) nhdr;
+  char name[4];
+  int32_t desc[4];
+} __abi_tag = {
+  { .n_namesz = sizeof __abi_tag.name,
+    .n_descsz = sizeof __abi_tag.desc,
+    .n_type = 1 },
+  "GNU",
+  { __ABI_TAG_OS, __ABI_TAG_VERSION }
+};
diff --git a/sysdeps/arm/abi-note.S b/sysdeps/arm/abi-note.S
deleted file mode 100644
index 07bd4c4619..0000000000
--- a/sysdeps/arm/abi-note.S
+++ /dev/null
@@ -1,8 +0,0 @@ 
-/* Tag_ABI_align8_preserved: This code preserves 8-byte
-   alignment in any callee.  */
-	.eabi_attribute 25, 1
-/* Tag_ABI_align8_needed: This code may require 8-byte alignment from
-   the caller.  */
-	.eabi_attribute 24, 1
-
-#include <csu/abi-note.S>