[PATCH] unwinder: move .eh_frame to RODATA

The .eh_frame section contents is never written to, so it can as well
benefit from CONFIG_DEBUG_RODATA.

Diff-ed against firstfloor tree.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>

4 files changed, 13 insertions, 24 deletions

diff --git a/arch/i386/kernel/vmlinux.lds.S b/arch/i386/kernel/vmlinux.lds.S
index 25581e87c60d..56e6ad5cb045 100644
--- a/arch/i386/kernel/vmlinux.lds.S
+++ b/arch/i386/kernel/vmlinux.lds.S
@@ -102,15 +102,6 @@ SECTIONS
         _edata = .;             /* End of data section */
   }
 
-#ifdef CONFIG_STACK_UNWIND
-  . = ALIGN(4);
-  .eh_frame : AT(ADDR(.eh_frame) - LOAD_OFFSET) {
-        __start_unwind = .;
-        *(.eh_frame)
-        __end_unwind = .;
-  }
-#endif
-
   . = ALIGN(THREAD_SIZE);       /* init_task */
   .data.init_task : AT(ADDR(.data.init_task) - LOAD_OFFSET) {
         *(.data.init_task)
diff --git a/arch/x86_64/kernel/vmlinux.lds.S b/arch/x86_64/kernel/vmlinux.lds.S
index d9534e750d4f..6a1f8f491e5d 100644
--- a/arch/x86_64/kernel/vmlinux.lds.S
+++ b/arch/x86_64/kernel/vmlinux.lds.S
@@ -51,15 +51,6 @@ SECTIONS
 
   RODATA
 
-#ifdef CONFIG_STACK_UNWIND
-  . = ALIGN(8);
-  .eh_frame : AT(ADDR(.eh_frame) - LOAD_OFFSET) {
-        __start_unwind = .;
-        *(.eh_frame)
-        __end_unwind = .;
-  }
-#endif
-
   . = ALIGN(PAGE_SIZE);        /* Align data segment to page size boundary */
                                 /* Data */
   .data : AT(ADDR(.data) - LOAD_OFFSET) {
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 9f4747780dac..4d4c62d11059 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -119,8 +119,7 @@
                 *(__ksymtab_strings)                                    \
         }                                                               \
                                                                         \
-        /* Unwind data binary search table */                           \
-        EH_FRAME_HDR                                                    \
+        EH_FRAME                                                        \
                                                                         \
         /* Built-in module parameters. */                               \
         __param : AT(ADDR(__param) - LOAD_OFFSET) {                     \
@@ -162,15 +161,23 @@
                 VMLINUX_SYMBOL(__kprobes_text_end) = .;
 
 #ifdef CONFIG_STACK_UNWIND
-                /* Unwind data binary search table */
-#define EH_FRAME_HDR                                                    \
+#define EH_FRAME                                                        \
+                /* Unwind data binary search table */                   \
+                . = ALIGN(8);                                           \
                 .eh_frame_hdr : AT(ADDR(.eh_frame_hdr) - LOAD_OFFSET) { \
                         VMLINUX_SYMBOL(__start_unwind_hdr) = .;         \
                         *(.eh_frame_hdr)                                \
                         VMLINUX_SYMBOL(__end_unwind_hdr) = .;           \
+                }                                                       \
+                /* Unwind data */                                       \
+                . = ALIGN(8);                                           \
+                .eh_frame : AT(ADDR(.eh_frame) - LOAD_OFFSET) {         \
+                        VMLINUX_SYMBOL(__start_unwind) = .;             \
+                        *(.eh_frame)                                    \
+                        VMLINUX_SYMBOL(__end_unwind) = .;               \
                 }
 #else
-#define EH_FRAME_HDR
+#define EH_FRAME
 #endif
 
                 /* DWARF debug sections.
diff --git a/kernel/unwind.c b/kernel/unwind.c
index 08645aa7c2d6..09c261329249 100644
--- a/kernel/unwind.c
+++ b/kernel/unwind.c
@@ -19,7 +19,7 @@
 #include <asm/uaccess.h>
 #include <asm/unaligned.h>
 
-extern char __start_unwind[], __end_unwind[];
+extern const char __start_unwind[], __end_unwind[];
 extern const u8 __start_unwind_hdr[], __end_unwind_hdr[];
 
 #define MAX_STACK_DEPTH 8