[3/3] xen/arm: Make use of helpers defined in xen_lds.h

Commit Message

Michal Orzel March 21, 2022, 8:21 a.m. UTC

Header file xen_lds.h defines common macros to be used in arch specific
linker scripts. Include this header and make use of its helpers.

Making use of common helpers defined based on x86 linker script
improves arm linker script with:
-explicit list of debug sections that otherwise are seen as "orphans"
by the linker. This will allow to fix issues after enabling linker
option --orphan-handling one day
-re-arrangement of ordering/sorting in constructors section to match the
default linker script
-extended list of discarded section to include: .discard, desctructors
related sections, .fini_array which can reference .text.exit
-extended list of stabs section to include sections placed by ld.lld.
Even though Xen on arm compilation with LLVM support is not ready yet,
these sections do not cause problem to GNU ld

Signed-off-by: Michal Orzel <[e-mail]>
---
 xen/arch/arm/xen.lds.S | 37 ++++++++++++-------------------------
 1 file changed, 12 insertions(+), 25 deletions(-)

Comments

Jan Beulich March 21, 2022, 9:25 a.m. UTC | #1

On 21.03.2022 09:21, Michal Orzel wrote:
> Header file xen_lds.h defines common macros to be used in arch specific
> linker scripts. Include this header and make use of its helpers.
> 
> Making use of common helpers defined based on x86 linker script
> improves arm linker script with:
> -explicit list of debug sections that otherwise are seen as "orphans"
> by the linker. This will allow to fix issues after enabling linker
> option --orphan-handling one day
> -re-arrangement of ordering/sorting in constructors section to match the
> default linker script

As said in reply to patch 1 - I don't think this is correct on x86 right
now, and hence I don't think you want to propagate the same (at least
latent) issue to Arm.

Jan

Patch

diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
index 7921d8fa28..9e1832e94c 100644
--- a/xen/arch/arm/xen.lds.S
+++ b/xen/arch/arm/xen.lds.S
@@ -3,6 +3,7 @@ 
 /* Modified for ARM Xen by Ian Campbell */
 
 #include <xen/cache.h>
+#include <xen/xen_lds.h>
 #include <asm/page.h>
 #undef ENTRY
 #undef ALIGN
@@ -68,10 +69,7 @@  SECTIONS
        __proc_info_end = .;
 
 #ifdef CONFIG_HAS_VPCI
-       . = ALIGN(POINTER_ALIGN);
-       __start_vpci_array = .;
-       *(SORT(.data.vpci.*))
-       __end_vpci_array = .;
+       VPCI_SECTION
 #endif
   } :text
 
@@ -109,10 +107,7 @@  SECTIONS
        __end_schedulers_array = .;
 
 #ifdef CONFIG_HYPFS
-       . = ALIGN(8);
-       __paramhypfs_start = .;
-       *(.data.paramhypfs)
-       __paramhypfs_end = .;
+       HYPFS_SECTION
 #endif
 
        *(.data .data.*)
@@ -178,10 +173,7 @@  SECTIONS
        __alt_instructions_end = .;
 
 #ifdef CONFIG_DEBUG_LOCK_PROFILE
-       . = ALIGN(POINTER_ALIGN);
-       __lock_profile_start = .;
-       *(.lockprofile.data)
-       __lock_profile_end = .;
+       LOCK_PROFILE_SECTION
 #endif
 
        *(.init.data)
@@ -221,22 +213,17 @@  SECTIONS
   /* Section for the device tree blob (if any). */
   .dtb : { *(.dtb) } :text
 
+  /*
+   * Explicitly list debug sections, to avoid these sections being viewed as
+   * "orphan" by the linker.
+   */
+  DWARF_DEBUG_SECTIONS
+
   /* Sections to be discarded */
-  /DISCARD/ : {
-       *(.exit.text)
-       *(.exit.data)
-       *(.exitcall.exit)
-       *(.eh_frame)
-  }
+  DISCARD_SECTIONS
 
   /* Stabs debugging sections.  */
-  .stab 0 : { *(.stab) }
-  .stabstr 0 : { *(.stabstr) }
-  .stab.excl 0 : { *(.stab.excl) }
-  .stab.exclstr 0 : { *(.stab.exclstr) }
-  .stab.index 0 : { *(.stab.index) }
-  .stab.indexstr 0 : { *(.stab.indexstr) }
-  .comment 0 : { *(.comment) }
+  STABS_DEBUG_SECTIONS
 }
 
 /*