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s390: vmlinux.lds.S: explicitly handle '.got' and '.plt' sections

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When building with CONFIG_LD_ORPHAN_WARN after selecting
CONFIG_ARCH_HAS_LD_ORPHAN_WARN, there are a lot of warnings around the
GOT and PLT sections:

  s390-linux-ld: warning: orphan section `.plt' from `arch/s390/kernel/head64.o' being placed in section `.plt'
  s390-linux-ld: warning: orphan section `.got' from `arch/s390/kernel/head64.o' being placed in section `.got'
  s390-linux-ld: warning: orphan section `.got.plt' from `arch/s390/kernel/head64.o' being placed in section `.got.plt'
  s390-linux-ld: warning: orphan section `.iplt' from `arch/s390/kernel/head64.o' being placed in section `.iplt'
  s390-linux-ld: warning: orphan section `.igot.plt' from `arch/s390/kernel/head64.o' being placed in section `.igot.plt'

  s390-linux-ld: warning: orphan section `.iplt' from `arch/s390/boot/head.o' being placed in section `.iplt'
  s390-linux-ld: warning: orphan section `.igot.plt' from `arch/s390/boot/head.o' being placed in section `.igot.plt'
  s390-linux-ld: warning: orphan section `.got' from `arch/s390/boot/head.o' being placed in section `.got'

Currently, only the '.got' section is actually emitted in the final
binary. In a manner similar to other architectures, put the '.got'
section near the '.data' section and coalesce the PLT sections,
checking that the final section is zero sized, which is a safe/tested
approach versus full discard.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240207-s390-lld-and-orphan-warn-v1-3-8a665b3346ab@kernel.org
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Nathan Chancellor 2024-02-07 17:14:55 -07:00 • committed by Heiko Carstens
parent bdf2cd27a3
commit 30226853d6
2 changed files with 32 additions and 0 deletions
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16
arch/s390/boot/vmlinux.lds.S
View file

@ -39,6 +39,9 @@ SECTIONS
*(.rodata.*) *(.rodata.*)
_erodata = . ; _erodata = . ;
} }
.got : {
*(.got)
}
NOTES NOTES
.data : { .data : {
_data = . ; _data = . ;
@ -118,6 +121,19 @@ SECTIONS
} }
_end = .; _end = .;
/*
* Sections that should stay zero sized, which is safer to
* explicitly check instead of blindly discarding.
*/
.got.plt : {
*(.got.plt)
}
ASSERT(SIZEOF(.got.plt) == 0, "Unexpected GOT/PLT entries detected!")
.plt : {
*(.plt) *(.plt.*) *(.iplt) *(.igot .igot.plt)
}
ASSERT(SIZEOF(.plt) == 0, "Unexpected run-time procedure linkages detected!")
/* Sections to be discarded */ /* Sections to be discarded */
/DISCARD/ : { /DISCARD/ : {
*(.eh_frame) *(.eh_frame)

16
arch/s390/kernel/vmlinux.lds.S
View file

@ -62,6 +62,9 @@ SECTIONS
.data.rel.ro : { .data.rel.ro : {
*(.data.rel.ro .data.rel.ro.*) *(.data.rel.ro .data.rel.ro.*)
} }
.got : {
*(.got)
}
. = ALIGN(PAGE_SIZE); . = ALIGN(PAGE_SIZE);
_sdata = .; /* Start of data section */ _sdata = .; /* Start of data section */
@ -241,6 +244,19 @@ SECTIONS
DWARF_DEBUG DWARF_DEBUG
ELF_DETAILS ELF_DETAILS
/*
* Sections that should stay zero sized, which is safer to
* explicitly check instead of blindly discarding.
*/
.got.plt : {
*(.got.plt)
}
ASSERT(SIZEOF(.got.plt) == 0, "Unexpected GOT/PLT entries detected!")
.plt : {
*(.plt) *(.plt.*) *(.iplt) *(.igot .igot.plt)
}
ASSERT(SIZEOF(.plt) == 0, "Unexpected run-time procedure linkages detected!")
/* Sections to be discarded */ /* Sections to be discarded */
DISCARDS DISCARDS
/DISCARD/ : { /DISCARD/ : {