Hmm, this patch may need some more eyes. At least from the x86 maintainers.
-- Steve
On Thu, 30 Mar 2023 11:44:48 +0200
Ricardo Ribalda <ribalda@xxxxxxxxxxxx> wrote:
> Make sure that the .text section is not divided in multiple overlapping
> sections. This is not supported by kexec_file.
>
> Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
> ---
> arch/x86/purgatory/.gitignore | 2 ++
> arch/x86/purgatory/Makefile | 20 +++++++++----
> arch/x86/purgatory/kexec-purgatory.S | 2 +-
> arch/x86/purgatory/purgatory.lds.S | 57 ++++++++++++++++++++++++++++++++++++
> 4 files changed, 74 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/purgatory/.gitignore b/arch/x86/purgatory/.gitignore
> index d2be1500671d..1fe71fe5945d 100644
> --- a/arch/x86/purgatory/.gitignore
> +++ b/arch/x86/purgatory/.gitignore
> @@ -1 +1,3 @@
> purgatory.chk
> +purgatory.lds
> +purgatory
> diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
> index 17f09dc26381..4dc96d409bec 100644
> --- a/arch/x86/purgatory/Makefile
> +++ b/arch/x86/purgatory/Makefile
> @@ -16,10 +16,11 @@ CFLAGS_sha256.o := -D__DISABLE_EXPORTS
>
> # When linking purgatory.ro with -r unresolved symbols are not checked,
> # also link a purgatory.chk binary without -r to check for unresolved symbols.
> -PURGATORY_LDFLAGS := -e purgatory_start -z nodefaultlib
> -LDFLAGS_purgatory.ro := -r $(PURGATORY_LDFLAGS)
> -LDFLAGS_purgatory.chk := $(PURGATORY_LDFLAGS)
> -targets += purgatory.ro purgatory.chk
> +PURGATORY_LDFLAGS := -nostdlib -z nodefaultlib
> +LDFLAGS_purgatory := -r $(PURGATORY_LDFLAGS) -T
> +LDFLAGS_purgatory.chk := -e purgatory_start $(PURGATORY_LDFLAGS)
> +
> +targets += purgatory.lds purgatory.ro purgatory.chk
>
> # Sanitizer, etc. runtimes are unavailable and cannot be linked here.
> GCOV_PROFILE := n
> @@ -72,10 +73,17 @@ CFLAGS_string.o += $(PURGATORY_CFLAGS)
> AFLAGS_REMOVE_setup-x86_$(BITS).o += -Wa,-gdwarf-2
> AFLAGS_REMOVE_entry64.o += -Wa,-gdwarf-2
>
> -$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
> +OBJCOPYFLAGS_purgatory.ro := -O elf64-x86-64
> +OBJCOPYFLAGS_purgatory.ro += --remove-section='*debug*'
> +OBJCOPYFLAGS_purgatory.ro += --remove-section='.comment'
> +OBJCOPYFLAGS_purgatory.ro += --remove-section='.note.*'
> +$(obj)/purgatory.ro: $(obj)/purgatory FORCE
> + $(call if_changed,objcopy)
> +
> +$(obj)/purgatory.chk: $(obj)/purgatory FORCE
> $(call if_changed,ld)
>
> -$(obj)/purgatory.chk: $(obj)/purgatory.ro FORCE
> +$(obj)/purgatory: $(obj)/purgatory.lds $(PURGATORY_OBJS) FORCE
> $(call if_changed,ld)
>
> $(obj)/kexec-purgatory.o: $(obj)/purgatory.ro $(obj)/purgatory.chk
> diff --git a/arch/x86/purgatory/kexec-purgatory.S b/arch/x86/purgatory/kexec-purgatory.S
> index 8530fe93b718..54b0d0b4dc42 100644
> --- a/arch/x86/purgatory/kexec-purgatory.S
> +++ b/arch/x86/purgatory/kexec-purgatory.S
> @@ -5,7 +5,7 @@
> .align 8
> kexec_purgatory:
> .globl kexec_purgatory
> - .incbin "arch/x86/purgatory/purgatory.ro"
> + .incbin "arch/x86/purgatory/purgatory"
> .Lkexec_purgatory_end:
>
> .align 8
> diff --git a/arch/x86/purgatory/purgatory.lds.S b/arch/x86/purgatory/purgatory.lds.S
> new file mode 100644
> index 000000000000..610da88aafa0
> --- /dev/null
> +++ b/arch/x86/purgatory/purgatory.lds.S
> @@ -0,0 +1,57 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#include <asm-generic/vmlinux.lds.h>
> +
> +OUTPUT_FORMAT(CONFIG_OUTPUT_FORMAT)
> +
> +#undef i386
> +
> +#include <asm/cache.h>
> +#include <asm/page_types.h>
> +
> +ENTRY(purgatory_start)
> +
> +SECTIONS
> +{
> + . = 0;
> + .head.text : {
> + _head = . ;
> + HEAD_TEXT
> + _ehead = . ;
> + }
> + .rodata : {
> + _rodata = . ;
> + *(.rodata) /* read-only data */
> + *(.rodata.*)
> + _erodata = . ;
> + }
> + .text : {
> + _text = .; /* Text */
> + *(.text)
> + *(.text.*)
> + *(.noinstr.text)
> + _etext = . ;
> + }
> + .data : {
> + _data = . ;
> + *(.data)
> + *(.data.*)
> + *(.bss.efistub)
> + _edata = . ;
> + }
> + . = ALIGN(L1_CACHE_BYTES);
> + .bss : {
> + _bss = . ;
> + *(.bss)
> + *(.bss.*)
> + *(COMMON)
> + . = ALIGN(8); /* For convenience during zeroing */
> + _ebss = .;
> + }
> +
> + /* Sections to be discarded */
> + /DISCARD/ : {
> + *(.eh_frame)
> + *(*__ksymtab*)
> + *(___kcrctab*)
> + }
> +}
>
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