diff mbox series

[3/7] xen: remove -N from the linker command line

Message ID 20250318173547.59475-4-roger.pau@citrix.com (mailing list archive)
State New
Headers show
Series x86: generate xen.efi image with no write-execute sections | expand

Commit Message

Roger Pau Monne March 18, 2025, 5:35 p.m. UTC 
It's unclear why -N is being used in the first place.  It was added by
commit 40828c657dd0c back in 2004 without any justification.

When building a PE image it's actually detrimental to forcefully set the
.text section as writable.  The GNU LD man page contains the following
warning regarding the -N option:

> Note: Although a writable text section is allowed for PE-COFF targets, it
> does not conform to the format specification published by Microsoft.

Remove the usage of -N uniformly on all architectures, assuming that the
addition was simply done as a copy and paste of the original x86 linking
rune.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
 xen/arch/arm/Makefile   |  6 +++---
 xen/arch/ppc/Makefile   |  6 +++---
 xen/arch/riscv/Makefile |  6 +++---
 xen/arch/x86/Makefile   | 12 ++++++------
 4 files changed, 15 insertions(+), 15 deletions(-)

Comments

Andrew Cooper March 18, 2025, 5:53 p.m. UTC | #1 
On 18/03/2025 5:35 pm, Roger Pau Monne wrote:
> It's unclear why -N is being used in the first place.  It was added by
> commit 40828c657dd0c back in 2004 without any justification.
>
> When building a PE image it's actually detrimental to forcefully set the
> .text section as writable.  The GNU LD man page contains the following
> warning regarding the -N option:
>
>> Note: Although a writable text section is allowed for PE-COFF targets, it
>> does not conform to the format specification published by Microsoft.
> Remove the usage of -N uniformly on all architectures, assuming that the
> addition was simply done as a copy and paste of the original x86 linking
> rune.
>
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>

-N has been stripped out of other parts of x86 too (hvmloader, notably),
and clearly isn't intended to be used in combination with a linker script.

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Jan Beulich March 19, 2025, 10:20 a.m. UTC | #2 
On 18.03.2025 18:35, Roger Pau Monne wrote:
> It's unclear why -N is being used in the first place.  It was added by
> commit 40828c657dd0c back in 2004 without any justification.

Not really, no. That only moved it from LDFLAGS to an explicit use. Several
hops earlier it looks to be 4676bbf96dc8 (from 2002) where it was introduced,
when the linker script also first appeared.

> When building a PE image it's actually detrimental to forcefully set the
> .text section as writable.  The GNU LD man page contains the following
> warning regarding the -N option:
> 
>> Note: Although a writable text section is allowed for PE-COFF targets, it
>> does not conform to the format specification published by Microsoft.

There's also "Also, do not page-align the data segment, and disable linking
against shared libraries." None of this should be relevant with a script
either, so just to have mentioned it.

> Remove the usage of -N uniformly on all architectures, assuming that the
> addition was simply done as a copy and paste of the original x86 linking
> rune.
> 
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>

With the commit ref corrected:
Reviewed-by: Jan Beulich <jbeulich@suse.com>

Jan
diff mbox series

Patch

diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 4837ad467a06..129a109d6ec5 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -97,19 +97,19 @@  ifeq ($(CONFIG_ARM_64),y)
 endif
 
 $(TARGET)-syms: $(objtree)/prelink.o $(obj)/xen.lds
-	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds -N $< \
+	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds $< \
 	    $(objtree)/common/symbols-dummy.o -o $(dot-target).0
 	$(NM) -pa --format=sysv $(dot-target).0 \
 		| $(objtree)/tools/symbols $(all_symbols) --sysv --sort \
 		> $(dot-target).0.S
 	$(MAKE) $(build)=$(@D) $(dot-target).0.o
-	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds -N $< \
+	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds $< \
 	    $(dot-target).0.o -o $(dot-target).1
 	$(NM) -pa --format=sysv $(dot-target).1 \
 		| $(objtree)/tools/symbols $(all_symbols) --sysv --sort \
 		> $(dot-target).1.S
 	$(MAKE) $(build)=$(@D) $(dot-target).1.o
-	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds -N $< $(build_id_linker) \
+	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds $< $(build_id_linker) \
 	    $(dot-target).1.o -o $@
 	$(NM) -pa --format=sysv $@ \
 		| $(objtree)/tools/symbols --all-symbols --xensyms --sysv --sort \
diff --git a/xen/arch/ppc/Makefile b/xen/arch/ppc/Makefile
index 655d212f6687..cf27bcebb25a 100644
--- a/xen/arch/ppc/Makefile
+++ b/xen/arch/ppc/Makefile
@@ -12,19 +12,19 @@  $(TARGET): $(TARGET)-syms
 	cp -f $< $@
 
 $(TARGET)-syms: $(objtree)/prelink.o $(obj)/xen.lds
-	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds -N $< \
+	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds $< \
 	    $(objtree)/common/symbols-dummy.o -o $(dot-target).0
 	$(NM) -pa --format=sysv $(dot-target).0 \
 		| $(objtree)/tools/symbols $(all_symbols) --sysv --sort \
 		> $(dot-target).0.S
 	$(MAKE) $(build)=$(@D) $(dot-target).0.o
-	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds -N $< \
+	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds $< \
 	    $(dot-target).0.o -o $(dot-target).1
 	$(NM) -pa --format=sysv $(dot-target).1 \
 		| $(objtree)/tools/symbols $(all_symbols) --sysv --sort \
 		> $(dot-target).1.S
 	$(MAKE) $(build)=$(@D) $(dot-target).1.o
-	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds -N $< $(build_id_linker) \
+	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds $< $(build_id_linker) \
 	    $(dot-target).1.o -o $@
 	$(NM) -pa --format=sysv $@ \
 		| $(objtree)/tools/symbols --all-symbols --xensyms --sysv --sort \
diff --git a/xen/arch/riscv/Makefile b/xen/arch/riscv/Makefile
index b0c8270a9947..516f5d505ca8 100644
--- a/xen/arch/riscv/Makefile
+++ b/xen/arch/riscv/Makefile
@@ -16,19 +16,19 @@  $(TARGET): $(TARGET)-syms
 	$(OBJCOPY) -O binary -S $< $@
 
 $(TARGET)-syms: $(objtree)/prelink.o $(obj)/xen.lds
-	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds -N $< \
+	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds $< \
 	    $(objtree)/common/symbols-dummy.o -o $(dot-target).0
 	$(NM) -pa --format=sysv $(dot-target).0 \
 		| $(objtree)/tools/symbols $(all_symbols) --sysv --sort \
 		> $(dot-target).0.S
 	$(MAKE) $(build)=$(@D) $(dot-target).0.o
-	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds -N $< \
+	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds $< \
 	    $(dot-target).0.o -o $(dot-target).1
 	$(NM) -pa --format=sysv $(dot-target).1 \
 		| $(objtree)/tools/symbols $(all_symbols) --sysv --sort \
 		> $(dot-target).1.S
 	$(MAKE) $(build)=$(@D) $(dot-target).1.o
-	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds -N $< $(build_id_linker) \
+	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds $< $(build_id_linker) \
 	    $(dot-target).1.o -o $@
 	$(NM) -pa --format=sysv $@ \
 		| $(objtree)/tools/symbols --all-symbols --xensyms --sysv --sort \
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index f59c9665fdd0..c2f1dcf301d6 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -139,19 +139,19 @@  $(TARGET): $(TARGET)-syms $(efi-y) $(obj)/boot/mkelf32
 CFLAGS-$(XEN_BUILD_EFI) += -DXEN_BUILD_EFI
 
 $(TARGET)-syms: $(objtree)/prelink.o $(obj)/xen.lds
-	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds -N $< $(build_id_linker) \
+	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds $< $(build_id_linker) \
 	    $(objtree)/common/symbols-dummy.o -o $(dot-target).0
 	$(NM) -pa --format=sysv $(dot-target).0 \
 		| $(objtree)/tools/symbols $(all_symbols) --sysv --sort \
 		> $(dot-target).0.S
 	$(MAKE) $(build)=$(@D) $(dot-target).0.o
-	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds -N $< $(build_id_linker) \
+	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds $< $(build_id_linker) \
 	    $(dot-target).0.o -o $(dot-target).1
 	$(NM) -pa --format=sysv $(dot-target).1 \
 		| $(objtree)/tools/symbols $(all_symbols) --sysv --sort $(syms-warn-dup-y) \
 		> $(dot-target).1.S
 	$(MAKE) $(build)=$(@D) $(dot-target).1.o
-	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds -N $< $(build_id_linker) \
+	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds $< $(build_id_linker) \
 	    $(orphan-handling-y) $(dot-target).1.o -o $@
 	$(NM) -pa --format=sysv $@ \
 		| $(objtree)/tools/symbols --all-symbols --xensyms --sysv --sort \
@@ -212,7 +212,7 @@  ifeq ($(CONFIG_DEBUG_INFO),y)
 	$(if $(filter --strip-debug,$(EFI_LDFLAGS)),echo,:) "Will strip debug info from $(@F)"
 endif
 	$(foreach base, $(VIRT_BASE) $(ALT_BASE), \
-	          $(LD) $(call EFI_LDFLAGS,$(base)) -T $(obj)/efi.lds -N $< $(relocs-dummy) \
+	          $(LD) $(call EFI_LDFLAGS,$(base)) -T $(obj)/efi.lds $< $(relocs-dummy) \
 	                $(objtree)/common/symbols-dummy.o $(note_file_option) \
 	                -o $(dot-target).$(base).0 &&) :
 	$(MKRELOC) $(foreach base,$(VIRT_BASE) $(ALT_BASE),$(dot-target).$(base).0) \
@@ -222,7 +222,7 @@  endif
 		> $(dot-target).0s.S
 	$(MAKE) $(build)=$(@D) .$(@F).0r.o .$(@F).0s.o
 	$(foreach base, $(VIRT_BASE) $(ALT_BASE), \
-	          $(LD) $(call EFI_LDFLAGS,$(base)) -T $(obj)/efi.lds -N $< \
+	          $(LD) $(call EFI_LDFLAGS,$(base)) -T $(obj)/efi.lds $< \
 	                $(dot-target).0r.o $(dot-target).0s.o $(note_file_option) \
 	                -o $(dot-target).$(base).1 &&) :
 	$(MKRELOC) $(foreach base,$(VIRT_BASE) $(ALT_BASE),$(dot-target).$(base).1) \
@@ -231,7 +231,7 @@  endif
 		| $(objtree)/tools/symbols $(all_symbols) --sysv --sort \
 		> $(dot-target).1s.S
 	$(MAKE) $(build)=$(@D) .$(@F).1r.o .$(@F).1s.o
-	$(LD) $(call EFI_LDFLAGS,$(VIRT_BASE)) -T $(obj)/efi.lds -N $< \
+	$(LD) $(call EFI_LDFLAGS,$(VIRT_BASE)) -T $(obj)/efi.lds $< \
 	      $(dot-target).1r.o $(dot-target).1s.o $(orphan-handling-y) \
 	      $(note_file_option) -o $@
 	$(NM) -pa --format=sysv $@ \