[PATCH v2 2/3] ia64: thin archives fix linking

[PATCH v2 2/3] ia64: thin archives fix linking

[Nicholas Piggin]

The VDSO symbols can't be linked into built-in.o when building with
thin archives, so change this to linking a new object file that is
included into the built-in.o.

Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: linux-ia64@vger.kernel.org
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/ia64/kernel/Makefile.gate | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/ia64/kernel/Makefile.gate b/arch/ia64/kernel/Makefile.gate
index a32903ada016..e20c711c2b1e 100644
--- a/arch/ia64/kernel/Makefile.gate
+++ b/arch/ia64/kernel/Makefile.gate
@@ -2,7 +2,9 @@
 
 targets += gate.so gate-syms.o
 
-extra-y += gate.so gate-syms.o gate.lds gate.o
+obj-y += gate-syms.o
+
+extra-y += gate.so gate.lds gate.o
 
 CPPFLAGS_gate.lds := -P -C -U$(ARCH)
 
@@ -14,12 +16,12 @@ GATECFLAGS_gate.so = -shared -s -Wl,-soname=linux-gate.so.1 \
 $(obj)/gate.so: $(obj)/gate.lds $(obj)/gate.o FORCE
 	$(call if_changed,gate)
 
-$(obj)/built-in.o: $(obj)/gate-syms.o
-$(obj)/built-in.o: ld_flags += -R $(obj)/gate-syms.o
+# create an object file to resolve gate symbols
+quiet_cmd_gate_syms = GATESYM $@
+      cmd_gate_syms = $(LD) -r -T $(obj)/gate.lds -R $(obj)/gate.o -o $@
 
-GATECFLAGS_gate-syms.o = -r
 $(obj)/gate-syms.o: $(obj)/gate.lds $(obj)/gate.o FORCE
-	$(call if_changed,gate)
+	$(call if_changed,gate_syms)
 
 # gate-data.o contains the gate DSO image as data in section .data..gate.
 # We must build gate.so before we can assemble it.
-- 
2.11.0

Re: [PATCH v2 2/3] ia64: thin archives fix linking

[Masahiro Yamada]

Hi Nicholas,


2017-06-22 21:39 GMT+09:00 Nicholas Piggin <npiggin@gmail.com>:
> The VDSO symbols can't be linked into built-in.o when building with
> thin archives, so change this to linking a new object file that is
> included into the built-in.o.
>
> Cc: Tony Luck <tony.luck@intel.com>
> Cc: Fenghua Yu <fenghua.yu@intel.com>
> Cc: linux-ia64@vger.kernel.org
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>  arch/ia64/kernel/Makefile.gate | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/arch/ia64/kernel/Makefile.gate b/arch/ia64/kernel/Makefile.gate
> index a32903ada016..e20c711c2b1e 100644
> --- a/arch/ia64/kernel/Makefile.gate
> +++ b/arch/ia64/kernel/Makefile.gate
> @@ -2,7 +2,9 @@
>
>  targets += gate.so gate-syms.o
>
> -extra-y += gate.so gate-syms.o gate.lds gate.o
> +obj-y += gate-syms.o
> +
> +extra-y += gate.so gate.lds gate.o
>
>  CPPFLAGS_gate.lds := -P -C -U$(ARCH)
>
> @@ -14,12 +16,12 @@ GATECFLAGS_gate.so = -shared -s -Wl,-soname=linux-gate.so.1 \
>  $(obj)/gate.so: $(obj)/gate.lds $(obj)/gate.o FORCE
>         $(call if_changed,gate)
>
> -$(obj)/built-in.o: $(obj)/gate-syms.o
> -$(obj)/built-in.o: ld_flags += -R $(obj)/gate-syms.o
> +# create an object file to resolve gate symbols
> +quiet_cmd_gate_syms = GATESYM $@
> +      cmd_gate_syms = $(LD) -r -T $(obj)/gate.lds -R $(obj)/gate.o -o $@
>
> -GATECFLAGS_gate-syms.o = -r
>  $(obj)/gate-syms.o: $(obj)/gate.lds $(obj)/gate.o FORCE
> -       $(call if_changed,gate)
> +       $(call if_changed,gate_syms)
>
>  # gate-data.o contains the gate DSO image as data in section .data..gate.
>  # We must build gate.so before we can assemble it.
> --
> 2.11.0


Build test passed, but the symbol table seems different.

For example,  __kernel_sigtramp will change
a000000000040740 T __kernel_sigtramp
 to
0000000000000020 A __kernel_sigtramp






Without this patch,

$ ia64-linux-nm -n arch/ia64/kernel/gate-syms.o
a000000000000600 D __start_gate_mckinley_e9_patchlist
a000000000000604 D __end_gate_mckinley_e9_patchlist
a000000000000604 D __end_gate_vtop_patchlist
a000000000000604 D __start_gate_fsyscall_patchlist
a000000000000604 D __start_gate_vtop_patchlist
a000000000000608 D __end_gate_fsyscall_patchlist
a000000000000608 D __start_gate_brl_fsys_bubble_down_patchlist
a00000000000060c D __end_gate_brl_fsys_bubble_down_patchlist
a000000000040720 T __kernel_syscall_via_break
a000000000040740 T __kernel_sigtramp
a000000000040770 t back_from_setup_rbs
a000000000040830 t back_from_restore_rbs
a0000000000408a0 t setup_rbs
a000000000040900 t restore_rbs
a000000000040a00 T __kernel_syscall_via_epc

$ ia64-linux-nm -n arch/ia64/kernel/built-in.o | grep  __kernel_sigtramp
a000000000040740 A __kernel_sigtramp


With this patch,

$ ia64-linux-nm -n arch/ia64/kernel/gate-syms.o
0000000000000000 A __kernel_syscall_via_break
0000000000000020 A __kernel_sigtramp
00000000000002e0 A __kernel_syscall_via_epc
a000000000000600 D __end_gate_brl_fsys_bubble_down_patchlist
a000000000000600 D __end_gate_fsyscall_patchlist
a000000000000600 D __end_gate_mckinley_e9_patchlist
a000000000000600 D __end_gate_vtop_patchlist
a000000000000600 D __start_gate_brl_fsys_bubble_down_patchlist
a000000000000600 D __start_gate_fsyscall_patchlist
a000000000000600 D __start_gate_mckinley_e9_patchlist
a000000000000600 D __start_gate_vtop_patchlist

$ ia64-linux-nm -n arch/ia64/kernel/built-in.o | grep __kernel_sigtramp
0000000000000020 A __kernel_sigtramp


Could you check it?




-- 
Best Regards
Masahiro Yamada

Re: [PATCH v2 2/3] ia64: thin archives fix linking

[Nicholas Piggin]

On Fri, 23 Jun 2017 18:56:32 +0900
Masahiro Yamada <yamada.masahiro@socionext.com> wrote:

> Hi Nicholas,
> 
> 
> 2017-06-22 21:39 GMT+09:00 Nicholas Piggin <npiggin@gmail.com>:


> Without this patch,
> 
> $ ia64-linux-nm -n arch/ia64/kernel/gate-syms.o
> a000000000000600 D __start_gate_mckinley_e9_patchlist
> a000000000000604 D __end_gate_mckinley_e9_patchlist
> a000000000000604 D __end_gate_vtop_patchlist
> a000000000000604 D __start_gate_fsyscall_patchlist
> a000000000000604 D __start_gate_vtop_patchlist
> a000000000000608 D __end_gate_fsyscall_patchlist
> a000000000000608 D __start_gate_brl_fsys_bubble_down_patchlist
> a00000000000060c D __end_gate_brl_fsys_bubble_down_patchlist
> a000000000040720 T __kernel_syscall_via_break
> a000000000040740 T __kernel_sigtramp
> a000000000040770 t back_from_setup_rbs
> a000000000040830 t back_from_restore_rbs
> a0000000000408a0 t setup_rbs
> a000000000040900 t restore_rbs
> a000000000040a00 T __kernel_syscall_via_epc
> 
> $ ia64-linux-nm -n arch/ia64/kernel/built-in.o | grep  __kernel_sigtramp
> a000000000040740 A __kernel_sigtramp
> 
> 
> With this patch,
> 
> $ ia64-linux-nm -n arch/ia64/kernel/gate-syms.o
> 0000000000000000 A __kernel_syscall_via_break

> 0000000000000020 A __kernel_sigtramp
> 00000000000002e0 A __kernel_syscall_via_epc
> a000000000000600 D __end_gate_brl_fsys_bubble_down_patchlist
> a000000000000600 D __end_gate_fsyscall_patchlist
> a000000000000600 D __end_gate_mckinley_e9_patchlist
> a000000000000600 D __end_gate_vtop_patchlist
> a000000000000600 D __start_gate_brl_fsys_bubble_down_patchlist
> a000000000000600 D __start_gate_fsyscall_patchlist
> a000000000000600 D __start_gate_mckinley_e9_patchlist
> a000000000000600 D __start_gate_vtop_patchlist
> 
> $ ia64-linux-nm -n arch/ia64/kernel/built-in.o | grep __kernel_sigtramp
> 0000000000000020 A __kernel_sigtramp
> 
> 
> Could you check it?

Sorry about this, thank you for catching it.

This needs a dummy .o file as well. It seems we cannot do both -T and -R
operations in one step. This patch follows more like sh and tile fixes.

Thanks,
Nick

---
 arch/ia64/kernel/Makefile.gate | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/ia64/kernel/Makefile.gate b/arch/ia64/kernel/Makefile.gate
index a32903ada016..e8ca862e7b21 100644
--- a/arch/ia64/kernel/Makefile.gate
+++ b/arch/ia64/kernel/Makefile.gate
@@ -1,8 +1,10 @@
 # The gate DSO image is built using a special linker script.
 
-targets += gate.so gate-syms.o
+targets += gate.so gate-syms.o gate-dummy.o
 
-extra-y += gate.so gate-syms.o gate.lds gate.o
+obj-y += gate-syms.o
+
+extra-y += gate.so gate.lds gate.o
 
 CPPFLAGS_gate.lds := -P -C -U$(ARCH)
 
@@ -14,13 +16,17 @@ GATECFLAGS_gate.so = -shared -s -Wl,-soname=linux-gate.so.1 \
 $(obj)/gate.so: $(obj)/gate.lds $(obj)/gate.o FORCE
 	$(call if_changed,gate)
 
-$(obj)/built-in.o: $(obj)/gate-syms.o
-$(obj)/built-in.o: ld_flags += -R $(obj)/gate-syms.o
+# create an object file to resolve gate symbols
+quiet_cmd_gate_syms = GATESYM $@
+      cmd_gate_syms = $(LD) -r -R $(obj)/gate-dummy.o -o $@
 
-GATECFLAGS_gate-syms.o = -r
-$(obj)/gate-syms.o: $(obj)/gate.lds $(obj)/gate.o FORCE
+GATECFLAGS_gate-dummy.o = -r
+$(obj)/gate-dummy.o: $(obj)/gate.lds $(obj)/gate.o FORCE
 	$(call if_changed,gate)
 
+$(obj)/gate-syms.o: $(obj)/gate-dummy.o FORCE
+	$(call if_changed,gate_syms)
+
 # gate-data.o contains the gate DSO image as data in section .data..gate.
 # We must build gate.so before we can assemble it.
 # Note: kbuild does not track this dependency due to usage of .incbin
-- 
2.11.0

Re: [PATCH v2 2/3] ia64: thin archives fix linking

[Masahiro Yamada]

2017-06-23 22:44 GMT+09:00 Nicholas Piggin <npiggin@gmail.com>:
> On Fri, 23 Jun 2017 18:56:32 +0900
> Masahiro Yamada <yamada.masahiro@socionext.com> wrote:
>
>> Hi Nicholas,
>>
>>
>> 2017-06-22 21:39 GMT+09:00 Nicholas Piggin <npiggin@gmail.com>:
>
>
>> Without this patch,
>>
>> $ ia64-linux-nm -n arch/ia64/kernel/gate-syms.o
>> a000000000000600 D __start_gate_mckinley_e9_patchlist
>> a000000000000604 D __end_gate_mckinley_e9_patchlist
>> a000000000000604 D __end_gate_vtop_patchlist
>> a000000000000604 D __start_gate_fsyscall_patchlist
>> a000000000000604 D __start_gate_vtop_patchlist
>> a000000000000608 D __end_gate_fsyscall_patchlist
>> a000000000000608 D __start_gate_brl_fsys_bubble_down_patchlist
>> a00000000000060c D __end_gate_brl_fsys_bubble_down_patchlist
>> a000000000040720 T __kernel_syscall_via_break
>> a000000000040740 T __kernel_sigtramp
>> a000000000040770 t back_from_setup_rbs
>> a000000000040830 t back_from_restore_rbs
>> a0000000000408a0 t setup_rbs
>> a000000000040900 t restore_rbs
>> a000000000040a00 T __kernel_syscall_via_epc
>>
>> $ ia64-linux-nm -n arch/ia64/kernel/built-in.o | grep  __kernel_sigtramp
>> a000000000040740 A __kernel_sigtramp
>>
>>
>> With this patch,
>>
>> $ ia64-linux-nm -n arch/ia64/kernel/gate-syms.o
>> 0000000000000000 A __kernel_syscall_via_break
>
>> 0000000000000020 A __kernel_sigtramp
>> 00000000000002e0 A __kernel_syscall_via_epc
>> a000000000000600 D __end_gate_brl_fsys_bubble_down_patchlist
>> a000000000000600 D __end_gate_fsyscall_patchlist
>> a000000000000600 D __end_gate_mckinley_e9_patchlist
>> a000000000000600 D __end_gate_vtop_patchlist
>> a000000000000600 D __start_gate_brl_fsys_bubble_down_patchlist
>> a000000000000600 D __start_gate_fsyscall_patchlist
>> a000000000000600 D __start_gate_mckinley_e9_patchlist
>> a000000000000600 D __start_gate_vtop_patchlist
>>
>> $ ia64-linux-nm -n arch/ia64/kernel/built-in.o | grep __kernel_sigtramp
>> 0000000000000020 A __kernel_sigtramp
>>
>>
>> Could you check it?
>
> Sorry about this, thank you for catching it.
>
> This needs a dummy .o file as well. It seems we cannot do both -T and -R
> operations in one step. This patch follows more like sh and tile fixes.
>
> Thanks,
> Nick
>
> ---
>  arch/ia64/kernel/Makefile.gate | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/arch/ia64/kernel/Makefile.gate b/arch/ia64/kernel/Makefile.gate
> index a32903ada016..e8ca862e7b21 100644
> --- a/arch/ia64/kernel/Makefile.gate
> +++ b/arch/ia64/kernel/Makefile.gate
> @@ -1,8 +1,10 @@
>  # The gate DSO image is built using a special linker script.
>
> -targets += gate.so gate-syms.o
> +targets += gate.so gate-syms.o gate-dummy.o
>
> -extra-y += gate.so gate-syms.o gate.lds gate.o
> +obj-y += gate-syms.o
> +
> +extra-y += gate.so gate.lds gate.o
>
>  CPPFLAGS_gate.lds := -P -C -U$(ARCH)
>
> @@ -14,13 +16,17 @@ GATECFLAGS_gate.so = -shared -s -Wl,-soname=linux-gate.so.1 \
>  $(obj)/gate.so: $(obj)/gate.lds $(obj)/gate.o FORCE
>         $(call if_changed,gate)
>
> -$(obj)/built-in.o: $(obj)/gate-syms.o
> -$(obj)/built-in.o: ld_flags += -R $(obj)/gate-syms.o
> +# create an object file to resolve gate symbols
> +quiet_cmd_gate_syms = GATESYM $@
> +      cmd_gate_syms = $(LD) -r -R $(obj)/gate-dummy.o -o $@
>
> -GATECFLAGS_gate-syms.o = -r
> -$(obj)/gate-syms.o: $(obj)/gate.lds $(obj)/gate.o FORCE
> +GATECFLAGS_gate-dummy.o = -r
> +$(obj)/gate-dummy.o: $(obj)/gate.lds $(obj)/gate.o FORCE
>         $(call if_changed,gate)
>
> +$(obj)/gate-syms.o: $(obj)/gate-dummy.o FORCE
> +       $(call if_changed,gate_syms)
> +
>  # gate-data.o contains the gate DSO image as data in section .data..gate.
>  # We must build gate.so before we can assemble it.
>  # Note: kbuild does not track this dependency due to usage of .incbin
> --


I replaced the patch.  Thanks!


I locally changed to the following part to not repeat gate-dummy.o





diff --git a/arch/ia64/kernel/Makefile.gate b/arch/ia64/kernel/Makefile.gate
index e8ca862..8cd125a 100644
--- a/arch/ia64/kernel/Makefile.gate
+++ b/arch/ia64/kernel/Makefile.gate
@@ -18,7 +18,7 @@ $(obj)/gate.so: $(obj)/gate.lds $(obj)/gate.o FORCE

 # create an object file to resolve gate symbols
 quiet_cmd_gate_syms = GATESYM $@
-      cmd_gate_syms = $(LD) -r -R $(obj)/gate-dummy.o -o $@
+      cmd_gate_syms = $(LD) -r -o $@ -R $<

 GATECFLAGS_gate-dummy.o = -r
 $(obj)/gate-dummy.o: $(obj)/gate.lds $(obj)/gate.o FORCE




-- 
Best Regards
Masahiro Yamada