Re: crypto: p10-aes-gcm - Add asm markings necessary for kernel code

[Sathvika Vasireddy]

Hi Stephen,

On 18/01/23 08:34, Stephen Rothwell wrote:
> Hi Herbert,
>
> On Tue, 17 Jan 2023 15:26:24 +0800 Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote:
> > On Tue, Jan 17, 2023 at 02:47:47PM +1100, Stephen Rothwell wrote:
> > > Hi all,
> > >
> > > After merging the crypto tree, today's linux-next build (powerpc
> > > pseries_le_defconfig) failed like this:
> > >
> > > arch/powerpc/crypto/p10_aes_gcm.o: warning: objtool: .text+0x884: unannotated intra-function call
> > > arch/powerpc/crypto/aesp8-ppc.o: warning: objtool: aes_p8_set_encrypt_key+0x44: unannotated intra-function call
> > > ld: arch/powerpc/crypto/p10_aes_gcm.o: ABI version 1 is not compatible with ABI version 2 output
> > > ld: failed to merge target specific data of file arch/powerpc/crypto/p10_aes_gcm.o
> > >
> > > Caused by commit
> > >
> > >    ca68a96c37eb ("crypto: p10-aes-gcm - An accelerated AES/GCM stitched implementation")
> > >
> > > I have applied the following hack for today.
> > Thanks Stephen, I'm going to update the previous fix as follows:
> I still get:
>
> arch/powerpc/crypto/aesp8-ppc.o: warning: objtool: aes_p8_set_encrypt_key+0x44: unannotated intra-function call
>
> from the powerpc pseries_le_defconfig build (which is otherwise ok).

Warnings [1], [2], and [3] are seen with pseries_le_defconfig.

[1] - arch/powerpc/crypto/aesp8-ppc.o: warning: objtool: aes_p8_set_encrypt_key+0x44: unannotated intra-function call
[2] - arch/powerpc/crypto/aesp8-ppc.o: warning: objtool: .text+0x2448: unannotated intra-function call
[3] - arch/powerpc/crypto/aesp8-ppc.o: warning: objtool: .text+0x2d68: unannotated intra-function call

Given that there are no calls to _mcount, one way to address this warning, is by skipping objtool from running on arch/powerpc/crypto/aesp8-ppc.o file.
The below diff works for me.

=====
diff --git a/arch/powerpc/crypto/Makefile b/arch/powerpc/crypto/Makefile
index 5b8252013abd..d00664c8d761 100644
--- a/arch/powerpc/crypto/Makefile
+++ b/arch/powerpc/crypto/Makefile
@@ -31,3 +31,5 @@ targets += aesp8-ppc.S ghashp8-ppc.S
 
 $(obj)/aesp8-ppc.S $(obj)/ghashp8-ppc.S: $(obj)/%.S: $(src)/%.pl FORCE
        $(call if_changed,perl)
+
+OBJECT_FILES_NON_STANDARD_aesp8-ppc.o := y
=====


The other way to fix these warnings is by using ANNOTATE_INTRA_FUNCTION_CALL macro to indicate that the branch target is valid. And, by annotating symbols with SYM_FUNC_START_LOCAL and SYM_FUNC_END macros.
The below diff works for me:

=====
diff --git a/arch/powerpc/crypto/aesp8-ppc.pl b/arch/powerpc/crypto/aesp8-ppc.pl
index cdbcf6e13efc..355e0036869a 100644
--- a/arch/powerpc/crypto/aesp8-ppc.pl
+++ b/arch/powerpc/crypto/aesp8-ppc.pl
@@ -80,6 +80,9 @@
 # POWER8[le]   3.96/0.72       0.74    1.1
 # POWER8[be]   3.75/0.65       0.66    1.0
 
+print "#include <linux/objtool.h>\n";
+print "#include <linux/linkage.h>\n";
+
 $flavour = shift;
 
 if ($flavour =~ /64/) {
@@ -185,7 +188,8 @@ Lset_encrypt_key:
        lis             r0,0xfff0
        mfspr           $vrsave,256
        mtspr           256,r0
-
+
+       ANNOTATE_INTRA_FUNCTION_CALL
        bl              Lconsts
        mtlr            r11
 
@@ -3039,7 +3043,7 @@ Lxts_enc6x_ret:
        .long           0
 
 .align 5
-_aesp8_xts_enc5x:
+SYM_FUNC_START_LOCAL(_aesp8_xts_enc5x)
        vcipher         $out0,$out0,v24
        vcipher         $out1,$out1,v24
        vcipher         $out2,$out2,v24
@@ -3121,6 +3125,7 @@ _aesp8_xts_enc5x:
        blr
         .long          0
         .byte          0,12,0x14,0,0,0,0,0
+SYM_FUNC_END(_aesp8_xts_enc5x)
 
 .align 5
 _aesp8_xts_decrypt6x:
@@ -3727,7 +3732,7 @@ Lxts_dec6x_ret:
        .long           0
 
 .align 5
-_aesp8_xts_dec5x:
+SYM_FUNC_START_LOCAL(_aesp8_xts_dec5x)
        vncipher        $out0,$out0,v24
        vncipher        $out1,$out1,v24
        vncipher        $out2,$out2,v24
@@ -3809,6 +3814,7 @@ _aesp8_xts_dec5x:
        blr
         .long          0
         .byte          0,12,0x14,0,0,0,0,0
+SYM_FUNC_END(_aesp8_xts_dec5x)
 ___
 }}     }}}

=====


Thanks,
Sathvika