Re: [RFC PATCH 0/3] grub powerpc64 little-endian enablement

[Andrei Borzenkov <arvidjaar@gmail.com>]

В Thu, 25 Sep 2014 19:48:04 -0300
Paulo Flabiano Smorigo <pfsmorigo@linux.vnet.ibm.com> пишет:

> Sun, Sep 21, 2014 at 06:24:25PM +0400, Andrei Borzenkov wrote:
> > В Sun, 21 Sep 2014 17:58:44 +0400
> > Andrei Borzenkov <arvidjaar@gmail.com> пишет:
> > 
> > > В Thu, 28 Aug 2014 16:56:02 -0300
> > > Paulo Flabiano Smorigo <pfsmorigo@linux.vnet.ibm.com> пишет:
> > > 
> > > > From: Paulo Flabiano Smorigo <pfsmorigo@br.ibm.com>
> > > > 
> > > > Hi,
> > > > 
> > > > At the beginning of the year we provide a patchset that enabled GRUB for
> > > > little-endian PowerPC. Our approach at the time was to build GRUB itself and
> > > > its tools in 64-bit little-endian. One of the reasons of build in 64-bit is
> > > > to avoid 32-bit dependencies in the distro and build a system entirely 64-bit.
> > > > 
> > > > This patchset was not welcomed at the time because it would bring a
> > > > high-maintainance-cost, without real gain since it could just be cross-compiled.
> > > > 
> > > > After that, Brent Baude, Vladmir (phcoder) and I started to work in a solution
> > > > that would cross-compile but without 32-bit dependencies. This patchset is the
> > > > result of this new approach. It's based on the work of Brent Baude, Vladimir
> > > > (phcoder), and Tomohiro.
> > > > 
> > > > It can be devided in two parts:
> > > > 
> > > >   1) Skip libgcc dependency just for ppc64el (patch 1 and 2);
> > > >   2) Check elf endianess and byteswap if necessary (patch 3);
> > > > 
> > > > The result is GRUB itself in 32-bit BE and its tools in 64-bit LE. This solution
> > > > satisfies the needs of the distros. I tested it in three different distros, in
> > > > both endianess and it's fine.
> > > > 
> > > 
> > > Unfortunately I'm still not able to boot this version on QEMU. I build
> > > on openSUSE for three acrhs - ppc, ppc64, ppc64le. First two are OK and
> > > boot successfully. Third one does not work - it ends up in exception. I
> > > get initial GRUB greeting and that's all.
> > > 
> > > Same problem I got with Vladimir libgcc patch series.
> > > 
> > > It could be toolkit issue of course; but still it would need fixing
> > > before we can merge it.
> > > 
> > > Could you help in debugging this issue? I have near to zero experience
> > > with PPC; I can do what you tell me, but not much more.
> > > 
> > > I run it with
> > > 
> > > qemu-system-ppc64 -M pseries -cdrom /tmp/grub2-ppc64le.iso -boot d
> > > 
> > > Attached is screenshot of error.
> > > 
> > > 
> > 
> > And here is the difference in generated code in case it helps (one
> > random module as example) ...
> > 
> > --- /tmp/a1	2014-09-21 18:19:59.316494117 +0400
> > +++ /tmp/a2	2014-09-21 18:20:06.169398736 +0400
> > @@ -1,5 +1,5 @@
> >  
> > -usr.ppc/lib/grub2/powerpc-ieee1275/ext2.mod:     file format elf32-powerpc
> > +usr.ppc64le/lib/grub2/powerpc-ieee1275/ext2.mod:     file format elf32-powerpc
> >  
> >  
> >  Disassembly of section .text:
> > @@ -18,15 +18,15 @@ Disassembly of section .text:
> >    28:	38 21 00 10 	addi    r1,r1,16
> >    2c:	7c 08 03 a6 	mtlr    r0
> >    30:	4e 80 00 20 	blr
> > -  34:	94 21 ff a0 	stwu    r1,-96(r1)
> > +  34:	94 21 ff 90 	stwu    r1,-112(r1)
> >    38:	38 e3 00 28 	addi    r7,r3,40
> >    3c:	7d 80 00 26 	mfcr    r12
> >    40:	39 23 00 14 	addi    r9,r3,20
> >    44:	7c 08 02 a6 	mflr    r0
> >    48:	39 43 00 18 	addi    r10,r3,24
> > -  4c:	bf 61 00 4c 	stmw    r27,76(r1)
> > -  50:	90 01 00 64 	stw     r0,100(r1)
> > -  54:	91 81 00 48 	stw     r12,72(r1)
> > +  4c:	bf 61 00 5c 	stmw    r27,92(r1)
> > +  50:	90 01 00 74 	stw     r0,116(r1)
> > +  54:	91 81 00 58 	stw     r12,88(r1)
> >    58:	3b c4 ff ff 	addi    r30,r4,-1
> >    5c:	7c 7f 1b 78 	mr      r31,r3
> >    60:	7c bc 2b 78 	mr      r28,r5
> > @@ -103,10 +103,10 @@ Disassembly of section .text:
> >   17c:	2f 83 00 00 	cmpwi   cr7,r3,0
> >   180:	41 9e 00 08 	beq     cr7,188 <grub_mod_init-0xd50>
> >   184:	81 3d 00 00 	lwz     r9,0(r29)
> > - 188:	81 81 00 48 	lwz     r12,72(r1)
> > - 18c:	39 61 00 60 	addi    r11,r1,96
> > + 188:	81 81 00 58 	lwz     r12,88(r1)
> > + 18c:	39 61 00 70 	addi    r11,r1,112
> >   190:	7d 23 4b 78 	mr      r3,r9
> > - 194:	7d 80 81 20 	mtcrf   8,r12
> > + 194:	7d 90 81 20 	mtocrf  8,r12
> >   198:	48 00 00 00 	b       198 <grub_mod_init-0xd40>
> >   19c:	94 21 ff e0 	stwu    r1,-32(r1)
> >   1a0:	7c 08 02 a6 	mflr    r0
> > @@ -234,10 +234,10 @@ Disassembly of section .text:
> >   388:	39 61 00 20 	addi    r11,r1,32
> >   38c:	80 69 00 00 	lwz     r3,0(r9)
> >   390:	48 00 00 00 	b       390 <grub_mod_init-0xb48>
> > - 394:	94 21 ff b0 	stwu    r1,-80(r1)
> > + 394:	94 21 ff a0 	stwu    r1,-96(r1)
> >   398:	7c 08 02 a6 	mflr    r0
> > - 39c:	be 61 00 1c 	stmw    r19,28(r1)
> > - 3a0:	90 01 00 54 	stw     r0,84(r1)
> > + 39c:	be 61 00 2c 	stmw    r19,44(r1)
> > + 3a0:	90 01 00 64 	stw     r0,100(r1)
> >   3a4:	7c df 33 78 	mr      r31,r6
> >   3a8:	7c be 2b 78 	mr      r30,r5
> >   3ac:	83 63 00 00 	lwz     r27,0(r3)
> > @@ -489,12 +489,12 @@ Disassembly of section .text:
> >   784:	48 00 00 0c 	b       790 <grub_mod_init-0x748>
> >   788:	7f c3 f3 78 	mr      r3,r30
> >   78c:	7f e4 fb 78 	mr      r4,r31
> > - 790:	39 61 00 50 	addi    r11,r1,80
> > + 790:	39 61 00 60 	addi    r11,r1,96
> >   794:	48 00 00 00 	b       794 <grub_mod_init-0x744>
> > - 798:	94 21 ff e0 	stwu    r1,-32(r1)
> > + 798:	94 21 ff d0 	stwu    r1,-48(r1)
> >   79c:	7c 08 02 a6 	mflr    r0
> > - 7a0:	bf a1 00 14 	stmw    r29,20(r1)
> > - 7a4:	90 01 00 24 	stw     r0,36(r1)
> > + 7a0:	bf a1 00 24 	stmw    r29,36(r1)
> > + 7a4:	90 01 00 34 	stw     r0,52(r1)
> >   7a8:	3f a0 00 00 	lis     r29,0
> >   7ac:	7c 9e 23 78 	mr      r30,r4
> >   7b0:	83 e3 00 00 	lwz     r31,0(r3)
> > @@ -525,7 +525,7 @@ Disassembly of section .text:
> >   814:	7f e3 fb 78 	mr      r3,r31
> >   818:	48 00 00 01 	bl      818 <grub_mod_init-0x6c0>
> >   81c:	3d 20 00 00 	lis     r9,0
> > - 820:	39 61 00 20 	addi    r11,r1,32
> > + 820:	39 61 00 30 	addi    r11,r1,48
> >   824:	80 69 00 00 	lwz     r3,0(r9)
> >   828:	48 00 00 00 	b       828 <grub_mod_init-0x6b0>
> >   82c:	94 21 ff e0 	stwu    r1,-32(r1)
> > @@ -555,13 +555,13 @@ Disassembly of section .text:
> >   88c:	39 61 00 20 	addi    r11,r1,32
> >   890:	80 69 00 00 	lwz     r3,0(r9)
> >   894:	48 00 00 00 	b       894 <grub_mod_init-0x644>
> > - 898:	94 21 ff d0 	stwu    r1,-48(r1)
> > + 898:	94 21 ff c0 	stwu    r1,-64(r1)
> >   89c:	7c 6b 1b 78 	mr      r11,r3
> >   8a0:	7c 08 02 a6 	mflr    r0
> >   8a4:	7c a6 2b 78 	mr      r6,r5
> >   8a8:	38 ab 00 08 	addi    r5,r11,8
> > - 8ac:	bf c1 00 28 	stmw    r30,40(r1)
> > - 8b0:	90 01 00 34 	stw     r0,52(r1)
> > + 8ac:	bf c1 00 38 	stmw    r30,56(r1)
> > + 8b0:	90 01 00 44 	stw     r0,68(r1)
> >   8b4:	3b cb 00 70 	addi    r30,r11,112
> >   8b8:	7c 80 23 78 	mr      r0,r4
> >   8bc:	80 63 00 00 	lwz     r3,0(r3)
> > @@ -584,7 +584,7 @@ Disassembly of section .text:
> >   900:	7d 64 5b 78 	mr      r4,r11
> >   904:	7c 05 03 78 	mr      r5,r0
> >   908:	48 00 00 01 	bl      908 <grub_mod_init-0x5d0>
> > - 90c:	39 61 00 30 	addi    r11,r1,48
> > + 90c:	39 61 00 40 	addi    r11,r1,64
> >   910:	48 00 00 00 	b       910 <grub_mod_init-0x5c8>
> >   914:	7c 68 1b 78 	mr      r8,r3
> >   918:	80 63 00 44 	lwz     r3,68(r3)
> > @@ -596,10 +596,10 @@ Disassembly of section .text:
> >   930:	81 08 00 14 	lwz     r8,20(r8)
> >   934:	38 63 01 5c 	addi    r3,r3,348
> >   938:	4b ff ff 60 	b       898 <grub_mod_init-0x640>
> > - 93c:	94 21 fe c0 	stwu    r1,-320(r1)
> > + 93c:	94 21 fe b0 	stwu    r1,-336(r1)
> >   940:	7c 08 02 a6 	mflr    r0
> > - 944:	be c1 01 18 	stmw    r22,280(r1)
> > - 948:	90 01 01 44 	stw     r0,324(r1)
> > + 944:	be c1 01 28 	stmw    r22,296(r1)
> > + 948:	90 01 01 54 	stw     r0,340(r1)
> >   94c:	7c 7f 1b 78 	mr      r31,r3
> >   950:	7c 9a 23 78 	mr      r26,r4
> >   954:	7c b9 2b 78 	mr      r25,r5
> > @@ -715,7 +715,7 @@ Disassembly of section .text:
> >   b0c:	2f 83 00 00 	cmpwi   cr7,r3,0
> >   b10:	41 9e fe b0 	beq     cr7,9c0 <grub_mod_init-0x518>
> >   b14:	38 60 00 01 	li      r3,1
> > - b18:	39 61 01 40 	addi    r11,r1,320
> > + b18:	39 61 01 50 	addi    r11,r1,336
> >   b1c:	48 00 00 00 	b       b1c <grub_mod_init-0x3bc>
> >   b20:	94 21 ff d0 	stwu    r1,-48(r1)
> >   b24:	39 20 00 00 	li      r9,0
> > @@ -769,10 +769,10 @@ Disassembly of section .text:
> >   be4:	39 61 00 30 	addi    r11,r1,48
> >   be8:	80 7f 00 00 	lwz     r3,0(r31)
> >   bec:	48 00 00 00 	b       bec <grub_mod_init-0x2ec>
> > - bf0:	94 21 ff f0 	stwu    r1,-16(r1)
> > + bf0:	94 21 ff e0 	stwu    r1,-32(r1)
> >   bf4:	7c 08 02 a6 	mflr    r0
> > - bf8:	bf c1 00 08 	stmw    r30,8(r1)
> > - bfc:	90 01 00 14 	stw     r0,20(r1)
> > + bf8:	bf c1 00 18 	stmw    r30,24(r1)
> > + bfc:	90 01 00 24 	stw     r0,36(r1)
> >   c00:	7c 7f 1b 78 	mr      r31,r3
> >   c04:	81 23 00 88 	lwz     r9,136(r3)
> >   c08:	2f 89 00 00 	cmpwi   cr7,r9,0
> > @@ -821,7 +821,7 @@ Disassembly of section .text:
> >   cb4:	7d 20 fc 2c 	lwbrx   r9,0,r31
> >   cb8:	7f c3 f3 78 	mr      r3,r30
> >   cbc:	7d 5e 49 ae 	stbx    r10,r30,r9
> > - cc0:	39 61 00 10 	addi    r11,r1,16
> > + cc0:	39 61 00 20 	addi    r11,r1,32
> >   cc4:	48 00 00 00 	b       cc4 <grub_mod_init-0x214>
> >   cc8:	94 21 ff d0 	stwu    r1,-48(r1)
> >   ccc:	7c 08 02 a6 	mflr    r0
> > @@ -878,14 +878,14 @@ Disassembly of section .text:
> >   d98:	4e 80 04 21 	bctrl
> >   d9c:	39 61 00 30 	addi    r11,r1,48
> >   da0:	48 00 00 00 	b       da0 <grub_mod_init-0x138>
> > - da4:	94 21 ff d0 	stwu    r1,-48(r1)
> > + da4:	94 21 ff c0 	stwu    r1,-64(r1)
> >   da8:	39 20 00 00 	li      r9,0
> >   dac:	7c 08 02 a6 	mflr    r0
> > - db0:	bf 41 00 18 	stmw    r26,24(r1)
> > + db0:	bf 41 00 28 	stmw    r26,40(r1)
> >   db4:	3f a0 00 00 	lis     r29,0
> >   db8:	7c 7f 1b 78 	mr      r31,r3
> >   dbc:	80 7d 00 00 	lwz     r3,0(r29)
> > - dc0:	90 01 00 34 	stw     r0,52(r1)
> > + dc0:	90 01 00 44 	stw     r0,68(r1)
> >   dc4:	7c 9a 23 78 	mr      r26,r4
> >   dc8:	91 21 00 08 	stw     r9,8(r1)
> >   dcc:	48 00 00 01 	bl      dcc <grub_mod_init-0x10c>
> > @@ -953,23 +953,23 @@ Disassembly of section .text:
> >   ec4:	80 7b 00 00 	lwz     r3,0(r27)
> >   ec8:	48 00 00 01 	bl      ec8 <grub_mod_init-0x10>
> >   ecc:	7f a3 eb 78 	mr      r3,r29
> > - ed0:	39 61 00 30 	addi    r11,r1,48
> > + ed0:	39 61 00 40 	addi    r11,r1,64
> >   ed4:	48 00 00 00 	b       ed4 <grub_mod_init-0x4>
> >  
> >  00000ed8 <grub_mod_init>:
> > - ed8:	94 21 ff f0 	stwu    r1,-16(r1)
> > + ed8:	94 21 ff e0 	stwu    r1,-32(r1)
> >   edc:	3c 80 00 00 	lis     r4,0
> >   ee0:	7c 08 02 a6 	mflr    r0
> >   ee4:	38 84 00 00 	addi    r4,r4,0
> > - ee8:	93 e1 00 0c 	stw     r31,12(r1)
> > + ee8:	93 e1 00 1c 	stw     r31,28(r1)
> >   eec:	7c 7f 1b 78 	mr      r31,r3
> >   ef0:	3c 60 00 00 	lis     r3,0
> > - ef4:	90 01 00 14 	stw     r0,20(r1)
> > + ef4:	90 01 00 24 	stw     r0,36(r1)
> >   ef8:	38 63 00 00 	addi    r3,r3,0
> >   efc:	48 00 00 01 	bl      efc <grub_mod_init+0x24>
> >   f00:	3d 20 00 00 	lis     r9,0
> >   f04:	93 e9 00 00 	stw     r31,0(r9)
> > - f08:	39 61 00 10 	addi    r11,r1,16
> > + f08:	39 61 00 20 	addi    r11,r1,32
> >   f0c:	48 00 00 00 	b       f0c <grub_mod_init+0x34>
> >  
> >  00000f10 <grub_mod_fini>:
> > 
> > 
> > _______________________________________________
> > Grub-devel mailing list
> > Grub-devel@gnu.org
> > https://lists.gnu.org/mailman/listinfo/grub-devel
> 
> 
> Hi Andrei,
> 
> I find out that VSX was the culprit. Can you please take a look at this
> patch?
> http://lists.gnu.org/archive/html/grub-devel/2014-09/msg00077.html
> 
> 



With this patch it works. I'm really surprised - the same sources built
on different platform (ppc BE) did work without problems. I do not
understand how this can be possible if the problem was in specific CPU
mode. It should have been the same in both cases ...