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

[Andrei Borzenkov <arvidjaar@gmail.com>]

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>: