On Wed, Jan 22, 2020 at 12:42:53AM -0500, George Koehler wrote:
> On Sun, 19 Jan 2020 11:32:26 +0900
> rgc <[email protected]> wrote:
>
> > ...
> >
> > On Sun, Jan 19, 2020 at 11:12:15AM +0900, rgc wrote:
> > > ppc@
> > >
> > > as title ... i've been playing around since i got 6.6-current installed.
> > >
> > > first build a gcc4 kernel and test if it boots properly. OK
> > >
> > > modified share/mk/bsd.own.mk; modified links to cc, c++, cpp; kernel
> > > build without errors; these steps are from a 2018 mail on how to
> > > "switch armv7 to clang"
> > >
> > > ... but does not boot
> > >
> > > -----
> > > [ using 1135748 bytes of bsd ELF symbol table ]
> > > console out [ATY,Jasper_A] console in [keyboard], using USB
> > > using parent ATY,JasperParent:[]-2147483648/0 sp=6db6db6d inside
> > > 80210194-38214000: not MAP_STACK
> > > -----
> > >
> > > ...
>
> clang still has bugs and can emit wrong assembly code.
>
and i think it is what i am seeing right now. for example
/usr/src/sys/arch/macppc/macppc/locore.S:295
lwz %r30,_C_LABEL(battable)@l(%r31) /* get batu */
mtcr %r30
bc 4,30,1f /* branch if supervisor valid is false
*/
lwz %r31,_C_LABEL(battable)+4@l(%r31) /* get batl */
/* We randomly use the highest two bat registers here */
mftb %r28
andi. %r28,%r28,1
bne 2f
mtdbatu 2,%r30
generates
--- gcc4-obj/locore.s Wed Jan 22 04:29:10 2020
+++ clang-obj/locore.s Wed Jan 22 04:29:05 2020
@@ -197,9 +197,9 @@
21a: R_PPC_ADDR16_LO battable
21c: 7f cf f1 20 mtcr r30
220: 40 9e 00 48 bne- cr7,268 <nopbat_1e>
- 224: 83 ff 00 04 lwz r31,4(r31)
+ 224: 83 ff 00 00 lwz r31,0(r31)
226: R_PPC_ADDR16_LO battable+0x4
- 228: 7f 8c 42 e6 mftb r28
+ 228: 7f 8c 42 a6 mfspr r28,268
22c: 73 9c 00 01 andi. r28,r28,1
230: 40 82 00 10 bne- 240 <nopbat_1s+0x3c>
234: 7f dc 83 a6 mtdbatu 2,r30
(full diff attached at the end)
> MAP_STACK is documented in mmap(2). The kernel sometimes checks that
> the cpu's stack pointer (register %r1 on PowerPC) points to MAP_STACK
> memory. The check would fail if something corrupted the stack pointer;
> "sp=6db6db6d" might be a corrupt value. You might get more info by
> adding printf() calls and rebuilding the kernel.
>
> I reported https://bugs.llvm.org/show_bug.cgi?id=40736 where clang and
> gcc use incompatible assembly code to return small structs, and am
> working on a possible fix. Without a fix, user commands built by clang
> might have trouble calling libraries built by gcc. If we fix enough
> compatibility bugs, we might try building user commands with clang.
> This might be easier than building the kernel.
>
> --George
goodluck on you work.
yorosiku ~
--- gcc4-obj/locore.s Wed Jan 22 04:29:10 2020
+++ clang-obj/locore.s Wed Jan 22 04:29:05 2020
@@ -197,9 +197,9 @@
21a: R_PPC_ADDR16_LO battable
21c: 7f cf f1 20 mtcr r30
220: 40 9e 00 48 bne- cr7,268 <nopbat_1e>
- 224: 83 ff 00 04 lwz r31,4(r31)
+ 224: 83 ff 00 00 lwz r31,0(r31)
226: R_PPC_ADDR16_LO battable+0x4
- 228: 7f 8c 42 e6 mftb r28
+ 228: 7f 8c 42 a6 mfspr r28,268
22c: 73 9c 00 01 andi. r28,r28,1
230: 40 82 00 10 bne- 240 <nopbat_1s+0x3c>
234: 7f dc 83 a6 mtdbatu 2,r30
@@ -219,7 +219,7 @@
00000268 <nopbat_1e>:
nopbat_1e():
268: 7f 88 02 a6 mflr r28
- 26c: 48 00 08 7f bla 87c <s_dsitrap>
+ 26c: 48 00 00 03 bla 0 <cpu_switchto_asm>
26c: R_PPC_ADDR24 .text+0x87c
00000270 <isitrap>:
@@ -240,7 +240,7 @@
28c: 7f a0 00 26 mfcr r29
290: 7f fb 02 a6 mfsrr1 r31
294: 7c 31 42 a6 mfsprg r1,1
- 298: 48 00 09 5b bla 958 <s_isitrap>
+ 298: 48 00 00 03 bla 0 <cpu_switchto_asm>
298: R_PPC_ADDR24 .text+0x958
0000029c <extint>:
@@ -266,7 +266,7 @@
2cc: 80 21 01 bc lwz r1,444(r1)
2d0: 41 82 00 08 beq- 2d8 <nop32_5e+0x2c>
2d4: 7c 31 42 a6 mfsprg r1,1
- 2d8: 48 00 09 ca ba 9c8 <extintr>
+ 2d8: 48 00 00 02 ba 0 <cpu_switchto_asm>
2d8: R_PPC_ADDR24 .text+0x9c8
000002dc <decrint>:
@@ -418,9 +418,9 @@
4dc: 38 42 ff f8 addi r2,r2,-8
4e0: 4b ff ff ac b 48c <tlbdsmiss+0x14>
4e4: 54 23 f0 03 rlwinm. r3,r1,30,0,1
- 4e8: 40 80 00 18 bge- 500 <tlbdsmiss+0x88>
+ 4e8: 40 c0 00 18 bge- 500 <tlbdsmiss+0x88>
4ec: 70 23 00 01 andi. r3,r1,1
- 4f0: 41 a2 00 28 beq+ 518 <tlbdsmiss+0xa0>
+ 4f0: 41 e2 00 28 beq+ 518 <tlbdsmiss+0xa0>
4f4: 7c 7b 02 a6 mfsrr1 r3
4f8: 3c 20 0a 00 lis r1,2560
4fc: 48 00 00 34 b 530 <tlbdsmiss+0xb8>
@@ -429,7 +429,7 @@
508: 7c 7b 02 a6 mfsrr1 r3
50c: 54 63 97 fe rlwinm r3,r3,18,31,31
510: 5c 21 18 43 rlwnm. r1,r1,r3,1,1
- 514: 40 a2 ff e0 bne- 4f4 <tlbdsmiss+0x7c>
+ 514: 40 c2 ff e0 bne+ 4f4 <tlbdsmiss+0x7c>
518: 80 22 00 04 lwz r1,4(r2)
51c: 60 21 01 80 ori r1,r1,384
520: b0 22 00 06 sth r1,6(r2)
@@ -468,7 +468,7 @@
580: 7f d0 42 a6 mfsprg r30,0
584: 83 de 01 bc lwz r30,444(r30)
588: 38 3e 20 00 addi r1,r30,8192
- 58c: 48 00 0d 83 bla d80 <ddbtrap>
+ 58c: 48 00 00 03 bla 0 <cpu_switchto_asm>
58c: R_PPC_ADDR24 .text+0xd80
00000590 <disitrap>:
@@ -487,8 +487,7 @@
5b0: 7c 3b 02 a6 mfsrr1 r1
5b4: 7c 2f f1 20 mtcr r1
5b8: 7c 31 42 a6 mfsprg r1,1
- 5bc: 40 91 00 00 ble- cr4,5bc <realtrap+0xc>
- 5bc: R_PPC_REL14 s_trap
+ 5bc: 40 91 00 10 ble- cr4,5cc <s_trap>
5c0: 7c 30 42 a6 mfsprg r1,0
5c4: 80 21 01 94 lwz r1,404(r1)
5c8: 38 21 40 00 addi r1,r1,16384
@@ -566,7 +565,7 @@
6d4: 90 c5 01 b4 stw r6,436(r5)
6d8: 3f c0 00 00 lis r30,0
6da: R_PPC_ADDR16_HA .text+0x128
- 6dc: 3b de 01 28 addi r30,r30,296
+ 6dc: 3b de 00 00 addi r30,r30,0
6de: R_PPC_ADDR16_LO .text+0x128
6e0: 93 c1 00 98 stw r30,152(r1)
6e4: 93 e1 00 9c stw r31,156(r1)
@@ -684,8 +683,7 @@
86c: 7f e8 03 a6 mtlr r31
870: 7f c3 f3 78 mr r3,r30
874: 4e 80 00 21 blrl
- 878: 48 00 00 00 b 878 <fork_trampoline+0x14>
- 878: R_PPC_REL24 trapexit
+ 878: 4b ff fe 94 b 70c <trapexit>
0000087c <s_dsitrap>:
s_dsitrap():
@@ -854,7 +852,6 @@
00000ac4 <extint_call>:
extint_call():
ac4: 48 00 00 01 bl ac4 <extint_call>
- ac4: R_PPC_REL24 extint_call
00000ac8 <intr_exit>:
intr_exit():
@@ -1121,7 +1118,7 @@
e88: 90 c5 01 b4 stw r6,436(r5)
e8c: 3f c0 00 00 lis r30,0
e8e: R_PPC_ADDR16_HA .text+0x128
- e90: 3b de 01 28 addi r30,r30,296
+ e90: 3b de 00 00 addi r30,r30,0
e92: R_PPC_ADDR16_LO .text+0x128
e94: 93 c1 00 98 stw r30,152(r1)
e98: 93 e1 00 9c stw r31,156(r1)
@@ -1302,61 +1299,34 @@
1114: 60 00 00 00 nop
00001118 <rfi_start>:
-rfi_start():
- 1118: 00 00 08 60 .long 0x860
+ ...
1118: R_PPC_ADDR32 .text+0x860
- 111c: 00 00 08 64 .long 0x864
111c: R_PPC_ADDR32 .text+0x864
- 1120: 00 00 09 54 .long 0x954
1120: R_PPC_ADDR32 .text+0x954
- 1124: 00 00 09 58 .long 0x958
1124: R_PPC_ADDR32 .text+0x958
- 1128: 00 00 0c 18 .long 0xc18
1128: R_PPC_ADDR32 .text+0xc18
- 112c: 00 00 0c 1c .long 0xc1c
112c: R_PPC_ADDR32 .text+0xc1c
- 1130: 00 00 11 08 .long 0x1108
1130: R_PPC_ADDR32 .text+0x1108
- 1134: 00 00 11 0c .long 0x110c
1134: R_PPC_ADDR32 .text+0x110c
- ...
00001140 <nopbat_start>:
-nopbat_start():
- 1140: 00 00 02 04 .long 0x204
+ ...
1140: R_PPC_ADDR32 .text+0x204
- 1144: 00 00 02 68 .long 0x268
1144: R_PPC_ADDR32 .text+0x268
- ...
00001150 <nop32_start>:
-nop32_start():
- 1150: 00 00 01 50 .long 0x150
+ ...
1150: R_PPC_ADDR32 .text+0x150
- 1154: 00 00 01 5c .long 0x15c
1154: R_PPC_ADDR32 .text+0x15c
- 1158: 00 00 01 90 .long 0x190
1158: R_PPC_ADDR32 .text+0x190
- 115c: 00 00 01 9c .long 0x19c
115c: R_PPC_ADDR32 .text+0x19c
- 1160: 00 00 01 e4 .long 0x1e4
1160: R_PPC_ADDR32 .text+0x1e4
- 1164: 00 00 01 f0 .long 0x1f0
1164: R_PPC_ADDR32 .text+0x1f0
- 1168: 00 00 02 74 .long 0x274
1168: R_PPC_ADDR32 .text+0x274
- 116c: 00 00 02 80 .long 0x280
116c: R_PPC_ADDR32 .text+0x280
- 1170: 00 00 02 a0 .long 0x2a0
1170: R_PPC_ADDR32 .text+0x2a0
- 1174: 00 00 02 ac .long 0x2ac
1174: R_PPC_ADDR32 .text+0x2ac
- 1178: 00 00 02 e0 .long 0x2e0
1178: R_PPC_ADDR32 .text+0x2e0
- 117c: 00 00 02 ec .long 0x2ec
117c: R_PPC_ADDR32 .text+0x2ec
- 1180: 00 00 05 64 .long 0x564
1180: R_PPC_ADDR32 .text+0x564
- 1184: 00 00 05 70 .long 0x570
1184: R_PPC_ADDR32 .text+0x570
- ...
