PS3: Strange issue with kexec and FreeBSD loader
Phileas Fogg
phileas-fogg at mail.ru
Fri Feb 22 07:38:15 EST 2013
Benjamin Herrenschmidt wrote:
> On Wed, 2013-02-20 at 21:43 +0100, Phileas Fogg wrote:
>
>> I found the single commit which brakes kexec stuff for FreeBSD loader or other
>> custom ELF kernels on the PS3 console.
>>
>>
>> From 7230c5644188cd9e3fb380cc97dde00c464a3ba7 Mon Sep 17 00:00:00 2001
>> From: Benjamin Herrenschmidt <benh at kernel.crashing.org>
>> Date: Tue, 6 Mar 2012 18:27:59 +1100
>> Subject: [PATCH] powerpc: Rework lazy-interrupt handling
>
> Odd... That rework had its own issues and so several patches went in
> subsequently to address them. It's possible that the PS3 does more
> horrid stuff we missed here but I don't quite see how to relate that to
> your specific memory corruption problem...
>
> Do you see any "pattern" to the corruption ? Does it looks like
> something known ? IE., exception frame, ASCII data, MSR values, ...
>
> Ben.
>
>
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> Linuxppc-dev at lists.ozlabs.org
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>
Hi,
here is some data for analyzing.
First, i modified kexec-tools and dumped the kernel and DT segments before they
are passed to the kexec_load syscall. I also modified the purgatory code and
made it dump the computed SHA256 checksum, the original SHA256 checksum and
the DT.
Here is the output from kexec-tools:
--------------------------------------
root at ps3-linux:~# kexec -l loader.ps3
segment[0].mem:0x1371000 memsz:262144
segment[1].mem:0x13b1000 memsz:36864
segment[2].mem:0x7fff000 memsz:4096
sha256_digest: 66 a6 c0 be d5 3c ba c2 85 6 97 4 d2 e1 aa 28 63 fa 7f 79 ce de
e7 7f 26 14 a1 fa 2a ea bc 83
Here is the output from the purgatory code:
---------------------------------------------
I'm in purgatory
sha256 digests do not match :(
digest: d4 dc 50 0a ef 78 8e 28 e0 9a fe 52 e1 72 1c b3 23 a6 f4 ea 40
7a 2d fd 6b 2a 66 95 63 f6 99 2a
sha256_digest: 66 a6 c0 be d5 3c ba c2 85 06 97 04 d2 e1 aa 28 63 fa 7f 79 ce
de e7 7f 26 14 a1 fa 2a ea bc 83
sha256_regions:
start=0x0000000001371000 len=0x0000000000040000
start=0x0000000007fff000 len=0x0000000000001000
Here is the DT dump from kexec-tools:
---------------------------------------
00000000 d0 0d fe ed 00 00 03 70 00 00 00 40 00 00 02 74 |.......p... at ...t|
00000010 00 00 00 20 00 00 00 02 00 00 00 02 00 00 00 00 |... ............|
00000020 00 00 00 00 07 ff f0 00 00 00 00 00 00 00 03 70 |...............p|
00000030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00000040 00 00 00 01 2f 00 00 00 00 00 00 03 00 00 00 04 |..../...........|
00000050 00 00 00 00 00 00 00 02 00 00 00 03 00 00 00 04 |................|
00000060 00 00 00 0f 00 00 00 02 00 00 00 03 00 00 00 09 |................|
00000070 00 00 00 1b 00 00 00 00 73 6f 6e 79 2c 70 73 33 |........sony,ps3|
00000080 00 00 00 00 00 00 00 03 00 00 00 04 00 00 00 26 |...............&|
00000090 00 00 00 00 00 00 00 03 00 00 00 08 00 00 00 39 |...............9|
000000a0 00 00 00 00 38 6d 43 80 00 00 00 03 00 00 00 08 |....8mC.........|
000000b0 00 00 00 48 00 00 00 00 53 6f 6e 79 50 53 33 00 |...H....SonyPS3.|
000000c0 00 00 00 03 00 00 00 01 00 00 00 4e 00 00 00 00 |...........N....|
000000d0 00 00 00 01 2f 63 68 6f 73 65 6e 00 00 00 00 03 |..../chosen.....|
000000e0 00 00 00 08 00 00 00 53 00 00 00 00 00 00 00 00 |.......S........|
000000f0 00 00 00 03 00 00 00 07 00 00 00 4e 63 68 6f 73 |...........Nchos|
00000100 65 6e 00 00 00 00 00 03 00 00 00 02 00 00 00 66 |en.............f|
00000110 20 00 00 00 00 00 00 02 00 00 00 01 2f 63 70 75 | .........../cpu|
00000120 73 00 00 00 00 00 00 03 00 00 00 04 00 00 00 00 |s...............|
00000130 00 00 00 01 00 00 00 03 00 00 00 04 00 00 00 0f |................|
00000140 00 00 00 00 00 00 00 03 00 00 00 05 00 00 00 4e |...............N|
00000150 63 70 75 73 00 00 00 00 00 00 00 01 2f 63 70 75 |cpus......../cpu|
00000160 73 2f 63 70 75 40 30 00 00 00 00 03 00 00 00 04 |s/cpu at 0.........|
00000170 00 00 00 6f 00 00 00 00 00 00 00 03 00 00 00 04 |...o............|
00000180 00 00 00 7f 00 00 00 80 00 00 00 03 00 00 00 04 |................|
00000190 00 00 00 91 00 00 80 00 00 00 00 03 00 00 00 04 |................|
000001a0 00 00 00 9e 63 70 75 00 00 00 00 03 00 00 00 04 |....cpu.........|
000001b0 00 00 00 aa 00 00 00 80 00 00 00 03 00 00 00 04 |................|
000001c0 00 00 00 bc 00 00 80 00 00 00 00 03 00 00 00 08 |................|
000001d0 00 00 00 c9 00 00 00 00 00 00 00 00 00 00 00 01 |................|
000001e0 00 00 00 03 00 00 00 04 00 00 00 4e 63 70 75 00 |...........Ncpu.|
000001f0 00 00 00 03 00 00 00 04 00 00 00 e4 00 00 00 00 |................|
00000200 00 00 00 03 00 00 00 04 00 00 00 e8 00 00 00 00 |................|
00000210 00 00 00 02 00 00 00 02 00 00 00 01 2f 6d 65 6d |............/mem|
00000220 6f 72 79 00 00 00 00 03 00 00 00 07 00 00 00 9e |ory.............|
00000230 6d 65 6d 6f 72 79 00 00 00 00 00 03 00 00 00 07 |memory..........|
00000240 00 00 00 4e 6d 65 6d 6f 72 79 00 00 00 00 00 03 |...Nmemory......|
00000250 00 00 00 10 00 00 00 e4 00 00 00 00 00 00 00 00 |................|
00000260 00 00 00 00 08 00 00 00 00 00 00 02 00 00 00 02 |................|
00000270 00 00 00 09 23 61 64 64 72 65 73 73 2d 63 65 6c |....#address-cel|
00000280 6c 73 00 23 73 69 7a 65 2d 63 65 6c 6c 73 00 63 |ls.#size-cells.c|
00000290 6f 6d 70 61 74 69 62 6c 65 00 6c 69 6e 75 78 2c |ompatible.linux,|
000002a0 61 76 5f 6d 75 6c 74 69 5f 6f 75 74 00 6c 69 6e |av_multi_out.lin|
000002b0 75 78 2c 72 74 63 5f 64 69 66 66 00 6d 6f 64 65 |ux,rtc_diff.mode|
000002c0 6c 00 6e 61 6d 65 00 6c 69 6e 75 78 2c 6d 65 6d |l.name.linux,mem|
000002d0 6f 72 79 2d 6c 69 6d 69 74 00 62 6f 6f 74 61 72 |ory-limit.bootar|
000002e0 67 73 00 63 6c 6f 63 6b 2d 66 72 65 71 75 65 6e |gs.clock-frequen|
000002f0 63 79 00 64 2d 63 61 63 68 65 2d 6c 69 6e 65 2d |cy.d-cache-line-|
00000300 73 69 7a 65 00 64 2d 63 61 63 68 65 2d 73 69 7a |size.d-cache-siz|
00000310 65 00 64 65 76 69 63 65 5f 74 79 70 65 00 69 2d |e.device_type.i-|
00000320 63 61 63 68 65 2d 6c 69 6e 65 2d 73 69 7a 65 00 |cache-line-size.|
00000330 69 2d 63 61 63 68 65 2d 73 69 7a 65 00 69 62 6d |i-cache-size.ibm|
00000340 2c 70 70 63 2d 69 6e 74 65 72 72 75 70 74 2d 73 |,ppc-interrupt-s|
00000350 65 72 76 65 72 23 73 00 72 65 67 00 74 69 6d 65 |erver#s.reg.time|
00000360 62 61 73 65 2d 66 72 65 71 75 65 6e 63 79 00 00 |base-frequency..|
00000370
Here is the DT dump from the purgatory code after the verify function failed:
------------------------------------------------------------------------------
00000000 d0 0d fe ed 00 00 03 70 00 00 00 40 00 00 02 74 |.......p... at ...t|
00000010 00 00 00 20 00 00 00 02 00 00 00 02 00 00 00 00 |... ............|
00000020 00 00 00 00 07 ff f0 00 00 00 00 00 00 00 03 70 |...............p|
00000030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00000040 00 00 00 01 2f 00 00 00 00 00 00 03 00 00 00 04 |..../...........|
00000050 00 00 00 00 00 00 00 02 00 00 00 03 00 00 00 04 |................|
00000060 00 00 00 0f 00 00 00 02 00 00 00 03 00 00 00 09 |................|
00000070 00 00 00 1b 00 00 00 00 73 6f 6e 79 2c 70 73 33 |........sony,ps3|
00000080 80 00 00 00 00 00 80 30 80 00 00 00 00 00 80 02 |.......0........|
00000090 c0 00 00 00 00 01 a4 a0 00 00 00 08 00 00 00 39 |...............9|
000000a0 00 00 00 00 38 6d 43 80 00 00 00 03 00 00 00 08 |....8mC.........|
000000b0 00 00 00 48 00 00 00 00 53 6f 6e 79 50 53 33 00 |...H....SonyPS3.|
000000c0 00 00 00 03 00 00 00 01 00 00 00 4e 00 00 00 00 |...........N....|
000000d0 00 00 00 01 2f 63 68 6f 73 65 6e 00 00 00 00 03 |..../chosen.....|
000000e0 00 00 00 08 00 00 00 53 00 00 00 00 00 00 00 00 |.......S........|
000000f0 00 00 00 03 00 00 00 07 00 00 00 4e 63 68 6f 73 |...........Nchos|
00000100 65 6e 00 00 00 00 00 03 00 00 00 02 00 00 00 66 |en.............f|
00000110 20 00 00 00 00 00 00 02 00 00 00 01 2f 63 70 75 | .........../cpu|
00000120 73 00 00 00 00 00 00 03 00 00 00 04 00 00 00 00 |s...............|
00000130 00 00 00 01 00 00 00 03 00 00 00 04 00 00 00 0f |................|
00000140 00 00 00 00 00 00 00 03 00 00 00 05 00 00 00 4e |...............N|
00000150 63 70 75 73 00 00 00 00 00 00 00 01 2f 63 70 75 |cpus......../cpu|
00000160 73 2f 63 70 75 40 30 00 00 00 00 03 00 00 00 04 |s/cpu at 0.........|
00000170 00 00 00 6f 00 00 00 00 00 00 00 03 00 00 00 04 |...o............|
00000180 00 00 00 7f 00 00 00 80 00 00 00 03 00 00 00 04 |................|
00000190 00 00 00 91 00 00 80 00 00 00 00 03 00 00 00 04 |................|
000001a0 00 00 00 9e 63 70 75 00 00 00 00 03 00 00 00 04 |....cpu.........|
000001b0 00 00 00 aa 00 00 00 80 00 00 00 03 00 00 00 04 |................|
000001c0 00 00 00 bc 00 00 80 00 00 00 00 03 00 00 00 08 |................|
000001d0 00 00 00 c9 00 00 00 00 00 00 00 00 00 00 00 01 |................|
000001e0 00 00 00 03 00 00 00 04 00 00 00 4e 63 70 75 00 |...........Ncpu.|
000001f0 00 00 00 03 00 00 00 04 00 00 00 e4 00 00 00 00 |................|
00000200 00 00 00 03 00 00 00 04 00 00 00 e8 00 00 00 00 |................|
00000210 00 00 00 02 00 00 00 02 00 00 00 09 2f 6d 65 6d |............/mem|
00000220 6f 72 79 00 00 00 00 03 00 00 00 07 00 00 00 9e |ory.............|
00000230 6d 65 6d 6f 72 79 00 00 00 00 00 03 00 00 00 07 |memory..........|
00000240 00 00 00 4e 6d 65 6d 6f 72 79 00 00 00 00 00 03 |...Nmemory......|
00000250 00 00 00 10 00 00 00 e4 00 00 00 00 00 00 00 00 |................|
00000260 00 00 00 00 08 00 00 00 00 00 00 02 00 00 00 02 |................|
00000270 00 00 00 09 23 61 64 64 72 65 73 73 2d 63 65 6c |....#address-cel|
00000280 6c 73 00 23 73 69 7a 65 2d 63 65 6c 6c 73 00 63 |ls.#size-cells.c|
00000290 6f 6d 70 61 74 69 62 6c 65 00 6c 69 6e 75 78 2c |ompatible.linux,|
000002a0 61 76 5f 6d 75 6c 74 69 5f 6f 75 74 00 6c 69 6e |av_multi_out.lin|
000002b0 75 78 2c 72 74 63 5f 64 69 66 66 00 6d 6f 64 65 |ux,rtc_diff.mode|
000002c0 6c 00 6e 61 6d 65 00 6c 69 6e 75 78 2c 6d 65 6d |l.name.linux,mem|
000002d0 6f 72 79 2d 6c 69 6d 69 74 00 62 6f 6f 74 61 72 |ory-limit.bootar|
000002e0 67 73 00 63 6c 6f 63 6b 2d 66 72 65 71 75 65 6e |gs.clock-frequen|
000002f0 63 79 00 64 2d 63 61 63 68 65 2d 6c 69 6e 65 2d |cy.d-cache-line-|
00000300 73 69 7a 65 00 64 2d 63 61 63 68 65 2d 73 69 7a |size.d-cache-siz|
00000310 65 00 64 65 76 69 63 65 5f 74 79 70 65 00 69 2d |e.device_type.i-|
00000320 63 61 63 68 65 2d 6c 69 6e 65 2d 73 69 7a 65 00 |cache-line-size.|
00000330 69 2d 63 61 63 68 65 2d 73 69 7a 65 00 69 62 6d |i-cache-size.ibm|
00000340 2c 70 70 63 2d 69 6e 74 65 72 72 75 70 74 2d 73 |,ppc-interrupt-s|
00000350 65 72 76 65 72 23 73 00 72 65 67 00 74 69 6d 65 |erver#s.reg.time|
00000360 62 61 73 65 2d 66 72 65 71 75 65 6e 63 79 00 00 |base-frequency..|
00000370
And here is the diff between 2 hexdumps:
-----------------------------------------
--- dt.kexec.hex
+++ dt.dump.hex
@@ -6,8 +6,8 @@
00000050 00 00 00 00 00 00 00 02 00 00 00 03 00 00 00 04 |................|
00000060 00 00 00 0f 00 00 00 02 00 00 00 03 00 00 00 09 |................|
00000070 00 00 00 1b 00 00 00 00 73 6f 6e 79 2c 70 73 33 |........sony,ps3|
-00000080 00 00 00 00 00 00 00 03 00 00 00 04 00 00 00 26 |...............&|
-00000090 00 00 00 00 00 00 00 03 00 00 00 08 00 00 00 39 |...............9|
+00000080 80 00 00 00 00 00 80 30 80 00 00 00 00 00 80 02 |.......0........|
+00000090 c0 00 00 00 00 01 a4 a0 00 00 00 08 00 00 00 39 |...............9|
000000a0 00 00 00 00 38 6d 43 80 00 00 00 03 00 00 00 08 |....8mC.........|
000000b0 00 00 00 48 00 00 00 00 53 6f 6e 79 50 53 33 00 |...H....SonyPS3.|
000000c0 00 00 00 03 00 00 00 01 00 00 00 4e 00 00 00 00 |...........N....|
@@ -31,7 +31,7 @@
000001e0 00 00 00 03 00 00 00 04 00 00 00 4e 63 70 75 00 |...........Ncpu.|
000001f0 00 00 00 03 00 00 00 04 00 00 00 e4 00 00 00 00 |................|
00000200 00 00 00 03 00 00 00 04 00 00 00 e8 00 00 00 00 |................|
-00000210 00 00 00 02 00 00 00 02 00 00 00 01 2f 6d 65 6d |............/mem|
+00000210 00 00 00 02 00 00 00 02 00 00 00 09 2f 6d 65 6d |............/mem|
00000220 6f 72 79 00 00 00 00 03 00 00 00 07 00 00 00 9e |ory.............|
00000230 6d 65 6d 6f 72 79 00 00 00 00 00 03 00 00 00 07 |memory..........|
00000240 00 00 00 4e 6d 65 6d 6f 72 79 00 00 00 00 00 03 |...Nmemory......|
As you see, the data is different at offsets 0x80, 0x90 and 0x210.
The new 8 bytes at offset 0x90 in dt.dump.hex look suspicously like the kernel
virtual address: 0xc00000000001a4a0.
I'll try out the advice with DABR register from Geoff later and see if i can get
the code address which corrupts the data in DT.
regards
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