On 02/13/2020 02:28 PM, Larry Finger wrote:
On 2/11/20 1:23 PM, Christophe Leroy wrote:
Can you send me a picture of that BUG Unable to handle kernel data
access with all the registers values etc..., together with the
matching vmlinux ?
First thing is to identify where we are when that happens. That mean
see what is at 0xc0013674. Can be done with 'ppc-linux-objdump -d
vmlinux' (Or whatever your PPC objdump is named) and get the function
code.
Then we need to understand how we reach that function and why it tries
to access a physical address.
Another thing I'm thinking about, not necessarily related to that
problem: Some buggy drivers do DMA from stack. This doesn't work
anymore with CONFIG_VMAP_STACK. Most of them can be detected with
CONFIG_DEBUG_VIRTUAL so you should activate it.
Christophe,
The previous send of this message failed because the attached vmlinux
was too large.
I have gone about as far as I can in debugging the problem. Setting
CONFIG_DEBUG_VIRTUAL made no difference.
Attached are the final screenshot, and the patches that I have applied.
You already have the gzipped vmlinux.
This screenshot makes more sense with the vmlinux you provided, problem
at 0xc00136dc.
That's in function power_save_ppc32_restore() in
arch/powerpc/kernel/idle_6xx.S.
c00136c0 <power_save_ppc32_restore>:
c00136c0: 81 2b 00 a0 lwz r9,160(r11)
c00136c4: 91 2b 00 90 stw r9,144(r11)
c00136c8: 39 60 00 00 li r11,0
c00136cc: 7d 30 fa a6 mfspr r9,1008
c00136d0: 75 29 00 40 andis. r9,r9,64
c00136d4: 41 82 00 18 beq c00136ec <power_save_ppc32_restore+0x2c>
c00136d8: 3d 2b 00 7c addis r9,r11,124
>> c00136dc: 81 29 92 5c lwz r9,-28068(r9)
c00136e0: 7d 36 fb a6 mtspr 1014,r9
c00136e4: 7c 00 04 ac hwsync
c00136e8: 4c 00 01 2c isync
c00136ec: 3d 2b 00 7c addis r9,r11,124
c00136f0: 81 29 92 60 lwz r9,-28064(r9)
c00136f4: 7d 31 fb a6 mtspr 1009,r9
c00136f8: 48 00 19 c4 b c00150bc <transfer_to_handler_cont>
c00136fc: 00 00 00 00 .long 0x0
Can you try the change below (won't work anymore without
CONFIG_VMAP_STACK, will fix it properly later when you confirm it is OK).
diff --git a/arch/powerpc/kernel/idle_6xx.S b/arch/powerpc/kernel/idle_6xx.S
index 0ffdd18b9f26..7be8a0f3fac8 100644
--- a/arch/powerpc/kernel/idle_6xx.S
+++ b/arch/powerpc/kernel/idle_6xx.S
@@ -166,7 +166,7 @@ BEGIN_FTR_SECTION
mfspr r9,SPRN_HID0
andis. r9,r9,HID0_NAP@h
beq 1f
- addis r9,r11,(nap_save_msscr0-KERNELBASE)@ha
+ addis r9,r11,nap_save_msscr0@ha
lwz r9,nap_save_msscr0@l(r9)
mtspr SPRN_MSSCR0, r9
sync
@@ -174,7 +174,7 @@ BEGIN_FTR_SECTION
1:
END_FTR_SECTION_IFSET(CPU_FTR_NAP_DISABLE_L2_PR)
BEGIN_FTR_SECTION
- addis r9,r11,(nap_save_hid1-KERNELBASE)@ha
+ addis r9,r11,nap_save_hid1@ha
lwz r9,nap_save_hid1@l(r9)
mtspr SPRN_HID1, r9
END_FTR_SECTION_IFSET(CPU_FTR_DUAL_PLL_750FX)
Thanks
Christophe
