[haiku-bugs] Re: [Haiku] #5956: PPC boot fails on double lock of mutex
- From: "stevenh" <trac@xxxxxxxxxxxx>
- Date: Thu, 13 May 2010 12:56:55 -0000
#5956: PPC boot fails on double lock of mutex
---------------------------+------------------------------------------------
Reporter: stevenh | Owner: axeld
Type: bug | Status: new
Priority: normal | Milestone: R1
Component: System/Kernel | Version: R1/Development
Keywords: | Blockedby:
Platform: PowerPC | Blocking: 1048
---------------------------+------------------------------------------------
Comment(by stevenh):
Right, I've been trying to make sense of this... and I miss my push/pop
stack calls!
I've commented out the code from arch_debug.cpp and moved to arch_asm.S;
since it's mentioned that this should be implemented in assembler.
I've tried to understand the basic idea from x86 (http://dev.haiku-
os.org/browser/haiku/trunk/src/system/kernel/arch/x86/arch_x86.S) and came
up with the following. My goal has just been to call the stack_trace
method... and implement the fault handling logic once i've conquered the
call. It seems that either the null pointer is killing me, or I'm not
passing in parameters properly:
{{{
//call a debugging command but make sure that we have a fault handler
handy?
// \param cpu details on the current cpu this is on (smp? maybe?)
[%r3?]
// \param jumpBuffer Buffer to be used for setjmp()/longjmp().
[%r4?]
// \param function The function to be called.
[%r5?]
// \param parameter The parameter to be passed to the
[%r6?]
// function to be called.
FUNCTION(arch_debug_call_with_fault_handler):
mlr %r3 //move the jump target to LR
mtctr %r5 //r5 contains our debug call
li %r3, 0x1 // argc = 1?
mr %r4, %r6 // argv = r6? .. should contain the params
to pass to it
bctr
blr
}}}
I attempted two blr calls, instead of bctr and blr respectively, but the
latter seems to work a little better... unfortunately it ends up with a
'circular stack' error.
The output is:
{{{
stack trace for thread 0x0 ---
kernel stack: 0x00000000 to 0x00000000
frame caller <image>:function + offset
80087a90 (+1682632) 00000002
80222758 (+ 0) 0000002
circular stack frame: x80222758
}}}
Meanwhile:
kernel entry: 0x8010dfd0
kernel stack top at: 0x80088000
Apart from an easy answer, I'd really love to get my head around this..
I'm continuing reading on PPC ASM howtos/manuals/tutorials, but not many
people are as low level as this.
Any help is appreciated.
--
Ticket URL: <http://dev.haiku-os.org/ticket/5956#comment:3>
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