Andi Kleen wrote:
In the boot decompressor for the kernel in the image Iouri provided, I
32bit or 64bit image?
As you can plainly see, the call to memcpy (which is redefined in
boot/compressed/misc.c) is made using stack calling convention.
Unfortunately, the compiler generated the memcpy function itself using
regparm(3) convention. I am guessing this happened because a leftover
I can't find any here grepping .i files and includes. None of the memcpy
prototypes in include have a __fastcall
Are you sure this still happens in mainline?
When I look at my scroll it also looks correct:
c0: 0f af f8 imul %eax,%edi
c3: 01 c0 add %eax,%eax
c5: 89 c2 mov %eax,%edx
c7: 01 f2 add %esi,%edx
c9: 89 45 f0 mov %eax,0xfffffff0(%ebp)
cc: 89 f0 mov %esi,%eax
ce: 89 f9 mov %edi,%ecx
d0: e8 7b ff ff ff call 50 <memcpy>
Does anyone recall compiler problems (I noticed this VM was booting a
64-bit kernel,
Ok 64bit, that was 32bit above.
Since some time the decompressor is 64bit and 64bit always uses
regparms. 64bit Scroll is ok too:
92: 0f af eb imul %ebx,%ebp
95: 01 db add %ebx,%ebx
97: 48 63 f3 movslq %ebx,%rsi
9a: 4c 01 ee add %r13,%rsi
9d: 89 ea mov %ebp,%edx
9f: e8 9c ff ff ff callq 40 <memcpy>
but the decompressor was 32-bit code,
That must be a old kernel.
Can you people please verify this all still happens with a mainline or
2.6.22 kernel?
It doesn't.
so perhaps at some
time the 64-bit makefile or toolchain for Linux had some kind of
compiler bug).
I'm not aware of any such bugs.
Me neither, nor do any of my current 32-bit or 64-bit kernels have this
problem. I was just wondering if it got fixed deliberately, or if some
old gcc bug out there could still cause such problems with specific
toolchains.
I'll look up what version the kernel was; Iouri, can you provide us with
the binutils / gcc versions used to build your kernel?
Zach
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