Re: [Valgrind-users] Valgrind (compiled with n64 ABI) out of memory on MIPS64

[John R. <jr...@bi...>]

On 06/14/2015 10:22 PM, Matt Bennett wrote:
> On Sun, 2015-06-14 at 22:01 -0700, John Reiser wrote:
>>> mmap(0x802001000, 4194304, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, 0, 0) = -1 EINVAL (Invalid argument)
>>
>> What is SHMLBA for this configuration?  [grep -sr SHMLBA /usr/include]
>

> /usr/include/valgrind/vki/vki-mips32-linux.h:#define VKI_SHMLBA  0x40000
> /usr/include/valgrind/vki/vki-mips64-linux.h:#define VKI_SHMLBA  0x40000

[Note that 0x40000 is 256KiB, which is rather large and likely to cause
noticeable fragmentation of address space.]

Notice that all those files are from /usr/include/valgrind/vki/.
Your compilation environment apparently lacked the definitions
that correspond to the target hardware [these for x86_64]:
-----
/usr/include/bits/shm.h:#define SHM_RND		020000		/* round attach address to SHMLBA */
/usr/include/bits/shm.h:#define SHMLBA		(__getpagesize ())
/usr/include/linux/shm.h:#define	SHM_RND		020000	/* round attach address to SHMLBA boundary */
/usr/include/asm-generic/shmparam.h:#define SHMLBA PAGE_SIZE	 /* attach addr a multiple of this */
-----

>
>> And on the same topic, what is the page size?  [grep -sr PAGE_SIZE /usr/include]
>
> /usr/include/valgrind/pub_tool_libcbase.h:#define VG_IS_PAGE_ALIGNED(aaa_p) (0 == (((Addr)(aaa_p)) & ((Addr)(VKI_PAGE_SIZE-1))))
> /usr/include/valgrind/pub_tool_libcbase.h:#define VG_PGROUNDDN(p)    VG_ROUNDDN(p, VKI_PAGE_SIZE)
> /usr/include/valgrind/pub_tool_libcbase.h:#define VG_PGROUNDUP(p)    VG_ROUNDUP(p, VKI_PAGE_SIZE)

> /usr/include/valgrind/vki/vki-mips32-linux.h:#define VKI_PAGE_SIZE           (1UL << VKI_PAGE_SHIFT)
> /usr/include/valgrind/vki/vki-mips32-linux.h:#define VKI_PAGE_MASK           (~(VKI_PAGE_SIZE-1))
> /usr/include/valgrind/vki/vki-mips32-linux.h:#define VKI_MAX_PAGE_SIZE       VKI_PAGE_SIZE
> /usr/include/valgrind/vki/vki-mips64-linux.h:#define VKI_PAGE_SIZE   (1UL << VKI_PAGE_SHIFT)
> /usr/include/valgrind/vki/vki-mips64-linux.h:#define VKI_PAGE_MASK   (~(VKI_PAGE_SIZE-1))
> /usr/include/valgrind/vki/vki-mips64-linux.h:#define VKI_MAX_PAGE_SIZE       VKI_PAGE_SIZE

Well, what is VKI_PAGE_SHIFT; and does one of {vki-mips32-linux.h, vki-mips64-linux.h}
actually apply to the target machine?

>
>> Every successful mmap() return value happens to be a multiple of 0x2000 (8KiB);
>> there are no odd multiples of 0x1000 (4KiB).
>> [Some ARM machines have an SHMLBA of 0x4000 (16KiB) even though the page size is 0x1000 (4KiB).]
>
> This is on a MIPS chip, specifically Cavium (cnMIPS). The kernel page size is configured to 8kB and since I didn't configure the page size when
> cross compiling valgrind it looks like it took the page size of my local machine (4kB). Looking at the upstream source code it appears that
> 8kB page size isn't currently supported however there are some patches here that may make it work. https://bugs.kde.org/show_bug.cgi?id=342356
>
> Either way if this is indeed the issue here perhaps this is something that should be fixed upstream (supporting 8k and 32k pages)?

Some of the blame belongs to you and the marketing/sales/support team
that sold you the chips.  Sometimes inexpensive hardware is *TOO* cheap!
In this case it looks like Cavium (cnMIPS) is an architectural variant
that does not have all the properties previously promised by MIPS.

Also, successful cross-compiling requires setting the declarations
and #includes correctly.  Nothing in the valgrind source can prevent
operator error in this department.

Therefore: arrange for the proper definitions of VKI_PAGE_SHIFT and VKI_SHMLBA,
and tell us the numerical values.  (Write a test program which prints them!)
If valgrind attempts MAP_FIXED at an address such as 0x802001000 which is not
a multiple of the hardware page size (apparently 8KiB) then that is a clue
that the compilation environment is not correct.  If necessary, edit the
definitions by hand _after_ performing "automatic configuration" and
_before_ compiling.

Look carefully at ARM:
	/usr/include/valgrind/vki/vki-arm-linux.h:#define VKI_SHMLBA  (4 * VKI_PAGE_SIZE)
which does work, and contrast with your case.

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