[PATCH] BISECTED x86: avoid qword access in memcpy_*io
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From: Hidetoshi Seto on 20 Jul 2010 21:30 With v2.6.35-rc5, my x86-64 server doesn't boot but reports a Completer Abort on lpfc card. The result of git-bisect is: 6175ddf06b6172046a329e3abfd9c901a43efd2e is the first bad commit commit 6175ddf06b6172046a329e3abfd9c901a43efd2e Author: Brian Gerst <brgerst(a)gmail.com> Date: Fri Feb 5 09:37:07 2010 -0500 x86: Clean up mem*io functions. What I found are: - memcpy for 64bit uses movq if count >= 64 (arch/x86/lib/memcpy_64.S) - memcpy_toio and memcpy_fromio have changed to use this memcpy by the above commit. - my debug shows that lpfc calls memcpy_toio with not-qword-aligned addresses and count >= 64, e.g.: memcpy_toio(0xffffc900118de004, 0xffff88047293d614, 124); and it seems that it comes from: [drivers/scsi/lpfc/lpfc_sli.c] 4929 /* First copy mbox command data to HBA SLIM, skip past first 4930 word */ 4931 to_slim = phba->MBslimaddr + sizeof (uint32_t); 4932 lpfc_memcpy_to_slim(to_slim, &mb->un.varWords[0], 4933 MAILBOX_CMD_SIZE - sizeof (uint32_t)); Still I'm not sure what is wrong in software or hardware, however I suppose that qword access to iomem is not always safe, so it will be OK to back to use __inline_memcpy which uses movsl. I confirmed that my server (w/ lpfc) boots with 35-rc5 + this patch. Signed-off-by: Hidetoshi Seto <seto.hidetoshi(a)jp.fujitsu.com> --- arch/x86/include/asm/io.h | 8 ++++++++ 1 files changed, 8 insertions(+), 0 deletions(-) diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index 30a3e97..e15a74a 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -227,13 +227,21 @@ memset_io(volatile void __iomem *addr, unsigned char val, size_t count) static inline void memcpy_fromio(void *dst, const volatile void __iomem *src, size_t count) { +#ifdef CONFIG_X86_64 + __inline_memcpy(dst, (const void __force *)src, count); +#else memcpy(dst, (const void __force *)src, count); +#endif } static inline void memcpy_toio(volatile void __iomem *dst, const void *src, size_t count) { +#ifdef CONFIG_X86_64 + __inline_memcpy((void __force *)dst, src, count); +#else memcpy((void __force *)dst, src, count); +#endif } /* -- 1.7.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |