> -----Original Message----- > From: Wood Scott-B07421 > Sent: Thursday, March 14, 2013 12:38 AM > To: David Laight > Cc: Jia Hongtao-B38951; Wood Scott-B07421; linuxppc-dev@lists.ozlabs.org; > Stuart Yoder > Subject: Re: [PATCH V4] powerpc/85xx: Add machine check handler to fix > PCIe erratum on mpc85xx > > On 03/13/2013 04:40:40 AM, David Laight wrote: > > > Hmm, seems there's no probe_user_address() -- for userspace we > > > basically want the same thing minus the KERNEL_DS. See > > > arch/powerpc/perf/callchain.c for an example. > > > > Isn't that just copy_from_user() ? > > Plus pagefault_disable/enable(). > > -Scott
pagefault_disable() is identical to preempt_disable(). So I think this could not avoid other cpu to swap out the instruction we want to read back. probe_kernel_address() also have the same issue. Does this mean we can't just use pagefault_disable() to prevent from getting the wrong instruction? -Hongtao. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
