Messages in this thread | | | Date | Thu, 12 Nov 2015 08:53:13 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH 3/3] x86, ras: Add mcsafe_memcpy() function to recover from machine checks |
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* Tony Luck <tony.luck@intel.com> wrote:
> Using __copy_user_nocache() as inspiration create a memory copy > routine for use by kernel code with annotations to allow for > recovery from machine checks. > > Notes: > 1) Unlike the original we make no attempt to copy all the bytes > up to the faulting address. The original achieves that by > re-executing the failing part as a byte-by-byte copy, > which will take another page fault. We don't want to have > a second machine check! > 2) Likewise the return value for the original indicates exactly > how many bytes were not copied. Instead we provide the physical > address of the fault (thanks to help from do_machine_check()
> +extern phys_addr_t mcsafe_memcpy(void *dst, const void __user *src, > + unsigned size);
So what's the longer term purpose, where will mcsafe_memcpy() be used?
Thanks,
Ingo
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