forked from Minki/linux
e00b12e64b
Now that we can deal with nested NMI due to IRET re-enabling NMIs and can deal with faults from NMI by making sure we preserve CR2 over NMIs we can in fact simply access user-space memory from NMI context. So rewrite copy_from_user_nmi() to use __copy_from_user_inatomic() and rework the fault path to do the minimal required work before taking the in_atomic() fault handler. In particular avoid perf_sw_event() which would make perf recurse on itself (it should be harmless as our recursion protections should be able to deal with this -- but why tempt fate). Also rename notify_page_fault() to kprobes_fault() as that is a much better name; there is no notifier in it and its specific to kprobes. Don measured that his worst case NMI path shrunk from ~300K cycles to ~150K cycles. Cc: Stephane Eranian <eranian@google.com> Cc: jmario@redhat.com Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: dave.hansen@linux.intel.com Tested-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131024105206.GM2490@laptop.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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| .. | ||
| .gitignore | ||
| atomic64_32.c | ||
| atomic64_386_32.S | ||
| atomic64_cx8_32.S | ||
| cache-smp.c | ||
| checksum_32.S | ||
| clear_page_64.S | ||
| cmpxchg8b_emu.S | ||
| cmpxchg16b_emu.S | ||
| copy_page_64.S | ||
| copy_user_64.S | ||
| copy_user_nocache_64.S | ||
| csum-copy_64.S | ||
| csum-partial_64.c | ||
| csum-wrappers_64.c | ||
| delay.c | ||
| getuser.S | ||
| inat.c | ||
| insn.c | ||
| iomap_copy_64.S | ||
| Makefile | ||
| memcpy_32.c | ||
| memcpy_64.S | ||
| memmove_64.S | ||
| memset_64.S | ||
| mmx_32.c | ||
| msr-reg-export.c | ||
| msr-reg.S | ||
| msr-smp.c | ||
| msr.c | ||
| putuser.S | ||
| rwlock.S | ||
| rwsem.S | ||
| string_32.c | ||
| strstr_32.c | ||
| thunk_32.S | ||
| thunk_64.S | ||
| usercopy_32.c | ||
| usercopy_64.c | ||
| usercopy.c | ||
| x86-opcode-map.txt | ||