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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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74193ef0ec
__copy_from_user_inatomic() isn't NMI safe in that it can trigger the page fault handler which is another trap and its return path invokes IRET which will also close the NMI context. Therefore use a GUP based approach to copy the stack frames over. We tried an alternative solution as well: we used a forward ported version of Mathieu Desnoyers's "NMI safe INT3 and Page Fault" patch that modifies the exception return path to use an open-coded IRET with explicit stack unrolling and TF checking. This didnt work as it interacted with faulting user-space instructions, causing them not to restart properly, which corrupts user-space registers. Solving that would probably involve disassembling those instructions and backtracing the RIP. But even without that, the code was deemed rather complex to the already non-trivial x86 entry assembly code, so instead we went for this GUP based method that does a software-walk of the pagetables. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Nick Piggin <npiggin@suse.de> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu> |
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| cpufreq | ||
| mcheck | ||
| mtrr | ||
| .gitignore | ||
| addon_cpuid_features.c | ||
| amd.c | ||
| bugs_64.c | ||
| bugs.c | ||
| centaur.c | ||
| cmpxchg.c | ||
| common.c | ||
| cpu_debug.c | ||
| cpu.h | ||
| cyrix.c | ||
| hypervisor.c | ||
| intel_cacheinfo.c | ||
| intel.c | ||
| Makefile | ||
| mkcapflags.pl | ||
| perf_counter.c | ||
| perfctr-watchdog.c | ||
| powerflags.c | ||
| proc.c | ||
| transmeta.c | ||
| umc.c | ||
| vmware.c | ||