This patchset enables strict percpu address space checks via x86 named address space qualifiers. Percpu variables are declared in __seg_gs/__seg_fs named AS and kept named AS qualified until they are dereferenced via percpu accessor. This approach enables various compiler checks for cross-namespace variable assignments. Please note that sparse doesn't know anything about __typeof_unqual__() operator, so the usage of __typeof_unqual__() breaks sparse checking. Also, the last patch hijacks __percpu tag and repurposes it as a named address space qualifier. While this works surprisingly well in this RFC patchset, I would really appreciate some help on how to rewrite this hack into some "production ready" code. Cc: Dennis Zhou <dennis@xxxxxxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Nadav Amit <nadav.amit@xxxxxxxxx> Cc: Brian Gerst <brgerst@xxxxxxxxx> Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx> Uros Bizjak (3): percpu: Define __pcpu_typeof() percpu: Assorted fixes found by strict percpu address space checks percpu/x86: [RFH] Enable strict percpu checks via named AS qualifiers arch/x86/include/asm/percpu.h | 53 ++++++++++++++++++++++++---------- arch/x86/kernel/head64.c | 3 +- drivers/base/devres.c | 2 +- fs/aio.c | 2 +- include/linux/cleanup.h | 4 +-- include/linux/compiler_types.h | 2 +- include/linux/part_stat.h | 2 +- include/linux/percpu-defs.h | 39 ++++++++++++++++++++----- include/linux/prandom.h | 1 + init/Kconfig | 3 ++ kernel/events/hw_breakpoint.c | 4 +-- kernel/locking/percpu-rwsem.c | 2 +- kernel/workqueue.c | 2 +- lib/percpu_counter.c | 2 +- net/core/dev.c | 2 +- 15 files changed, 87 insertions(+), 36 deletions(-) -- 2.45.2
