Calls into UV BIOS were not being serialised which is wrong as it violates EFI runtime rules, and bad as it does result in all sorts of potentially hard to track down hangs and panics when efi_scratch gets clobbered.
Patch #1 makes the efi_runtime_lock semaphore visible to EFI runtime callers defined outside drivers/firmware/efi/runtime-wrappers.c in preparation for using it to serialise calls into UV BIOS. Patch #2 removes uv_bios_call_reentrant() because it's dead code. Patch #3 makes uv_bios_call() variants use efi_runtime_sem to protect against concurrency. Hedi Berriche (3): efi/x86: turn EFI runtime semaphore into a global lock x86/platform/UV: kill uv_bios_call_reentrant() as it has no callers x86/platform/UV: use efi_runtime_sem to serialise BIOS calls arch/x86/include/asm/uv/bios.h | 4 +- arch/x86/platform/uv/bios_uv.c | 37 +++++++++++-------- drivers/firmware/efi/runtime-wrappers.c | 60 ++++++++++++++++---------------- include/linux/efi.h | 3 + 4 files changed, 57 insertions(+), 47 deletions(-) -- 2.20.0
