3037bb8ff3
update_saved_ttbr0 mandates that mm->pgd is not swapper, since swapper
contains kernel mappings and should never be installed into ttbr0. However,
this means that callers must avoid passing the init_mm to update_saved_ttbr0
which in turn can cause the saved ttbr0 value to be out-of-date in the context
of the idle thread. For example, EFI runtime services may leave the saved ttbr0
pointing at the EFI page table, and kernel threads may end up with stale
references to freed page tables.
This patch changes update_saved_ttbr0 so that the init_mm points the saved
ttbr0 value to the empty zero page, which always exists and never contains
valid translations. EFI and switch can then call into update_saved_ttbr0
unconditionally.
Test: boot successfuuly with hikey/hikey960 boards
Fixes: 5ea8fac20639d99b ("UPSTREAM: arm64: SW PAN: Update saved ttbr0 value on enter_lazy_tlb")
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Cc: <stable@vger.kernel.org>
Fixes: 39bc88e5e38e9b21 ("arm64: Disable TTBR0_EL1 during normal kernel execution")
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Vinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Change-Id: I0396c3f97e17369e323e713003f8a2efc28a85ff
Signed-off-by: Yongqin Liu <yongqin.liu@linaro.org>
(cherry picked from commit 0adbdfde8cfc9415aeed2a4955d2d17b3bd9bf13)
(cherry picked from commit 9c9f57920570e80147a818055c702474ab7fff28)
6.2 KiB
6.2 KiB