Commit 8ac5abfe authored Jan 25, 2016 by Mark Rutland Committed by Jeff Vander Stoep Sep 18, 2016

UPSTREAM: arm64: unmap idmap earlier



During boot we leave the idmap in place until paging_init, as we
previously had to wait for the zero page to become allocated and
accessible.

Now that we have a statically-allocated zero page, we can uninstall the
idmap much earlier in the boot process, making it far easier to spot
accidental use of physical addresses. This also brings the cold boot
path in line with the secondary boot path.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Cc: Laura Abbott <labbott@fedoraproject.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Bug: 30369029
Patchset: rework-pagetable

(cherry picked from commit 86ccce896cb0aa800a7a6dcd29b41ffc4eeb1a75)
Signed-off-by: Jeff Vander Stoep <jeffv@google.com>
Change-Id: I6375bd9855e45727790697875b7cd19f84a4dd7f

parent c66ef5f9

arch/arm64/kernel/setup.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -314,6 +314,12 @@ void __init setup_arch(char **cmdline_p)
		*/
		local_async_enable();

		/*
		* TTBR0 is only used for the identity mapping at this stage. Make it
		* point to zero page to avoid speculatively fetching new entries.
		*/
		cpu_uninstall_idmap();

		efi_init();
		arm64_memblock_init();

arch/arm64/mm/mmu.c

+0 −6

Original line number	Diff line number	Diff line
		@@ -460,12 +460,6 @@ void __init paging_init(void)
		fixup_executable();

		bootmem_init();

		/*
		* TTBR0 is only used for the identity mapping at this stage. Make it
		* point to zero page to avoid speculatively fetching new entries.
		*/
		cpu_uninstall_idmap();
		}

		/*