From mboxrd@z Thu Jan 1 00:00:00 1970 From: hanjun.guo@linaro.org (Hanjun Guo) Date: Wed, 14 Jan 2015 16:22:08 +0800 Subject: [PATCH] arm64: allow late use of early_ioremap In-Reply-To: <1421089778.12632.2.camel@t520.localdomain> References: <1421081711-1128-1-git-send-email-msalter@redhat.com> <20150112172534.GJ13360@arm.com> <1421089778.12632.2.camel@t520.localdomain> Message-ID: <54B62730.6090107@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Mark, On 2015?01?13? 03:09, Mark Salter wrote: > On Mon, 2015-01-12 at 17:25 +0000, Will Deacon wrote: >> On Mon, Jan 12, 2015 at 04:55:11PM +0000, Mark Salter wrote: >>> Commit 0e63ea48b4d8 (arm64/efi: add missing call to early_ioremap_reset()) >>> added a missing call to early_ioremap_reset(). This triggers a BUG if code >>> tries using early_ioremap() after the early_ioremap_reset(). This is a >>> problem for some ACPI code which needs short-lived temporary mappings >>> after paging_init() but before mm_init(). This patch adds definitions for Minor update: ... after paging_init() but before acpi_early_init() in start_kernel(). In ACPI, permanent mapping will be used after acpi_gbl_permanent_mmap set to 1 in acpi_early_init(), since GIC init and Arch timer init will be called before acpi_early_init(), early_ioremap() is still needed after mm_init(). >>> the __late_set_fixmap() and __late_clear_fixmap() which avoids the BUG >>> by allowing later use of early_ioremap(). >>> >>> Signed-off-by: Mark Salter >>> CC: Leif Lindholm >>> CC: Ard Biesheuvel >>> --- >>> arch/arm64/include/asm/fixmap.h | 3 +++ >>> 1 file changed, 3 insertions(+) >> >> Given that we don't support ACPI on arm64 in mainline, I assume this can >> wait until at least 3.20? > > Sure. Just needs it to go in before ACPI code. And tbh, the ACPI code > could change and make this unneeded. This is the best solution for now, so I need to add this patch as the first one for ACPI core patch set, is it ok for you? Thanks Hanjun