Messages in this thread | | | From | Stephen Boyd <> | Subject | [PATCH v3 0/5] Read-only memremap() | Date | Tue, 10 Sep 2019 09:08:58 -0700 |
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This patch series implements a read-only version of memremap() via a new MEMREMAP_RO flag. If this is passed in the mapping call, we'll try to map the memory region as read-only if it doesn't intersect with an existing mapping. Otherwise, we'll try to fallback to other flags to try to map the memory that way.
The main use case I have is to map the command-db memory region on Qualcomm devices with a read-only mapping. It's already a const marked pointer and the API returns const pointers as well, so this series makes sure that even stray writes can't modify the memory. To get there we introduce a devm version of memremap() for a reserved memory region, add a memremap() flag, and implement support for that flag on arm64.
Changes from v2 (https://lkml.kernel.org/r/20190614203717.75479-1-swboyd@chromium.org): * Added a comment to kerneldoc for the new MEMREMAP_RO flag * Rebased to v5.3-rc1
Changes from v1: * Picked up tags and rebased to v5.2-rc3
Stephen Boyd (5): reserved_mem: Add a devm_memremap_reserved_mem() API soc: qcom: cmd-db: Migrate to devm_memremap_reserved_mem() memremap: Add support for read-only memory mappings arm64: Add support for arch_memremap_ro() soc: qcom: cmd-db: Map with read-only mappings
Cc: Evan Green <evgreen@chromium.org> Cc: Rob Herring <robh+dt@kernel.org> Cc: Bjorn Andersson <bjorn.andersson@linaro.org> Cc: Andy Gross <agross@kernel.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com>
arch/arm64/include/asm/io.h | 1 + drivers/of/of_reserved_mem.c | 45 +++++++++++++++++++++++++++++++++ drivers/soc/qcom/cmd-db.c | 14 +++------- include/linux/io.h | 1 + include/linux/of_reserved_mem.h | 6 +++++ kernel/iomem.c | 20 ++++++++++++--- 6 files changed, 74 insertions(+), 13 deletions(-)
base-commit: 5f9e832c137075045d15cd6899ab0505cfb2ca4b -- Sent by a computer through tubes
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