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linux/drivers/firmware
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Ard Biesheuvel c8f325a59c efi/fdt: Avoid FDT manipulation after ExitBootServices() 
Some AArch64 UEFI implementations disable the MMU in ExitBootServices(),
after which unaligned accesses to RAM are no longer supported.

Commit:

  abfb7b686a ("efi/libstub/arm*: Pass latest memory map to the kernel")

fixed an issue in the memory map handling of the stub FDT code, but
inadvertently created an issue with such firmware, by moving some
of the FDT manipulation to after the invocation of ExitBootServices().

Given that the stub's libfdt implementation uses the ordinary, accelerated
string functions, which rely on hardware handling of unaligned accesses,
manipulating the FDT with the MMU off may result in alignment faults.

So fix the situation by moving the update_fdt_memmap() call into the
callback function invoked by efi_exit_boot_services() right before it
calls the ExitBootServices() UEFI service (which is arguably a better
place for it anyway)

Note that disabling the MMU in ExitBootServices() is not compliant with
the UEFI spec, and carries great risk due to the fact that switching from
cached to uncached memory accesses halfway through compiler generated code
(i.e., involving a stack) can never be done in a way that is architecturally
safe.

Fixes: abfb7b686a ("efi/libstub/arm*: Pass latest memory map to the kernel")
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Riku Voipio <riku.voipio@linaro.org>
Cc: <stable@vger.kernel.org>
Cc: mark.rutland@arm.com
Cc: linux-efi@vger.kernel.org
Cc: matt@codeblueprint.co.uk
Cc: leif.lindholm@linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1485971102-23330-2-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-01 21:17:49 +01:00
..
broadcom tree-wide: replace config_enabled() with IS_ENABLED() 2016-08-04 08:50:07 -04:00
efi efi/fdt: Avoid FDT manipulation after ExitBootServices() 2017-02-01 21:17:49 +01:00
google firmware-gsmi: Delete an unnecessary check before the function call "dma_pool_destroy" 2016-09-09 16:08:45 +01:00
meson firmware: Amlogic: Add secure monitor driver 2016-09-01 14:23:39 -07:00
tegra firmware: tegra: Add BPMP support 2016-11-18 14:33:43 +01:00
arm_scpi.c firmware: arm_scpi: fix reading sensor values on pre-1.0 SCPI firmwares 2016-12-30 14:53:36 +00:00
dcdbas.c dcdbas: Make use of smp_call_on_cpu() 2016-09-05 13:52:40 +02:00
dcdbas.h
dell_rbu.c
dmi_scan.c firmware: dmi_scan: Always show system identification string 2016-12-19 10:01:47 +01:00
dmi-id.c dmi-id: don't free dev structure after calling device_register 2016-09-08 10:35:50 +02:00
dmi-sysfs.c
edd.c
iscsi_ibft_find.c
iscsi_ibft.c
Kconfig Merge branch 'for-4.10-ti-sci-base' of https://github.com/t-kristo/linux-pm into next/drivers 2016-11-30 17:13:13 +01:00
Makefile Merge branch 'for-4.10-ti-sci-base' of https://github.com/t-kristo/linux-pm into next/drivers 2016-11-30 17:13:13 +01:00
memmap.c
pcdp.c
pcdp.h
psci_checker.c drivers: psci: annotate timer on stack to silence odebug messages 2017-01-03 17:52:48 +00:00
psci.c drivers: psci: Allow PSCI node to be disabled 2016-11-25 23:26:05 +01:00
qcom_scm-32.c
qcom_scm-64.c
qcom_scm.c firmware: qcom: scm: Return PTR_ERR when devm_clk_get fails 2016-11-23 11:03:00 -06:00
qcom_scm.h
qemu_fw_cfg.c
raspberrypi.c
scpi_pm_domain.c
ti_sci.c firmware: ti_sci: Add support for reboot core service 2016-10-27 12:09:12 +03:00
ti_sci.h firmware: ti_sci: Add support for reboot core service 2016-10-27 12:09:12 +03:00