linux/drivers/firmware
Ard Biesheuvel b3879a4d3a efi/libstub: Make file I/O chunking x86-specific
The ARM decompressor is finicky when it comes to uninitialized variables
with local linkage, the reason being that it may relocate .text and .bss
independently when executing from ROM. This is only possible if all
references into .bss from .text are absolute, and this happens to be the
case for references emitted under -fpic to symbols with external linkage,
and so all .bss references must involve symbols with external linkage.

When building the ARM stub using clang, the initialized local variable
__chunk_size is optimized into a zero-initialized flag that indicates
whether chunking is in effect or not. This flag is therefore emitted into
.bss, which triggers the ARM decompressor's diagnostics, resulting in a
failed build.

Under UEFI, we never execute the decompressor from ROM, so the diagnostic
makes little sense here. But we can easily work around the issue by making
__chunk_size global instead.

However, given that the file I/O chunking that is controlled by the
__chunk_size variable is intended to work around known bugs on various
x86 implementations of UEFI, we can simply make the chunking an x86
specific feature. This is an improvement by itself, and also removes the
need to parse the efi= options in the stub entirely.

Tested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1486380166-31868-8-git-send-email-ard.biesheuvel@linaro.org
[ Small readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-07 10:42:11 +01:00
..
broadcom tree-wide: replace config_enabled() with IS_ENABLED() 2016-08-04 08:50:07 -04:00
efi efi/libstub: Make file I/O chunking x86-specific 2017-02-07 10:42:11 +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 firmware: dmi_scan: add SBMIOS entry and DMI tables 2015-06-25 09:06:56 +02:00
edd.c [SCSI] edd: Treat "XPRS" host bus type the same as "PCI" 2011-10-31 13:26:19 +04:00
iscsi_ibft_find.c efi: Make 'efi_enabled' a function to query EFI facilities 2013-01-30 11:51:59 -08:00
iscsi_ibft.c ibft: Expose iBFT acpi header via sysfs 2016-05-16 11:14:29 -04:00
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 drivers/firmware/memmap.c: fix kernel-doc format 2015-06-25 17:00:41 -07:00
pcdp.c serial: 8250_early: Remove setup_early_serial8250_console() 2015-03-26 17:25:27 +01:00
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 firmware: qcom: scm: Expose PAS command 10 as reset-controller 2016-06-24 22:53:52 -05:00
qcom_scm-64.c firmware: qcom: scm: Expose PAS command 10 as reset-controller 2016-06-24 22:53:52 -05:00
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 firmware: qcom: scm: Expose PAS command 10 as reset-controller 2016-06-24 22:53:52 -05:00
qemu_fw_cfg.c driver core update for 4.7-rc1 2016-05-20 21:26:15 -07:00
raspberrypi.c ARM: bcm2835: Add the Raspberry Pi firmware driver 2015-10-14 15:30:06 -07:00
scpi_pm_domain.c firmware: scpi: add device power domain support using genpd 2016-06-21 10:26:51 +01:00
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