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In `ret_to_user` we perform some conditional work depending on the thread flags, then perform some IRQ/context tracking which is intended to balance with the IRQ/context tracking performed in the entry C code. For simplicity and consistency, it would be preferable to move this all to C. As a step towards that, this patch moves the conditional work and IRQ/context tracking into a C helper function. To aid bisectability, this is called from the `ret_to_user` assembly, and a subsequent patch will move the call to C code. As local_daif_mask() handles all necessary tracing and PMR manipulation, we no longer need to handle this explicitly. As we call exit_to_user_mode() directly, the `user_enter_irqoff` macro is no longer used, and can be removed. As enter_from_user_mode() and exit_to_user_mode() are no longer called from assembly, these can be made static, and as these are typically very small, they are marked __always_inline to avoid the overhead of a function call. For now, enablement of single-step is left in entry.S, and for this we still need to read the flags in ret_to_user(). It is safe to read this separately as TIF_SINGLESTEP is not part of _TIF_WORK_MASK. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Will Deacon <will@kernel.org> Reviewed-by: Joey Gouly <joey.gouly@arm.com> Link: https://lore.kernel.org/r/20210802140733.52716-4-mark.rutland@arm.com [catalin.marinas@arm.com: removed unused gic_prio_kentry_setup macro] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> |
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arch | ||
block | ||
certs | ||
crypto | ||
Documentation | ||
drivers | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
LICENSES | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | ||
.cocciconfig | ||
.get_maintainer.ignore | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
COPYING | ||
CREDITS | ||
Kbuild | ||
Kconfig | ||
MAINTAINERS | ||
Makefile | ||
README |
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.