mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-09 11:23:09 -04:00
b3f11af9b2
Florian reports that when building with CONFIG_CC_OPTIMIZE_FOR_SIZE=y, he sees "Misaligned patch-site" warnings at boot, e.g. | Misaligned patch-site bcm2836_arm_irqchip_handle_irq+0x0/0x88 | WARNING: CPU: 0 PID: 0 at arch/arm64/kernel/ftrace.c:120 ftrace_call_adjust+0x4c/0x70 This is because GCC will silently ignore `-falign-functions=N` when passed `-Os`, resulting in functions not being aligned as we expect. This is a known issue, and to account for this we modified the kernel to avoid `-Os` generally. Unfortunately we forgot to account for CONFIG_CC_OPTIMIZE_FOR_SIZE. Forbid the use of CALL_OPS with CONFIG_CC_OPTIMIZE_FOR_SIZE=y to prevent this issue. All exising ftrace features will work as before, though without the performance benefit of CALL_OPS. Reported-by: Florian Fainelli <f.fainelli@gmail.com> Link: http://lore.kernel.org/linux-arm-kernel/2d9284c3-3805-402b-5423-520ced56d047@gmail.com Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Stefan Wahren <stefan.wahren@i2se.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Deacon <will@kernel.org> Tested-by: Florian Fainelli <f.fainelli@gmail.com> Link: https://lore.kernel.org/r/20230227115819.365630-1-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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.