[ Upstream commit 3cce9d44321e460e7c88cdec4e4537a6e9ad7c0d ] Commit f77ac2e378be9dd6 ("ARM: 9030/1: entry: omit FP emulation for UND exceptions taken in kernel mode") failed to take into account that there is in fact a case where we relied on this code path: during boot, the VFP detection code issues a read of FPSID, which will trigger an undef exception on cores that lack VFP support. So let's reinstate this logic using an undef hook which is registered only for the duration of the initcall to vpf_init(), and which sets VFP_arch to a non-zero value - as before - if no VFP support is present. Fixes: f77ac2e378be9dd6 ("ARM: 9030/1: entry: omit FP emulation for UND ...") Reported-by: "kernelci.org bot" <bot@kernelci.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.
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