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4b7d9c2a71
[ Upstream commit 990784b577 ]
When PTI is disabled at boot time either because the CPU is not affected or
PTI has been disabled on the command line, the boot code still calls into
pti_finalize() which then unconditionally invokes:
pti_clone_entry_text()
pti_clone_kernel_text()
pti_clone_kernel_text() was called unconditionally before the 32bit support
was added and 32bit added the call to pti_clone_entry_text().
The call has no side effects as cloning the page tables into the available
second one, which was allocated for PTI does not create damage. But it does
not make sense either and in case that this functionality would be extended
later this might actually lead to hard to diagnose issues.
Neither function should be called when PTI is runtime disabled. Make the
invocation conditional.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190828143124.063353972@linutronix.de
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.