powerpc/64s: Fix __pte_needs_flush() false positive warning

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commit 1abce0580b upstream.

Userspace PROT_NONE ptes set _PAGE_PRIVILEGED, triggering a false
positive debug assertion that __pte_flags_need_flush() is not called
on a kernel mapping.

Detect when it is a userspace PROT_NONE page by checking the required
bits of PAGE_NONE are set, and none of the RWX bits are set.
pte_protnone() is insufficient here because it always returns 0 when
CONFIG_NUMA_BALANCING=n.

Fixes: b11931e9ad ("powerpc/64s: add pte_needs_flush and huge_pmd_needs_flush")
Cc: stable@vger.kernel.org # v6.1+
Reported-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230302225947.81083-1-bgray@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Benjamin Gray 2023-03-03 09:59:47 +11:00 • committed by Greg Kroah-Hartman

parent 0bb88976bd

commit 3f5ded2469

1 changed files with 7 additions and 2 deletions

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arch/powerpc/include/asm/book3s/64/tlbflush.h

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