[bug report] arm64/mm: Clear PXX_TYPE_MASK and set PXD_TYPE_SECT in [pmd|pud]_mkhuge()

[Dan Carpenter <dan.carpenter@linaro.org>]

Hello Anshuman Khandual,

Commit 1601df9e366e ("arm64/mm: Clear PXX_TYPE_MASK and set
PXD_TYPE_SECT in [pmd|pud]_mkhuge()") from Feb 21, 2025 (linux-next),
leads to the following (unpublished) Smatch static checker warning:

arch/arm64/include/asm/pgtable.h:587 pmd_mkhuge() warn: odd binop '0x1 & 0xfffffffffffffffe'
arch/arm64/include/asm/pgtable.h:626 pud_mkhuge() warn: odd binop '0x1 & 0xfffffffffffffffe'

arch/arm64/include/asm/pgtable.h
    579 static inline pmd_t pmd_mkhuge(pmd_t pmd)
    580 {
    581         /*
    582          * It's possible that the pmd is present-invalid on entry
    583          * and in that case it needs to remain present-invalid on
    584          * exit. So ensure the VALID bit does not get modified.
    585          */
    586         pmdval_t mask = PMD_TYPE_MASK & ~PTE_VALID;
--> 587         pmdval_t val = PMD_TYPE_SECT & ~PTE_VALID;

This is "1 & ~1".  I see the comment, but I'm too stupid to know even
after reading he comment whether it's intentional or not.  :P

    588 
    589         return __pmd((pmd_val(pmd) & ~mask) | val);
    590 }

regards,
dan carpenter