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a9b3c355c2
We already have a generic implementation of alloc/free up to P4D level, as
well as pgd_free(). Let's finish the work and add a generic PGD-level
alloc helper as well.
Unlike at lower levels, almost all architectures need some specific magic
at PGD level (typically initialising PGD entries), so introducing a
generic pgd_alloc() isn't worth it. Instead we introduce two new helpers,
__pgd_alloc() and __pgd_free(), and make use of them in the arch-specific
pgd_alloc() and pgd_free() wherever possible. To accommodate as many arch
as possible, __pgd_alloc() takes a page allocation order.
Because pagetable_alloc() allocates zeroed pages, explicit zeroing in
pgd_alloc() becomes redundant and we can get rid of it. Some trivial
implementations of pgd_free() also become unnecessary once __pgd_alloc()
is used; remove them.
Another small improvement is consistent accounting of PGD pages by using
GFP_PGTABLE_{USER,KERNEL} as appropriate.
Not all PGD allocations can be handled by the generic helpers. In
particular, multiple architectures allocate PGDs from a kmem_cache, and
those PGDs may not be page-sized.
Link: https://lkml.kernel.org/r/20250103184415.2744423-6-kevin.brodsky@arm.com
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_PGALLOC_H
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#define _ASM_PGALLOC_H
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#include <linux/gfp.h>
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#include <linux/mm.h>
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#include <linux/threads.h>
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#include <asm/processor.h>
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#include <asm/fixmap.h>
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#include <asm/cache.h>
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#define __HAVE_ARCH_PMD_ALLOC_ONE
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#include <asm-generic/pgalloc.h>
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/* Allocate the top level pgd (page directory) */
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static inline pgd_t *pgd_alloc(struct mm_struct *mm)
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{
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return __pgd_alloc(mm, PGD_TABLE_ORDER);
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}
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#if CONFIG_PGTABLE_LEVELS == 3
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/* Three Level Page Table Support for pmd's */
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static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
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{
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set_pud(pud, __pud((PxD_FLAG_PRESENT | PxD_FLAG_VALID) +
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(__u32)(__pa((unsigned long)pmd) >> PxD_VALUE_SHIFT)));
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}
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static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
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{
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struct ptdesc *ptdesc;
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gfp_t gfp = GFP_PGTABLE_USER;
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if (mm == &init_mm)
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gfp = GFP_PGTABLE_KERNEL;
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ptdesc = pagetable_alloc(gfp, PMD_TABLE_ORDER);
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if (!ptdesc)
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return NULL;
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if (!pagetable_pmd_ctor(ptdesc)) {
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pagetable_free(ptdesc);
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return NULL;
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}
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return ptdesc_address(ptdesc);
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}
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#endif
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static inline void
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pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
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{
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set_pmd(pmd, __pmd((PxD_FLAG_PRESENT | PxD_FLAG_VALID)
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+ (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT)));
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}
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#define pmd_populate(mm, pmd, pte_page) \
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pmd_populate_kernel(mm, pmd, page_address(pte_page))
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#endif
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