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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>
75 lines
1.7 KiB
C
75 lines
1.7 KiB
C
/*
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* Copyright (C) 2009 Wind River Systems Inc
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* Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <asm/cpuinfo.h>
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#include <asm/pgalloc.h>
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/* pteaddr:
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* ptbase | vpn* | zero
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* 31-22 | 21-2 | 1-0
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*
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* *vpn is preserved on double fault
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*
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* tlbacc:
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* IG |*flags| pfn
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* 31-25|24-20 | 19-0
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*
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* *crwxg
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*
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* tlbmisc:
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* resv |way |rd | we|pid |dbl|bad|perm|d
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* 31-24 |23-20 |19 | 20|17-4|3 |2 |1 |0
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*
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*/
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/*
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* Initialize a new pgd / pmd table with invalid pointers.
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*/
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static void pgd_init(pgd_t *pgd)
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{
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unsigned long *p = (unsigned long *) pgd;
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int i;
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for (i = 0; i < USER_PTRS_PER_PGD; i += 8) {
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p[i + 0] = (unsigned long) invalid_pte_table;
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p[i + 1] = (unsigned long) invalid_pte_table;
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p[i + 2] = (unsigned long) invalid_pte_table;
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p[i + 3] = (unsigned long) invalid_pte_table;
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p[i + 4] = (unsigned long) invalid_pte_table;
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p[i + 5] = (unsigned long) invalid_pte_table;
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p[i + 6] = (unsigned long) invalid_pte_table;
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p[i + 7] = (unsigned long) invalid_pte_table;
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}
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}
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pgd_t *pgd_alloc(struct mm_struct *mm)
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{
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pgd_t *ret, *init;
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ret = __pgd_alloc(mm, 0);
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if (ret) {
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init = pgd_offset(&init_mm, 0UL);
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pgd_init(ret);
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memcpy(ret + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
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(PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
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}
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return ret;
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}
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void __init pagetable_init(void)
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{
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/* Initialize the entire pgd. */
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pgd_init(swapper_pg_dir);
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pgd_init(swapper_pg_dir + USER_PTRS_PER_PGD);
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}
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