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17b226dcf8
This will be useful for GPU drivers who want to keep page tables in a pool so they can: - keep freed page tables in a free pool and speed-up upcoming page table allocations - batch page table allocation instead of allocating one page at a time - pre-reserve pages for page tables needed for map/unmap operations, to ensure map/unmap operations don't try to allocate memory in paths they're allowed to block or fail It might also be valuable for other aspects of GPU and similar use-cases, like fine-grained memory accounting and resource limiting. We will extend the Arm LPAE format to support custom allocators in a separate commit. Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com> Reviewed-by: Steven Price <steven.price@arm.com> Reviewed-by: Robin Murphy <robin.murphy@arm.com> Link: https://lore.kernel.org/r/20231124142434.1577550-2-boris.brezillon@collabora.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
101 lines
2.5 KiB
C
101 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Generic page table allocator for IOMMUs.
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*
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* Copyright (C) 2014 ARM Limited
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*
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* Author: Will Deacon <will.deacon@arm.com>
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*/
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#include <linux/bug.h>
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#include <linux/io-pgtable.h>
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#include <linux/kernel.h>
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#include <linux/types.h>
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static const struct io_pgtable_init_fns *
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io_pgtable_init_table[IO_PGTABLE_NUM_FMTS] = {
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#ifdef CONFIG_IOMMU_IO_PGTABLE_LPAE
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[ARM_32_LPAE_S1] = &io_pgtable_arm_32_lpae_s1_init_fns,
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[ARM_32_LPAE_S2] = &io_pgtable_arm_32_lpae_s2_init_fns,
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[ARM_64_LPAE_S1] = &io_pgtable_arm_64_lpae_s1_init_fns,
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[ARM_64_LPAE_S2] = &io_pgtable_arm_64_lpae_s2_init_fns,
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[ARM_MALI_LPAE] = &io_pgtable_arm_mali_lpae_init_fns,
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#endif
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#ifdef CONFIG_IOMMU_IO_PGTABLE_DART
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[APPLE_DART] = &io_pgtable_apple_dart_init_fns,
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[APPLE_DART2] = &io_pgtable_apple_dart_init_fns,
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#endif
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#ifdef CONFIG_IOMMU_IO_PGTABLE_ARMV7S
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[ARM_V7S] = &io_pgtable_arm_v7s_init_fns,
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#endif
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#ifdef CONFIG_AMD_IOMMU
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[AMD_IOMMU_V1] = &io_pgtable_amd_iommu_v1_init_fns,
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[AMD_IOMMU_V2] = &io_pgtable_amd_iommu_v2_init_fns,
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#endif
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};
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static int check_custom_allocator(enum io_pgtable_fmt fmt,
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struct io_pgtable_cfg *cfg)
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{
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/* No custom allocator, no need to check the format. */
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if (!cfg->alloc && !cfg->free)
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return 0;
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/* When passing a custom allocator, both the alloc and free
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* functions should be provided.
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*/
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if (!cfg->alloc || !cfg->free)
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return -EINVAL;
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/* Make sure the format supports custom allocators. */
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if (io_pgtable_init_table[fmt]->caps & IO_PGTABLE_CAP_CUSTOM_ALLOCATOR)
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return 0;
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return -EINVAL;
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}
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struct io_pgtable_ops *alloc_io_pgtable_ops(enum io_pgtable_fmt fmt,
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struct io_pgtable_cfg *cfg,
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void *cookie)
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{
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struct io_pgtable *iop;
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const struct io_pgtable_init_fns *fns;
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if (fmt >= IO_PGTABLE_NUM_FMTS)
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return NULL;
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if (check_custom_allocator(fmt, cfg))
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return NULL;
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fns = io_pgtable_init_table[fmt];
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if (!fns)
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return NULL;
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iop = fns->alloc(cfg, cookie);
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if (!iop)
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return NULL;
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iop->fmt = fmt;
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iop->cookie = cookie;
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iop->cfg = *cfg;
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return &iop->ops;
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}
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EXPORT_SYMBOL_GPL(alloc_io_pgtable_ops);
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/*
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* It is the IOMMU driver's responsibility to ensure that the page table
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* is no longer accessible to the walker by this point.
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*/
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void free_io_pgtable_ops(struct io_pgtable_ops *ops)
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{
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struct io_pgtable *iop;
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if (!ops)
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return;
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iop = io_pgtable_ops_to_pgtable(ops);
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io_pgtable_tlb_flush_all(iop);
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io_pgtable_init_table[iop->fmt]->free(iop);
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}
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EXPORT_SYMBOL_GPL(free_io_pgtable_ops);
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