RISC-V: Implement compile-time fixed mappings (f2c17aab) · Commits · 戴 / test

arch/riscv/Kconfig

+3 −0

Original line number	Diff line number	Diff line
		@@ -89,6 +89,9 @@ config GENERIC_CSUM
		config GENERIC_HWEIGHT
		def_bool y

		config FIX_EARLYCON_MEM
		def_bool y

		config PGTABLE_LEVELS
		int
		default 3 if 64BIT

arch/riscv/include/asm/fixmap.h

0 → 100644

+44 −0

Original line number	Diff line number	Diff line
		/* SPDX-License-Identifier: GPL-2.0 */
		/*
		* Copyright (C) 2019 Western Digital Corporation or its affiliates.
		*/

		#ifndef _ASM_RISCV_FIXMAP_H
		#define _ASM_RISCV_FIXMAP_H

		#include <linux/kernel.h>
		#include <linux/sizes.h>
		#include <asm/page.h>
		#include <asm/pgtable.h>

		/*
		* Here we define all the compile-time 'special' virtual addresses.
		* The point is to have a constant address at compile time, but to
		* set the physical address only in the boot process.
		*
		* These 'compile-time allocated' memory buffers are page-sized. Use
		* set_fixmap(idx,phys) to associate physical memory with fixmap indices.
		*/
		enum fixed_addresses {
		FIX_HOLE,
		FIX_EARLYCON_MEM_BASE,
		__end_of_fixed_addresses
		};

		#define FIXADDR_SIZE (__end_of_fixed_addresses * PAGE_SIZE)
		#define FIXADDR_TOP (PAGE_OFFSET)
		#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)

		#define FIXMAP_PAGE_IO PAGE_KERNEL

		#define __early_set_fixmap __set_fixmap

		#define __late_set_fixmap __set_fixmap
		#define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR)

		extern void __set_fixmap(enum fixed_addresses idx,
		phys_addr_t phys, pgprot_t prot);

		#include <asm-generic/fixmap.h>

		#endif /* _ASM_RISCV_FIXMAP_H */

arch/riscv/mm/init.c

+34 −0

Original line number	Diff line number	Diff line
		@@ -19,6 +19,7 @@
		#include <linux/sizes.h>
		#include <linux/of_fdt.h>

		#include <asm/fixmap.h>
		#include <asm/tlbflush.h>
		#include <asm/sections.h>
		#include <asm/pgtable.h>
		@@ -148,8 +149,28 @@ pgd_t trampoline_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
		#define NUM_SWAPPER_PMDS ((uintptr_t)-PAGE_OFFSET >> PGDIR_SHIFT)
		pmd_t swapper_pmd[PTRS_PER_PMD*((-PAGE_OFFSET)/PGDIR_SIZE)] __page_aligned_bss;
		pmd_t trampoline_pmd[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
		pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss;
		#endif

		pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;

		void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)
		{
		unsigned long addr = __fix_to_virt(idx);
		pte_t *ptep;

		BUG_ON(idx <= FIX_HOLE \|\| idx >= __end_of_fixed_addresses);

		ptep = &fixmap_pte[pte_index(addr)];

		if (pgprot_val(prot)) {
		set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, prot));
		} else {
		pte_clear(&init_mm, addr, ptep);
		local_flush_tlb_page(addr);
		}
		}

		asmlinkage void __init setup_vm(void)
		{
		extern char _start;
		@@ -172,20 +193,33 @@ asmlinkage void __init setup_vm(void)

		for (i = 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) {
		size_t o = (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i;

		swapper_pg_dir[o] =
		pfn_pgd(PFN_DOWN((uintptr_t)swapper_pmd) + i,
		__pgprot(_PAGE_TABLE));
		}
		for (i = 0; i < ARRAY_SIZE(swapper_pmd); i++)
		swapper_pmd[i] = pfn_pmd(PFN_DOWN(pa + i * PMD_SIZE), prot);

		swapper_pg_dir[(FIXADDR_START >> PGDIR_SHIFT) % PTRS_PER_PGD] =
		pfn_pgd(PFN_DOWN((uintptr_t)fixmap_pmd),
		__pgprot(_PAGE_TABLE));
		fixmap_pmd[(FIXADDR_START >> PMD_SHIFT) % PTRS_PER_PMD] =
		pfn_pmd(PFN_DOWN((uintptr_t)fixmap_pte),
		__pgprot(_PAGE_TABLE));
		#else
		trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =
		pfn_pgd(PFN_DOWN(pa), prot);

		for (i = 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) {
		size_t o = (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i;

		swapper_pg_dir[o] =
		pfn_pgd(PFN_DOWN(pa + i * PGDIR_SIZE), prot);
		}

		swapper_pg_dir[(FIXADDR_START >> PGDIR_SHIFT) % PTRS_PER_PGD] =
		pfn_pgd(PFN_DOWN((uintptr_t)fixmap_pte),
		__pgprot(_PAGE_TABLE));
		#endif
		}

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