ARM: 8415/1: early fixmap support for earlycon (a5f4c561) · Commits · 戴 / test

arch/arm/Kconfig

+3 −0

Original line number	Diff line number	Diff line
		@@ -188,6 +188,9 @@ config ARCH_HAS_ILOG2_U64
		config ARCH_HAS_BANDGAP
		bool

		config FIX_EARLYCON_MEM
		def_bool y if MMU

		config GENERIC_HWEIGHT
		bool
		default y

arch/arm/include/asm/fixmap.h

+14 −1

Original line number	Diff line number	Diff line
		@@ -6,9 +6,13 @@
		#define FIXADDR_TOP (FIXADDR_END - PAGE_SIZE)

		#include <asm/kmap_types.h>
		#include <asm/pgtable.h>

		enum fixed_addresses {
		FIX_KMAP_BEGIN,
		FIX_EARLYCON_MEM_BASE,
		__end_of_permanent_fixed_addresses,

		FIX_KMAP_BEGIN = __end_of_permanent_fixed_addresses,
		FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1,

		/* Support writing RO kernel text via kprobes, jump labels, etc. */
		@@ -18,7 +22,16 @@ enum fixed_addresses {
		__end_of_fixed_addresses
		};

		#define FIXMAP_PAGE_COMMON (L_PTE_YOUNG \| L_PTE_PRESENT \| L_PTE_XN \| L_PTE_DIRTY)

		#define FIXMAP_PAGE_NORMAL (FIXMAP_PAGE_COMMON \| L_PTE_MT_WRITEBACK)

		/* Used by set_fixmap_(io\|nocache), both meant for mapping a device */
		#define FIXMAP_PAGE_IO (FIXMAP_PAGE_COMMON \| L_PTE_MT_DEV_SHARED \| L_PTE_SHARED)
		#define FIXMAP_PAGE_NOCACHE FIXMAP_PAGE_IO

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

		#include <asm-generic/fixmap.h>

arch/arm/kernel/setup.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -37,6 +37,7 @@
		#include <asm/cpu.h>
		#include <asm/cputype.h>
		#include <asm/elf.h>
		#include <asm/fixmap.h>
		#include <asm/procinfo.h>
		#include <asm/psci.h>
		#include <asm/sections.h>
		@@ -954,6 +955,9 @@ void __init setup_arch(char **cmdline_p)
		strlcpy(cmd_line, boot_command_line, COMMAND_LINE_SIZE);
		*cmdline_p = cmd_line;

		if (IS_ENABLED(CONFIG_FIX_EARLYCON_MEM))
		early_fixmap_init();

		parse_early_param();

		#ifdef CONFIG_MMU

arch/arm/mm/highmem.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -79,7 +79,7 @@ void kmap_atomic(struct page page)

		type = kmap_atomic_idx_push();

		idx = type + KM_TYPE_NR * smp_processor_id();
		idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
		vaddr = __fix_to_virt(idx);
		#ifdef CONFIG_DEBUG_HIGHMEM
		/*
		@@ -106,7 +106,7 @@ void __kunmap_atomic(void *kvaddr)

		if (kvaddr >= (void *)FIXADDR_START) {
		type = kmap_atomic_idx();
		idx = type + KM_TYPE_NR * smp_processor_id();
		idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();

		if (cache_is_vivt())
		__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
		@@ -138,7 +138,7 @@ void *kmap_atomic_pfn(unsigned long pfn)
		return page_address(page);

		type = kmap_atomic_idx_push();
		idx = type + KM_TYPE_NR * smp_processor_id();
		idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
		vaddr = __fix_to_virt(idx);
		#ifdef CONFIG_DEBUG_HIGHMEM
		BUG_ON(!pte_none(get_fixmap_pte(vaddr)));

arch/arm/mm/mmu.c

+81 −7

Original line number	Diff line number	Diff line
		@@ -357,6 +357,47 @@ const struct mem_type *get_mem_type(unsigned int type)
		}
		EXPORT_SYMBOL(get_mem_type);

		static pte_t (pte_offset_fixmap)(pmd_t *dir, unsigned long addr);

		static pte_t bm_pte[PTRS_PER_PTE + PTE_HWTABLE_PTRS]
		__aligned(PTE_HWTABLE_OFF + PTE_HWTABLE_SIZE) __initdata;

		static pte_t * __init pte_offset_early_fixmap(pmd_t *dir, unsigned long addr)
		{
		return &bm_pte[pte_index(addr)];
		}

		static pte_t pte_offset_late_fixmap(pmd_t dir, unsigned long addr)
		{
		return pte_offset_kernel(dir, addr);
		}

		static inline pmd_t * __init fixmap_pmd(unsigned long addr)
		{
		pgd_t *pgd = pgd_offset_k(addr);
		pud_t *pud = pud_offset(pgd, addr);
		pmd_t *pmd = pmd_offset(pud, addr);

		return pmd;
		}

		void __init early_fixmap_init(void)
		{
		pmd_t *pmd;

		/*
		* The early fixmap range spans multiple pmds, for which
		* we are not prepared:
		*/
		BUILD_BUG_ON((__fix_to_virt(__end_of_permanent_fixed_addresses) >> PMD_SHIFT)
		!= FIXADDR_TOP >> PMD_SHIFT);

		pmd = fixmap_pmd(FIXADDR_TOP);
		pmd_populate_kernel(&init_mm, pmd, bm_pte);

		pte_offset_fixmap = pte_offset_early_fixmap;
		}

		/*
		* To avoid TLB flush broadcasts, this uses local_flush_tlb_kernel_range().
		* As a result, this can only be called with preemption disabled, as under
		@@ -365,7 +406,7 @@ EXPORT_SYMBOL(get_mem_type);
		void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)
		{
		unsigned long vaddr = __fix_to_virt(idx);
		pte_t *pte = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
		pte_t *pte = pte_offset_fixmap(pmd_off_k(vaddr), vaddr);

		/* Make sure fixmap region does not exceed available allocation. */
		BUILD_BUG_ON(FIXADDR_START + (__end_of_fixed_addresses * PAGE_SIZE) >
		@@ -855,7 +896,7 @@ static void __init create_mapping(struct map_desc *md)
		}

		if ((md->type == MT_DEVICE \|\| md->type == MT_ROM) &&
		md->virtual >= PAGE_OFFSET &&
		md->virtual >= PAGE_OFFSET && md->virtual < FIXADDR_START &&
		(md->virtual < VMALLOC_START \|\| md->virtual >= VMALLOC_END)) {
		pr_warn("BUG: mapping for 0x%08llx at 0x%08lx out of vmalloc space\n",
		(long long)__pfn_to_phys((u64)md->pfn), md->virtual);
		@@ -1213,10 +1254,10 @@ void __init arm_mm_memblock_reserve(void)

		/*
		* Set up the device mappings. Since we clear out the page tables for all
		* mappings above VMALLOC_START, we will remove any debug device mappings.
		* This means you have to be careful how you debug this function, or any
		* called function. This means you can't use any function or debugging
		* method which may touch any device, otherwise the kernel _will_ crash.
		* mappings above VMALLOC_START, except early fixmap, we might remove debug
		* device mappings. This means earlycon can be used to debug this function
		* Any other function or debugging method which may touch any device _will_
		* crash the kernel.
		*/
		static void __init devicemaps_init(const struct machine_desc *mdesc)
		{
		@@ -1231,7 +1272,10 @@ static void __init devicemaps_init(const struct machine_desc *mdesc)

		early_trap_init(vectors);

		for (addr = VMALLOC_START; addr; addr += PMD_SIZE)
		/*
		* Clear page table except top pmd used by early fixmaps
		*/
		for (addr = VMALLOC_START; addr < (FIXADDR_TOP & PMD_MASK); addr += PMD_SIZE)
		pmd_clear(pmd_off_k(addr));

		/*
		@@ -1483,6 +1527,35 @@ void __init early_paging_init(const struct machine_desc *mdesc)

		#endif

		static void __init early_fixmap_shutdown(void)
		{
		int i;
		unsigned long va = fix_to_virt(__end_of_permanent_fixed_addresses - 1);

		pte_offset_fixmap = pte_offset_late_fixmap;
		pmd_clear(fixmap_pmd(va));
		local_flush_tlb_kernel_page(va);

		for (i = 0; i < __end_of_permanent_fixed_addresses; i++) {
		pte_t *pte;
		struct map_desc map;

		map.virtual = fix_to_virt(i);
		pte = pte_offset_early_fixmap(pmd_off_k(map.virtual), map.virtual);

		/* Only i/o device mappings are supported ATM */
		if (pte_none(*pte) \|\|
		(pte_val(*pte) & L_PTE_MT_MASK) != L_PTE_MT_DEV_SHARED)
		continue;

		map.pfn = pte_pfn(*pte);
		map.type = MT_DEVICE;
		map.length = PAGE_SIZE;

		create_mapping(&map);
		}
		}

		/*
		* paging_init() sets up the page tables, initialises the zone memory
		* maps, and sets up the zero page, bad page and bad page tables.
		@@ -1495,6 +1568,7 @@ void __init paging_init(const struct machine_desc *mdesc)
		prepare_page_table();
		map_lowmem();
		dma_contiguous_remap();
		early_fixmap_shutdown();
		devicemaps_init(mdesc);
		kmap_init();
		tcm_init();

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