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Unverified Commit 13fd5de0 authored by Palmer Dabbelt's avatar Palmer Dabbelt
Browse files

RISC-V: Fixmap support and MM cleanups 

This patchset does:
1. Moves MM related code from kernel/setup.c to mm/init.c
2. Implements compile-time fixed mappings

Using fixed mappings, we get earlyprints even without SBI calls.

For example, we can now use kernel parameter
"earlycon=uart8250,mmio,0x10000000"
to get early prints on QEMU virt machine without using SBI calls.

The patchset is tested on QEMU virt machine.

Palmer: It looks like some of the code movement here conflicted with the
patches to move hartid handling around.  As far as I can tell the only
changed code was in smp_setup_processor_id(), and I've kept the one in
smp.c.
parents f7ccc35a 823900cd

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/include/asm/pgtable.h

+1 −0
Original line number Diff line number Diff line
@@ -404,6 +404,7 @@ static inline int ptep_clear_flush_young(struct vm_area_struct *vma, 
#define kern_addr_valid(addr)   (1) /* FIXME */

#endif



extern void setup_bootmem(void);

extern void paging_init(void);



static inline void pgtable_cache_init(void)

arch/riscv/kernel/setup.c

+4 −126
Original line number Diff line number Diff line
@@ -23,7 +23,6 @@ 
#include <linux/mm.h>

#include <linux/memblock.h>

#include <linux/sched.h>

#include <linux/initrd.h>

#include <linux/console.h>

#include <linux/screen_info.h>

#include <linux/of_fdt.h>
@@ -61,83 +60,6 @@ EXPORT_SYMBOL(empty_zero_page); 
atomic_t hart_lottery;

unsigned long boot_cpu_hartid;



#ifdef CONFIG_BLK_DEV_INITRD

static void __init setup_initrd(void)

{

	unsigned long size;



	if (initrd_start >= initrd_end) {

		pr_info("initrd not found or empty");

		goto disable;

	}

	if (__pa(initrd_end) > PFN_PHYS(max_low_pfn)) {

		pr_err("initrd extends beyond end of memory");

		goto disable;

	}



	size =  initrd_end - initrd_start;

	memblock_reserve(__pa(initrd_start), size);

	initrd_below_start_ok = 1;



	pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",

		(void *)(initrd_start), size);

	return;

disable:

	pr_cont(" - disabling initrd\n");

	initrd_start = 0;

	initrd_end = 0;

}

#endif /* CONFIG_BLK_DEV_INITRD */



pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;

pgd_t trampoline_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);



#ifndef __PAGETABLE_PMD_FOLDED

#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);

#endif



asmlinkage void __init setup_vm(void)

{

	extern char _start;

	uintptr_t i;

	uintptr_t pa = (uintptr_t) &_start;

	pgprot_t prot = __pgprot(pgprot_val(PAGE_KERNEL) | _PAGE_EXEC);



	va_pa_offset = PAGE_OFFSET - pa;

	pfn_base = PFN_DOWN(pa);



	/* Sanity check alignment and size */

	BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);

	BUG_ON((pa % (PAGE_SIZE * PTRS_PER_PTE)) != 0);



#ifndef __PAGETABLE_PMD_FOLDED

	trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =

		pfn_pgd(PFN_DOWN((uintptr_t)trampoline_pmd),

			__pgprot(_PAGE_TABLE));

	trampoline_pmd[0] = pfn_pmd(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((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);

#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);

	}

#endif

}



void __init parse_dtb(unsigned int hartid, void *dtb)

{

	if (early_init_dt_scan(__va(dtb)))
@@ -150,60 +72,17 @@ void __init parse_dtb(unsigned int hartid, void *dtb) 
#endif

}



static void __init setup_bootmem(void)

{

	struct memblock_region *reg;

	phys_addr_t mem_size = 0;



	/* Find the memory region containing the kernel */

	for_each_memblock(memory, reg) {

		phys_addr_t vmlinux_end = __pa(_end);

		phys_addr_t end = reg->base + reg->size;



		if (reg->base <= vmlinux_end && vmlinux_end <= end) {

			/*

			 * Reserve from the start of the region to the end of

			 * the kernel

			 */

			memblock_reserve(reg->base, vmlinux_end - reg->base);

			mem_size = min(reg->size, (phys_addr_t)-PAGE_OFFSET);

		}

	}

	BUG_ON(mem_size == 0);



	set_max_mapnr(PFN_DOWN(mem_size));

	max_low_pfn = PFN_DOWN(memblock_end_of_DRAM());



#ifdef CONFIG_BLK_DEV_INITRD

	setup_initrd();

#endif /* CONFIG_BLK_DEV_INITRD */



	early_init_fdt_reserve_self();

	early_init_fdt_scan_reserved_mem();

	memblock_allow_resize();

	memblock_dump_all();



	for_each_memblock(memory, reg) {

		unsigned long start_pfn = memblock_region_memory_base_pfn(reg);

		unsigned long end_pfn = memblock_region_memory_end_pfn(reg);



		memblock_set_node(PFN_PHYS(start_pfn),

		                  PFN_PHYS(end_pfn - start_pfn),

		                  &memblock.memory, 0);

	}

}



void __init setup_arch(char **cmdline_p)

{

	*cmdline_p = boot_command_line;



	parse_early_param();



	init_mm.start_code = (unsigned long) _stext;

	init_mm.end_code   = (unsigned long) _etext;

	init_mm.end_data   = (unsigned long) _edata;

	init_mm.brk        = (unsigned long) _end;



	*cmdline_p = boot_command_line;



	parse_early_param();



	setup_bootmem();

	paging_init();

	unflatten_device_tree();
@@ -222,4 +101,3 @@ void __init setup_arch(char **cmdline_p) 


	riscv_fill_hwcap();

}

arch/riscv/mm/init.c

+155 −1
Original line number Diff line number Diff line
@@ -17,7 +17,9 @@ 
#include <linux/initrd.h>

#include <linux/swap.h>

#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>
@@ -66,7 +68,159 @@ void free_initmem(void) 
}



#ifdef CONFIG_BLK_DEV_INITRD

void free_initrd_mem(unsigned long start, unsigned long end)

static void __init setup_initrd(void)

{

	unsigned long size;



	if (initrd_start >= initrd_end) {

		pr_info("initrd not found or empty");

		goto disable;

	}

	if (__pa(initrd_end) > PFN_PHYS(max_low_pfn)) {

		pr_err("initrd extends beyond end of memory");

		goto disable;

	}



	size = initrd_end - initrd_start;

	memblock_reserve(__pa(initrd_start), size);

	initrd_below_start_ok = 1;



	pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",

		(void *)(initrd_start), size);

	return;

disable:

	pr_cont(" - disabling initrd\n");

	initrd_start = 0;

	initrd_end = 0;

}



void __init free_initrd_mem(unsigned long start, unsigned long end)

{

	free_reserved_area((void *)start, (void *)end, -1, "initrd");

}

#endif /* CONFIG_BLK_DEV_INITRD */



void __init setup_bootmem(void)

{

	struct memblock_region *reg;

	phys_addr_t mem_size = 0;



	/* Find the memory region containing the kernel */

	for_each_memblock(memory, reg) {

		phys_addr_t vmlinux_end = __pa(_end);

		phys_addr_t end = reg->base + reg->size;



		if (reg->base <= vmlinux_end && vmlinux_end <= end) {

			/*

			 * Reserve from the start of the region to the end of

			 * the kernel

			 */

			memblock_reserve(reg->base, vmlinux_end - reg->base);

			mem_size = min(reg->size, (phys_addr_t)-PAGE_OFFSET);

		}

	}

	BUG_ON(mem_size == 0);



	set_max_mapnr(PFN_DOWN(mem_size));

	max_low_pfn = PFN_DOWN(memblock_end_of_DRAM());



#ifdef CONFIG_BLK_DEV_INITRD

	setup_initrd();

#endif /* CONFIG_BLK_DEV_INITRD */



	early_init_fdt_reserve_self();

	early_init_fdt_scan_reserved_mem();

	memblock_allow_resize();

	memblock_dump_all();



	for_each_memblock(memory, reg) {

		unsigned long start_pfn = memblock_region_memory_base_pfn(reg);

		unsigned long end_pfn = memblock_region_memory_end_pfn(reg);



		memblock_set_node(PFN_PHYS(start_pfn),

				  PFN_PHYS(end_pfn - start_pfn),

				  &memblock.memory, 0);

	}

}



pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;

pgd_t trampoline_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);



#ifndef __PAGETABLE_PMD_FOLDED

#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;

	uintptr_t i;

	uintptr_t pa = (uintptr_t) &_start;

	pgprot_t prot = __pgprot(pgprot_val(PAGE_KERNEL) | _PAGE_EXEC);



	va_pa_offset = PAGE_OFFSET - pa;

	pfn_base = PFN_DOWN(pa);



	/* Sanity check alignment and size */

	BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);

	BUG_ON((pa % (PAGE_SIZE * PTRS_PER_PTE)) != 0);



#ifndef __PAGETABLE_PMD_FOLDED

	trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =

		pfn_pgd(PFN_DOWN((uintptr_t)trampoline_pmd),

			__pgprot(_PAGE_TABLE));

	trampoline_pmd[0] = pfn_pmd(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((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

}

arch/riscv/kernel/smp.c

+1 −1

File changed.

Contains only whitespace changes.