8f3a2b4a96
Currently, RISC-V reserves 1MB of fixmap memory for device tree. However, it maps only single PMD (2MB) space for fixmap which leaves only < 1MB space left for other kernel features such as early ioremap which requires fixmap as well. The fixmap size can be increased by another 2MB but it brings additional complexity and changes the virtual memory layout as well. If we require some additional feature requiring fixmap again, it has to be moved again. Technically, DT doesn't need a fixmap as the memory occupied by the DT is only used during boot. That's why, We map device tree in early page table using two consecutive PGD mappings at lower addresses (< PAGE_OFFSET). This frees lot of space in fixmap and also makes maximum supported device tree size supported as PGDIR_SIZE. Thus, init memory section can be used for the same purpose as well. This simplifies fixmap implementation. Signed-off-by: Anup Patel <anup.patel@wdc.com> Signed-off-by: Atish Patra <atish.patra@wdc.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
120 lines
2.5 KiB
C
120 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
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* Chen Liqin <liqin.chen@sunplusct.com>
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* Lennox Wu <lennox.wu@sunplusct.com>
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* Copyright (C) 2012 Regents of the University of California
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*/
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/memblock.h>
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#include <linux/sched.h>
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#include <linux/console.h>
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#include <linux/screen_info.h>
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#include <linux/of_fdt.h>
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#include <linux/of_platform.h>
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#include <linux/sched/task.h>
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#include <linux/swiotlb.h>
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#include <linux/smp.h>
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#include <asm/cpu_ops.h>
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#include <asm/setup.h>
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#include <asm/sections.h>
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#include <asm/sbi.h>
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#include <asm/tlbflush.h>
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#include <asm/thread_info.h>
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#include <asm/kasan.h>
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#include "head.h"
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#ifdef CONFIG_DUMMY_CONSOLE
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struct screen_info screen_info = {
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.orig_video_lines = 30,
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.orig_video_cols = 80,
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.orig_video_mode = 0,
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.orig_video_ega_bx = 0,
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.orig_video_isVGA = 1,
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.orig_video_points = 8
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};
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#endif
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/*
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* The lucky hart to first increment this variable will boot the other cores.
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* This is used before the kernel initializes the BSS so it can't be in the
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* BSS.
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*/
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atomic_t hart_lottery __section(.sdata);
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unsigned long boot_cpu_hartid;
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static DEFINE_PER_CPU(struct cpu, cpu_devices);
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static void __init parse_dtb(void)
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{
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/* Early scan of device tree from init memory */
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if (early_init_dt_scan(dtb_early_va))
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return;
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pr_err("No DTB passed to the kernel\n");
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#ifdef CONFIG_CMDLINE_FORCE
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strlcpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
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pr_info("Forcing kernel command line to: %s\n", boot_command_line);
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#endif
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}
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void __init setup_arch(char **cmdline_p)
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{
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parse_dtb();
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init_mm.start_code = (unsigned long) _stext;
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init_mm.end_code = (unsigned long) _etext;
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init_mm.end_data = (unsigned long) _edata;
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init_mm.brk = (unsigned long) _end;
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*cmdline_p = boot_command_line;
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parse_early_param();
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setup_bootmem();
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paging_init();
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#if IS_ENABLED(CONFIG_BUILTIN_DTB)
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unflatten_and_copy_device_tree();
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#else
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if (early_init_dt_verify(__va(dtb_early_pa)))
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unflatten_device_tree();
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else
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pr_err("No DTB found in kernel mappings\n");
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#endif
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#ifdef CONFIG_SWIOTLB
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swiotlb_init(1);
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#endif
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#ifdef CONFIG_KASAN
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kasan_init();
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#endif
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#if IS_ENABLED(CONFIG_RISCV_SBI)
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sbi_init();
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#endif
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#ifdef CONFIG_SMP
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setup_smp();
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#endif
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riscv_fill_hwcap();
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}
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static int __init topology_init(void)
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{
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int i;
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for_each_possible_cpu(i) {
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struct cpu *cpu = &per_cpu(cpu_devices, i);
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cpu->hotpluggable = cpu_has_hotplug(i);
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register_cpu(cpu, i);
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}
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return 0;
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}
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subsys_initcall(topology_init);
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