kernel-hacking-2024-linux-s.../arch/arc/mm/init.c
Santosh Shilimkar 374d5c9964 of: Specify initrd location using 64-bit
On some PAE architectures, the entire range of physical memory could reside
outside the 32-bit limit.  These systems need the ability to specify the
initrd location using 64-bit numbers.

This patch globally modifies the early_init_dt_setup_initrd_arch() function to
use 64-bit numbers instead of the current unsigned long.

There has been quite a bit of debate about whether to use u64 or phys_addr_t.
It was concluded to stick to u64 to be consistent with rest of the device
tree code. As summarized by Geert, "The address to load the initrd is decided
by the bootloader/user and set at that point later in time. The dtb should not
be tied to the kernel you are booting"

More details on the discussion can be found here:
https://lkml.org/lkml/2013/6/20/690
https://lkml.org/lkml/2012/9/13/544

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Grant Likely <grant.likely@linaro.org>
2013-07-24 11:10:01 +01:00

134 lines
3.7 KiB
C

/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/bootmem.h>
#include <linux/memblock.h>
#include <linux/swap.h>
#include <linux/module.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
#include <asm/arcregs.h>
pgd_t swapper_pg_dir[PTRS_PER_PGD] __aligned(PAGE_SIZE);
char empty_zero_page[PAGE_SIZE] __aligned(PAGE_SIZE);
EXPORT_SYMBOL(empty_zero_page);
/* Default tot mem from .config */
static unsigned long arc_mem_sz = 0x20000000; /* some default */
/* User can over-ride above with "mem=nnn[KkMm]" in cmdline */
static int __init setup_mem_sz(char *str)
{
arc_mem_sz = memparse(str, NULL) & PAGE_MASK;
/* early console might not be setup yet - it will show up later */
pr_info("\"mem=%s\": mem sz set to %ldM\n", str, TO_MB(arc_mem_sz));
return 0;
}
early_param("mem", setup_mem_sz);
void __init early_init_dt_add_memory_arch(u64 base, u64 size)
{
arc_mem_sz = size & PAGE_MASK;
pr_info("Memory size set via devicetree %ldM\n", TO_MB(arc_mem_sz));
}
/*
* First memory setup routine called from setup_arch()
* 1. setup swapper's mm @init_mm
* 2. Count the pages we have and setup bootmem allocator
* 3. zone setup
*/
void __init setup_arch_memory(void)
{
unsigned long zones_size[MAX_NR_ZONES] = { 0, 0 };
unsigned long end_mem = CONFIG_LINUX_LINK_BASE + arc_mem_sz;
init_mm.start_code = (unsigned long)_text;
init_mm.end_code = (unsigned long)_etext;
init_mm.end_data = (unsigned long)_edata;
init_mm.brk = (unsigned long)_end;
/*
* We do it here, so that memory is correctly instantiated
* even if "mem=xxx" cmline over-ride is given and/or
* DT has memory node. Each causes an update to @arc_mem_sz
* and we finally add memory one here
*/
memblock_add(CONFIG_LINUX_LINK_BASE, arc_mem_sz);
/*------------- externs in mm need setting up ---------------*/
/* first page of system - kernel .vector starts here */
min_low_pfn = PFN_DOWN(CONFIG_LINUX_LINK_BASE);
/* Last usable page of low mem (no HIGHMEM yet for ARC port) */
max_low_pfn = max_pfn = PFN_DOWN(end_mem);
max_mapnr = max_low_pfn - min_low_pfn;
/*------------- reserve kernel image -----------------------*/
memblock_reserve(CONFIG_LINUX_LINK_BASE,
__pa(_end) - CONFIG_LINUX_LINK_BASE);
memblock_dump_all();
/*-------------- node setup --------------------------------*/
memset(zones_size, 0, sizeof(zones_size));
zones_size[ZONE_NORMAL] = max_low_pfn - min_low_pfn;
/*
* We can't use the helper free_area_init(zones[]) because it uses
* PAGE_OFFSET to compute the @min_low_pfn which would be wrong
* when our kernel doesn't start at PAGE_OFFSET, i.e.
* PAGE_OFFSET != CONFIG_LINUX_LINK_BASE
*/
free_area_init_node(0, /* node-id */
zones_size, /* num pages per zone */
min_low_pfn, /* first pfn of node */
NULL); /* NO holes */
}
/*
* mem_init - initializes memory
*
* Frees up bootmem
* Calculates and displays memory available/used
*/
void __init mem_init(void)
{
high_memory = (void *)(CONFIG_LINUX_LINK_BASE + arc_mem_sz);
free_all_bootmem();
mem_init_print_info(NULL);
}
/*
* free_initmem: Free all the __init memory.
*/
void __init_refok free_initmem(void)
{
free_initmem_default(-1);
}
#ifdef CONFIG_BLK_DEV_INITRD
void __init free_initrd_mem(unsigned long start, unsigned long end)
{
free_reserved_area((void *)start, (void *)end, -1, "initrd");
}
#endif
#ifdef CONFIG_OF_FLATTREE
void __init early_init_dt_setup_initrd_arch(u64 start, u64 end)
{
pr_err("%s(%llx, %llx)\n", __func__, start, end);
}
#endif /* CONFIG_OF_FLATTREE */