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arm64: add early_ioremap support

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Add support for early IO or memory mappings which are needed before the
normal ioremap() is usable.  This also adds fixmap support for permanent
fixed mappings such as that used by the earlyprintk device register
region.

Signed-off-by: Mark Salter <msalter@redhat.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mark Salter 2014-04-07 15:39:52 -07:00 committed by Linus Torvalds
parent 0bf757c73d
commit bf4b558eba
11 changed files with 169 additions and 52 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
Documentation/arm64/memory.txt
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@ -39,7 +39,7 @@ ffffffbffa000000 ffffffbffaffffff 16MB PCI I/O space
ffffffbffb000000 ffffffbffbbfffff 12MB [guard]
ffffffbffbc00000 ffffffbffbdfffff 2MB earlyprintk device
ffffffbffbc00000 ffffffbffbdfffff 2MB fixed mappings
ffffffbffbe00000 ffffffbffbffffff 2MB [guard]
@ -66,7 +66,7 @@ fffffdfffa000000 fffffdfffaffffff 16MB PCI I/O space
fffffdfffb000000 fffffdfffbbfffff 12MB [guard]
fffffdfffbc00000 fffffdfffbdfffff 2MB earlyprintk device
fffffdfffbc00000 fffffdfffbdfffff 2MB fixed mappings
fffffdfffbe00000 fffffdfffbffffff 2MB [guard]

1
arch/arm64/Kconfig
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@ -17,6 +17,7 @@ config ARM64
select GENERIC_CLOCKEVENTS
select GENERIC_CLOCKEVENTS_BROADCAST if SMP
select GENERIC_CPU_AUTOPROBE
select GENERIC_EARLY_IOREMAP
select GENERIC_IOMAP
select GENERIC_IRQ_PROBE
select GENERIC_IRQ_SHOW

1
arch/arm64/include/asm/Kbuild
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@ -10,6 +10,7 @@ generic-y += delay.h
generic-y += div64.h
generic-y += dma.h
generic-y += emergency-restart.h
generic-y += early_ioremap.h
generic-y += errno.h
generic-y += ftrace.h
generic-y += hash.h

67
arch/arm64/include/asm/fixmap.h Normal file
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@ -0,0 +1,67 @@
/*
* fixmap.h: compile-time virtual memory allocation
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1998 Ingo Molnar
* Copyright (C) 2013 Mark Salter <msalter@redhat.com>
*
* Adapted from arch/x86_64 version.
*
*/
#ifndef _ASM_ARM64_FIXMAP_H
#define _ASM_ARM64_FIXMAP_H
#ifndef __ASSEMBLY__
#include <linux/kernel.h>
#include <asm/page.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_EARLYCON_MEM_BASE,
__end_of_permanent_fixed_addresses,
/*
* Temporary boot-time mappings, used by early_ioremap(),
* before ioremap() is functional.
*/
#ifdef CONFIG_ARM64_64K_PAGES
#define NR_FIX_BTMAPS 4
#else
#define NR_FIX_BTMAPS 64
#endif
#define FIX_BTMAPS_SLOTS 7
#define TOTAL_FIX_BTMAPS (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
__end_of_fixed_addresses
};
#define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
#define FIXMAP_PAGE_IO __pgprot(PROT_DEVICE_nGnRE)
extern void __early_set_fixmap(enum fixed_addresses idx,
phys_addr_t phys, pgprot_t flags);
#define __set_fixmap __early_set_fixmap
#include <asm-generic/fixmap.h>
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_ARM64_FIXMAP_H */

1
arch/arm64/include/asm/io.h
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@ -27,6 +27,7 @@
#include <asm/byteorder.h>
#include <asm/barrier.h>
#include <asm/pgtable.h>
#include <asm/early_ioremap.h>
#include <xen/xen.h>

2
arch/arm64/include/asm/memory.h
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@ -49,7 +49,7 @@
#define PAGE_OFFSET (UL(0xffffffffffffffff) << (VA_BITS - 1))
#define MODULES_END (PAGE_OFFSET)
#define MODULES_VADDR (MODULES_END - SZ_64M)
#define EARLYCON_IOBASE (MODULES_VADDR - SZ_4M)
#define FIXADDR_TOP (MODULES_VADDR - SZ_2M - PAGE_SIZE)
#define TASK_SIZE_64 (UL(1) << VA_BITS)
#ifdef CONFIG_COMPAT

8
arch/arm64/kernel/early_printk.c
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@ -26,6 +26,8 @@
#include <linux/amba/serial.h>
#include <linux/serial_reg.h>
#include <asm/fixmap.h>
static void __iomem *early_base;
static void (*printch)(char ch);
@ -141,8 +143,10 @@ static int __init setup_early_printk(char *buf)
}
/* no options parsing yet */
if (paddr)
early_base = early_io_map(paddr, EARLYCON_IOBASE);
if (paddr) {
set_fixmap_io(FIX_EARLYCON_MEM_BASE, paddr);
early_base = (void __iomem *)fix_to_virt(FIX_EARLYCON_MEM_BASE);
}
printch = match->printch;
early_console = &early_console_dev;

9
arch/arm64/kernel/head.S
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@ -404,7 +404,7 @@ ENDPROC(__calc_phys_offset)
* - identity mapping to enable the MMU (low address, TTBR0)
* - first few MB of the kernel linear mapping to jump to once the MMU has
* been enabled, including the FDT blob (TTBR1)
* - UART mapping if CONFIG_EARLY_PRINTK is enabled (TTBR1)
* - pgd entry for fixed mappings (TTBR1)
*/
__create_page_tables:
pgtbl x25, x26, x24 // idmap_pg_dir and swapper_pg_dir addresses
@ -461,15 +461,12 @@ __create_page_tables:
sub x6, x6, #1 // inclusive range
create_block_map x0, x7, x3, x5, x6
1:
#ifdef CONFIG_EARLY_PRINTK
/*
* Create the pgd entry for the UART mapping. The full mapping is done
* later based earlyprintk kernel parameter.
* Create the pgd entry for the fixed mappings.
*/
ldr x5, =EARLYCON_IOBASE // UART virtual address
ldr x5, =FIXADDR_TOP // Fixed mapping virtual address
add x0, x26, #2 * PAGE_SIZE // section table address
create_pgd_entry x26, x0, x5, x6, x7
#endif
ret
ENDPROC(__create_page_tables)
.ltorg

2
arch/arm64/kernel/setup.c
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@ -42,6 +42,7 @@
#include <linux/of_fdt.h>
#include <linux/of_platform.h>
#include <asm/fixmap.h>
#include <asm/cputype.h>
#include <asm/elf.h>
#include <asm/cputable.h>
@ -361,6 +362,7 @@ void __init setup_arch(char **cmdline_p)
*cmdline_p = boot_command_line;
init_mem_pgprot();
early_ioremap_init();
parse_early_param();

85
arch/arm64/mm/ioremap.c
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@ -25,6 +25,10 @@
#include <linux/vmalloc.h>
#include <linux/io.h>
#include <asm/fixmap.h>
#include <asm/tlbflush.h>
#include <asm/pgalloc.h>
static void __iomem *__ioremap_caller(phys_addr_t phys_addr, size_t size,
pgprot_t prot, void *caller)
{
@ -98,3 +102,84 @@ void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size)
__builtin_return_address(0));
}
EXPORT_SYMBOL(ioremap_cache);
#ifndef CONFIG_ARM64_64K_PAGES
static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
#endif
static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
{
pgd_t *pgd;
pud_t *pud;
pgd = pgd_offset_k(addr);
BUG_ON(pgd_none(*pgd) || pgd_bad(*pgd));
pud = pud_offset(pgd, addr);
BUG_ON(pud_none(*pud) || pud_bad(*pud));
return pmd_offset(pud, addr);
}
static inline pte_t * __init early_ioremap_pte(unsigned long addr)
{
pmd_t *pmd = early_ioremap_pmd(addr);
BUG_ON(pmd_none(*pmd) || pmd_bad(*pmd));
return pte_offset_kernel(pmd, addr);
}
void __init early_ioremap_init(void)
{
pmd_t *pmd;
pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
#ifndef CONFIG_ARM64_64K_PAGES
/* need to populate pmd for 4k pagesize only */
pmd_populate_kernel(&init_mm, pmd, bm_pte);
#endif
/*
* The boot-ioremap range spans multiple pmds, for which
* we are not prepared:
*/
BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
!= (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) {
WARN_ON(1);
pr_warn("pmd %p != %p\n",
pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END)));
pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
fix_to_virt(FIX_BTMAP_BEGIN));
pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n",
fix_to_virt(FIX_BTMAP_END));
pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END);
pr_warn("FIX_BTMAP_BEGIN: %d\n",
FIX_BTMAP_BEGIN);
}
early_ioremap_setup();
}
void __init __early_set_fixmap(enum fixed_addresses idx,
phys_addr_t phys, pgprot_t flags)
{
unsigned long addr = __fix_to_virt(idx);
pte_t *pte;
if (idx >= __end_of_fixed_addresses) {
BUG();
return;
}
pte = early_ioremap_pte(addr);
if (pgprot_val(flags))
set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
else {
pte_clear(&init_mm, addr, pte);
flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
}
}

41
arch/arm64/mm/mmu.c
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@ -260,47 +260,6 @@ static void __init create_mapping(phys_addr_t phys, unsigned long virt,
} while (pgd++, addr = next, addr != end);
}
#ifdef CONFIG_EARLY_PRINTK
/*
* Create an early I/O mapping using the pgd/pmd entries already populated
* in head.S as this function is called too early to allocated any memory. The
* mapping size is 2MB with 4KB pages or 64KB or 64KB pages.
*/
void __iomem * __init early_io_map(phys_addr_t phys, unsigned long virt)
{
unsigned long size, mask;
bool page64k = IS_ENABLED(CONFIG_ARM64_64K_PAGES);
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
/*
* No early pte entries with !ARM64_64K_PAGES configuration, so using
* sections (pmd).
*/
size = page64k ? PAGE_SIZE : SECTION_SIZE;
mask = ~(size - 1);
pgd = pgd_offset_k(virt);
pud = pud_offset(pgd, virt);
if (pud_none(*pud))
return NULL;
pmd = pmd_offset(pud, virt);
if (page64k) {
if (pmd_none(*pmd))
return NULL;
pte = pte_offset_kernel(pmd, virt);
set_pte(pte, __pte((phys & mask) | PROT_DEVICE_nGnRE));
} else {
set_pmd(pmd, __pmd((phys & mask) | PROT_SECT_DEVICE_nGnRE));
}
return (void __iomem *)((virt & mask) + (phys & ~mask));
}
#endif
static void __init map_mem(void)
{
struct memblock_region *reg;