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ARM: Section based HYP idmap

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Add a method (hyp_idmap_setup) to populate a hyp pgd with an
identity mapping of the code contained in the .hyp.idmap.text
section.

Offer a method to drop this identity mapping through
hyp_idmap_teardown.

Make all the above depend on CONFIG_ARM_VIRT_EXT and CONFIG_ARM_LPAE.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
This commit is contained in:
Christoffer Dall 2013-01-20 18:43:10 -05:00
parent cc577c26e2
commit 9e9a367c29
4 changed files with 51 additions and 12 deletions
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1
arch/arm/include/asm/idmap.h
View file

@ -8,6 +8,7 @@
#define __idmap __section(.idmap.text) noinline notrace
extern pgd_t *idmap_pgd;
extern pgd_t *hyp_pgd;
void setup_mm_for_reboot(void);

1
arch/arm/include/asm/pgtable-3level-hwdef.h
View file

@ -44,6 +44,7 @@
#define PMD_SECT_XN (_AT(pmdval_t, 1) << 54)
#define PMD_SECT_AP_WRITE (_AT(pmdval_t, 0))
#define PMD_SECT_AP_READ (_AT(pmdval_t, 0))
#define PMD_SECT_AP1 (_AT(pmdval_t, 1) << 6)
#define PMD_SECT_TEX(x) (_AT(pmdval_t, 0))
/*

6
arch/arm/kernel/vmlinux.lds.S
View file

@ -19,7 +19,11 @@
ALIGN_FUNCTION(); \
VMLINUX_SYMBOL(__idmap_text_start) = .; \
*(.idmap.text) \
VMLINUX_SYMBOL(__idmap_text_end) = .;
VMLINUX_SYMBOL(__idmap_text_end) = .; \
ALIGN_FUNCTION(); \
VMLINUX_SYMBOL(__hyp_idmap_text_start) = .; \
*(.hyp.idmap.text) \
VMLINUX_SYMBOL(__hyp_idmap_text_end) = .;
#ifdef CONFIG_HOTPLUG_CPU
#define ARM_CPU_DISCARD(x)

55
arch/arm/mm/idmap.c
View file

@ -1,4 +1,6 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <asm/cputype.h>
#include <asm/idmap.h>
@ -6,6 +8,7 @@
#include <asm/pgtable.h>
#include <asm/sections.h>
#include <asm/system_info.h>
#include <asm/virt.h>
pgd_t *idmap_pgd;
@ -59,11 +62,17 @@ static void idmap_add_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
} while (pud++, addr = next, addr != end);
}
static void identity_mapping_add(pgd_t *pgd, unsigned long addr, unsigned long end)
static void identity_mapping_add(pgd_t *pgd, const char *text_start,
const char *text_end, unsigned long prot)
{
unsigned long prot, next;
unsigned long addr, end;
unsigned long next;
addr = virt_to_phys(text_start);
end = virt_to_phys(text_end);
prot |= PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF;
prot = PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF;
if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale())
prot |= PMD_BIT4;
@ -74,28 +83,52 @@ static void identity_mapping_add(pgd_t *pgd, unsigned long addr, unsigned long e
} while (pgd++, addr = next, addr != end);
}
#if defined(CONFIG_ARM_VIRT_EXT) && defined(CONFIG_ARM_LPAE)
pgd_t *hyp_pgd;
extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[];
static int __init init_static_idmap_hyp(void)
{
hyp_pgd = kzalloc(PTRS_PER_PGD * sizeof(pgd_t), GFP_KERNEL);
if (!hyp_pgd)
return -ENOMEM;
pr_info("Setting up static HYP identity map for 0x%p - 0x%p\n",
__hyp_idmap_text_start, __hyp_idmap_text_end);
identity_mapping_add(hyp_pgd, __hyp_idmap_text_start,
__hyp_idmap_text_end, PMD_SECT_AP1);
return 0;
}
#else
static int __init init_static_idmap_hyp(void)
{
return 0;
}
#endif
extern char __idmap_text_start[], __idmap_text_end[];
static int __init init_static_idmap(void)
{
phys_addr_t idmap_start, idmap_end;
int ret;
idmap_pgd = pgd_alloc(&init_mm);
if (!idmap_pgd)
return -ENOMEM;
/* Add an identity mapping for the physical address of the section. */
idmap_start = virt_to_phys((void *)__idmap_text_start);
idmap_end = virt_to_phys((void *)__idmap_text_end);
pr_info("Setting up static identity map for 0x%p - 0x%p\n",
__idmap_text_start, __idmap_text_end);
identity_mapping_add(idmap_pgd, __idmap_text_start,
__idmap_text_end, 0);
pr_info("Setting up static identity map for 0x%llx - 0x%llx\n",
(long long)idmap_start, (long long)idmap_end);
identity_mapping_add(idmap_pgd, idmap_start, idmap_end);
ret = init_static_idmap_hyp();
/* Flush L1 for the hardware to see this page table content */
flush_cache_louis();
return 0;
return ret;
}
early_initcall(init_static_idmap);