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Commit 9e9a367c authored by Christoffer Dall's avatar Christoffer Dall
Browse files

ARM: Section based HYP idmap 



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: default avatarWill Deacon <will.deacon@arm.com>
Reviewed-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarChristoffer Dall <c.dall@virtualopensystems.com>
parent cc577c26

arch/arm/include/asm/idmap.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

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

+1 −0
Original line number Diff line number Diff line
@@ -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))



/*

arch/arm/kernel/vmlinux.lds.S

+5 −1
Original line number Diff line number Diff line
@@ -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)

arch/arm/mm/idmap.c

+44 −11
Original line number Diff line number Diff line 
#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);