diff mbox

[v4,02/14] ARM: Section based HYP idmap

Message ID 20121110154224.2836.21775.stgit@chazy-air (mailing list archive)
State New, archived
Headers show

Commit Message

Christoffer Dall Nov. 10, 2012, 3:42 p.m. UTC
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.

Cc: 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>
---
 arch/arm/include/asm/idmap.h                |    5 ++
 arch/arm/include/asm/pgtable-3level-hwdef.h |    1 
 arch/arm/kernel/vmlinux.lds.S               |    6 ++
 arch/arm/mm/idmap.c                         |   74 +++++++++++++++++++++++----
 4 files changed, 73 insertions(+), 13 deletions(-)

Comments

Will Deacon Nov. 19, 2012, 2:16 p.m. UTC | #1
On Sat, Nov 10, 2012 at 03:42:24PM +0000, Christoffer Dall wrote:
> 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.
> 
> Cc: 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>
> ---
>  arch/arm/include/asm/idmap.h                |    5 ++
>  arch/arm/include/asm/pgtable-3level-hwdef.h |    1 
>  arch/arm/kernel/vmlinux.lds.S               |    6 ++
>  arch/arm/mm/idmap.c                         |   74 +++++++++++++++++++++++----
>  4 files changed, 73 insertions(+), 13 deletions(-)
> 
> diff --git a/arch/arm/include/asm/idmap.h b/arch/arm/include/asm/idmap.h
> index bf863ed..36708ba 100644
> --- a/arch/arm/include/asm/idmap.h
> +++ b/arch/arm/include/asm/idmap.h
> @@ -11,4 +11,9 @@ extern pgd_t *idmap_pgd;
>  
>  void setup_mm_for_reboot(void);
>  
> +#ifdef CONFIG_ARM_VIRT_EXT
> +void hyp_idmap_teardown(pgd_t *hyp_pgd);
> +void hyp_idmap_setup(pgd_t *hyp_pgd);
> +#endif

I wonder whether the dependency is quite right here. Functionally, we're
only dependent on LPAE but it doesn't make sense if !ARM_VIRT_EXT. In
fact, I start to question whether CONFIG_ARM_VIRT_EXT is worthwhile at
all as it stands. Maybe it would be better to add the LPAE dependency
there and make the hyp_stub stuff that's currently in mainline
unconditional?

> +/*
> + * This version actually frees the underlying pmds for all pgds in range and
> + * clear the pgds themselves afterwards.
> + */
> +void hyp_idmap_teardown(pgd_t *hyp_pgd)
> +{
> +	unsigned long addr, end;
> +	unsigned long next;
> +	pgd_t *pgd = hyp_pgd;
> +
> +	addr = virt_to_phys(__hyp_idmap_text_start);
> +	end = virt_to_phys(__hyp_idmap_text_end);
> +
> +	pgd += pgd_index(addr);
> +	do {
> +		next = pgd_addr_end(addr, end);
> +		if (!pgd_none_or_clear_bad(pgd))
> +			hyp_idmap_del_pmd(pgd, addr);
> +	} while (pgd++, addr = next, addr < end);
> +}
> +EXPORT_SYMBOL_GPL(hyp_idmap_teardown);
> +
> +void hyp_idmap_setup(pgd_t *hyp_pgd)
> +{
> +	identity_mapping_add(hyp_pgd, __hyp_idmap_text_start,
> +			     __hyp_idmap_text_end, PMD_SECT_AP1);
> +}
> +EXPORT_SYMBOL_GPL(hyp_idmap_setup);
> +#endif

Again, do we need these exports?

I also think it might be cleaner to declare the hyp_pgd next to the
idmap_pgd then add the hyp_idmap_setup code to init_static_idmap, so
that we don't add new entry points to this file. The teardown can all be
moved into the kvm/ code as it doesn't need any of the existing idmap
functions.

Will
Rob Herring Nov. 19, 2012, 2:25 p.m. UTC | #2
On 11/10/2012 09:42 AM, Christoffer Dall wrote:
> 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.
> 
> Cc: 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>
> ---
>  arch/arm/include/asm/idmap.h                |    5 ++
>  arch/arm/include/asm/pgtable-3level-hwdef.h |    1 
>  arch/arm/kernel/vmlinux.lds.S               |    6 ++
>  arch/arm/mm/idmap.c                         |   74 +++++++++++++++++++++++----
>  4 files changed, 73 insertions(+), 13 deletions(-)
> 
> diff --git a/arch/arm/include/asm/idmap.h b/arch/arm/include/asm/idmap.h
> index bf863ed..36708ba 100644
> --- a/arch/arm/include/asm/idmap.h
> +++ b/arch/arm/include/asm/idmap.h
> @@ -11,4 +11,9 @@ extern pgd_t *idmap_pgd;
>  
>  void setup_mm_for_reboot(void);
>  
> +#ifdef CONFIG_ARM_VIRT_EXT
> +void hyp_idmap_teardown(pgd_t *hyp_pgd);
> +void hyp_idmap_setup(pgd_t *hyp_pgd);
> +#endif

Minor nit. You don't need ifdefs around declarations.

Rob
diff mbox

Patch

diff --git a/arch/arm/include/asm/idmap.h b/arch/arm/include/asm/idmap.h
index bf863ed..36708ba 100644
--- a/arch/arm/include/asm/idmap.h
+++ b/arch/arm/include/asm/idmap.h
@@ -11,4 +11,9 @@  extern pgd_t *idmap_pgd;
 
 void setup_mm_for_reboot(void);
 
+#ifdef CONFIG_ARM_VIRT_EXT
+void hyp_idmap_teardown(pgd_t *hyp_pgd);
+void hyp_idmap_setup(pgd_t *hyp_pgd);
+#endif
+
 #endif	/* __ASM_IDMAP_H */
diff --git a/arch/arm/include/asm/pgtable-3level-hwdef.h b/arch/arm/include/asm/pgtable-3level-hwdef.h
index d795282..a2d404e 100644
--- a/arch/arm/include/asm/pgtable-3level-hwdef.h
+++ b/arch/arm/include/asm/pgtable-3level-hwdef.h
@@ -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))
 
 /*
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index 36ff15b..12fd2eb 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -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)
diff --git a/arch/arm/mm/idmap.c b/arch/arm/mm/idmap.c
index ab88ed4..ea7430e 100644
--- a/arch/arm/mm/idmap.c
+++ b/arch/arm/mm/idmap.c
@@ -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 +62,20 @@  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);
+
+	pr_info("Setting up static %sidentity map for 0x%llx - 0x%llx\n",
+		prot ? "HYP " : "",
+		(long long)addr, (long long)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;
 
@@ -78,24 +90,62 @@  extern char  __idmap_text_start[], __idmap_text_end[];
 
 static int __init init_static_idmap(void)
 {
-	phys_addr_t idmap_start, idmap_end;
-
 	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%llx - 0x%llx\n",
-		(long long)idmap_start, (long long)idmap_end);
-	identity_mapping_add(idmap_pgd, idmap_start, idmap_end);
+	identity_mapping_add(idmap_pgd, __idmap_text_start,
+			     __idmap_text_end, 0);
 
 	return 0;
 }
 early_initcall(init_static_idmap);
 
+#if defined(CONFIG_ARM_VIRT_EXT) && defined(CONFIG_ARM_LPAE)
+static void hyp_idmap_del_pmd(pgd_t *pgd, unsigned long addr)
+{
+	pud_t *pud;
+	pmd_t *pmd;
+
+	pud = pud_offset(pgd, addr);
+	pmd = pmd_offset(pud, addr);
+	pud_clear(pud);
+	clean_pmd_entry(pmd);
+	pmd_free(NULL, (pmd_t *)((unsigned long)pmd & PAGE_MASK));
+}
+
+extern char  __hyp_idmap_text_start[], __hyp_idmap_text_end[];
+
+/*
+ * This version actually frees the underlying pmds for all pgds in range and
+ * clear the pgds themselves afterwards.
+ */
+void hyp_idmap_teardown(pgd_t *hyp_pgd)
+{
+	unsigned long addr, end;
+	unsigned long next;
+	pgd_t *pgd = hyp_pgd;
+
+	addr = virt_to_phys(__hyp_idmap_text_start);
+	end = virt_to_phys(__hyp_idmap_text_end);
+
+	pgd += pgd_index(addr);
+	do {
+		next = pgd_addr_end(addr, end);
+		if (!pgd_none_or_clear_bad(pgd))
+			hyp_idmap_del_pmd(pgd, addr);
+	} while (pgd++, addr = next, addr < end);
+}
+EXPORT_SYMBOL_GPL(hyp_idmap_teardown);
+
+void hyp_idmap_setup(pgd_t *hyp_pgd)
+{
+	identity_mapping_add(hyp_pgd, __hyp_idmap_text_start,
+			     __hyp_idmap_text_end, PMD_SECT_AP1);
+}
+EXPORT_SYMBOL_GPL(hyp_idmap_setup);
+#endif
+
 /*
  * In order to soft-boot, we need to switch to a 1:1 mapping for the
  * cpu_reset functions. This will then ensure that we have predictable