On Wed, Nov 27, 2013 at 4:44 PM, Mark Rutland mark.rutland@arm.com wrote:
Hi,
On Wed, Nov 27, 2013 at 07:34:24AM +0000, mohun106@gmail.com wrote:
From: Radha Mohan Chintakuntla rchintakuntla@cavium.com
This patch adds support for 48-bit physical addresses in the ARMv8 based SoCs. The VA_BITS is expanded to 48 enabling access to 128TB of kernel space. The Linux will now be using 4 levels of page tables for address translations for 4KB page size.
Given that this requires an additional level of page table to be allocated, it would be nice if this were a compile-time configuration option.
Having a compile time option increases the number of #ifdefs. Is this acceptable?
As you mentioned you'd run LTP tests, what was the additional memory and time cost over 3 levels with 40-bit addressing?
Additional memory cost will be another page table. Haven't checked the time cost though. I will get back on the time costs.
Has this been tested in conjunction with hugepages?
This is still under progress.
Signed-off-by: Radha Mohan Chintakuntla rchintakuntla@cavium.com
arch/arm64/include/asm/memory.h | 6 +-- arch/arm64/include/asm/page.h | 2 +- arch/arm64/include/asm/pgalloc.h | 16 ++++++ arch/arm64/include/asm/pgtable-4level-hwdef.h | 57 ++++++++++++++++++++ arch/arm64/include/asm/pgtable-4level-types.h | 71 +++++++++++++++++++++++++
As they're unused after this patch, it feels very odd to leave pgtable-3level-*.h lying around...
pgtable-3level-*.h is for 64KB page size. I can remove pgtable-2level*.h.
arch/arm64/include/asm/pgtable-hwdef.h | 7 ++- arch/arm64/include/asm/pgtable.h | 41 +++++++++++++-- arch/arm64/kernel/head.S | 33 +++++++++-- arch/arm64/kernel/traps.c | 5 ++ arch/arm64/mm/proc.S | 2 +- 10 files changed, 220 insertions(+), 20 deletions(-)
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 3776217..91e92b4 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -41,11 +41,7 @@
- The module space lives between the addresses given by TASK_SIZE
- and PAGE_OFFSET - it must be within 128MB of the kernel text.
*/ -#ifdef CONFIG_ARM64_64K_PAGES -#define VA_BITS (42) -#else -#define VA_BITS (39) -#endif +#define VA_BITS (48)
Doesn't this break 64k page support until the next patch?
No, for 64KB also the max width is 48.
#define PAGE_OFFSET (UL(0xffffffffffffffff) << (VA_BITS - 1)) #define MODULES_END (PAGE_OFFSET) #define MODULES_VADDR (MODULES_END - SZ_64M) diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h index 46bf666..64faf71 100644 --- a/arch/arm64/include/asm/page.h +++ b/arch/arm64/include/asm/page.h @@ -36,7 +36,7 @@ #ifdef CONFIG_ARM64_64K_PAGES #include <asm/pgtable-2level-types.h> #else -#include <asm/pgtable-3level-types.h> +#include <asm/pgtable-4level-types.h> #endif
extern void __cpu_clear_user_page(void *p, unsigned long user); diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h index 9bea6e7..482816c 100644 --- a/arch/arm64/include/asm/pgalloc.h +++ b/arch/arm64/include/asm/pgalloc.h @@ -44,6 +44,22 @@ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd) set_pud(pud, __pud(__pa(pmd) | PMD_TYPE_TABLE)); }
+static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr) +{
return (pud_t *)get_zeroed_page(GFP_KERNEL | __GFP_REPEAT);+}
This is probably a stupid question, but why do we use __GFP_REPEAT in pmd_alloc_one (and here pud_alloc_one), but not pgd_alloc or pte_alloc_one?
[...]
diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h index 755f861..05fadaf 100644 --- a/arch/arm64/include/asm/pgtable-hwdef.h +++ b/arch/arm64/include/asm/pgtable-hwdef.h @@ -19,7 +19,7 @@ #ifdef CONFIG_ARM64_64K_PAGES #include <asm/pgtable-2level-hwdef.h> #else -#include <asm/pgtable-3level-hwdef.h> +#include <asm/pgtable-4level-hwdef.h> #endif
/* @@ -100,9 +100,9 @@ #define PTE_HYP PTE_USER
/*
- 40-bit physical address supported.
*/
- 48-bit physical address supported.
-#define PHYS_MASK_SHIFT (40) +#define PHYS_MASK_SHIFT (48)
The 64k page needs to be updated to handle this or it will be broken, no?
#define PHYS_MASK ((UL(1) << PHYS_MASK_SHIFT) - 1)
/* @@ -123,6 +123,7 @@ #define TCR_TG0_64K (UL(1) << 14) #define TCR_TG1_64K (UL(1) << 30) #define TCR_IPS_40BIT (UL(2) << 32) +#define TCR_IPS_48BIT (UL(5) << 32) #define TCR_ASID16 (UL(1) << 36) #define TCR_TBI0 (UL(1) << 37)
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 17bd3af..57efd3d 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -43,12 +43,14 @@ #ifndef __ASSEMBLY__ extern void __pte_error(const char *file, int line, unsigned long val); extern void __pmd_error(const char *file, int line, unsigned long val); +extern void __pud_error(const char *file, int line, unsigned long val); extern void __pgd_error(const char *file, int line, unsigned long val);
#define pte_ERROR(pte) __pte_error(__FILE__, __LINE__, pte_val(pte)) #ifndef CONFIG_ARM64_64K_PAGES #define pmd_ERROR(pmd) __pmd_error(__FILE__, __LINE__, pmd_val(pmd)) #endif +#define pud_ERROR(pud) __pud_error(__FILE__, __LINE__, pud_val(pud)) #define pgd_ERROR(pgd) __pgd_error(__FILE__, __LINE__, pgd_val(pgd))
Given that these don't seem to be called from assembly, and currently are identical other than the "pte", "pmd, or "pgd" string, could we not have a single implementation and pass the requisite "pte", "pmd", "pud", or "pgd" in as a parameter here?
[...]
@@ -352,8 +385,8 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; extern pgd_t idmap_pg_dir[PTRS_PER_PGD];
-#define SWAPPER_DIR_SIZE (3 * PAGE_SIZE) -#define IDMAP_DIR_SIZE (2 * PAGE_SIZE) +#define SWAPPER_DIR_SIZE (4 * PAGE_SIZE) +#define IDMAP_DIR_SIZE (3 * PAGE_SIZE)
/*
- Encode and decode a swap entry:
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 7009387..cc764e5 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -45,8 +45,10 @@ #error KERNEL_RAM_VADDR must start at 0xXXX80000 #endif
-#define SWAPPER_DIR_SIZE (3 * PAGE_SIZE) -#define IDMAP_DIR_SIZE (2 * PAGE_SIZE) +#define create_page_entry create_pud_entry
+#define SWAPPER_DIR_SIZE (4 * PAGE_SIZE) +#define IDMAP_DIR_SIZE (3 * PAGE_SIZE)
I hadn't realised that SWAPPER_DIR_SIZE and IDMAP_DIR_SIZE were duplicated. Could we not moved the definition in pgtable.h before the #ifndef __ASSEMBLY__? head.S includes pgtable.h, and page.h defines PAGE_SIZE before its #ifndef __ASSEMBLY__.
[...]
@@ -336,6 +336,11 @@ void __pmd_error(const char *file, int line, unsigned long val) printk("%s:%d: bad pmd %016lx.\n", file, line, val); }
+void __pud_error(const char *file, int line, unsigned long val) +{
printk("%s:%d: bad pud %016lx.\n", file, line, val);+}
As mentioned above, I think we can unify the __p*_error functions rather than introducing a new one.
Thanks, Mark.