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ARC: Make vmalloc size configurable 

On ARC, lower 2G of address space is translated and used for
 - user vaddr space (region 0 to 5)
 - unused kernel-user gutter (region 6)
 - kernel vaddr space (region 7)

where each region simply represents 256MB of address space.

The kernel vaddr space of 256MB is used to implement vmalloc, modules
So far this was enough, but not on EZChip system with 4K CPUs (given
that per cpu mechanism uses vmalloc for allocating chunks)

So allow VMALLOC_SIZE to be configurable by expanding down into the unused
kernel-user gutter region which at default 256M was excessive anyways.

Also use _BITUL() to fix a build error since PGDIR_SIZE cannot use "1UL"
as called from assembly code in mm/tlbex.S

Signed-off-by: Noam Camus <noamc@ezchip.com>
[vgupta: rewrote changelog, debugged bootup crash due to int vs. hex]
Acked-by: Vineet Gupta <vgupta@synopsys.com>
This commit is contained in:
Noam Camus 2014-09-07 22:52:33 +03:00 committed by Vineet Gupta
parent 4bb40c6d6c
commit 15ca68a993
4 changed files with 26 additions and 11 deletions
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11
arch/arc/Kconfig
View File

@ -492,6 +492,17 @@ config ARCH_DMA_ADDR_T_64BIT
config ARC_PLAT_NEEDS_PHYS_TO_DMA
bool
config ARC_KVADDR_SIZE
int "Kernel Virtaul Address Space size (MB)"
range 0 512
default "256"
help
The kernel address space is carved out of 256MB of translated address
space for catering to vmalloc, modules, pkmap, fixmap. This however may
not suffice vmalloc requirements of a 4K CPU EZChip system. So allow
this to be stretched to 512 MB (by extending into the reserved
kernel-user gutter)
config ARC_CURR_IN_REG
bool "Dedicate Register r25 for current_task pointer"
default y

2
arch/arc/include/asm/pgtable.h
View File

@ -217,7 +217,7 @@
#define BITS_FOR_PTE (PGDIR_SHIFT - PAGE_SHIFT)
#define BITS_FOR_PGD (32 - PGDIR_SHIFT)
#define PGDIR_SIZE (1UL << PGDIR_SHIFT) /* vaddr span, not PDG sz */
#define PGDIR_SIZE _BITUL(PGDIR_SHIFT) /* vaddr span, not PDG sz */
#define PGDIR_MASK (~(PGDIR_SIZE-1))
#define PTRS_PER_PTE _BITUL(BITS_FOR_PTE)

19
arch/arc/include/asm/processor.h
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@ -97,7 +97,7 @@ extern unsigned int get_wchan(struct task_struct *p);
#endif /* !__ASSEMBLY__ */
/*
* System Memory Map on ARC
* Default System Memory Map on ARC
*
* ---------------------------- (lower 2G, Translated) -------------------------
* 0x0000_0000 0x5FFF_FFFF (user vaddr: TASK_SIZE)
@ -109,18 +109,17 @@ extern unsigned int get_wchan(struct task_struct *p);
* 0xC000_0000 0xFFFF_FFFF (peripheral uncached space)
* -----------------------------------------------------------------------------
*/
#define VMALLOC_START 0x70000000
/*
* 1 PGDIR_SIZE each for fixmap/pkmap, 2 PGDIR_SIZE gutter
* See asm/highmem.h for details
*/
#define VMALLOC_SIZE (PAGE_OFFSET - VMALLOC_START - PGDIR_SIZE * 4)
#define TASK_SIZE 0x60000000
#define VMALLOC_START (PAGE_OFFSET - (CONFIG_ARC_KVADDR_SIZE << 20))
/* 1 PGDIR_SIZE each for fixmap/pkmap, 2 PGDIR_SIZE gutter (see asm/highmem.h) */
#define VMALLOC_SIZE ((CONFIG_ARC_KVADDR_SIZE << 20) - PGDIR_SIZE * 4)
#define VMALLOC_END (VMALLOC_START + VMALLOC_SIZE)
#define USER_KERNEL_GUTTER 0x10000000
#define TASK_SIZE (VMALLOC_START - USER_KERNEL_GUTTER)
#define USER_KERNEL_GUTTER (VMALLOC_START - TASK_SIZE)
#define STACK_TOP TASK_SIZE
#define STACK_TOP_MAX STACK_TOP

5
arch/arc/mm/tlb.c
View File

@ -814,6 +814,11 @@ void arc_mmu_init(void)
printk(arc_mmu_mumbojumbo(0, str, sizeof(str)));
/*
* Can't be done in processor.h due to header include depenedencies
*/
BUILD_BUG_ON(!IS_ALIGNED((CONFIG_ARC_KVADDR_SIZE << 20), PMD_SIZE));
/* For efficiency sake, kernel is compile time built for a MMU ver
* This must match the hardware it is running on.
* Linux built for MMU V2, if run on MMU V1 will break down because V1