diff options
| author | Vineet Gupta <vgupta@synopsys.com> | 2015-03-05 14:46:20 +0530 |
|---|---|---|
| committer | Vineet Gupta <vgupta@synopsys.com> | 2015-06-19 18:09:29 +0530 |
| commit | 4db27dca607aed14a852b21db02ddb530551c5eb (patch) | |
| tree | 91463e5f4fb503b0abcb1fdf7837713cb3ab230d /arch/arc/include/asm/processor.h | |
| parent | def32fad84975d5d28e070215038224ea7f0d4bc (diff) | |
ARC: mm: document system mem map clearly
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'arch/arc/include/asm/processor.h')
| -rw-r--r-- | arch/arc/include/asm/processor.h | 35 |
1 files changed, 16 insertions, 19 deletions
diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h index 649e4398ed8e..ee682d8e0213 100644 --- a/arch/arc/include/asm/processor.h +++ b/arch/arc/include/asm/processor.h @@ -100,29 +100,26 @@ extern unsigned int get_wchan(struct task_struct *p); #endif /* !__ASSEMBLY__ */ -/* Kernels Virtual memory area. - * Unlike other architectures(MIPS, sh, cris ) ARC 700 does not have a - * "kernel translated" region (like KSEG2 in MIPS). So we use a upper part - * of the translated bottom 2GB for kernel virtual memory and protect - * these pages from user accesses by disabling Ru, Eu and Wu. +/* + * System Memory Map on ARC + * + * ---------------------------- (lower 2G, Translated) ------------------------- + * 0x0000_0000 0x5FFF_FFFF (user vaddr: TASK_SIZE) + * 0x6000_0000 0x6FFF_FFFF (reserved gutter between U/K) + * 0x7000_0000 0x7FFF_FFFF (kvaddr: vmalloc/modules/pkmap..) + * + * PAGE_OFFSET ---------------- (Upper 2G, Untranslated) ----------------------- + * 0x8000_0000 0xBFFF_FFFF (kernel direct mapped) + * 0xC000_0000 0xFFFF_FFFF (peripheral uncached space) + * ----------------------------------------------------------------------------- */ -#define VMALLOC_SIZE (0x10000000) /* 256M */ -#define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE) -#define VMALLOC_END (PAGE_OFFSET) +#define VMALLOC_START 0x70000000 +#define VMALLOC_SIZE (PAGE_OFFSET - VMALLOC_START) +#define VMALLOC_END (VMALLOC_START + VMALLOC_SIZE) -/* Most of the architectures seem to be keeping some kind of padding between - * userspace TASK_SIZE and PAGE_OFFSET. i.e TASK_SIZE != PAGE_OFFSET. - */ #define USER_KERNEL_GUTTER 0x10000000 -/* User address space: - * On ARC700, CPU allows the entire lower half of 32 bit address space to be - * translated. Thus potentially 2G (0:0x7FFF_FFFF) could be User vaddr space. - * However we steal 256M for kernel addr (0x7000_0000:0x7FFF_FFFF) and another - * 256M (0x6000_0000:0x6FFF_FFFF) is gutter between user/kernel spaces - * Thus total User vaddr space is (0:0x5FFF_FFFF) - */ -#define TASK_SIZE (PAGE_OFFSET - VMALLOC_SIZE - USER_KERNEL_GUTTER) +#define TASK_SIZE (VMALLOC_START - USER_KERNEL_GUTTER) #define STACK_TOP TASK_SIZE #define STACK_TOP_MAX STACK_TOP |