diff options
| author | Noam Camus <noamc@ezchip.com> | 2015-12-06 14:40:55 +0100 |
|---|---|---|
| committer | Vineet Gupta <vgupta@synopsys.com> | 2016-05-09 06:02:32 +0200 |
| commit | 8bcf2c48f32e22f923b69f779c95b1348308d5b1 (patch) | |
| tree | de985a3469686b3dfc5cb59c2c180c5ba53e6e44 /arch | |
| parent | ARC: [plat-eznps] Add eznps platform (diff) | |
| download | linux-8bcf2c48f32e22f923b69f779c95b1348308d5b1.tar.xz linux-8bcf2c48f32e22f923b69f779c95b1348308d5b1.zip | |
ARC: [plat-eznps] Use dedicated user stack top
NPS use special mapping right below TASK_SIZE.
Hence we need to lower STACK_TOP so that user stack won't
overlap NPS special mapping.
Signed-off-by: Noam Camus <noamc@ezchip.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arc/include/asm/processor.h | 18 | ||||
| -rw-r--r-- | arch/arc/mm/tlb.c | 6 |
2 files changed, 24 insertions, 0 deletions
diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h index d0a9211ec769..194a09fce198 100644 --- a/arch/arc/include/asm/processor.h +++ b/arch/arc/include/asm/processor.h @@ -121,7 +121,25 @@ extern unsigned int get_wchan(struct task_struct *p); #define USER_KERNEL_GUTTER (VMALLOC_START - TASK_SIZE) +#ifdef CONFIG_ARC_PLAT_EZNPS +/* NPS architecture defines special window of 129M in user address space for + * special memory areas, when accessing this window the MMU do not use TLB. + * Instead MMU direct the access to: + * 0x57f00000:0x57ffffff -- 1M of closely coupled memory (aka CMEM) + * 0x58000000:0x5fffffff -- 16 huge pages, 8M each, with fixed map (aka FMTs) + * + * CMEM - is the fastest memory we got and its size is 16K. + * FMT - is used to map either to internal/external memory. + * Internal memory is the second fast memory and its size is 16M + * External memory is the biggest memory (16G) and also the slowest. + * + * STACK_TOP need to be PMD align (21bit) that is why we supply 0x57e00000. + */ +#define STACK_TOP 0x57e00000 +#else #define STACK_TOP TASK_SIZE +#endif + #define STACK_TOP_MAX STACK_TOP /* This decides where the kernel will search for a free chunk of vm diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c index 745a9aeb2d96..ec868a9081a1 100644 --- a/arch/arc/mm/tlb.c +++ b/arch/arc/mm/tlb.c @@ -819,6 +819,12 @@ void arc_mmu_init(void) */ BUILD_BUG_ON(!IS_ALIGNED((CONFIG_ARC_KVADDR_SIZE << 20), PMD_SIZE)); + /* + * stack top size sanity check, + * Can't be done in processor.h due to header include depenedencies + */ + BUILD_BUG_ON(!IS_ALIGNED(STACK_TOP, 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 |