diff options
| -rw-r--r-- | arch/powerpc/include/asm/book3s/64/mmu-hash.h | 60 | ||||
| -rw-r--r-- | arch/powerpc/mm/mmu_context_book3s64.c | 2 | ||||
| -rw-r--r-- | arch/powerpc/mm/slb_low.S | 20 |
3 files changed, 41 insertions, 41 deletions
diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h index 52d8d1e4b772..a5ab6f5b8a7f 100644 --- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h +++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h @@ -491,13 +491,14 @@ extern void slb_set_size(u16 size); * We first generate a 37-bit "proto-VSID". Proto-VSIDs are generated * from mmu context id and effective segment id of the address. * - * For user processes max context id is limited to ((1ul << 19) - 5) - * for kernel space, we use the top 4 context ids to map address as below + * For user processes max context id is limited to MAX_USER_CONTEXT. + + * For kernel space, we use context ids 1-5 to map address as below: * NOTE: each context only support 64TB now. - * 0x7fffc - [ 0xc000000000000000 - 0xc0003fffffffffff ] - * 0x7fffd - [ 0xd000000000000000 - 0xd0003fffffffffff ] - * 0x7fffe - [ 0xe000000000000000 - 0xe0003fffffffffff ] - * 0x7ffff - [ 0xf000000000000000 - 0xf0003fffffffffff ] + * 0x00001 - [ 0xc000000000000000 - 0xc0003fffffffffff ] + * 0x00002 - [ 0xd000000000000000 - 0xd0003fffffffffff ] + * 0x00003 - [ 0xe000000000000000 - 0xe0003fffffffffff ] + * 0x00004 - [ 0xf000000000000000 - 0xf0003fffffffffff ] * * The proto-VSIDs are then scrambled into real VSIDs with the * multiplicative hash: @@ -511,15 +512,13 @@ extern void slb_set_size(u16 size); * robust scattering in the hash table (at least based on some initial * results). * - * We also consider VSID 0 special. We use VSID 0 for slb entries mapping - * bad address. This enables us to consolidate bad address handling in - * hash_page. + * We use VSID 0 to indicate an invalid VSID. The means we can't use context id + * 0, because a context id of 0 and an EA of 0 gives a proto-VSID of 0, which + * will produce a VSID of 0. * * We also need to avoid the last segment of the last context, because that * would give a protovsid of 0x1fffffffff. That will result in a VSID 0 - * because of the modulo operation in vsid scramble. But the vmemmap - * (which is what uses region 0xf) will never be close to 64TB in size - * (it's 56 bytes per page of system memory). + * because of the modulo operation in vsid scramble. */ #define CONTEXT_BITS 19 @@ -532,12 +531,19 @@ extern void slb_set_size(u16 size); /* * 256MB segment * The proto-VSID space has 2^(CONTEX_BITS + ESID_BITS) - 1 segments - * available for user + kernel mapping. The top 4 contexts are used for - * kernel mapping. Each segment contains 2^28 bytes. Each - * context maps 2^46 bytes (64TB) so we can support 2^19-1 contexts - * (19 == 37 + 28 - 46). + * available for user + kernel mapping. VSID 0 is reserved as invalid, contexts + * 1-4 are used for kernel mapping. Each segment contains 2^28 bytes. Each + * context maps 2^46 bytes (64TB). + * + * We also need to avoid the last segment of the last context, because that + * would give a protovsid of 0x1fffffffff. That will result in a VSID 0 + * because of the modulo operation in vsid scramble. */ -#define MAX_USER_CONTEXT ((ASM_CONST(1) << CONTEXT_BITS) - 5) +#define MAX_USER_CONTEXT ((ASM_CONST(1) << CONTEXT_BITS) - 2) +#define MIN_USER_CONTEXT (5) + +/* Would be nice to use KERNEL_REGION_ID here */ +#define KERNEL_REGION_CONTEXT_OFFSET (0xc - 1) /* * This should be computed such that protovosid * vsid_mulitplier @@ -671,21 +677,25 @@ static inline unsigned long get_vsid(unsigned long context, unsigned long ea, /* * This is only valid for addresses >= PAGE_OFFSET - * - * For kernel space, we use the top 4 context ids to map address as below - * 0x7fffc - [ 0xc000000000000000 - 0xc0003fffffffffff ] - * 0x7fffd - [ 0xd000000000000000 - 0xd0003fffffffffff ] - * 0x7fffe - [ 0xe000000000000000 - 0xe0003fffffffffff ] - * 0x7ffff - [ 0xf000000000000000 - 0xf0003fffffffffff ] */ static inline unsigned long get_kernel_vsid(unsigned long ea, int ssize) { unsigned long context; /* - * kernel take the top 4 context from the available range + * For kernel space, we use context ids 1-4 to map the address space as + * below: + * + * 0x00001 - [ 0xc000000000000000 - 0xc0003fffffffffff ] + * 0x00002 - [ 0xd000000000000000 - 0xd0003fffffffffff ] + * 0x00003 - [ 0xe000000000000000 - 0xe0003fffffffffff ] + * 0x00004 - [ 0xf000000000000000 - 0xf0003fffffffffff ] + * + * So we can compute the context from the region (top nibble) by + * subtracting 11, or 0xc - 1. */ - context = (MAX_USER_CONTEXT) + ((ea >> 60) - 0xc) + 1; + context = (ea >> 60) - KERNEL_REGION_CONTEXT_OFFSET; + return get_vsid(context, ea, ssize); } diff --git a/arch/powerpc/mm/mmu_context_book3s64.c b/arch/powerpc/mm/mmu_context_book3s64.c index e5da551edde3..a10e972221c4 100644 --- a/arch/powerpc/mm/mmu_context_book3s64.c +++ b/arch/powerpc/mm/mmu_context_book3s64.c @@ -59,7 +59,7 @@ again: int hash__alloc_context_id(void) { - return alloc_context_id(1, MAX_USER_CONTEXT); + return alloc_context_id(MIN_USER_CONTEXT, MAX_USER_CONTEXT); } EXPORT_SYMBOL_GPL(hash__alloc_context_id); diff --git a/arch/powerpc/mm/slb_low.S b/arch/powerpc/mm/slb_low.S index a85e06ea6c20..ba1f8696c338 100644 --- a/arch/powerpc/mm/slb_low.S +++ b/arch/powerpc/mm/slb_low.S @@ -45,13 +45,6 @@ _GLOBAL(slb_allocate_realmode) /* r3 = address, r10 = esid, cr7 = <> PAGE_OFFSET */ blt cr7,0f /* user or kernel? */ - /* kernel address: proto-VSID = ESID */ - /* WARNING - MAGIC: we don't use the VSID 0xfffffffff, but - * this code will generate the protoVSID 0xfffffffff for the - * top segment. That's ok, the scramble below will translate - * it to VSID 0, which is reserved as a bad VSID - one which - * will never have any pages in it. */ - /* Check if hitting the linear mapping or some other kernel space */ bne cr7,1f @@ -63,12 +56,10 @@ _GLOBAL(slb_allocate_realmode) slb_miss_kernel_load_linear: li r11,0 /* - * context = (MAX_USER_CONTEXT) + ((ea >> 60) - 0xc) + 1 + * context = (ea >> 60) - (0xc - 1) * r9 = region id. */ - addis r9,r9,(MAX_USER_CONTEXT - 0xc + 1)@ha - addi r9,r9,(MAX_USER_CONTEXT - 0xc + 1)@l - + subi r9,r9,KERNEL_REGION_CONTEXT_OFFSET BEGIN_FTR_SECTION b .Lslb_finish_load @@ -77,9 +68,9 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_1T_SEGMENT) 1: #ifdef CONFIG_SPARSEMEM_VMEMMAP - /* Check virtual memmap region. To be patches at kernel boot */ cmpldi cr0,r9,0xf bne 1f +/* Check virtual memmap region. To be patched at kernel boot */ .globl slb_miss_kernel_load_vmemmap slb_miss_kernel_load_vmemmap: li r11,0 @@ -102,11 +93,10 @@ slb_miss_kernel_load_io: li r11,0 6: /* - * context = (MAX_USER_CONTEXT) + ((ea >> 60) - 0xc) + 1 + * context = (ea >> 60) - (0xc - 1) * r9 = region id. */ - addis r9,r9,(MAX_USER_CONTEXT - 0xc + 1)@ha - addi r9,r9,(MAX_USER_CONTEXT - 0xc + 1)@l + subi r9,r9,KERNEL_REGION_CONTEXT_OFFSET BEGIN_FTR_SECTION b .Lslb_finish_load |