/* Bits in the SLB VSID word */
#define SLB_VSID_SHIFT 12
+#define SLB_VSID_SHIFT_256M SLB_VSID_SHIFT
#define SLB_VSID_SHIFT_1T 24
#define SLB_VSID_SSIZE_SHIFT 62
#define SLB_VSID_B ASM_CONST(0xc000000000000000)
static inline unsigned long hpt_hash(unsigned long vpn,
unsigned int shift, int ssize)
{
- int mask;
+ unsigned long mask;
unsigned long hash, vsid;
/* VPN_SHIFT can be atmost 12 */
* 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 1-4 to map addresses 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:
* 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.
*/
+/*
+ * Max Va bits we support as of now is 68 bits. We want 19 bit
+ * context ID.
+ * Restrictions:
+ * GPU has restrictions of not able to access beyond 128TB
+ * (47 bit effective address). We also cannot do more than 20bit PID.
+ * For p4 and p5 which can only do 65 bit VA, we restrict our CONTEXT_BITS
+ * to 16 bits (ie, we can only have 2^16 pids at the same time).
+ */
+#define VA_BITS 68
#define CONTEXT_BITS 19
-#define ESID_BITS 18
-#define ESID_BITS_1T 6
+#define ESID_BITS (VA_BITS - (SID_SHIFT + CONTEXT_BITS))
+#define ESID_BITS_1T (VA_BITS - (SID_SHIFT_1T + CONTEXT_BITS))
#define ESID_BITS_MASK ((1 << ESID_BITS) - 1)
#define ESID_BITS_1T_MASK ((1 << ESID_BITS_1T) - 1)
/*
* 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 2^49 bytes (512TB).
+ *
+ * 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) - 2)
+#define MIN_USER_CONTEXT (5)
+
+/* Would be nice to use KERNEL_REGION_ID here */
+#define KERNEL_REGION_CONTEXT_OFFSET (0xc - 1)
+
+/*
+ * For platforms that support on 65bit VA we limit the context bits
*/
-#define MAX_USER_CONTEXT ((ASM_CONST(1) << CONTEXT_BITS) - 5)
+#define MAX_USER_CONTEXT_65BIT_VA ((ASM_CONST(1) << (65 - (SID_SHIFT + ESID_BITS))) - 2)
/*
* This should be computed such that protovosid * vsid_mulitplier
- * doesn't overflow 64 bits. It should also be co-prime to vsid_modulus
+ * doesn't overflow 64 bits. The vsid_mutliplier should also be
+ * co-prime to vsid_modulus. We also need to make sure that number
+ * of bits in multiplied result (dividend) is less than twice the number of
+ * protovsid bits for our modulus optmization to work.
+ *
+ * The below table shows the current values used.
+ * |-------+------------+----------------------+------------+-------------------|
+ * | | Prime Bits | proto VSID_BITS_65VA | Total Bits | 2* prot VSID_BITS |
+ * |-------+------------+----------------------+------------+-------------------|
+ * | 1T | 24 | 25 | 49 | 50 |
+ * |-------+------------+----------------------+------------+-------------------|
+ * | 256MB | 24 | 37 | 61 | 74 |
+ * |-------+------------+----------------------+------------+-------------------|
+ *
+ * |-------+------------+----------------------+------------+--------------------|
+ * | | Prime Bits | proto VSID_BITS_68VA | Total Bits | 2* proto VSID_BITS |
+ * |-------+------------+----------------------+------------+--------------------|
+ * | 1T | 24 | 28 | 52 | 56 |
+ * |-------+------------+----------------------+------------+--------------------|
+ * | 256MB | 24 | 40 | 64 | 80 |
+ * |-------+------------+----------------------+------------+--------------------|
+ *
*/
#define VSID_MULTIPLIER_256M ASM_CONST(12538073) /* 24-bit prime */
-#define VSID_BITS_256M (CONTEXT_BITS + ESID_BITS)
-#define VSID_MODULUS_256M ((1UL<<VSID_BITS_256M)-1)
+#define VSID_BITS_256M (VA_BITS - SID_SHIFT)
+#define VSID_BITS_65_256M (65 - SID_SHIFT)
+/*
+ * Modular multiplicative inverse of VSID_MULTIPLIER under modulo VSID_MODULUS
+ */
+#define VSID_MULINV_256M ASM_CONST(665548017062)
#define VSID_MULTIPLIER_1T ASM_CONST(12538073) /* 24-bit prime */
-#define VSID_BITS_1T (CONTEXT_BITS + ESID_BITS_1T)
-#define VSID_MODULUS_1T ((1UL<<VSID_BITS_1T)-1)
-
+#define VSID_BITS_1T (VA_BITS - SID_SHIFT_1T)
+#define VSID_BITS_65_1T (65 - SID_SHIFT_1T)
+#define VSID_MULINV_1T ASM_CONST(209034062)
+/* 1TB VSID reserved for VRMA */
+#define VRMA_VSID 0x1ffffffUL
#define USER_VSID_RANGE (1UL << (ESID_BITS + SID_SHIFT))
-/*
- * This macro generates asm code to compute the VSID scramble
- * function. Used in slb_allocate() and do_stab_bolted. The function
- * computed is: (protovsid*VSID_MULTIPLIER) % VSID_MODULUS
- *
- * rt = register containing the proto-VSID and into which the
- * VSID will be stored
- * rx = scratch register (clobbered)
- *
- * - rt and rx must be different registers
- * - The answer will end up in the low VSID_BITS bits of rt. The higher
- * bits may contain other garbage, so you may need to mask the
- * result.
- */
-#define ASM_VSID_SCRAMBLE(rt, rx, size) \
- lis rx,VSID_MULTIPLIER_##size@h; \
- ori rx,rx,VSID_MULTIPLIER_##size@l; \
- mulld rt,rt,rx; /* rt = rt * MULTIPLIER */ \
- \
- srdi rx,rt,VSID_BITS_##size; \
- clrldi rt,rt,(64-VSID_BITS_##size); \
- add rt,rt,rx; /* add high and low bits */ \
- /* NOTE: explanation based on VSID_BITS_##size = 36 \
- * Now, r3 == VSID (mod 2^36-1), and lies between 0 and \
- * 2^36-1+2^28-1. That in particular means that if r3 >= \
- * 2^36-1, then r3+1 has the 2^36 bit set. So, if r3+1 has \
- * the bit clear, r3 already has the answer we want, if it \
- * doesn't, the answer is the low 36 bits of r3+1. So in all \
- * cases the answer is the low 36 bits of (r3 + ((r3+1) >> 36))*/\
- addi rx,rt,1; \
- srdi rx,rx,VSID_BITS_##size; /* extract 2^VSID_BITS bit */ \
- add rt,rt,rx
-
/* 4 bits per slice and we have one slice per 1TB */
-#define SLICE_ARRAY_SIZE (H_PGTABLE_RANGE >> 41)
+#define SLICE_ARRAY_SIZE (H_PGTABLE_RANGE >> 41)
+#define TASK_SLICE_ARRAY_SZ(x) ((x)->context.addr_limit >> 41)
#ifndef __ASSEMBLY__
#define vsid_scramble(protovsid, size) \
((((protovsid) * VSID_MULTIPLIER_##size) % VSID_MODULUS_##size))
-#else /* 1 */
+/* simplified form avoiding mod operation */
#define vsid_scramble(protovsid, size) \
({ \
unsigned long x; \
x = (x >> VSID_BITS_##size) + (x & VSID_MODULUS_##size); \
(x + ((x+1) >> VSID_BITS_##size)) & VSID_MODULUS_##size; \
})
+
+#else /* 1 */
+static inline unsigned long vsid_scramble(unsigned long protovsid,
+ unsigned long vsid_multiplier, int vsid_bits)
+{
+ unsigned long vsid;
+ unsigned long vsid_modulus = ((1UL << vsid_bits) - 1);
+ /*
+ * We have same multipler for both 256 and 1T segements now
+ */
+ vsid = protovsid * vsid_multiplier;
+ vsid = (vsid >> vsid_bits) + (vsid & vsid_modulus);
+ return (vsid + ((vsid + 1) >> vsid_bits)) & vsid_modulus;
+}
+
#endif /* 1 */
/* Returns the segment size indicator for a user address */
static inline unsigned long get_vsid(unsigned long context, unsigned long ea,
int ssize)
{
+ unsigned long va_bits = VA_BITS;
+ unsigned long vsid_bits;
+ unsigned long protovsid;
+
/*
* Bad address. We return VSID 0 for that
*/
if ((ea & ~REGION_MASK) >= H_PGTABLE_RANGE)
return 0;
- if (ssize == MMU_SEGSIZE_256M)
- return vsid_scramble((context << ESID_BITS)
- | ((ea >> SID_SHIFT) & ESID_BITS_MASK), 256M);
- return vsid_scramble((context << ESID_BITS_1T)
- | ((ea >> SID_SHIFT_1T) & ESID_BITS_1T_MASK), 1T);
+ if (!mmu_has_feature(MMU_FTR_68_BIT_VA))
+ va_bits = 65;
+
+ if (ssize == MMU_SEGSIZE_256M) {
+ vsid_bits = va_bits - SID_SHIFT;
+ protovsid = (context << ESID_BITS) |
+ ((ea >> SID_SHIFT) & ESID_BITS_MASK);
+ return vsid_scramble(protovsid, VSID_MULTIPLIER_256M, vsid_bits);
+ }
+ /* 1T segment */
+ vsid_bits = va_bits - SID_SHIFT_1T;
+ protovsid = (context << ESID_BITS_1T) |
+ ((ea >> SID_SHIFT_1T) & ESID_BITS_1T_MASK);
+ return vsid_scramble(protovsid, VSID_MULTIPLIER_1T, vsid_bits);
}
/*
* 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;
+ if (!is_kernel_addr(ea))
+ return 0;
+
/*
- * 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);
}
git.samba.org / sfrench / cifs-2.6.git / blobdiff