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alistair23-linux/arch/sparc/kernel/sun4v_tlb_miss.S
David S. Miller 37b3a8ff3e sparc64: Move from 4MB to 8MB huge pages. 
The impetus for this is that we would like to move to 64-bit PMDs and
PGDs, but that would result in only supporting a 42-bit address space
with the current page table layout.  It'd be nice to support at least
43-bits.

The reason we'd end up with only 42-bits after making PMDs and PGDs
64-bit is that we only use half-page sized PTE tables in order to make
PMDs line up to 4MB, the hardware huge page size we use.

So what we do here is we make huge pages 8MB, and fabricate them using
4MB hw TLB entries.

Facilitate this by providing a "REAL_HPAGE_SHIFT" which is used in
places that really need to operate on hardware 4MB pages.

Use full pages (512 entries) for PTE tables, and adjust PMD_SHIFT,
PGD_SHIFT, and the build time CPP test as needed.  Use a CPP test to
make sure REAL_HPAGE_SHIFT and the _PAGE_SZHUGE_* we use match up.

This makes the pgtable cache completely unused, so remove the code
managing it and the state used in mm_context_t.  Now we have less
spinlocks taken in the page table allocation path.

The technique we use to fabricate the 8MB pages is to transfer bit 22
from the missing virtual address into the PTEs physical address field.
That takes care of the transparent huge pages case.

For hugetlb, we fill things in at the PTE level and that code already
puts the sub huge page physical bits into the PTEs, based upon the
offset, so there is nothing special we need to do.  It all just works
out.

So, a small amount of complexity in the THP case, but this code is
about to get much simpler when we move the 64-bit PMDs as we can move
away from the fancy 32-bit huge PMD encoding and just put a real PTE
value in there.

With bug fixes and help from Bob Picco.

Signed-off-by: David S. Miller <davem@davemloft.net>
2013-11-12 15:22:34 -08:00

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/* sun4v_tlb_miss.S: Sun4v TLB miss handlers.
*
* Copyright (C) 2006 <davem@davemloft.net>
*/
.text
.align 32
/* Load ITLB fault information into VADDR and CTX, using BASE. */
#define LOAD_ITLB_INFO(BASE, VADDR, CTX) \
ldx [BASE + HV_FAULT_I_ADDR_OFFSET], VADDR; \
ldx [BASE + HV_FAULT_I_CTX_OFFSET], CTX;
/* Load DTLB fault information into VADDR and CTX, using BASE. */
#define LOAD_DTLB_INFO(BASE, VADDR, CTX) \
ldx [BASE + HV_FAULT_D_ADDR_OFFSET], VADDR; \
ldx [BASE + HV_FAULT_D_CTX_OFFSET], CTX;
/* DEST = (VADDR >> 22)
*
* Branch to ZERO_CTX_LABEL if context is zero.
*/
#define COMPUTE_TAG_TARGET(DEST, VADDR, CTX, ZERO_CTX_LABEL) \
srlx VADDR, 22, DEST; \
brz,pn CTX, ZERO_CTX_LABEL; \
nop;
/* Create TSB pointer. This is something like:
*
* index_mask = (512 << (tsb_reg & 0x7UL)) - 1UL;
* tsb_base = tsb_reg & ~0x7UL;
* tsb_index = ((vaddr >> HASH_SHIFT) & tsb_mask);
* tsb_ptr = tsb_base + (tsb_index * 16);
*/
#define COMPUTE_TSB_PTR(TSB_PTR, VADDR, HASH_SHIFT, TMP1, TMP2) \
and TSB_PTR, 0x7, TMP1; \
mov 512, TMP2; \
andn TSB_PTR, 0x7, TSB_PTR; \
sllx TMP2, TMP1, TMP2; \
srlx VADDR, HASH_SHIFT, TMP1; \
sub TMP2, 1, TMP2; \
and TMP1, TMP2, TMP1; \
sllx TMP1, 4, TMP1; \
add TSB_PTR, TMP1, TSB_PTR;
sun4v_itlb_miss:
/* Load MMU Miss base into %g2. */
ldxa [%g0] ASI_SCRATCHPAD, %g2
/* Load UTSB reg into %g1. */
mov SCRATCHPAD_UTSBREG1, %g1
ldxa [%g1] ASI_SCRATCHPAD, %g1
LOAD_ITLB_INFO(%g2, %g4, %g5)
COMPUTE_TAG_TARGET(%g6, %g4, %g5, kvmap_itlb_4v)
COMPUTE_TSB_PTR(%g1, %g4, PAGE_SHIFT, %g3, %g7)
/* Load TSB tag/pte into %g2/%g3 and compare the tag. */
ldda [%g1] ASI_QUAD_LDD_PHYS_4V, %g2
cmp %g2, %g6
bne,a,pn %xcc, tsb_miss_page_table_walk
mov FAULT_CODE_ITLB, %g3
andcc %g3, _PAGE_EXEC_4V, %g0
be,a,pn %xcc, tsb_do_fault
mov FAULT_CODE_ITLB, %g3
/* We have a valid entry, make hypervisor call to load
* I-TLB and return from trap.
*
* %g3: PTE
* %g4: vaddr
*/
sun4v_itlb_load:
ldxa [%g0] ASI_SCRATCHPAD, %g6
mov %o0, %g1 ! save %o0
mov %o1, %g2 ! save %o1
mov %o2, %g5 ! save %o2
mov %o3, %g7 ! save %o3
mov %g4, %o0 ! vaddr
ldx [%g6 + HV_FAULT_I_CTX_OFFSET], %o1 ! ctx
mov %g3, %o2 ! PTE
mov HV_MMU_IMMU, %o3 ! flags
ta HV_MMU_MAP_ADDR_TRAP
brnz,pn %o0, sun4v_itlb_error
mov %g2, %o1 ! restore %o1
mov %g1, %o0 ! restore %o0
mov %g5, %o2 ! restore %o2
mov %g7, %o3 ! restore %o3
retry
sun4v_dtlb_miss:
/* Load MMU Miss base into %g2. */
ldxa [%g0] ASI_SCRATCHPAD, %g2
/* Load UTSB reg into %g1. */
mov SCRATCHPAD_UTSBREG1, %g1
ldxa [%g1] ASI_SCRATCHPAD, %g1
LOAD_DTLB_INFO(%g2, %g4, %g5)
COMPUTE_TAG_TARGET(%g6, %g4, %g5, kvmap_dtlb_4v)
COMPUTE_TSB_PTR(%g1, %g4, PAGE_SHIFT, %g3, %g7)
/* Load TSB tag/pte into %g2/%g3 and compare the tag. */
ldda [%g1] ASI_QUAD_LDD_PHYS_4V, %g2
cmp %g2, %g6
bne,a,pn %xcc, tsb_miss_page_table_walk
mov FAULT_CODE_DTLB, %g3
/* We have a valid entry, make hypervisor call to load
* D-TLB and return from trap.
*
* %g3: PTE
* %g4: vaddr
*/
sun4v_dtlb_load:
ldxa [%g0] ASI_SCRATCHPAD, %g6
mov %o0, %g1 ! save %o0
mov %o1, %g2 ! save %o1
mov %o2, %g5 ! save %o2
mov %o3, %g7 ! save %o3
mov %g4, %o0 ! vaddr
ldx [%g6 + HV_FAULT_D_CTX_OFFSET], %o1 ! ctx
mov %g3, %o2 ! PTE
mov HV_MMU_DMMU, %o3 ! flags
ta HV_MMU_MAP_ADDR_TRAP
brnz,pn %o0, sun4v_dtlb_error
mov %g2, %o1 ! restore %o1
mov %g1, %o0 ! restore %o0
mov %g5, %o2 ! restore %o2
mov %g7, %o3 ! restore %o3
retry
sun4v_dtlb_prot:
SET_GL(1)
/* Load MMU Miss base into %g5. */
ldxa [%g0] ASI_SCRATCHPAD, %g5
ldx [%g5 + HV_FAULT_D_ADDR_OFFSET], %g5
rdpr %tl, %g1
cmp %g1, 1
bgu,pn %xcc, winfix_trampoline
mov FAULT_CODE_DTLB | FAULT_CODE_WRITE, %g4
ba,pt %xcc, sparc64_realfault_common
nop
/* Called from trap table:
* %g4: vaddr
* %g5: context
* %g6: TAG TARGET
*/
sun4v_itsb_miss:
mov SCRATCHPAD_UTSBREG1, %g1
ldxa [%g1] ASI_SCRATCHPAD, %g1
brz,pn %g5, kvmap_itlb_4v
mov FAULT_CODE_ITLB, %g3
ba,a,pt %xcc, sun4v_tsb_miss_common
/* Called from trap table:
* %g4: vaddr
* %g5: context
* %g6: TAG TARGET
*/
sun4v_dtsb_miss:
mov SCRATCHPAD_UTSBREG1, %g1
ldxa [%g1] ASI_SCRATCHPAD, %g1
brz,pn %g5, kvmap_dtlb_4v
mov FAULT_CODE_DTLB, %g3
/* fallthrough */
sun4v_tsb_miss_common:
COMPUTE_TSB_PTR(%g1, %g4, PAGE_SHIFT, %g5, %g7)
sub %g2, TRAP_PER_CPU_FAULT_INFO, %g2
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
mov SCRATCHPAD_UTSBREG2, %g5
ldxa [%g5] ASI_SCRATCHPAD, %g5
cmp %g5, -1
be,pt %xcc, 80f
nop
COMPUTE_TSB_PTR(%g5, %g4, REAL_HPAGE_SHIFT, %g2, %g7)
/* That clobbered %g2, reload it. */
ldxa [%g0] ASI_SCRATCHPAD, %g2
sub %g2, TRAP_PER_CPU_FAULT_INFO, %g2
80: stx %g5, [%g2 + TRAP_PER_CPU_TSB_HUGE_TEMP]
#endif
ba,pt %xcc, tsb_miss_page_table_walk_sun4v_fastpath
ldx [%g2 + TRAP_PER_CPU_PGD_PADDR], %g7
sun4v_itlb_error:
sethi %hi(sun4v_err_itlb_vaddr), %g1
stx %g4, [%g1 + %lo(sun4v_err_itlb_vaddr)]
sethi %hi(sun4v_err_itlb_ctx), %g1
ldxa [%g0] ASI_SCRATCHPAD, %g6
ldx [%g6 + HV_FAULT_I_CTX_OFFSET], %o1
stx %o1, [%g1 + %lo(sun4v_err_itlb_ctx)]
sethi %hi(sun4v_err_itlb_pte), %g1
stx %g3, [%g1 + %lo(sun4v_err_itlb_pte)]
sethi %hi(sun4v_err_itlb_error), %g1
stx %o0, [%g1 + %lo(sun4v_err_itlb_error)]
rdpr %tl, %g4
cmp %g4, 1
ble,pt %icc, 1f
sethi %hi(2f), %g7
ba,pt %xcc, etraptl1
or %g7, %lo(2f), %g7
1: ba,pt %xcc, etrap
2: or %g7, %lo(2b), %g7
mov %l4, %o1
call sun4v_itlb_error_report
add %sp, PTREGS_OFF, %o0
/* NOTREACHED */
sun4v_dtlb_error:
sethi %hi(sun4v_err_dtlb_vaddr), %g1
stx %g4, [%g1 + %lo(sun4v_err_dtlb_vaddr)]
sethi %hi(sun4v_err_dtlb_ctx), %g1
ldxa [%g0] ASI_SCRATCHPAD, %g6
ldx [%g6 + HV_FAULT_D_CTX_OFFSET], %o1
stx %o1, [%g1 + %lo(sun4v_err_dtlb_ctx)]
sethi %hi(sun4v_err_dtlb_pte), %g1
stx %g3, [%g1 + %lo(sun4v_err_dtlb_pte)]
sethi %hi(sun4v_err_dtlb_error), %g1
stx %o0, [%g1 + %lo(sun4v_err_dtlb_error)]
rdpr %tl, %g4
cmp %g4, 1
ble,pt %icc, 1f
sethi %hi(2f), %g7
ba,pt %xcc, etraptl1
or %g7, %lo(2f), %g7
1: ba,pt %xcc, etrap
2: or %g7, %lo(2b), %g7
mov %l4, %o1
call sun4v_dtlb_error_report
add %sp, PTREGS_OFF, %o0
/* NOTREACHED */
/* Instruction Access Exception, tl0. */
sun4v_iacc:
ldxa [%g0] ASI_SCRATCHPAD, %g2
ldx [%g2 + HV_FAULT_I_TYPE_OFFSET], %g3
ldx [%g2 + HV_FAULT_I_ADDR_OFFSET], %g4
ldx [%g2 + HV_FAULT_I_CTX_OFFSET], %g5
sllx %g3, 16, %g3
or %g5, %g3, %g5
ba,pt %xcc, etrap
rd %pc, %g7
mov %l4, %o1
mov %l5, %o2
call sun4v_insn_access_exception
add %sp, PTREGS_OFF, %o0
ba,a,pt %xcc, rtrap
/* Instruction Access Exception, tl1. */
sun4v_iacc_tl1:
ldxa [%g0] ASI_SCRATCHPAD, %g2
ldx [%g2 + HV_FAULT_I_TYPE_OFFSET], %g3
ldx [%g2 + HV_FAULT_I_ADDR_OFFSET], %g4
ldx [%g2 + HV_FAULT_I_CTX_OFFSET], %g5
sllx %g3, 16, %g3
or %g5, %g3, %g5
ba,pt %xcc, etraptl1
rd %pc, %g7
mov %l4, %o1
mov %l5, %o2
call sun4v_insn_access_exception_tl1
add %sp, PTREGS_OFF, %o0
ba,a,pt %xcc, rtrap
/* Data Access Exception, tl0. */
sun4v_dacc:
ldxa [%g0] ASI_SCRATCHPAD, %g2
ldx [%g2 + HV_FAULT_D_TYPE_OFFSET], %g3
ldx [%g2 + HV_FAULT_D_ADDR_OFFSET], %g4
ldx [%g2 + HV_FAULT_D_CTX_OFFSET], %g5
sllx %g3, 16, %g3
or %g5, %g3, %g5
ba,pt %xcc, etrap
rd %pc, %g7
mov %l4, %o1
mov %l5, %o2
call sun4v_data_access_exception
add %sp, PTREGS_OFF, %o0
ba,a,pt %xcc, rtrap
/* Data Access Exception, tl1. */
sun4v_dacc_tl1:
ldxa [%g0] ASI_SCRATCHPAD, %g2
ldx [%g2 + HV_FAULT_D_TYPE_OFFSET], %g3
ldx [%g2 + HV_FAULT_D_ADDR_OFFSET], %g4
ldx [%g2 + HV_FAULT_D_CTX_OFFSET], %g5
sllx %g3, 16, %g3
or %g5, %g3, %g5
ba,pt %xcc, etraptl1
rd %pc, %g7
mov %l4, %o1
mov %l5, %o2
call sun4v_data_access_exception_tl1
add %sp, PTREGS_OFF, %o0
ba,a,pt %xcc, rtrap
/* Memory Address Unaligned. */
sun4v_mna:
/* Window fixup? */
rdpr %tl, %g2
cmp %g2, 1
ble,pt %icc, 1f
nop
SET_GL(1)
ldxa [%g0] ASI_SCRATCHPAD, %g2
ldx [%g2 + HV_FAULT_D_ADDR_OFFSET], %g5
mov HV_FAULT_TYPE_UNALIGNED, %g3
ldx [%g2 + HV_FAULT_D_CTX_OFFSET], %g4
sllx %g3, 16, %g3
or %g4, %g3, %g4
ba,pt %xcc, winfix_mna
rdpr %tpc, %g3
/* not reached */
1: ldxa [%g0] ASI_SCRATCHPAD, %g2
mov HV_FAULT_TYPE_UNALIGNED, %g3
ldx [%g2 + HV_FAULT_D_ADDR_OFFSET], %g4
ldx [%g2 + HV_FAULT_D_CTX_OFFSET], %g5
sllx %g3, 16, %g3
or %g5, %g3, %g5
ba,pt %xcc, etrap
rd %pc, %g7
mov %l4, %o1
mov %l5, %o2
call sun4v_do_mna
add %sp, PTREGS_OFF, %o0
ba,a,pt %xcc, rtrap
/* Privileged Action. */
sun4v_privact:
ba,pt %xcc, etrap
rd %pc, %g7
call do_privact
add %sp, PTREGS_OFF, %o0
ba,a,pt %xcc, rtrap
/* Unaligned ldd float, tl0. */
sun4v_lddfmna:
ldxa [%g0] ASI_SCRATCHPAD, %g2
ldx [%g2 + HV_FAULT_D_TYPE_OFFSET], %g3
ldx [%g2 + HV_FAULT_D_ADDR_OFFSET], %g4
ldx [%g2 + HV_FAULT_D_CTX_OFFSET], %g5
sllx %g3, 16, %g3
or %g5, %g3, %g5
ba,pt %xcc, etrap
rd %pc, %g7
mov %l4, %o1
mov %l5, %o2
call handle_lddfmna
add %sp, PTREGS_OFF, %o0
ba,a,pt %xcc, rtrap
/* Unaligned std float, tl0. */
sun4v_stdfmna:
ldxa [%g0] ASI_SCRATCHPAD, %g2
ldx [%g2 + HV_FAULT_D_TYPE_OFFSET], %g3
ldx [%g2 + HV_FAULT_D_ADDR_OFFSET], %g4
ldx [%g2 + HV_FAULT_D_CTX_OFFSET], %g5
sllx %g3, 16, %g3
or %g5, %g3, %g5
ba,pt %xcc, etrap
rd %pc, %g7
mov %l4, %o1
mov %l5, %o2
call handle_stdfmna
add %sp, PTREGS_OFF, %o0
ba,a,pt %xcc, rtrap
#define BRANCH_ALWAYS 0x10680000
#define NOP 0x01000000
#define SUN4V_DO_PATCH(OLD, NEW) \
sethi %hi(NEW), %g1; \
or %g1, %lo(NEW), %g1; \
sethi %hi(OLD), %g2; \
or %g2, %lo(OLD), %g2; \
sub %g1, %g2, %g1; \
sethi %hi(BRANCH_ALWAYS), %g3; \
sll %g1, 11, %g1; \
srl %g1, 11 + 2, %g1; \
or %g3, %lo(BRANCH_ALWAYS), %g3; \
or %g3, %g1, %g3; \
stw %g3, [%g2]; \
sethi %hi(NOP), %g3; \
or %g3, %lo(NOP), %g3; \
stw %g3, [%g2 + 0x4]; \
flush %g2;
.globl sun4v_patch_tlb_handlers
.type sun4v_patch_tlb_handlers,#function
sun4v_patch_tlb_handlers:
SUN4V_DO_PATCH(tl0_iamiss, sun4v_itlb_miss)
SUN4V_DO_PATCH(tl1_iamiss, sun4v_itlb_miss)
SUN4V_DO_PATCH(tl0_damiss, sun4v_dtlb_miss)
SUN4V_DO_PATCH(tl1_damiss, sun4v_dtlb_miss)
SUN4V_DO_PATCH(tl0_daprot, sun4v_dtlb_prot)
SUN4V_DO_PATCH(tl1_daprot, sun4v_dtlb_prot)
SUN4V_DO_PATCH(tl0_iax, sun4v_iacc)
SUN4V_DO_PATCH(tl1_iax, sun4v_iacc_tl1)
SUN4V_DO_PATCH(tl0_dax, sun4v_dacc)
SUN4V_DO_PATCH(tl1_dax, sun4v_dacc_tl1)
SUN4V_DO_PATCH(tl0_mna, sun4v_mna)
SUN4V_DO_PATCH(tl1_mna, sun4v_mna)
SUN4V_DO_PATCH(tl0_lddfmna, sun4v_lddfmna)
SUN4V_DO_PATCH(tl0_stdfmna, sun4v_stdfmna)
SUN4V_DO_PATCH(tl0_privact, sun4v_privact)
retl
nop
.size sun4v_patch_tlb_handlers,.-sun4v_patch_tlb_handlers
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