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linux/arch/sparc64/kernel/sun4v_tlb_miss.S
David S. Miller 86d43258bc [SPARC64]: Set g4/g5 properly in sun4v dtlb-prot handling. 
Mirror the logic in the sun4u handler, we have to update
both registers even when we branch out to window fault
fixup handling.

The way it works is that if we are in etrap processing a
fault already, g4/g5 holds the original fault information.
If we take a window spill fault while doing etrap, then
we put the window spill fault info into g4/g5 and this is
what the top-level fault handler ends up processing first.

Then we retry the originally faulting instruction, and
process the original fault at that time.

This is all necessary because of how constrained the trap
registers are in these code paths.  These cases trigger
very rarely, so even if there is some performance implication
it's doesn't happen very often.  In fact the rarity is why
it took so long to trigger and find this particular bug.

Signed-off-by: David S. Miller <davem@davemloft.net>
2007-01-26 18:56:01 -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
#ifdef CONFIG_HUGETLB_PAGE
mov SCRATCHPAD_UTSBREG2, %g5
ldxa [%g5] ASI_SCRATCHPAD, %g5
cmp %g5, -1
be,pt %xcc, 80f
nop
COMPUTE_TSB_PTR(%g5, %g4, 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
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
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_clr_l6
/* 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_clr_l6
/* 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_clr_l6
/* 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_clr_l6
/* 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_clr_l6
/* Privileged Action. */
sun4v_privact:
ba,pt %xcc, etrap
rd %pc, %g7
call do_privact
add %sp, PTREGS_OFF, %o0
ba,a,pt %xcc, rtrap_clr_l6
/* 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_clr_l6
/* 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_clr_l6
#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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