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linux/arch/sparc64/kernel/tsb.S

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[SPARC64]: Move away from virtual page tables, part 1. We now use the TSB hardware assist features of the UltraSPARC MMUs. SMP is currently knowingly broken, we need to find another place to store the per-cpu base pointers. We hid them away in the TSB base register, and that obviously will not work any more :-) Another known broken case is non-8KB base page size. Also noticed that flush_tlb_all() is not referenced anywhere, only the internal __flush_tlb_all() (local cpu only) is used by the sparc64 port, so we can get rid of flush_tlb_all(). The kernel gets it's own 8KB TSB (swapper_tsb) and each address space gets it's own private 8K TSB. Later we can add code to dynamically increase the size of per-process TSB as the RSS grows. An 8KB TSB is good enough for up to about a 4MB RSS, after which the TSB starts to incur many capacity and conflict misses. We even accumulate OBP translations into the kernel TSB. Another area for refinement is large page size support. We could use a secondary address space TSB to handle those. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:29:18 +00:00
/* tsb.S: Sparc64 TSB table handling.
*
* Copyright (C) 2006 David S. Miller <davem@davemloft.net>
*/
#include <asm/tsb.h>
.text
.align 32
/* Invoked from TLB miss handler, we are in the
* MMU global registers and they are setup like
* this:
*
* %g1: TSB entry pointer
* %g2: available temporary
* %g3: FAULT_CODE_{D,I}TLB
* %g4: available temporary
* %g5: available temporary
* %g6: TAG TARGET
* %g7: physical address base of the linux page
* tables for the current address space
*/
.globl tsb_miss_dtlb
tsb_miss_dtlb:
mov TLB_TAG_ACCESS, %g4
ldxa [%g4] ASI_DMMU, %g4
ba,pt %xcc, tsb_miss_page_table_walk
nop
.globl tsb_miss_itlb
tsb_miss_itlb:
mov TLB_TAG_ACCESS, %g4
ldxa [%g4] ASI_IMMU, %g4
ba,pt %xcc, tsb_miss_page_table_walk
nop
tsb_miss_page_table_walk:
[SPARC64]: Elminate all usage of hard-coded trap globals. UltraSPARC has special sets of global registers which are switched to for certain trap types. There is one set for MMU related traps, one set of Interrupt Vector processing, and another set (called the Alternate globals) for all other trap types. For what seems like forever we've hard coded the values in some of these trap registers. Some examples include: 1) Interrupt Vector global %g6 holds current processors interrupt work struct where received interrupts are managed for IRQ handler dispatch. 2) MMU global %g7 holds the base of the page tables of the currently active address space. 3) Alternate global %g6 held the current_thread_info() value. Such hardcoding has resulted in some serious issues in many areas. There are some code sequences where having another register available would help clean up the implementation. Taking traps such as cross-calls from the OBP firmware requires some trick code sequences wherein we have to save away and restore all of the special sets of global registers when we enter/exit OBP. We were also using the IMMU TSB register on SMP to hold the per-cpu area base address, which doesn't work any longer now that we actually use the TSB facility of the cpu. The implementation is pretty straight forward. One tricky bit is getting the current processor ID as that is different on different cpu variants. We use a stub with a fancy calling convention which we patch at boot time. The calling convention is that the stub is branched to and the (PC - 4) to return to is in register %g1. The cpu number is left in %g6. This stub can be invoked by using the __GET_CPUID macro. We use an array of per-cpu trap state to store the current thread and physical address of the current address space's page tables. The TRAP_LOAD_THREAD_REG loads %g6 with the current thread from this table, it uses __GET_CPUID and also clobbers %g1. TRAP_LOAD_IRQ_WORK is used by the interrupt vector processing to load the current processor's IRQ software state into %g6. It also uses __GET_CPUID and clobbers %g1. Finally, TRAP_LOAD_PGD_PHYS loads the physical address base of the current address space's page tables into %g7, it clobbers %g1 and uses __GET_CPUID. Many refinements are possible, as well as some tuning, with this stuff in place. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-27 07:24:22 +00:00
/* This clobbers %g1 and %g6, preserve them... */
mov %g1, %g5
mov %g6, %g2
TRAP_LOAD_PGD_PHYS
mov %g2, %g6
mov %g5, %g1
[SPARC64]: Move away from virtual page tables, part 1. We now use the TSB hardware assist features of the UltraSPARC MMUs. SMP is currently knowingly broken, we need to find another place to store the per-cpu base pointers. We hid them away in the TSB base register, and that obviously will not work any more :-) Another known broken case is non-8KB base page size. Also noticed that flush_tlb_all() is not referenced anywhere, only the internal __flush_tlb_all() (local cpu only) is used by the sparc64 port, so we can get rid of flush_tlb_all(). The kernel gets it's own 8KB TSB (swapper_tsb) and each address space gets it's own private 8K TSB. Later we can add code to dynamically increase the size of per-process TSB as the RSS grows. An 8KB TSB is good enough for up to about a 4MB RSS, after which the TSB starts to incur many capacity and conflict misses. We even accumulate OBP translations into the kernel TSB. Another area for refinement is large page size support. We could use a secondary address space TSB to handle those. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:29:18 +00:00
USER_PGTABLE_WALK_TL1(%g4, %g7, %g5, %g2, tsb_do_fault)
tsb_reload:
TSB_LOCK_TAG(%g1, %g2, %g4)
/* Load and check PTE. */
ldxa [%g5] ASI_PHYS_USE_EC, %g5
brgez,a,pn %g5, tsb_do_fault
stx %g0, [%g1]
[SPARC64]: TSB refinements. Move {init_new,destroy}_context() out of line. Do not put huge pages into the TSB, only base page size translations. There are some clever things we could do here, but for now let's be correct instead of fancy. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:31:06 +00:00
/* If it is larger than the base page size, don't
* bother putting it into the TSB.
*/
srlx %g5, 32, %g2
sethi %hi(_PAGE_ALL_SZ_BITS >> 32), %g4
sethi %hi(_PAGE_SZBITS >> 32), %g7
and %g2, %g4, %g2
cmp %g2, %g7
bne,a,pn %xcc, tsb_tlb_reload
stx %g0, [%g1]
[SPARC64]: Move away from virtual page tables, part 1. We now use the TSB hardware assist features of the UltraSPARC MMUs. SMP is currently knowingly broken, we need to find another place to store the per-cpu base pointers. We hid them away in the TSB base register, and that obviously will not work any more :-) Another known broken case is non-8KB base page size. Also noticed that flush_tlb_all() is not referenced anywhere, only the internal __flush_tlb_all() (local cpu only) is used by the sparc64 port, so we can get rid of flush_tlb_all(). The kernel gets it's own 8KB TSB (swapper_tsb) and each address space gets it's own private 8K TSB. Later we can add code to dynamically increase the size of per-process TSB as the RSS grows. An 8KB TSB is good enough for up to about a 4MB RSS, after which the TSB starts to incur many capacity and conflict misses. We even accumulate OBP translations into the kernel TSB. Another area for refinement is large page size support. We could use a secondary address space TSB to handle those. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:29:18 +00:00
TSB_WRITE(%g1, %g5, %g6)
/* Finally, load TLB and return from trap. */
tsb_tlb_reload:
cmp %g3, FAULT_CODE_DTLB
bne,pn %xcc, tsb_itlb_load
nop
tsb_dtlb_load:
stxa %g5, [%g0] ASI_DTLB_DATA_IN
retry
tsb_itlb_load:
stxa %g5, [%g0] ASI_ITLB_DATA_IN
retry
/* No valid entry in the page tables, do full fault
* processing.
*/
.globl tsb_do_fault
tsb_do_fault:
cmp %g3, FAULT_CODE_DTLB
rdpr %pstate, %g5
bne,pn %xcc, tsb_do_itlb_fault
wrpr %g5, PSTATE_AG | PSTATE_MG, %pstate
tsb_do_dtlb_fault:
rdpr %tl, %g4
cmp %g4, 1
mov TLB_TAG_ACCESS, %g4
ldxa [%g4] ASI_DMMU, %g5
be,pt %xcc, sparc64_realfault_common
mov FAULT_CODE_DTLB, %g4
ba,pt %xcc, winfix_trampoline
nop
tsb_do_itlb_fault:
rdpr %tpc, %g5
ba,pt %xcc, sparc64_realfault_common
mov FAULT_CODE_ITLB, %g4
.globl sparc64_realfault_common
sparc64_realfault_common:
stb %g4, [%g6 + TI_FAULT_CODE] ! Save fault code
stx %g5, [%g6 + TI_FAULT_ADDR] ! Save fault address
ba,pt %xcc, etrap ! Save trap state
1: rd %pc, %g7 ! ...
call do_sparc64_fault ! Call fault handler
add %sp, PTREGS_OFF, %o0 ! Compute pt_regs arg
ba,pt %xcc, rtrap_clr_l6 ! Restore cpu state
nop ! Delay slot (fill me)
.globl winfix_trampoline
winfix_trampoline:
rdpr %tpc, %g3 ! Prepare winfixup TNPC
or %g3, 0x7c, %g3 ! Compute branch offset
wrpr %g3, %tnpc ! Write it into TNPC
done ! Trap return
[SPARC64]: Preload TSB entries from update_mmu_cache(). Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:32:04 +00:00
/* Insert an entry into the TSB.
*
* %o0: TSB entry pointer
* %o1: tag
* %o2: pte
*/
.align 32
.globl tsb_insert
tsb_insert:
rdpr %pstate, %o5
wrpr %o5, PSTATE_IE, %pstate
TSB_LOCK_TAG(%o0, %g2, %g3)
TSB_WRITE(%o0, %o2, %o1)
wrpr %o5, %pstate
retl
nop
[SPARC64]: Move away from virtual page tables, part 1. We now use the TSB hardware assist features of the UltraSPARC MMUs. SMP is currently knowingly broken, we need to find another place to store the per-cpu base pointers. We hid them away in the TSB base register, and that obviously will not work any more :-) Another known broken case is non-8KB base page size. Also noticed that flush_tlb_all() is not referenced anywhere, only the internal __flush_tlb_all() (local cpu only) is used by the sparc64 port, so we can get rid of flush_tlb_all(). The kernel gets it's own 8KB TSB (swapper_tsb) and each address space gets it's own private 8K TSB. Later we can add code to dynamically increase the size of per-process TSB as the RSS grows. An 8KB TSB is good enough for up to about a 4MB RSS, after which the TSB starts to incur many capacity and conflict misses. We even accumulate OBP translations into the kernel TSB. Another area for refinement is large page size support. We could use a secondary address space TSB to handle those. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:29:18 +00:00
/* Reload MMU related context switch state at
* schedule() time.
*
* %o0: page table physical address
[SPARC64]: Add infrastructure for dynamic TSB sizing. This also cleans up tsb_context_switch(). The assembler routine is now __tsb_context_switch() and the former is an inline function that picks out the bits from the mm_struct and passes it into the assembler code as arguments. setup_tsb_parms() computes the locked TLB entry to map the TSB. Later when we support using the physical address quad load instructions of Cheetah+ and later, we'll simply use the physical address for the TSB register value and set the map virtual and PTE both to zero. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:31:20 +00:00
* %o1: TSB register value
* %o2: TSB virtual address
* %o3: TSB mapping locked PTE
*
* We have to run this whole thing with interrupts
* disabled so that the current cpu doesn't change
* due to preemption.
[SPARC64]: Move away from virtual page tables, part 1. We now use the TSB hardware assist features of the UltraSPARC MMUs. SMP is currently knowingly broken, we need to find another place to store the per-cpu base pointers. We hid them away in the TSB base register, and that obviously will not work any more :-) Another known broken case is non-8KB base page size. Also noticed that flush_tlb_all() is not referenced anywhere, only the internal __flush_tlb_all() (local cpu only) is used by the sparc64 port, so we can get rid of flush_tlb_all(). The kernel gets it's own 8KB TSB (swapper_tsb) and each address space gets it's own private 8K TSB. Later we can add code to dynamically increase the size of per-process TSB as the RSS grows. An 8KB TSB is good enough for up to about a 4MB RSS, after which the TSB starts to incur many capacity and conflict misses. We even accumulate OBP translations into the kernel TSB. Another area for refinement is large page size support. We could use a secondary address space TSB to handle those. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:29:18 +00:00
*/
[SPARC64]: Elminate all usage of hard-coded trap globals. UltraSPARC has special sets of global registers which are switched to for certain trap types. There is one set for MMU related traps, one set of Interrupt Vector processing, and another set (called the Alternate globals) for all other trap types. For what seems like forever we've hard coded the values in some of these trap registers. Some examples include: 1) Interrupt Vector global %g6 holds current processors interrupt work struct where received interrupts are managed for IRQ handler dispatch. 2) MMU global %g7 holds the base of the page tables of the currently active address space. 3) Alternate global %g6 held the current_thread_info() value. Such hardcoding has resulted in some serious issues in many areas. There are some code sequences where having another register available would help clean up the implementation. Taking traps such as cross-calls from the OBP firmware requires some trick code sequences wherein we have to save away and restore all of the special sets of global registers when we enter/exit OBP. We were also using the IMMU TSB register on SMP to hold the per-cpu area base address, which doesn't work any longer now that we actually use the TSB facility of the cpu. The implementation is pretty straight forward. One tricky bit is getting the current processor ID as that is different on different cpu variants. We use a stub with a fancy calling convention which we patch at boot time. The calling convention is that the stub is branched to and the (PC - 4) to return to is in register %g1. The cpu number is left in %g6. This stub can be invoked by using the __GET_CPUID macro. We use an array of per-cpu trap state to store the current thread and physical address of the current address space's page tables. The TRAP_LOAD_THREAD_REG loads %g6 with the current thread from this table, it uses __GET_CPUID and also clobbers %g1. TRAP_LOAD_IRQ_WORK is used by the interrupt vector processing to load the current processor's IRQ software state into %g6. It also uses __GET_CPUID and clobbers %g1. Finally, TRAP_LOAD_PGD_PHYS loads the physical address base of the current address space's page tables into %g7, it clobbers %g1 and uses __GET_CPUID. Many refinements are possible, as well as some tuning, with this stuff in place. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-27 07:24:22 +00:00
.align 32
[SPARC64]: Add infrastructure for dynamic TSB sizing. This also cleans up tsb_context_switch(). The assembler routine is now __tsb_context_switch() and the former is an inline function that picks out the bits from the mm_struct and passes it into the assembler code as arguments. setup_tsb_parms() computes the locked TLB entry to map the TSB. Later when we support using the physical address quad load instructions of Cheetah+ and later, we'll simply use the physical address for the TSB register value and set the map virtual and PTE both to zero. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:31:20 +00:00
.globl __tsb_context_switch
__tsb_context_switch:
[SPARC64]: Elminate all usage of hard-coded trap globals. UltraSPARC has special sets of global registers which are switched to for certain trap types. There is one set for MMU related traps, one set of Interrupt Vector processing, and another set (called the Alternate globals) for all other trap types. For what seems like forever we've hard coded the values in some of these trap registers. Some examples include: 1) Interrupt Vector global %g6 holds current processors interrupt work struct where received interrupts are managed for IRQ handler dispatch. 2) MMU global %g7 holds the base of the page tables of the currently active address space. 3) Alternate global %g6 held the current_thread_info() value. Such hardcoding has resulted in some serious issues in many areas. There are some code sequences where having another register available would help clean up the implementation. Taking traps such as cross-calls from the OBP firmware requires some trick code sequences wherein we have to save away and restore all of the special sets of global registers when we enter/exit OBP. We were also using the IMMU TSB register on SMP to hold the per-cpu area base address, which doesn't work any longer now that we actually use the TSB facility of the cpu. The implementation is pretty straight forward. One tricky bit is getting the current processor ID as that is different on different cpu variants. We use a stub with a fancy calling convention which we patch at boot time. The calling convention is that the stub is branched to and the (PC - 4) to return to is in register %g1. The cpu number is left in %g6. This stub can be invoked by using the __GET_CPUID macro. We use an array of per-cpu trap state to store the current thread and physical address of the current address space's page tables. The TRAP_LOAD_THREAD_REG loads %g6 with the current thread from this table, it uses __GET_CPUID and also clobbers %g1. TRAP_LOAD_IRQ_WORK is used by the interrupt vector processing to load the current processor's IRQ software state into %g6. It also uses __GET_CPUID and clobbers %g1. Finally, TRAP_LOAD_PGD_PHYS loads the physical address base of the current address space's page tables into %g7, it clobbers %g1 and uses __GET_CPUID. Many refinements are possible, as well as some tuning, with this stuff in place. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-27 07:24:22 +00:00
rdpr %pstate, %o5
wrpr %o5, PSTATE_IE, %pstate
[SPARC64]: Move away from virtual page tables, part 1. We now use the TSB hardware assist features of the UltraSPARC MMUs. SMP is currently knowingly broken, we need to find another place to store the per-cpu base pointers. We hid them away in the TSB base register, and that obviously will not work any more :-) Another known broken case is non-8KB base page size. Also noticed that flush_tlb_all() is not referenced anywhere, only the internal __flush_tlb_all() (local cpu only) is used by the sparc64 port, so we can get rid of flush_tlb_all(). The kernel gets it's own 8KB TSB (swapper_tsb) and each address space gets it's own private 8K TSB. Later we can add code to dynamically increase the size of per-process TSB as the RSS grows. An 8KB TSB is good enough for up to about a 4MB RSS, after which the TSB starts to incur many capacity and conflict misses. We even accumulate OBP translations into the kernel TSB. Another area for refinement is large page size support. We could use a secondary address space TSB to handle those. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:29:18 +00:00
[SPARC64]: Add infrastructure for dynamic TSB sizing. This also cleans up tsb_context_switch(). The assembler routine is now __tsb_context_switch() and the former is an inline function that picks out the bits from the mm_struct and passes it into the assembler code as arguments. setup_tsb_parms() computes the locked TLB entry to map the TSB. Later when we support using the physical address quad load instructions of Cheetah+ and later, we'll simply use the physical address for the TSB register value and set the map virtual and PTE both to zero. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:31:20 +00:00
ldub [%g6 + TI_CPU], %g1
sethi %hi(trap_block), %g2
sllx %g1, TRAP_BLOCK_SZ_SHIFT, %g1
or %g2, %lo(trap_block), %g2
add %g2, %g1, %g2
stx %o0, [%g2 + TRAP_PER_CPU_PGD_PADDR]
[SPARC64]: Move away from virtual page tables, part 1. We now use the TSB hardware assist features of the UltraSPARC MMUs. SMP is currently knowingly broken, we need to find another place to store the per-cpu base pointers. We hid them away in the TSB base register, and that obviously will not work any more :-) Another known broken case is non-8KB base page size. Also noticed that flush_tlb_all() is not referenced anywhere, only the internal __flush_tlb_all() (local cpu only) is used by the sparc64 port, so we can get rid of flush_tlb_all(). The kernel gets it's own 8KB TSB (swapper_tsb) and each address space gets it's own private 8K TSB. Later we can add code to dynamically increase the size of per-process TSB as the RSS grows. An 8KB TSB is good enough for up to about a 4MB RSS, after which the TSB starts to incur many capacity and conflict misses. We even accumulate OBP translations into the kernel TSB. Another area for refinement is large page size support. We could use a secondary address space TSB to handle those. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:29:18 +00:00
mov TSB_REG, %g1
[SPARC64]: Add infrastructure for dynamic TSB sizing. This also cleans up tsb_context_switch(). The assembler routine is now __tsb_context_switch() and the former is an inline function that picks out the bits from the mm_struct and passes it into the assembler code as arguments. setup_tsb_parms() computes the locked TLB entry to map the TSB. Later when we support using the physical address quad load instructions of Cheetah+ and later, we'll simply use the physical address for the TSB register value and set the map virtual and PTE both to zero. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:31:20 +00:00
stxa %o1, [%g1] ASI_DMMU
[SPARC64]: Move away from virtual page tables, part 1. We now use the TSB hardware assist features of the UltraSPARC MMUs. SMP is currently knowingly broken, we need to find another place to store the per-cpu base pointers. We hid them away in the TSB base register, and that obviously will not work any more :-) Another known broken case is non-8KB base page size. Also noticed that flush_tlb_all() is not referenced anywhere, only the internal __flush_tlb_all() (local cpu only) is used by the sparc64 port, so we can get rid of flush_tlb_all(). The kernel gets it's own 8KB TSB (swapper_tsb) and each address space gets it's own private 8K TSB. Later we can add code to dynamically increase the size of per-process TSB as the RSS grows. An 8KB TSB is good enough for up to about a 4MB RSS, after which the TSB starts to incur many capacity and conflict misses. We even accumulate OBP translations into the kernel TSB. Another area for refinement is large page size support. We could use a secondary address space TSB to handle those. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:29:18 +00:00
membar #Sync
[SPARC64]: Add infrastructure for dynamic TSB sizing. This also cleans up tsb_context_switch(). The assembler routine is now __tsb_context_switch() and the former is an inline function that picks out the bits from the mm_struct and passes it into the assembler code as arguments. setup_tsb_parms() computes the locked TLB entry to map the TSB. Later when we support using the physical address quad load instructions of Cheetah+ and later, we'll simply use the physical address for the TSB register value and set the map virtual and PTE both to zero. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:31:20 +00:00
stxa %o1, [%g1] ASI_IMMU
[SPARC64]: Move away from virtual page tables, part 1. We now use the TSB hardware assist features of the UltraSPARC MMUs. SMP is currently knowingly broken, we need to find another place to store the per-cpu base pointers. We hid them away in the TSB base register, and that obviously will not work any more :-) Another known broken case is non-8KB base page size. Also noticed that flush_tlb_all() is not referenced anywhere, only the internal __flush_tlb_all() (local cpu only) is used by the sparc64 port, so we can get rid of flush_tlb_all(). The kernel gets it's own 8KB TSB (swapper_tsb) and each address space gets it's own private 8K TSB. Later we can add code to dynamically increase the size of per-process TSB as the RSS grows. An 8KB TSB is good enough for up to about a 4MB RSS, after which the TSB starts to incur many capacity and conflict misses. We even accumulate OBP translations into the kernel TSB. Another area for refinement is large page size support. We could use a secondary address space TSB to handle those. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:29:18 +00:00
membar #Sync
[SPARC64]: Add infrastructure for dynamic TSB sizing. This also cleans up tsb_context_switch(). The assembler routine is now __tsb_context_switch() and the former is an inline function that picks out the bits from the mm_struct and passes it into the assembler code as arguments. setup_tsb_parms() computes the locked TLB entry to map the TSB. Later when we support using the physical address quad load instructions of Cheetah+ and later, we'll simply use the physical address for the TSB register value and set the map virtual and PTE both to zero. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:31:20 +00:00
brz %o2, 9f
nop
[SPARC64]: Move away from virtual page tables, part 1. We now use the TSB hardware assist features of the UltraSPARC MMUs. SMP is currently knowingly broken, we need to find another place to store the per-cpu base pointers. We hid them away in the TSB base register, and that obviously will not work any more :-) Another known broken case is non-8KB base page size. Also noticed that flush_tlb_all() is not referenced anywhere, only the internal __flush_tlb_all() (local cpu only) is used by the sparc64 port, so we can get rid of flush_tlb_all(). The kernel gets it's own 8KB TSB (swapper_tsb) and each address space gets it's own private 8K TSB. Later we can add code to dynamically increase the size of per-process TSB as the RSS grows. An 8KB TSB is good enough for up to about a 4MB RSS, after which the TSB starts to incur many capacity and conflict misses. We even accumulate OBP translations into the kernel TSB. Another area for refinement is large page size support. We could use a secondary address space TSB to handle those. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:29:18 +00:00
[SPARC64]: Use sparc64_highest_unlocked_tlb_ent in __tsb_context_switch() Instead of ugly hard-coded value. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:33:12 +00:00
sethi %hi(sparc64_highest_unlocked_tlb_ent), %o4
mov TLB_TAG_ACCESS, %g1
lduw [%o4 + %lo(sparc64_highest_unlocked_tlb_ent)], %g2
stxa %o2, [%g1] ASI_DMMU
membar #Sync
sllx %g2, 3, %g2
stxa %o3, [%g2] ASI_DTLB_DATA_ACCESS
membar #Sync
[SPARC64]: Move away from virtual page tables, part 1. We now use the TSB hardware assist features of the UltraSPARC MMUs. SMP is currently knowingly broken, we need to find another place to store the per-cpu base pointers. We hid them away in the TSB base register, and that obviously will not work any more :-) Another known broken case is non-8KB base page size. Also noticed that flush_tlb_all() is not referenced anywhere, only the internal __flush_tlb_all() (local cpu only) is used by the sparc64 port, so we can get rid of flush_tlb_all(). The kernel gets it's own 8KB TSB (swapper_tsb) and each address space gets it's own private 8K TSB. Later we can add code to dynamically increase the size of per-process TSB as the RSS grows. An 8KB TSB is good enough for up to about a 4MB RSS, after which the TSB starts to incur many capacity and conflict misses. We even accumulate OBP translations into the kernel TSB. Another area for refinement is large page size support. We could use a secondary address space TSB to handle those. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:29:18 +00:00
9:
[SPARC64]: Elminate all usage of hard-coded trap globals. UltraSPARC has special sets of global registers which are switched to for certain trap types. There is one set for MMU related traps, one set of Interrupt Vector processing, and another set (called the Alternate globals) for all other trap types. For what seems like forever we've hard coded the values in some of these trap registers. Some examples include: 1) Interrupt Vector global %g6 holds current processors interrupt work struct where received interrupts are managed for IRQ handler dispatch. 2) MMU global %g7 holds the base of the page tables of the currently active address space. 3) Alternate global %g6 held the current_thread_info() value. Such hardcoding has resulted in some serious issues in many areas. There are some code sequences where having another register available would help clean up the implementation. Taking traps such as cross-calls from the OBP firmware requires some trick code sequences wherein we have to save away and restore all of the special sets of global registers when we enter/exit OBP. We were also using the IMMU TSB register on SMP to hold the per-cpu area base address, which doesn't work any longer now that we actually use the TSB facility of the cpu. The implementation is pretty straight forward. One tricky bit is getting the current processor ID as that is different on different cpu variants. We use a stub with a fancy calling convention which we patch at boot time. The calling convention is that the stub is branched to and the (PC - 4) to return to is in register %g1. The cpu number is left in %g6. This stub can be invoked by using the __GET_CPUID macro. We use an array of per-cpu trap state to store the current thread and physical address of the current address space's page tables. The TRAP_LOAD_THREAD_REG loads %g6 with the current thread from this table, it uses __GET_CPUID and also clobbers %g1. TRAP_LOAD_IRQ_WORK is used by the interrupt vector processing to load the current processor's IRQ software state into %g6. It also uses __GET_CPUID and clobbers %g1. Finally, TRAP_LOAD_PGD_PHYS loads the physical address base of the current address space's page tables into %g7, it clobbers %g1 and uses __GET_CPUID. Many refinements are possible, as well as some tuning, with this stuff in place. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-27 07:24:22 +00:00
wrpr %o5, %pstate
[SPARC64]: Move away from virtual page tables, part 1. We now use the TSB hardware assist features of the UltraSPARC MMUs. SMP is currently knowingly broken, we need to find another place to store the per-cpu base pointers. We hid them away in the TSB base register, and that obviously will not work any more :-) Another known broken case is non-8KB base page size. Also noticed that flush_tlb_all() is not referenced anywhere, only the internal __flush_tlb_all() (local cpu only) is used by the sparc64 port, so we can get rid of flush_tlb_all(). The kernel gets it's own 8KB TSB (swapper_tsb) and each address space gets it's own private 8K TSB. Later we can add code to dynamically increase the size of per-process TSB as the RSS grows. An 8KB TSB is good enough for up to about a 4MB RSS, after which the TSB starts to incur many capacity and conflict misses. We even accumulate OBP translations into the kernel TSB. Another area for refinement is large page size support. We could use a secondary address space TSB to handle those. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:29:18 +00:00
retl
[SPARC64]: Add infrastructure for dynamic TSB sizing. This also cleans up tsb_context_switch(). The assembler routine is now __tsb_context_switch() and the former is an inline function that picks out the bits from the mm_struct and passes it into the assembler code as arguments. setup_tsb_parms() computes the locked TLB entry to map the TSB. Later when we support using the physical address quad load instructions of Cheetah+ and later, we'll simply use the physical address for the TSB register value and set the map virtual and PTE both to zero. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-01 02:31:20 +00:00
nop
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