linux/arch/sparc64/kernel/winfixup.S
David S. Miller 74bf4312ff [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>
2006-03-20 01:11:13 -08:00

387 lines
12 KiB
ArmAsm

/* $Id: winfixup.S,v 1.30 2002/02/09 19:49:30 davem Exp $
*
* winfixup.S: Handle cases where user stack pointer is found to be bogus.
*
* Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
*/
#include <asm/asi.h>
#include <asm/head.h>
#include <asm/page.h>
#include <asm/ptrace.h>
#include <asm/processor.h>
#include <asm/spitfire.h>
#include <asm/thread_info.h>
.text
set_pcontext:
sethi %hi(sparc64_kern_pri_context), %l1
ldx [%l1 + %lo(sparc64_kern_pri_context)], %l1
mov PRIMARY_CONTEXT, %g1
stxa %l1, [%g1] ASI_DMMU
flush %g6
retl
nop
.align 32
/* Here are the rules, pay attention.
*
* The kernel is disallowed from touching user space while
* the trap level is greater than zero, except for from within
* the window spill/fill handlers. This must be followed
* so that we can easily detect the case where we tried to
* spill/fill with a bogus (or unmapped) user stack pointer.
*
* These are layed out in a special way for cache reasons,
* don't touch...
*/
.globl fill_fixup, spill_fixup
fill_fixup:
rdpr %tstate, %g1
andcc %g1, TSTATE_PRIV, %g0
or %g4, FAULT_CODE_WINFIXUP, %g4
be,pt %xcc, window_scheisse_from_user_common
and %g1, TSTATE_CWP, %g1
/* This is the extremely complex case, but it does happen from
* time to time if things are just right. Essentially the restore
* done in rtrap right before going back to user mode, with tl=1
* and that levels trap stack registers all setup, took a fill trap,
* the user stack was not mapped in the tlb, and tlb miss occurred,
* the pte found was not valid, and a simple ref bit watch update
* could not satisfy the miss, so we got here.
*
* We must carefully unwind the state so we get back to tl=0, preserve
* all the register values we were going to give to the user. Luckily
* most things are where they need to be, we also have the address
* which triggered the fault handy as well.
*
* Also note that we must preserve %l5 and %l6. If the user was
* returning from a system call, we must make it look this way
* after we process the fill fault on the users stack.
*
* First, get into the window where the original restore was executed.
*/
rdpr %wstate, %g2 ! Grab user mode wstate.
wrpr %g1, %cwp ! Get into the right window.
sll %g2, 3, %g2 ! NORMAL-->OTHER
wrpr %g0, 0x0, %canrestore ! Standard etrap stuff.
wrpr %g2, 0x0, %wstate ! This must be consistent.
wrpr %g0, 0x0, %otherwin ! We know this.
call set_pcontext ! Change contexts...
nop
rdpr %pstate, %l1 ! Prepare to change globals.
mov %g6, %o7 ! Get current.
andn %l1, PSTATE_MM, %l1 ! We want to be in RMO
stb %g4, [%g6 + TI_FAULT_CODE]
stx %g5, [%g6 + TI_FAULT_ADDR]
wrpr %g0, 0x0, %tl ! Out of trap levels.
wrpr %l1, (PSTATE_IE | PSTATE_AG | PSTATE_RMO), %pstate
mov %o7, %g6
ldx [%g6 + TI_TASK], %g4
#ifdef CONFIG_SMP
#error IMMU TSB usage must be fixed
mov TSB_REG, %g1
ldxa [%g1] ASI_IMMU, %g5
#endif
/* This is the same as below, except we handle this a bit special
* since we must preserve %l5 and %l6, see comment above.
*/
call do_sparc64_fault
add %sp, PTREGS_OFF, %o0
ba,pt %xcc, rtrap
nop ! yes, nop is correct
/* Be very careful about usage of the alternate globals here.
* You cannot touch %g4/%g5 as that has the fault information
* should this be from usermode. Also be careful for the case
* where we get here from the save instruction in etrap.S when
* coming from either user or kernel (does not matter which, it
* is the same problem in both cases). Essentially this means
* do not touch %g7 or %g2 so we handle the two cases fine.
*/
spill_fixup:
ldx [%g6 + TI_FLAGS], %g1
andcc %g1, _TIF_32BIT, %g0
ldub [%g6 + TI_WSAVED], %g1
sll %g1, 3, %g3
add %g6, %g3, %g3
stx %sp, [%g3 + TI_RWIN_SPTRS]
sll %g1, 7, %g3
bne,pt %xcc, 1f
add %g6, %g3, %g3
stx %l0, [%g3 + TI_REG_WINDOW + 0x00]
stx %l1, [%g3 + TI_REG_WINDOW + 0x08]
stx %l2, [%g3 + TI_REG_WINDOW + 0x10]
stx %l3, [%g3 + TI_REG_WINDOW + 0x18]
stx %l4, [%g3 + TI_REG_WINDOW + 0x20]
stx %l5, [%g3 + TI_REG_WINDOW + 0x28]
stx %l6, [%g3 + TI_REG_WINDOW + 0x30]
stx %l7, [%g3 + TI_REG_WINDOW + 0x38]
stx %i0, [%g3 + TI_REG_WINDOW + 0x40]
stx %i1, [%g3 + TI_REG_WINDOW + 0x48]
stx %i2, [%g3 + TI_REG_WINDOW + 0x50]
stx %i3, [%g3 + TI_REG_WINDOW + 0x58]
stx %i4, [%g3 + TI_REG_WINDOW + 0x60]
stx %i5, [%g3 + TI_REG_WINDOW + 0x68]
stx %i6, [%g3 + TI_REG_WINDOW + 0x70]
b,pt %xcc, 2f
stx %i7, [%g3 + TI_REG_WINDOW + 0x78]
1: stw %l0, [%g3 + TI_REG_WINDOW + 0x00]
stw %l1, [%g3 + TI_REG_WINDOW + 0x04]
stw %l2, [%g3 + TI_REG_WINDOW + 0x08]
stw %l3, [%g3 + TI_REG_WINDOW + 0x0c]
stw %l4, [%g3 + TI_REG_WINDOW + 0x10]
stw %l5, [%g3 + TI_REG_WINDOW + 0x14]
stw %l6, [%g3 + TI_REG_WINDOW + 0x18]
stw %l7, [%g3 + TI_REG_WINDOW + 0x1c]
stw %i0, [%g3 + TI_REG_WINDOW + 0x20]
stw %i1, [%g3 + TI_REG_WINDOW + 0x24]
stw %i2, [%g3 + TI_REG_WINDOW + 0x28]
stw %i3, [%g3 + TI_REG_WINDOW + 0x2c]
stw %i4, [%g3 + TI_REG_WINDOW + 0x30]
stw %i5, [%g3 + TI_REG_WINDOW + 0x34]
stw %i6, [%g3 + TI_REG_WINDOW + 0x38]
stw %i7, [%g3 + TI_REG_WINDOW + 0x3c]
2: add %g1, 1, %g1
stb %g1, [%g6 + TI_WSAVED]
rdpr %tstate, %g1
andcc %g1, TSTATE_PRIV, %g0
saved
and %g1, TSTATE_CWP, %g1
be,pn %xcc, window_scheisse_from_user_common
mov FAULT_CODE_WRITE | FAULT_CODE_DTLB | FAULT_CODE_WINFIXUP, %g4
retry
window_scheisse_from_user_common:
stb %g4, [%g6 + TI_FAULT_CODE]
stx %g5, [%g6 + TI_FAULT_ADDR]
wrpr %g1, %cwp
ba,pt %xcc, etrap
rd %pc, %g7
call do_sparc64_fault
add %sp, PTREGS_OFF, %o0
ba,a,pt %xcc, rtrap_clr_l6
.globl winfix_mna, fill_fixup_mna, spill_fixup_mna
winfix_mna:
andn %g3, 0x7f, %g3
add %g3, 0x78, %g3
wrpr %g3, %tnpc
done
fill_fixup_mna:
rdpr %tstate, %g1
andcc %g1, TSTATE_PRIV, %g0
be,pt %xcc, window_mna_from_user_common
and %g1, TSTATE_CWP, %g1
/* Please, see fill_fixup commentary about why we must preserve
* %l5 and %l6 to preserve absolute correct semantics.
*/
rdpr %wstate, %g2 ! Grab user mode wstate.
wrpr %g1, %cwp ! Get into the right window.
sll %g2, 3, %g2 ! NORMAL-->OTHER
wrpr %g0, 0x0, %canrestore ! Standard etrap stuff.
wrpr %g2, 0x0, %wstate ! This must be consistent.
wrpr %g0, 0x0, %otherwin ! We know this.
call set_pcontext ! Change contexts...
nop
rdpr %pstate, %l1 ! Prepare to change globals.
mov %g4, %o2 ! Setup args for
mov %g5, %o1 ! final call to mem_address_unaligned.
andn %l1, PSTATE_MM, %l1 ! We want to be in RMO
mov %g6, %o7 ! Stash away current.
wrpr %g0, 0x0, %tl ! Out of trap levels.
wrpr %l1, (PSTATE_IE | PSTATE_AG | PSTATE_RMO), %pstate
mov %o7, %g6 ! Get current back.
ldx [%g6 + TI_TASK], %g4 ! Finish it.
#ifdef CONFIG_SMP
#error IMMU TSB usage must be fixed
mov TSB_REG, %g1
ldxa [%g1] ASI_IMMU, %g5
#endif
call mem_address_unaligned
add %sp, PTREGS_OFF, %o0
b,pt %xcc, rtrap
nop ! yes, the nop is correct
spill_fixup_mna:
ldx [%g6 + TI_FLAGS], %g1
andcc %g1, _TIF_32BIT, %g0
ldub [%g6 + TI_WSAVED], %g1
sll %g1, 3, %g3
add %g6, %g3, %g3
stx %sp, [%g3 + TI_RWIN_SPTRS]
sll %g1, 7, %g3
bne,pt %xcc, 1f
add %g6, %g3, %g3
stx %l0, [%g3 + TI_REG_WINDOW + 0x00]
stx %l1, [%g3 + TI_REG_WINDOW + 0x08]
stx %l2, [%g3 + TI_REG_WINDOW + 0x10]
stx %l3, [%g3 + TI_REG_WINDOW + 0x18]
stx %l4, [%g3 + TI_REG_WINDOW + 0x20]
stx %l5, [%g3 + TI_REG_WINDOW + 0x28]
stx %l6, [%g3 + TI_REG_WINDOW + 0x30]
stx %l7, [%g3 + TI_REG_WINDOW + 0x38]
stx %i0, [%g3 + TI_REG_WINDOW + 0x40]
stx %i1, [%g3 + TI_REG_WINDOW + 0x48]
stx %i2, [%g3 + TI_REG_WINDOW + 0x50]
stx %i3, [%g3 + TI_REG_WINDOW + 0x58]
stx %i4, [%g3 + TI_REG_WINDOW + 0x60]
stx %i5, [%g3 + TI_REG_WINDOW + 0x68]
stx %i6, [%g3 + TI_REG_WINDOW + 0x70]
stx %i7, [%g3 + TI_REG_WINDOW + 0x78]
b,pt %xcc, 2f
add %g1, 1, %g1
1: std %l0, [%g3 + TI_REG_WINDOW + 0x00]
std %l2, [%g3 + TI_REG_WINDOW + 0x08]
std %l4, [%g3 + TI_REG_WINDOW + 0x10]
std %l6, [%g3 + TI_REG_WINDOW + 0x18]
std %i0, [%g3 + TI_REG_WINDOW + 0x20]
std %i2, [%g3 + TI_REG_WINDOW + 0x28]
std %i4, [%g3 + TI_REG_WINDOW + 0x30]
std %i6, [%g3 + TI_REG_WINDOW + 0x38]
add %g1, 1, %g1
2: stb %g1, [%g6 + TI_WSAVED]
rdpr %tstate, %g1
andcc %g1, TSTATE_PRIV, %g0
saved
be,pn %xcc, window_mna_from_user_common
and %g1, TSTATE_CWP, %g1
retry
window_mna_from_user_common:
wrpr %g1, %cwp
sethi %hi(109f), %g7
ba,pt %xcc, etrap
109: or %g7, %lo(109b), %g7
mov %l4, %o2
mov %l5, %o1
call mem_address_unaligned
add %sp, PTREGS_OFF, %o0
ba,pt %xcc, rtrap
clr %l6
.globl winfix_dax, fill_fixup_dax, spill_fixup_dax
winfix_dax:
andn %g3, 0x7f, %g3
add %g3, 0x74, %g3
wrpr %g3, %tnpc
done
fill_fixup_dax:
rdpr %tstate, %g1
andcc %g1, TSTATE_PRIV, %g0
be,pt %xcc, window_dax_from_user_common
and %g1, TSTATE_CWP, %g1
/* Please, see fill_fixup commentary about why we must preserve
* %l5 and %l6 to preserve absolute correct semantics.
*/
rdpr %wstate, %g2 ! Grab user mode wstate.
wrpr %g1, %cwp ! Get into the right window.
sll %g2, 3, %g2 ! NORMAL-->OTHER
wrpr %g0, 0x0, %canrestore ! Standard etrap stuff.
wrpr %g2, 0x0, %wstate ! This must be consistent.
wrpr %g0, 0x0, %otherwin ! We know this.
call set_pcontext ! Change contexts...
nop
rdpr %pstate, %l1 ! Prepare to change globals.
mov %g4, %o1 ! Setup args for
mov %g5, %o2 ! final call to spitfire_data_access_exception.
andn %l1, PSTATE_MM, %l1 ! We want to be in RMO
mov %g6, %o7 ! Stash away current.
wrpr %g0, 0x0, %tl ! Out of trap levels.
wrpr %l1, (PSTATE_IE | PSTATE_AG | PSTATE_RMO), %pstate
mov %o7, %g6 ! Get current back.
ldx [%g6 + TI_TASK], %g4 ! Finish it.
#ifdef CONFIG_SMP
#error IMMU TSB usage must be fixed
mov TSB_REG, %g1
ldxa [%g1] ASI_IMMU, %g5
#endif
call spitfire_data_access_exception
add %sp, PTREGS_OFF, %o0
b,pt %xcc, rtrap
nop ! yes, the nop is correct
spill_fixup_dax:
ldx [%g6 + TI_FLAGS], %g1
andcc %g1, _TIF_32BIT, %g0
ldub [%g6 + TI_WSAVED], %g1
sll %g1, 3, %g3
add %g6, %g3, %g3
stx %sp, [%g3 + TI_RWIN_SPTRS]
sll %g1, 7, %g3
bne,pt %xcc, 1f
add %g6, %g3, %g3
stx %l0, [%g3 + TI_REG_WINDOW + 0x00]
stx %l1, [%g3 + TI_REG_WINDOW + 0x08]
stx %l2, [%g3 + TI_REG_WINDOW + 0x10]
stx %l3, [%g3 + TI_REG_WINDOW + 0x18]
stx %l4, [%g3 + TI_REG_WINDOW + 0x20]
stx %l5, [%g3 + TI_REG_WINDOW + 0x28]
stx %l6, [%g3 + TI_REG_WINDOW + 0x30]
stx %l7, [%g3 + TI_REG_WINDOW + 0x38]
stx %i0, [%g3 + TI_REG_WINDOW + 0x40]
stx %i1, [%g3 + TI_REG_WINDOW + 0x48]
stx %i2, [%g3 + TI_REG_WINDOW + 0x50]
stx %i3, [%g3 + TI_REG_WINDOW + 0x58]
stx %i4, [%g3 + TI_REG_WINDOW + 0x60]
stx %i5, [%g3 + TI_REG_WINDOW + 0x68]
stx %i6, [%g3 + TI_REG_WINDOW + 0x70]
stx %i7, [%g3 + TI_REG_WINDOW + 0x78]
b,pt %xcc, 2f
add %g1, 1, %g1
1: std %l0, [%g3 + TI_REG_WINDOW + 0x00]
std %l2, [%g3 + TI_REG_WINDOW + 0x08]
std %l4, [%g3 + TI_REG_WINDOW + 0x10]
std %l6, [%g3 + TI_REG_WINDOW + 0x18]
std %i0, [%g3 + TI_REG_WINDOW + 0x20]
std %i2, [%g3 + TI_REG_WINDOW + 0x28]
std %i4, [%g3 + TI_REG_WINDOW + 0x30]
std %i6, [%g3 + TI_REG_WINDOW + 0x38]
add %g1, 1, %g1
2: stb %g1, [%g6 + TI_WSAVED]
rdpr %tstate, %g1
andcc %g1, TSTATE_PRIV, %g0
saved
be,pn %xcc, window_dax_from_user_common
and %g1, TSTATE_CWP, %g1
retry
window_dax_from_user_common:
wrpr %g1, %cwp
sethi %hi(109f), %g7
ba,pt %xcc, etrap
109: or %g7, %lo(109b), %g7
mov %l4, %o1
mov %l5, %o2
call spitfire_data_access_exception
add %sp, PTREGS_OFF, %o0
ba,pt %xcc, rtrap
clr %l6