winfixup.S
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- /* $Id: winfixup.S,v 1.29 2000/03/26 09:13:48 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/asm_offsets.h>
- .text
- .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 consistant.
- wrpr %g0, 0x0, %otherwin ! We know this.
- mov PRIMARY_CONTEXT, %g1 ! Change contexts...
- stxa %g0, [%g1] ASI_DMMU ! Back into the nucleus.
- flush %g6 ! Flush instruction buffers
- 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 + AOFF_task_thread + AOFF_thread_fault_code]
- stx %g5, [%g6 + AOFF_task_thread + AOFF_thread_fault_address]
- wrpr %g0, 0x0, %tl ! Out of trap levels.
- wrpr %l1, (PSTATE_IE | PSTATE_AG | PSTATE_RMO), %pstate
- sethi %uhi(PAGE_OFFSET), %g4 ! Prepare page_offset global reg
- mov %o7, %g6
- sllx %g4, 32, %g4 ! and finish it...
- /* 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, STACK_BIAS + REGWIN_SZ, %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:
- ldub [%g6 + AOFF_task_thread + AOFF_thread_flags], %g1
- andcc %g1, SPARC_FLAG_32BIT, %g0
- ldub [%g6 + AOFF_task_thread + AOFF_thread_w_saved], %g1
- sll %g1, 3, %g3
- add %g6, %g3, %g3
- stx %sp, [%g3 + AOFF_task_thread + AOFF_thread_rwbuf_stkptrs]
- sll %g1, 7, %g3
- bne,pt %xcc, 1f
- add %g6, %g3, %g3
- stx %l0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x00]
- stx %l1, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x08]
- stx %l2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x10]
- stx %l3, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x18]
- stx %l4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x20]
- stx %l5, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x28]
- stx %l6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x30]
- stx %l7, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x38]
- stx %i0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x40]
- stx %i1, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x48]
- stx %i2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x50]
- stx %i3, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x58]
- stx %i4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x60]
- stx %i5, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x68]
- stx %i6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x70]
- b,pt %xcc, 2f
- stx %i7, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x78]
- 1: stw %l0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x00]
- stw %l1, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x04]
- stw %l2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x08]
- stw %l3, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x0c]
- stw %l4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x10]
- stw %l5, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x14]
- stw %l6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x18]
- stw %l7, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x1c]
- stw %i0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x20]
- stw %i1, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x24]
- stw %i2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x28]
- stw %i3, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x2c]
- stw %i4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x30]
- stw %i5, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x34]
- stw %i6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x38]
- stw %i7, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x3c]
- 2: add %g1, 1, %g1
- stb %g1, [%g6 + AOFF_task_thread + AOFF_thread_w_saved]
- 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 + AOFF_task_thread + AOFF_thread_fault_code]
- stx %g5, [%g6 + AOFF_task_thread + AOFF_thread_fault_address]
- wrpr %g1, %cwp
- ba,pt %xcc, etrap
- rd %pc, %g7
- call do_sparc64_fault
- add %sp, STACK_BIAS + REGWIN_SZ, %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 consistant.
- wrpr %g0, 0x0, %otherwin ! We know this.
- mov PRIMARY_CONTEXT, %g1 ! Change contexts...
- stxa %g0, [%g1] ASI_DMMU ! Back into the nucleus.
- flush %g6 ! Flush instruction buffers
- 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
- sethi %uhi(PAGE_OFFSET), %g4 ! Set page_offset global reg.
- mov %o7, %g6 ! Get current back.
- sllx %g4, 32, %g4 ! Finish it.
- call mem_address_unaligned
- add %sp, STACK_BIAS + REGWIN_SZ, %o0
- b,pt %xcc, rtrap
- nop ! yes, the nop is correct
- spill_fixup_mna:
- ldub [%g6 + AOFF_task_thread + AOFF_thread_flags], %g1
- andcc %g1, SPARC_FLAG_32BIT, %g0
- ldub [%g6 + AOFF_task_thread + AOFF_thread_w_saved], %g1
- sll %g1, 3, %g3
- add %g6, %g3, %g3
- stx %sp, [%g3 + AOFF_task_thread + AOFF_thread_rwbuf_stkptrs]
- sll %g1, 7, %g3
- bne,pt %xcc, 1f
- add %g6, %g3, %g3
- stx %l0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x00]
- stx %l1, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x08]
- stx %l2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x10]
- stx %l3, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x18]
- stx %l4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x20]
- stx %l5, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x28]
- stx %l6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x30]
- stx %l7, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x38]
- stx %i0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x40]
- stx %i1, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x48]
- stx %i2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x50]
- stx %i3, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x58]
- stx %i4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x60]
- stx %i5, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x68]
- stx %i6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x70]
- stx %i7, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x78]
- b,pt %xcc, 2f
- add %g1, 1, %g1
- 1: std %l0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x00]
- std %l2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x08]
- std %l4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x10]
- std %l6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x18]
- std %i0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x20]
- std %i2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x28]
- std %i4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x30]
- std %i6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x38]
- add %g1, 1, %g1
- 2: stb %g1, [%g6 + AOFF_task_thread + AOFF_thread_w_saved]
- 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, STACK_BIAS + REGWIN_SZ, %o0
- ba,pt %xcc, rtrap
- clr %l6
-
- /* These are only needed for 64-bit mode processes which
- * put their stack pointer into the VPTE area and there
- * happens to be a VPTE tlb entry mapped there during
- * a spill/fill trap to that stack frame.
- */
- .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 consistant.
- wrpr %g0, 0x0, %otherwin ! We know this.
- mov PRIMARY_CONTEXT, %g1 ! Change contexts...
- stxa %g0, [%g1] ASI_DMMU ! Back into the nucleus.
- flush %g6 ! Flush instruction buffers
- rdpr %pstate, %l1 ! Prepare to change globals.
- mov %g4, %o1 ! Setup args for
- mov %g5, %o2 ! final call to 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
- sethi %uhi(PAGE_OFFSET), %g4 ! Set page_offset global reg.
- mov %o7, %g6 ! Get current back.
- sllx %g4, 32, %g4 ! Finish it.
- call data_access_exception
- add %sp, STACK_BIAS + REGWIN_SZ, %o0
- b,pt %xcc, rtrap
- nop ! yes, the nop is correct
- spill_fixup_dax:
- ldub [%g6 + AOFF_task_thread + AOFF_thread_flags], %g1
- andcc %g1, SPARC_FLAG_32BIT, %g0
- ldub [%g6 + AOFF_task_thread + AOFF_thread_w_saved], %g1
- sll %g1, 3, %g3
- add %g6, %g3, %g3
- stx %sp, [%g3 + AOFF_task_thread + AOFF_thread_rwbuf_stkptrs]
- sll %g1, 7, %g3
- bne,pt %xcc, 1f
- add %g6, %g3, %g3
- stx %l0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x00]
- stx %l1, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x08]
- stx %l2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x10]
- stx %l3, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x18]
- stx %l4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x20]
- stx %l5, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x28]
- stx %l6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x30]
- stx %l7, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x38]
- stx %i0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x40]
- stx %i1, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x48]
- stx %i2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x50]
- stx %i3, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x58]
- stx %i4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x60]
- stx %i5, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x68]
- stx %i6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x70]
- stx %i7, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x78]
- b,pt %xcc, 2f
- add %g1, 1, %g1
- 1: std %l0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x00]
- std %l2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x08]
- std %l4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x10]
- std %l6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x18]
- std %i0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x20]
- std %i2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x28]
- std %i4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x30]
- std %i6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x38]
- add %g1, 1, %g1
- 2: stb %g1, [%g6 + AOFF_task_thread + AOFF_thread_w_saved]
- 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 data_access_exception
- add %sp, STACK_BIAS + REGWIN_SZ, %o0
- ba,pt %xcc, rtrap
- clr %l6
-