/* $Id: rtrap.S,v 1.27 1996/04/03 02:14:41 davem Exp $ * rtrap.S: Return from Sparc trap low-level code. * * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu) */ #include <asm/cprefix.h> #include <asm/page.h> #include <asm/ptrace.h> #include <asm/psr.h> #include <asm/asi.h> #include <asm/smp.h> #include <asm/contregs.h> #include <asm/winmacro.h> #include <asm/asmmacro.h> #define t_psr l0 #define t_pc l1 #define t_npc l2 #define t_wim l3 #define twin_tmp1 l4 #define twin_tmp2 l5 #define twin_tmp3 l6 /* 7 WINDOW SPARC PATCH INSTRUCTIONS */ .globl rtrap_7win_patch1, rtrap_7win_patch2, rtrap_7win_patch3 .globl rtrap_7win_patch4, rtrap_7win_patch5 rtrap_7win_patch1: srl %t_wim, 0x6, %twin_tmp2 rtrap_7win_patch2: and %twin_tmp2, 0x7f, %twin_tmp2 rtrap_7win_patch3: srl %g1, 7, %g2 rtrap_7win_patch4: srl %g2, 6, %g2 rtrap_7win_patch5: and %g1, 0x7f, %g1 /* END OF PATCH INSTRUCTIONS */ /* We need to check for a few things which are: * 1) The need to call schedule() because this * processes quantum is up. * 2) Pending signals for this process, if any * exist we need to call do_signal() to do * the needy. * * Else we just check if the rett would land us * in an invalid window, if so we need to grab * it off the user/kernel stack first. */ .globl ret_trap_entry, rtrap_patch1, rtrap_patch2 .globl rtrap_patch3, rtrap_patch4, rtrap_patch5 ret_trap_entry: ld [%sp + REGWIN_SZ + PT_PSR], %t_psr andcc %t_psr, PSR_PS, %g0 bne ret_trap_kernel nop sethi %hi(C_LABEL(need_resched)), %twin_tmp1 ld [%twin_tmp1 + %lo(C_LABEL(need_resched))], %twin_tmp2 cmp %twin_tmp2, 0 be signal_p nop call C_LABEL(schedule) nop /* Try to return again... We are a different process, * most likely so load and then check if going back * to user or kernel this time. */ b ret_trap_entry nop signal_p: /* No signals for swapper. */ LOAD_CURRENT(twin_tmp1, twin_tmp3) set C_LABEL(init_task), %twin_tmp3 cmp %twin_tmp3, %twin_tmp1 be ret_trap_continue nop ld [%twin_tmp1 + TASK_SIGNAL], %twin_tmp2 ld [%twin_tmp1 + TASK_BLOCKED], %o0 andncc %twin_tmp2, %o0, %g0 be ret_trap_continue nop call C_LABEL(do_signal) add %sp, REGWIN_SZ, %o1 ! pt_regs ptr /* Fall through... */ ret_trap_continue: ld [%sp + REGWIN_SZ + PT_PSR], %t_psr wr %t_psr, 0x0, %psr WRITE_PAUSE LOAD_CURRENT(twin_tmp2, twin_tmp1) ld [%twin_tmp2 + THREAD_W_SAVED], %twin_tmp1 orcc %g0, %twin_tmp1, %g0 be ret_trap_nobufwins nop wr %t_psr, PSR_ET, %psr WRITE_PAUSE mov 1, %o1 call C_LABEL(try_to_clear_window_buffer) add %sp, REGWIN_SZ, %o0 b ret_trap_entry nop ret_trap_nobufwins: /* Load up the user's out registers so we can pull * a window from the stack, if necessary. */ LOAD_PT_INS(sp) /* If there are already live user windows in the * set we can return from trap safely. */ ld [%twin_tmp2 + THREAD_UMASK], %twin_tmp1 orcc %g0, %twin_tmp1, %g0 bne ret_trap_userwins_ok nop /* Calculate new %wim, we have to pull a register * window from the users stack. */ ret_trap_pull_one_window: rd %wim, %t_wim sll %t_wim, 0x1, %twin_tmp1 rtrap_patch1: srl %t_wim, 0x7, %twin_tmp2 or %twin_tmp2, %twin_tmp1, %twin_tmp2 rtrap_patch2: and %twin_tmp2, 0xff, %twin_tmp2 wr %twin_tmp2, 0x0, %wim WRITE_PAUSE /* Here comes the architecture specific * branch to the user stack checking routine * for return from traps. */ .globl C_LABEL(rtrap_mmu_patchme) C_LABEL(rtrap_mmu_patchme): b C_LABEL(sun4c_rett_stackchk) andcc %fp, 0x7, %g0 ret_trap_userwins_ok: LOAD_PT_PRIV(sp, t_psr, t_pc, t_npc) or %t_pc, %t_npc, %g2 andcc %g2, 0x3, %g0 bne ret_trap_unaligned_pc nop LOAD_PT_YREG(sp, g1) LOAD_PT_GLOBALS(sp) LEAVE_SYSCALL wr %t_psr, 0x0, %psr WRITE_PAUSE jmp %t_pc rett %t_npc ret_trap_unaligned_pc: add %sp, REGWIN_SZ, %o0 ld [%sp + REGWIN_SZ + PT_PC], %o1 ld [%sp + REGWIN_SZ + PT_NPC], %o2 ld [%sp + REGWIN_SZ + PT_PSR], %o3 wr %t_wim, 0x0, %wim ! or else... WRITE_PAUSE wr %t_psr, PSR_ET, %psr WRITE_PAUSE call C_LABEL(do_memaccess_unaligned) nop b ret_trap_entry ! maybe signal posted nop ret_trap_kernel: ld [%sp + REGWIN_SZ + PT_PSR], %t_psr wr %t_psr, 0x0, %psr WRITE_PAUSE /* Will the rett land us in the invalid window? */ mov 2, %g1 sll %g1, %t_psr, %g1 rtrap_patch3: srl %g1, 8, %g2 or %g1, %g2, %g1 rd %wim, %g2 andcc %g2, %g1, %g0 be 1f ! Nope, just return from the trap nop /* We have to grab a window before returning. */ sll %g2, 0x1, %g1 rtrap_patch4: srl %g2, 7, %g2 or %g1, %g2, %g1 rtrap_patch5: and %g1, 0xff, %g1 wr %g1, 0x0, %wim WRITE_PAUSE restore %g0, %g0, %g0 LOAD_WINDOW(sp) save %g0, %g0, %g0 /* Reload the entire frame in case this is from a * kernel system call or whatever... */ 1: LOAD_PT_ALL(sp, t_psr, t_pc, t_npc, g1) LEAVE_SYSCALL wr %t_psr, 0x0, %psr WRITE_PAUSE jmp %t_pc rett %t_npc ret_trap_user_stack_is_bolixed: wr %t_wim, 0x0, %wim WRITE_PAUSE wr %t_psr, PSR_ET, %psr WRITE_PAUSE call C_LABEL(window_ret_fault) add %sp, REGWIN_SZ, %o0 b ret_trap_entry nop .globl C_LABEL(sun4c_rett_stackchk) C_LABEL(sun4c_rett_stackchk): be 1f and %fp, 0xfff, %g1 ! delay slot b ret_trap_user_stack_is_bolixed nop /* See if we have to check the sanity of one page or two */ 1: add %g1, 0x38, %g1 sra %fp, 29, %g2 add %g2, 0x1, %g2 andncc %g2, 0x1, %g0 be 1f andncc %g1, 0xff8, %g0 /* %sp is in vma hole, yuck */ b ret_trap_user_stack_is_bolixed nop 1: be sun4c_rett_onepage /* Only one page to check */ lda [%fp] ASI_PTE, %g2 sun4c_rett_twopages: add %fp, 0x38, %g1 sra %g1, 29, %g2 add %g2, 0x1, %g2 andncc %g2, 0x1, %g0 be 1f lda [%g1] ASI_PTE, %g2 /* Second page is in vma hole */ b ret_trap_user_stack_is_bolixed nop 1: srl %g2, 29, %g2 andcc %g2, 0x4, %g0 bne sun4c_rett_onepage lda [%fp] ASI_PTE, %g2 /* Second page has bad perms */ b ret_trap_user_stack_is_bolixed nop sun4c_rett_onepage: srl %g2, 29, %g2 andcc %g2, 0x4, %g0 bne 1f nop /* A page had bad page permissions, losing... */ b ret_trap_user_stack_is_bolixed nop /* Whee, things are ok, load the window and continue. */ 1: restore %g0, %g0, %g0 LOAD_WINDOW(sp) save %g0, %g0, %g0 b ret_trap_userwins_ok nop .globl C_LABEL(srmmu_rett_stackchk) C_LABEL(srmmu_rett_stackchk): bne ret_trap_user_stack_is_bolixed sethi %hi(KERNBASE), %g1 cmp %g1, %fp bleu ret_trap_user_stack_is_bolixed mov AC_M_SFSR, %g1 lda [%g1] ASI_M_MMUREGS, %g0 lda [%g0] ASI_M_MMUREGS, %g1 or %g1, 0x2, %g1 sta %g1, [%g0] ASI_M_MMUREGS restore %g0, %g0, %g0 LOAD_WINDOW(sp) save %g0, %g0, %g0 andn %g1, 0x2, %g1 sta %g1, [%g0] ASI_M_MMUREGS mov AC_M_SFAR, %g2 lda [%g2] ASI_M_MMUREGS, %g2 mov AC_M_SFSR, %g1 lda [%g1] ASI_M_MMUREGS, %g1 andcc %g1, 0x2, %g0 bne ret_trap_user_stack_is_bolixed nop b ret_trap_userwins_ok nop