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[src/trunk]: src/sys/arch/sh3 sh3: make ASTs work as expected, and fix a few ...



details:   https://anonhg.NetBSD.org/src/rev/27595c47dca1
branches:  trunk
changeset: 967130:27595c47dca1
user:      ad <ad%NetBSD.org@localhost>
date:      Sun Dec 01 12:19:28 2019 +0000

description:
sh3: make ASTs work as expected, and fix a few things in the TLB refill path.
With help from uwe@ and martin@.

diffstat:

 sys/arch/sh3/include/userret.h      |  10 +++++-
 sys/arch/sh3/sh3/exception.c        |  58 ++++++++++++++++++++++--------------
 sys/arch/sh3/sh3/exception_vector.S |  40 +++++++++++++++++++++----
 3 files changed, 77 insertions(+), 31 deletions(-)

diffs (279 lines):

diff -r 6f54982f9df6 -r 27595c47dca1 sys/arch/sh3/include/userret.h
--- a/sys/arch/sh3/include/userret.h    Sun Dec 01 10:19:59 2019 +0000
+++ b/sys/arch/sh3/include/userret.h    Sun Dec 01 12:19:28 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: userret.h,v 1.16 2019/11/30 15:53:36 ad Exp $  */
+/*     $NetBSD: userret.h,v 1.17 2019/12/01 12:19:28 ad Exp $  */
 
 /*
  * Copyright (c) 1988 University of Utah.
@@ -51,6 +51,14 @@
 userret(struct lwp *l)
 {
 
+       /* This must come first... */
+       l->l_md.md_astpending = 0;
+
+       if (l->l_pflag & LP_OWEUPC) {
+               l->l_pflag &= ~LP_OWEUPC;
+               ADDUPROF(l);
+       }
+
        /* Invoke MI userret code */
        mi_userret(l);
 
diff -r 6f54982f9df6 -r 27595c47dca1 sys/arch/sh3/sh3/exception.c
--- a/sys/arch/sh3/sh3/exception.c      Sun Dec 01 10:19:59 2019 +0000
+++ b/sys/arch/sh3/sh3/exception.c      Sun Dec 01 12:19:28 2019 +0000
@@ -1,7 +1,7 @@
-/*     $NetBSD: exception.c,v 1.70 2019/11/30 15:53:36 ad Exp $        */
+/*     $NetBSD: exception.c,v 1.71 2019/12/01 12:19:28 ad Exp $        */
 
 /*-
- * Copyright (c) 2002 The NetBSD Foundation, Inc. All rights reserved.
+ * Copyright (c) 2002, 2019 The NetBSD Foundation, Inc. All rights reserved.
  * Copyright (c) 1990 The Regents of the University of California.
  * All rights reserved.
  *
@@ -79,7 +79,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: exception.c,v 1.70 2019/11/30 15:53:36 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: exception.c,v 1.71 2019/12/01 12:19:28 ad Exp $");
 
 #include "opt_ddb.h"
 #include "opt_kgdb.h"
@@ -89,6 +89,7 @@
 #include <sys/kernel.h>
 #include <sys/proc.h>
 #include <sys/signal.h>
+#include <sys/intr.h>
 
 #ifdef DDB
 #include <sh3/db_machdep.h>
@@ -295,12 +296,9 @@
                        }                               \
                } while(/*CONSTCOND*/0)
 
-       splx(tf->tf_ssr & PSL_IMASK);
-
        usermode = !KERNELMODE(tf->tf_ssr);
        if (usermode) {
                KDASSERT(l->l_md.md_regs == tf);
-               LWP_CACHE_CREDS(l, l->l_proc);
        } else {
 #if 0 /* FIXME: probably wrong for yamt-idlelwp */
                KDASSERT(l == NULL ||           /* idle */
@@ -330,6 +328,8 @@
                        ksi.ksi_signo = SIGSEGV;
                        ksi.ksi_code = SEGV_ACCERR;
                        ksi.ksi_addr = (void *)va;
+                       splx(tf->tf_ssr & PSL_IMASK);
+                       LWP_CACHE_CREDS(l, l->l_proc);
                        goto user_fault;
                } else {
                        TLB_ASSERT(l && onfault != NULL,
@@ -372,12 +372,12 @@
 
        /* Lookup page table. if entry found, load it. */
        if (track && __pmap_pte_load(pmap, va, track)) {
-               if (usermode)
-                       userret(l);
                return;
        }
 
        /* Page not found. call fault handler */
+       splx(tf->tf_ssr & PSL_IMASK);
+       LWP_CACHE_CREDS(l, l->l_proc);
        pcb->pcb_onfault = NULL;
        err = uvm_fault(map, va, ftype);
        pcb->pcb_onfault = onfault;
@@ -399,10 +399,21 @@
 
        /* Page in. load PTE to TLB. */
        if (err == 0) {
-               bool loaded = __pmap_pte_load(pmap, va, track);
+               bool loaded;
+               userret(l);
+               loaded = __pmap_pte_load(pmap, va, track);
+#if 0
+               /*
+                * XXXAD I don't think you should do this - consider
+                * a multithreaded program where another thread got
+                * switched to during UVM fault and it unmapped the
+                * page. I think you should just let the fault happen
+                * again.
+                */
                TLB_ASSERT(loaded, "page table entry not found");
-               if (usermode)
-                       userret(l);
+#else
+               __USE(loaded);
+#endif
                return;
        }
 
@@ -441,7 +452,6 @@
        ksi.ksi_trap = tf->tf_expevt;
        trapsignal(l, &ksi);
        userret(l);
-       ast(l, tf);
        return;
 
  tlb_panic:
@@ -459,27 +469,29 @@
  *     tf ... full user context.
  *     This is called when exception return. if return from kernel to user,
  *     handle asynchronous software traps and context switch if needed.
+ *     Interrupts are blocked on entry.
  */
 void
 ast(struct lwp *l, struct trapframe *tf)
 {
+       int s;
 
-       if (KERNELMODE(tf->tf_ssr)) {
+       if (__predict_true(l->l_md.md_astpending == 0)) {
+               return;
+       }
+       if (__predict_false(KERNELMODE(tf->tf_ssr))) {
+               /* should not occur but leave it here to be safe */
                return;
        }
 
        KDASSERT(l != NULL);
        KDASSERT(l->l_md.md_regs == tf);
 
-       while (l->l_md.md_astpending) {
-               //curcpu()->ci_data.cpu_nast++;
-               l->l_md.md_astpending = 0;
-
-               if (l->l_pflag & LP_OWEUPC) {
-                       l->l_pflag &= ~LP_OWEUPC;
-                       ADDUPROF(l);
-               }
-
+       s = tf->tf_ssr & PSL_IMASK;
+       do {
+               splx(s);
+               /* userret() clears l_md.md_astpending */
                userret(l);
-       }
+               s = splhigh();
+       } while (__predict_false(l->l_md.md_astpending));
 }
diff -r 6f54982f9df6 -r 27595c47dca1 sys/arch/sh3/sh3/exception_vector.S
--- a/sys/arch/sh3/sh3/exception_vector.S       Sun Dec 01 10:19:59 2019 +0000
+++ b/sys/arch/sh3/sh3/exception_vector.S       Sun Dec 01 12:19:28 2019 +0000
@@ -1,7 +1,7 @@
-/*     $NetBSD: exception_vector.S,v 1.50 2016/11/02 00:11:59 pgoyette Exp $   */
+/*     $NetBSD: exception_vector.S,v 1.51 2019/12/01 12:19:28 ad Exp $ */
 
 /*-
- * Copyright (c) 2002 The NetBSD Foundation, Inc.
+ * Copyright (c) 2002, 2019 The NetBSD Foundation, Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -48,7 +48,7 @@
 #define _ALIGN_TEXT    .align 5
 #include <sh3/asm.h>
 
-__KERNEL_RCSID(0, "$NetBSD: exception_vector.S,v 1.50 2016/11/02 00:11:59 pgoyette Exp $")
+__KERNEL_RCSID(0, "$NetBSD: exception_vector.S,v 1.51 2019/12/01 12:19:28 ad Exp $")
 
 
 /*
@@ -86,18 +86,25 @@
        /* Check TLB exception or not */
        mov.l   .Lg_TLB_PROT_ST, r1
        cmp/hi  r1, r0
-       bt      1f
+       bt/s    1f
+        mov    r4, r8  /* preserve curlwp across call */
 
        /* tlb_exception(curlwp, tf, TEA); */
        __INTR_MASK_EXCEPTION_UNBLOCK(r0, r1, r3)
        mov.l   .Lg_tlb_exception, r0
        jsr     @r0
         mov    r14, r5                 /* 2nd arg */
+
+       /* Check for ASTs on exit to user mode. */
+       __INTR_MASK(r0, r1)
+       mov.l   .Lg_ast, r0
+       mov     r8, r4
+       jsr     @r0
+        mov    r14, r5
        bra     .Lg_return_from_exception
         nop
 
-       /* general_exception(curlwp, tf, TEA); */
-1:     mov     r4, r8
+1:     /* general_exception(curlwp, tf, TEA); */
 #if defined(PTRACE_HOOKS) || defined(DDB)
        mov     #0, r2
        MOV     (BBRA, r1)
@@ -110,8 +117,9 @@
         mov    r14, r5                 /* 2nd arg */
 
        /* Check for ASTs on exit to user mode. */
+       __INTR_MASK(r0, r1)
+       mov.l   .Lg_ast, r0
        mov     r8, r4
-       mov.l   .Lg_ast, r0
        jsr     @r0
         mov    r14, r5
 
@@ -271,9 +279,17 @@
        mov.l   @r1, r4                 ! arg1: curlwp
        __INTR_MASK_EXCEPTION_UNBLOCK(r0, r1, r3)
        mov.l   .L3_tlb_exception, r0
+       mov     r4, r8                  ! save curlwp across the call
        mov.l   r2, @(TF_EXPEVT, r14)   ! tf->tf_expevt = EXPEVT
        jsr     @r0
         mov    r14, r5                 ! arg2: trapframe
+
+       /* Check for ASTs on exit to user mode. */
+       __INTR_MASK(r0, r1)
+       mov.l   .L3_ast, r0
+       mov     r8, r4                  ! arg1: curlwp
+       jsr     @r0
+        mov    r14, r5                 ! arg2: trapframe
        __EXCEPTION_RETURN
 
        .align  4
@@ -289,6 +305,7 @@
 .L3_SH3_EXPEVT:                        .long   SH3_EXPEVT
 .L3_curlwp:                    .long   _C_LABEL(curlwp)
 .L3_tlb_exception:             .long   _C_LABEL(tlb_exception)
+.L3_ast:                       .long   _C_LABEL(ast)
 
 /* LINTSTUB: Var: char sh3_vector_tlbmiss_end[1]; */
 VECTOR_END_MARKER(sh3_vector_tlbmiss_end)
@@ -421,9 +438,17 @@
        mov.l   @r1, r4                 ! arg1: curlwp
        __INTR_MASK_EXCEPTION_UNBLOCK(r0, r1, r3)
        mov.l   .L4_tlb_exception, r0
+       mov     r4, r8                  ! save curlwp across the call
        mov.l   r2, @(TF_EXPEVT, r14)   ! tf->tf_expevt = EXPEVT
        jsr     @r0
         mov    r14, r5                 ! arg2: trapframe
+
+       /* Check for ASTs on exit to user mode. */
+       __INTR_MASK(r0, r1)
+       mov.l   .L4_ast, r0
+       mov     r8, r4                  ! arg1: curlwp
+       jsr     @r0
+        mov    r14, r5                 ! arg2: trapframe
        __EXCEPTION_RETURN
 
        .align  5
@@ -439,6 +464,7 @@
 .L4_clear_ASID:                        .long   ~SH4_PTEH_ASID_MASK
 .L4_curlwp:                    .long   _C_LABEL(curlwp)
 .L4_tlb_exception:             .long   _C_LABEL(tlb_exception)
+.L4_ast:                       .long   _C_LABEL(ast)
 
 /* LINTSTUB: Var: char sh4_vector_tlbmiss_end[1]; */
 VECTOR_END_MARKER(sh4_vector_tlbmiss_end)



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