diff options
| author | Michael Shalayeff <mickey@cvs.openbsd.org> | 2002-09-15 09:37:19 +0000 |
|---|---|---|
| committer | Michael Shalayeff <mickey@cvs.openbsd.org> | 2002-09-15 09:37:19 +0000 |
| commit | 3772f43f97e4df1393dc6620367871dc48ee8428 (patch) | |
| tree | 98bdb0fda93cb271ef96423d7728ecbc6a6737d6 /sys/arch | |
| parent | 2a844bb312ee01600fad1b38f894ca9ae1632551 (diff) | |
fix for an interrupt happening in the 2 insn window during a syscall, comment added; from fredette@
Diffstat (limited to 'sys/arch')
| -rw-r--r-- | sys/arch/hppa/hppa/locore.S | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/sys/arch/hppa/hppa/locore.S b/sys/arch/hppa/hppa/locore.S index 067a67b4088..b9a95e9817b 100644 --- a/sys/arch/hppa/hppa/locore.S +++ b/sys/arch/hppa/hppa/locore.S @@ -1,4 +1,4 @@ -/* $OpenBSD: locore.S,v 1.87 2002/09/12 05:31:34 mickey Exp $ */ +/* $OpenBSD: locore.S,v 1.88 2002/09/15 09:37:18 mickey Exp $ */ /* * Copyright (c) 1998-2002 Michael Shalayeff @@ -1360,9 +1360,29 @@ ENTRY(TLABEL(all),0) stw t2, TF_IISQT(t3) mtctl r0, pcsq + /* + * Set up the kernel stack pointer. If the trap happened + * while we were in unprivileged code, or in privileged + * code in the SYSCALLGATE page, move to the kernel stack + * in curproc's PCB; otherwise, start a new stack frame + * on whatever kernel stack we're already on. + * + * This used to check only for a trap while we were in + * unprivileged code, but this ignored the possibility + * that a trap could come in during the period between + * a gateway instruction to raise privilege and the + * disabling of interrupts. During this period we're + * still on the user's stack, and we must move to the + * kernel stack. + * + * - fredette@ + */ mfctl pcoq, t1 + ldil L%SYSCALLGATE, t2 ldo TF_PHYS-1(sp), sp - bb,>= t1, 31, $trap_from_kernel + dep t1, 31, PGSHIFT, t2 + dep,<> t1, 31, 2, r0 + comb,<> t1, t2, $trap_from_kernel dep r0, 31, 6, sp mfctl cr30, t2 |