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Add interrupt stack "red zones". Reserve and unmap the virtual

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pages immediately above and below the x86 interrupt stack so that
both an overgrown interrupt stack and other faults produce a page
fault trap.  Condition this on the historical option NOREDZONE,
for now.
This commit is contained in:
dyoung 2007-08-29 22:21:51 +00:00
parent ecfdd24019
commit cdffb92c2f
1 changed files with 28 additions and 5 deletions
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33
sys/arch/x86/x86/intr.c
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@ -1,4 +1,4 @@
/* $NetBSD: intr.c,v 1.29 2007/07/09 20:52:38 ad Exp $ */
/* $NetBSD: intr.c,v 1.30 2007/08/29 22:21:51 dyoung Exp $ */
/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
@ -140,8 +140,9 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: intr.c,v 1.29 2007/07/09 20:52:38 ad Exp $");
__KERNEL_RCSID(0, "$NetBSD: intr.c,v 1.30 2007/08/29 22:21:51 dyoung Exp $");
#include "opt_noredzone.h"
#include "opt_multiprocessor.h"
#include "opt_acpi.h"
@ -850,6 +851,16 @@ struct intrhand fake_ipi_intrhand;
static const char *x86_ipi_names[X86_NIPI] = X86_IPI_NAMES;
#endif
static inline int
redzone_const_or_zero(int x)
{
#ifdef NOREDZONE
return 0;
#else
return x;
#endif /* !NOREDZONE */
}
/*
* Initialize all handlers that aren't dynamically allocated, and exist
* for each CPU.
@ -862,7 +873,7 @@ cpu_intr_init(struct cpu_info *ci)
int i;
#endif
#if defined(INTRSTACKSIZE)
char *cp;
vaddr_t istack;
#endif /* defined(INTRSTACKSIZE) */
MALLOC(isp, struct intrsource *, sizeof (struct intrsource), M_DEVBUF,
@ -939,8 +950,20 @@ cpu_intr_init(struct cpu_info *ci)
intr_calculatemasks(ci);
#if defined(INTRSTACKSIZE)
cp = (char *)uvm_km_alloc(kernel_map, INTRSTACKSIZE, 0, UVM_KMF_WIRED);
ci->ci_intrstack = cp + INTRSTACKSIZE - sizeof(register_t);
/* If the red zone is activated, protect both the top and
* the bottom of the stack with an unmapped page.
*/
istack = uvm_km_alloc(kernel_map,
INTRSTACKSIZE + redzone_const_or_zero(2 * PAGE_SIZE), 0,
UVM_KMF_WIRED);
if (redzone_const_or_zero(1)) {
pmap_kremove(istack, PAGE_SIZE);
pmap_kremove(istack + INTRSTACKSIZE + PAGE_SIZE, PAGE_SIZE);
pmap_update(pmap_kernel());
}
ci->ci_intrstack =
(char *)istack + redzone_const_or_zero(PAGE_SIZE) + INTRSTACKSIZE -
sizeof(register_t);
ci->ci_idepth = -1;
#endif /* defined(INTRSTACKSIZE) */
}