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add DEBUG code to detect modifications on free memory.

This commit is contained in:
yamt 2006-07-08 06:01:53 +00:00
parent 7d19947ffd
commit d9530c47ba
1 changed files with 73 additions and 4 deletions
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77
sys/kern/subr_kmem.c
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@ -1,4 +1,4 @@
/* $NetBSD: subr_kmem.c,v 1.3 2006/07/03 09:18:35 yamt Exp $ */
/* $NetBSD: subr_kmem.c,v 1.4 2006/07/08 06:01:53 yamt Exp $ */
/*-
* Copyright (c)2006 YAMAMOTO Takashi,
@ -34,7 +34,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_kmem.c,v 1.3 2006/07/03 09:18:35 yamt Exp $");
__KERNEL_RCSID(0, "$NetBSD: subr_kmem.c,v 1.4 2006/07/08 06:01:53 yamt Exp $");
#include <sys/param.h>
#include <sys/kmem.h>
@ -46,6 +46,14 @@ __KERNEL_RCSID(0, "$NetBSD: subr_kmem.c,v 1.3 2006/07/03 09:18:35 yamt Exp $");
static vmem_t *kmem_arena;
#if defined(DEBUG)
static void kmem_poison_fill(void *, size_t);
static void kmem_poison_check(void *, size_t);
#else /* defined(DEBUG) */
#define kmem_poison_fill(p, sz) /* nothing */
#define kmem_poison_check(p, sz) /* nothing */
#endif /* defined(DEBUG) */
static vmem_addr_t kmem_backend_alloc(vmem_t *, vmem_size_t, vmem_size_t *,
vm_flag_t);
static void kmem_backend_free(vmem_t *, vmem_addr_t, vmem_size_t);
@ -80,9 +88,12 @@ kmf_to_vmf(km_flag_t kmflags)
void *
kmem_alloc(size_t size, km_flag_t kmflags)
{
void *p;
return (void *)vmem_alloc(kmem_arena, size,
p = (void *)vmem_alloc(kmem_arena, size,
kmf_to_vmf(kmflags) | VM_INSTANTFIT);
kmem_poison_check(p, size);
return p;
}
/*
@ -113,6 +124,7 @@ void
kmem_free(void *p, size_t size)
{
kmem_poison_fill(p, size);
vmem_free(kmem_arena, (vmem_addr_t)p, size);
}
@ -140,6 +152,7 @@ kmem_backend_alloc(vmem_t *dummy, vmem_size_t size, vmem_size_t *resultsize,
vm_flag_t vmflags)
{
uvm_flag_t uflags;
vaddr_t va;
KASSERT(dummy == NULL);
KASSERT(size != 0);
@ -152,8 +165,10 @@ kmem_backend_alloc(vmem_t *dummy, vmem_size_t size, vmem_size_t *resultsize,
uflags = UVM_KMF_WAITVA;
}
*resultsize = size = round_page(size);
return (vmem_addr_t)uvm_km_alloc(kernel_map, size, 0,
va = uvm_km_alloc(kernel_map, size, 0,
uflags | UVM_KMF_WIRED | UVM_KMF_CANFAIL);
kmem_poison_fill((void *)va, size);
return (vmem_addr_t)va;
}
static void
@ -165,5 +180,59 @@ kmem_backend_free(vmem_t *dummy, vmem_addr_t addr, vmem_size_t size)
KASSERT(size != 0);
KASSERT(size == round_page(size));
kmem_poison_check((void *)addr, size);
uvm_km_free(kernel_map, (vaddr_t)addr, size, UVM_KMF_WIRED);
}
/* ---- debug */
#if defined(DEBUG)
#if defined(_LP64)
#define PRIME 0x9e37fffffffc0001UL
#else /* defined(_LP64) */
#define PRIME 0x9e3779b1
#endif /* defined(_LP64) */
static inline uint8_t
kmem_poison_pattern(const void *p)
{
return (uint8_t)((((uintptr_t)p) * PRIME)
>> ((sizeof(uintptr_t) - sizeof(uint8_t))) * CHAR_BIT);
}
static void
kmem_poison_fill(void *p, size_t sz)
{
uint8_t *cp;
const uint8_t *ep;
cp = p;
ep = cp + sz;
while (cp < ep) {
*cp = kmem_poison_pattern(cp);
cp++;
}
}
static void
kmem_poison_check(void *p, size_t sz)
{
uint8_t *cp;
const uint8_t *ep;
cp = p;
ep = cp + sz;
while (cp < ep) {
const uint8_t expected = kmem_poison_pattern(cp);
if (*cp != expected) {
panic("%s: %p: 0x%02x != 0x%02x\n",
__func__, cp, *cp, expected);
}
cp++;
}
}
#endif /* defined(DEBUG) */