NetBSD/share/man/man9/kmem_alloc.9

.\"	$NetBSD: kmem_alloc.9,v 1.6 2008/01/03 15:59:57 yamt Exp $
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.\" Copyright (c)2006 YAMAMOTO Takashi,
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.\" ------------------------------------------------------------
.Dd January 4, 2008
.Dt KMEM_ALLOC 9
.Os
.\" ------------------------------------------------------------
.Sh NAME
.Nm kmem_alloc
.Nd allocate kernel wired memory
.\" ------------------------------------------------------------
.Sh SYNOPSIS
.In sys/kmem.h
.\" - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
.Ft void *
.Fn kmem_alloc \
"size_t size" "km_flag_t kmflags"
.\" ------------------------------------------------------------
.Sh DESCRIPTION
.Fn kmem_alloc
allocates kernel wired memory.
It takes the following arguments.
.Bl -tag -width kmflags
.It Fa size
Specify the size of allocation in bytes.
.It Fa kmflags
Either of the following:
.Bl -tag -width KM_NOSLEEP -compact
.It KM_SLEEP
Can sleep until enough memory is available.
.It KM_NOSLEEP
Don't sleep.
Immediately return
.Dv NULL
if there is not enough memory available.
.El
.El
.Pp
The contents of allocated memory are uninitialized.
.Pp
Unlike Solaris, kmem_alloc(0, flags) is illegal.
.\" ------------------------------------------------------------
.Sh RETURN VALUES
On success,
.Fn kmem_alloc
returns a pointer to allocated memory.
Otherwise, it returns
.Dv NULL .
.\" ------------------------------------------------------------
.Sh SEE ALSO
.Xr intro 9 ,
.Xr kmem_free 9 ,
.Xr kmem_zalloc 9 ,
.Xr malloc 9 ,
.Xr memoryallocators 9
.\" ------------------------------------------------------------
.Sh CAVEATS
.Fn kmem_alloc
can not be used from interrupt context.
.\" ------------------------------------------------------------
.Sh SECURITY CONSIDERATION
As the allocated memory is uninitialized, it can contain security-sensitive
data left by its previous user.
It's the caller's responsibility not to expose it to the world.