seg_kpm.c revision 1bd5c35fd400f7f19eee9efd795c32cedb602b06
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
/*
* Kernel Physical Mapping (kpm) segment driver (segkpm).
*
* This driver delivers along with the hat_kpm* interfaces an alternative
* mechanism for kernel mappings within the 64-bit Solaris operating system,
* which allows the mapping of all physical memory into the kernel address
* space at once. This is feasible in 64 bit kernels, e.g. for Ultrasparc II
* and beyond processors, since the available VA range is much larger than
* possible physical memory. Momentarily all physical memory is supported,
* that is represented by the list of memory segments (memsegs).
*
* Segkpm mappings have also very low overhead and large pages are used
* (when possible) to minimize the TLB and TSB footprint. It is also
* extentable for other than Sparc architectures (e.g. AMD64). Main
* advantage is the avoidance of the TLB-shootdown X-calls, which are
* normally needed when a kernel (global) mapping has to be removed.
*
* First example of a kernel facility that uses the segkpm mapping scheme
* is seg_map, where it is used as an alternative to hat_memload().
* See also hat layer for more information about the hat_kpm* routines.
* The kpm facilty can be turned off at boot time (e.g. /etc/system).
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/sysmacros.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/cmn_err.h>
#include <sys/debug.h>
#include <sys/thread.h>
#include <sys/cpuvar.h>
#include <sys/bitmap.h>
#include <sys/atomic.h>
#include <sys/lgrp.h>
#include <vm/seg_kmem.h>
#include <vm/seg_kpm.h>
#include <vm/hat.h>
#include <vm/as.h>
#include <vm/seg.h>
#include <vm/page.h>
/*
* Global kpm controls.
* See also platform and mmu specific controls.
*
* kpm_enable -- global on/off switch for segkpm.
* . Set by default on 64bit platforms that have kpm support.
* . Will be disabled from platform layer if not supported.
* . Can be disabled via /etc/system.
*
* kpm_smallpages -- use only regular/system pagesize for kpm mappings.
* . Can be useful for critical debugging of kpm clients.
* . Set to zero by default for platforms that support kpm large pages.
* The use of kpm large pages reduces the footprint of kpm meta data
* and has all the other advantages of using large pages (e.g TLB
* miss reduction).
* . Set by default for platforms that don't support kpm large pages or
* where large pages cannot be used for other reasons (e.g. there are
* only few full associative TLB entries available for large pages).
*
* segmap_kpm -- separate on/off switch for segmap using segkpm:
* . Set by default.
* . Will be disabled when kpm_enable is zero.
* . Will be disabled when MAXBSIZE != PAGESIZE.
* . Can be disabled via /etc/system.
*
*/
int kpm_enable = 1;
int kpm_smallpages = 0;
int segmap_kpm = 1;
/*
* Private seg op routines.
*/
faultcode_t segkpm_fault(struct hat *hat, struct seg *seg, caddr_t addr,
size_t len, enum fault_type type, enum seg_rw rw);
static void segkpm_dump(struct seg *);
static void segkpm_badop(void);
static int segkpm_notsup(void);
static int segkpm_capable(struct seg *, segcapability_t);
#define SEGKPM_BADOP(t) (t(*)())segkpm_badop
#define SEGKPM_NOTSUP (int(*)())segkpm_notsup
static struct seg_ops segkpm_ops = {
SEGKPM_BADOP(int), /* dup */
SEGKPM_BADOP(int), /* unmap */
SEGKPM_BADOP(void), /* free */
segkpm_fault,
SEGKPM_BADOP(int), /* faulta */
SEGKPM_BADOP(int), /* setprot */
SEGKPM_BADOP(int), /* checkprot */
SEGKPM_BADOP(int), /* kluster */
SEGKPM_BADOP(size_t), /* swapout */
SEGKPM_BADOP(int), /* sync */
SEGKPM_BADOP(size_t), /* incore */
SEGKPM_BADOP(int), /* lockop */
SEGKPM_BADOP(int), /* getprot */
SEGKPM_BADOP(u_offset_t), /* getoffset */
SEGKPM_BADOP(int), /* gettype */
SEGKPM_BADOP(int), /* getvp */
SEGKPM_BADOP(int), /* advise */
segkpm_dump, /* dump */
SEGKPM_NOTSUP, /* pagelock */
SEGKPM_BADOP(int), /* setpgsz */
SEGKPM_BADOP(int), /* getmemid */
SEGKPM_BADOP(lgrp_mem_policy_info_t *), /* getpolicy */
segkpm_capable, /* capable */
};
/*
* kpm_pgsz and kpm_pgshft are set by platform layer.
*/
size_t kpm_pgsz; /* kpm page size */
uint_t kpm_pgshft; /* kpm page shift */
u_offset_t kpm_pgoff; /* kpm page offset mask */
uint_t kpmp2pshft; /* kpm page to page shift */
pgcnt_t kpmpnpgs; /* how many pages per kpm page */
#ifdef SEGKPM_SUPPORT
int
segkpm_create(struct seg *seg, void *argsp)
{
struct segkpm_data *skd;
struct segkpm_crargs *b = (struct segkpm_crargs *)argsp;
ushort_t *p;
int i, j;
ASSERT(seg->s_as && RW_WRITE_HELD(&seg->s_as->a_lock));
ASSERT(btokpmp(seg->s_size) >= 1 &&
kpmpageoff((uintptr_t)seg->s_base) == 0 &&
kpmpageoff((uintptr_t)seg->s_base + seg->s_size) == 0);
skd = kmem_zalloc(sizeof (struct segkpm_data), KM_SLEEP);
seg->s_data = (void *)skd;
seg->s_ops = &segkpm_ops;
skd->skd_prot = b->prot;
/*
* (1) Segkpm virtual addresses are based on physical adresses.
* From this and in opposite to other segment drivers it is
* often required to allocate a page first to be able to
* calculate the final segkpm virtual address.
* (2) Page allocation is done by calling page_create_va(),
* one important input argument is a virtual address (also
* expressed by the "va" in the function name). This function
* is highly optimized to select the right page for an optimal
* processor and platform support (e.g. virtual addressed
* caches (VAC), physical addressed caches, NUMA).
*
* Because of (1) the approach is to generate a faked virtual
* address for calling page_create_va(). In order to exploit
* the abilities of (2), especially to utilize the cache
* hierarchy (3) and to avoid VAC alias conflicts (4) the
* selection has to be done carefully. For each virtual color
* a separate counter is provided (4). The count values are
* used for the utilization of all cache lines (3) and are
* corresponding to the cache bins.
*/
skd->skd_nvcolors = b->nvcolors;
p = skd->skd_va_select =
kmem_zalloc(NCPU * b->nvcolors * sizeof (ushort_t), KM_SLEEP);
for (i = 0; i < NCPU; i++)
for (j = 0; j < b->nvcolors; j++, p++)
*p = j;
return (0);
}
/*
* This routine is called via a machine specific fault handling
* routine.
*/
/* ARGSUSED */
faultcode_t
segkpm_fault(struct hat *hat, struct seg *seg, caddr_t addr, size_t len,
enum fault_type type, enum seg_rw rw)
{
faultcode_t error;
ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
error = hat_kpm_fault(hat, addr);
return (error);
}
#define addr_to_vcolor(addr, vcolors) \
((int)(((uintptr_t)(addr) & ((vcolors << PAGESHIFT) - 1)) >> PAGESHIFT))
/*
* Create a virtual address that can be used for invocations of
* page_create_va. Goal is to utilize the cache hierarchy (round
* robin bins) and to select the right color for virtual indexed
* caches. It isn't exact since we also increment the bin counter
* when the caller uses VOP_GETPAGE and gets a hit in the page
* cache, but we keep the bins turning for cache distribution
* (see also segkpm_create block comment).
*/
caddr_t
segkpm_create_va(u_offset_t off)
{
int vcolor;
ushort_t *p;
struct segkpm_data *skd = (struct segkpm_data *)segkpm->s_data;
int nvcolors = skd->skd_nvcolors;
caddr_t va;
vcolor = (nvcolors > 1) ? addr_to_vcolor(off, nvcolors) : 0;
p = &skd->skd_va_select[(CPU->cpu_id * nvcolors) + vcolor];
va = (caddr_t)ptob(*p);
atomic_add_16(p, nvcolors);
return (va);
}
/*
* Unload mapping if the instance has an active kpm mapping.
*/
void
segkpm_mapout_validkpme(struct kpme *kpme)
{
caddr_t vaddr;
page_t *pp;
retry:
if ((pp = kpme->kpe_page) == NULL) {
return;
}
if (page_lock(pp, SE_SHARED, (kmutex_t *)NULL, P_RECLAIM) == 0)
goto retry;
/*
* Check if segkpm mapping is not unloaded in the meantime
*/
if (kpme->kpe_page == NULL) {
page_unlock(pp);
return;
}
vaddr = hat_kpm_page2va(pp, 1);
hat_kpm_mapout(pp, kpme, vaddr);
page_unlock(pp);
}
static void
segkpm_badop()
{
panic("segkpm_badop");
}
#else /* SEGKPM_SUPPORT */
/* segkpm stubs */
/*ARGSUSED*/
int segkpm_create(struct seg *seg, void *argsp) { return (0); }
/* ARGSUSED */
faultcode_t
segkpm_fault(struct hat *hat, struct seg *seg, caddr_t addr, size_t len,
enum fault_type type, enum seg_rw rw)
{
return ((faultcode_t)0);
}
/* ARGSUSED */
caddr_t segkpm_create_va(u_offset_t off) { return (NULL); }
/* ARGSUSED */
void segkpm_mapout_validkpme(struct kpme *kpme) {}
static void
segkpm_badop() {}
#endif /* SEGKPM_SUPPORT */
static int
segkpm_notsup()
{
return (ENOTSUP);
}
/*
* segkpm pages are not dumped, so we just return
*/
/*ARGSUSED*/
static void
segkpm_dump(struct seg *seg)
{}
/*
* We claim to have no special capabilities.
*/
/*ARGSUSED*/
static int
segkpm_capable(struct seg *seg, segcapability_t capability)
{
return (0);
}