Index: user/nwhitehorn/ppc64-pmap-rework/conf/GENERIC64 =================================================================== --- user/nwhitehorn/ppc64-pmap-rework/conf/GENERIC64 (revision 278943) +++ user/nwhitehorn/ppc64-pmap-rework/conf/GENERIC64 (revision 278944) @@ -1,218 +1,218 @@ # # GENERIC -- Generic kernel configuration file for FreeBSD/powerpc # # For more information on this file, please read the handbook section on # Kernel Configuration Files: # # http://www.FreeBSD.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig-config.html # # The handbook is also available locally in /usr/share/doc/handbook # if you've installed the doc distribution, otherwise always see the # FreeBSD World Wide Web server (http://www.FreeBSD.org/) for the # latest information. # # An exhaustive list of options and more detailed explanations of the # device lines is also present in the ../../conf/NOTES and NOTES files. # If you are in doubt as to the purpose or necessity of a line, check first # in NOTES. # # $FreeBSD$ cpu AIM ident GENERIC machine powerpc powerpc64 makeoptions DEBUG=-g #Build kernel with gdb(1) debug symbols makeoptions WITH_CTF=1 # Platform support options POWERMAC #NewWorld Apple PowerMacs -options PS3 #Sony Playstation 3 +#options PS3 #Sony Playstation 3 options MAMBO #IBM Mambo Full System Simulator options PSERIES #PAPR-compliant systems (e.g. IBM p) options FDT #Flattened Device Tree options SCHED_ULE #ULE scheduler options PREEMPTION #Enable kernel thread preemption options INET #InterNETworking options INET6 #IPv6 communications protocols options SCTP #Stream Control Transmission Protocol options FFS #Berkeley Fast Filesystem options SOFTUPDATES #Enable FFS soft updates support options UFS_ACL #Support for access control lists options UFS_DIRHASH #Improve performance on big directories options UFS_GJOURNAL #Enable gjournal-based UFS journaling options QUOTA #Enable disk quotas for UFS options MD_ROOT #MD is a potential root device options NFSCL #Network Filesystem Client options NFSD #Network Filesystem Server options NFSLOCKD #Network Lock Manager options NFS_ROOT #NFS usable as root device options MSDOSFS #MSDOS Filesystem options CD9660 #ISO 9660 Filesystem options PROCFS #Process filesystem (requires PSEUDOFS) options PSEUDOFS #Pseudo-filesystem framework options GEOM_PART_APM #Apple Partition Maps. options GEOM_PART_GPT #GUID Partition Tables. options GEOM_LABEL #Provides labelization options COMPAT_FREEBSD32 #Compatible with FreeBSD/powerpc binaries options COMPAT_FREEBSD5 #Compatible with FreeBSD5 options COMPAT_FREEBSD6 #Compatible with FreeBSD6 options COMPAT_FREEBSD7 #Compatible with FreeBSD7 options COMPAT_FREEBSD9 # Compatible with FreeBSD9 options COMPAT_FREEBSD10 # Compatible with FreeBSD10 options SCSI_DELAY=5000 #Delay (in ms) before probing SCSI options KTRACE #ktrace(1) syscall trace support options STACK #stack(9) support options SYSVSHM #SYSV-style shared memory options SYSVMSG #SYSV-style message queues options SYSVSEM #SYSV-style semaphores options _KPOSIX_PRIORITY_SCHEDULING #Posix P1003_1B real-time extensions options HWPMC_HOOKS # Necessary kernel hooks for hwpmc(4) options AUDIT # Security event auditing options CAPABILITY_MODE # Capsicum capability mode options CAPABILITIES # Capsicum capabilities options MAC # TrustedBSD MAC Framework options KDTRACE_HOOKS # Kernel DTrace hooks options DDB_CTF # Kernel ELF linker loads CTF data options INCLUDE_CONFIG_FILE # Include this file in kernel # Debugging support. Always need this: options KDB # Enable kernel debugger support. options KDB_TRACE # Print a stack trace for a panic. # For full debugger support use (turn off in stable branch): options DDB #Support DDB #options DEADLKRES #Enable the deadlock resolver options INVARIANTS #Enable calls of extra sanity checking options INVARIANT_SUPPORT #Extra sanity checks of internal structures, required by INVARIANTS options WITNESS #Enable checks to detect deadlocks and cycles options WITNESS_SKIPSPIN #Don't run witness on spinlocks for speed options MALLOC_DEBUG_MAXZONES=8 # Separate malloc(9) zones # Make an SMP-capable kernel by default options SMP # Symmetric MultiProcessor Kernel # CPU frequency control device cpufreq # Standard busses device pci device agp # ATA controllers device ahci # AHCI-compatible SATA controllers device ata # Legacy ATA/SATA controllers device mvs # Marvell 88SX50XX/88SX60XX/88SX70XX/SoC SATA device siis # SiliconImage SiI3124/SiI3132/SiI3531 SATA # SCSI Controllers device ahc # AHA2940 and onboard AIC7xxx devices options AHC_ALLOW_MEMIO # Attempt to use memory mapped I/O options AHC_REG_PRETTY_PRINT # Print register bitfields in debug # output. Adds ~128k to driver. device isp # Qlogic family device ispfw # Firmware module for Qlogic host adapters device mpt # LSI-Logic MPT-Fusion device mps # LSI-Logic MPT-Fusion 2 device sym # NCR/Symbios/LSI Logic 53C8XX/53C1010/53C1510D # ATA/SCSI peripherals device scbus # SCSI bus (required for ATA/SCSI) device da # Direct Access (disks) device sa # Sequential Access (tape etc) device cd # CD device pass # Passthrough device (direct ATA/SCSI access) # vt is the default console driver, resembling an SCO console device vt # Core console driver device kbdmux # Serial (COM) ports device scc device uart device uart_z8530 # Ethernet hardware device em # Intel PRO/1000 Gigabit Ethernet Family device igb # Intel PRO/1000 PCIE Server Gigabit Family device ixgbe # Intel PRO/10GbE PCIE Ethernet Family device glc # Sony Playstation 3 Ethernet device llan # IBM pSeries Virtual Ethernet # PCI Ethernet NICs that use the common MII bus controller code. device miibus # MII bus support device bge # Broadcom BCM570xx Gigabit Ethernet device gem # Sun GEM/Sun ERI/Apple GMAC device dc # DEC/Intel 21143 and various workalikes device fxp # Intel EtherExpress PRO/100B (82557, 82558) device re # RealTek 8139C+/8169/8169S/8110S device rl # RealTek 8129/8139 # Pseudo devices. device loop # Network loopback device random # Entropy device device ether # Ethernet support device vlan # 802.1Q VLAN support device tun # Packet tunnel. device md # Memory "disks" device ofwd # Open Firmware disks device gif # IPv6 and IPv4 tunneling device firmware # firmware assist module # The `bpf' device enables the Berkeley Packet Filter. # Be aware of the administrative consequences of enabling this! # Note that 'bpf' is required for DHCP. device bpf #Berkeley packet filter # USB support options USB_DEBUG # enable debug msgs device uhci # UHCI PCI->USB interface device ohci # OHCI PCI->USB interface device ehci # EHCI PCI->USB interface device usb # USB Bus (required) device uhid # "Human Interface Devices" device ukbd # Keyboard options KBD_INSTALL_CDEV # install a CDEV entry in /dev device ulpt # Printer device umass # Disks/Mass storage - Requires scbus and da0 device ums # Mouse device urio # Diamond Rio 500 MP3 player # USB Ethernet device aue # ADMtek USB Ethernet device axe # ASIX Electronics USB Ethernet device cdce # Generic USB over Ethernet device cue # CATC USB Ethernet device kue # Kawasaki LSI USB Ethernet # Wireless NIC cards options IEEE80211_SUPPORT_MESH options AH_SUPPORT_AR5416 # FireWire support device firewire # FireWire bus code device sbp # SCSI over FireWire (Requires scbus and da) device fwe # Ethernet over FireWire (non-standard!) # Misc device iicbus # I2C bus code device kiic # Keywest I2C device ad7417 # PowerMac7,2 temperature sensor device ds1631 # PowerMac11,2 temperature sensor device ds1775 # PowerMac7,2 temperature sensor device fcu # Apple Fan Control Unit device max6690 # PowerMac7,2 temperature sensor device powermac_nvram # Open Firmware configuration NVRAM device smu # Apple System Management Unit device atibl # ATI-based backlight driver for PowerBooks/iBooks device nvbl # nVidia-based backlight driver for PowerBooks/iBooks # ADB support device adb device pmu # Sound support device sound # Generic sound driver (required) device snd_ai2s # Apple I2S audio device snd_uaudio # USB Audio Index: user/nwhitehorn/ppc64-pmap-rework/pseries/mmu_phyp.c =================================================================== --- user/nwhitehorn/ppc64-pmap-rework/pseries/mmu_phyp.c (revision 278943) +++ user/nwhitehorn/ppc64-pmap-rework/pseries/mmu_phyp.c (revision 278944) @@ -1,449 +1,485 @@ /* * Copyright (C) 2010 Andreas Tobler * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "mmu_if.h" #include "moea64_if.h" #include "phyp-hvcall.h" extern int n_slbs; static struct rwlock mphyp_eviction_lock; /* * Kernel MMU interface */ static void mphyp_bootstrap(mmu_t mmup, vm_offset_t kernelstart, vm_offset_t kernelend); static void mphyp_cpu_bootstrap(mmu_t mmup, int ap); static int64_t mphyp_pte_synch(mmu_t, struct pvo_entry *pvo); static int64_t mphyp_pte_clear(mmu_t, struct pvo_entry *pvo, uint64_t ptebit); static void mphyp_pte_unset(mmu_t, struct pvo_entry *pvo); static void mphyp_pte_replace(mmu_t, struct pvo_entry *pvo, int flags); static int mphyp_pte_insert(mmu_t, struct pvo_entry *pvo); static mmu_method_t mphyp_methods[] = { MMUMETHOD(mmu_bootstrap, mphyp_bootstrap), MMUMETHOD(mmu_cpu_bootstrap, mphyp_cpu_bootstrap), MMUMETHOD(moea64_pte_synch, mphyp_pte_synch), MMUMETHOD(moea64_pte_clear, mphyp_pte_clear), MMUMETHOD(moea64_pte_unset, mphyp_pte_unset), MMUMETHOD(moea64_pte_replace, mphyp_pte_replace), MMUMETHOD(moea64_pte_insert, mphyp_pte_insert), /* XXX: pmap_copy_page, pmap_init_page with H_PAGE_INIT */ { 0, 0 } }; MMU_DEF_INHERIT(pseries_mmu, "mmu_phyp", mphyp_methods, 0, oea64_mmu); +static int brokenkvm = 0; + static void +print_kvm_bug_warning(void *data) +{ + + if (brokenkvm) + printf("WARNING: Running on a broken hypervisor that does " + "not support mandatory H_CLEAR_MOD and H_CLEAR_REF " + "hypercalls. Performance will be suboptimal.\n"); +} + +SYSINIT(kvmbugwarn1, SI_SUB_COPYRIGHT, SI_ORDER_THIRD + 1, + print_kvm_bug_warning, NULL); +SYSINIT(kvmbugwarn2, SI_SUB_LAST, SI_ORDER_THIRD + 1, print_kvm_bug_warning, + NULL); + +static void mphyp_bootstrap(mmu_t mmup, vm_offset_t kernelstart, vm_offset_t kernelend) { uint64_t final_pteg_count = 0; char buf[8]; uint32_t prop[2]; uint32_t nptlp, shift = 0, slb_encoding = 0; uint32_t lp_size, lp_encoding; phandle_t dev, node, root; int idx, len, res; rw_init(&mphyp_eviction_lock, "pte eviction"); moea64_early_bootstrap(mmup, kernelstart, kernelend); root = OF_peer(0); dev = OF_child(root); while (dev != 0) { res = OF_getprop(dev, "name", buf, sizeof(buf)); if (res > 0 && strcmp(buf, "cpus") == 0) break; dev = OF_peer(dev); } node = OF_child(dev); while (node != 0) { res = OF_getprop(node, "device_type", buf, sizeof(buf)); if (res > 0 && strcmp(buf, "cpu") == 0) break; node = OF_peer(node); } res = OF_getprop(node, "ibm,pft-size", prop, sizeof(prop)); if (res <= 0) panic("mmu_phyp: unknown PFT size"); final_pteg_count = 1 << prop[1]; res = OF_getprop(node, "ibm,slb-size", prop, sizeof(prop[0])); if (res > 0) n_slbs = prop[0]; moea64_pteg_count = final_pteg_count / sizeof(struct lpteg); /* * Scan the large page size property for PAPR compatible machines. * See PAPR D.5 Changes to Section 5.1.4, 'CPU Node Properties' * for the encoding of the property. */ len = OF_getproplen(node, "ibm,segment-page-sizes"); if (len > 0) { /* * We have to use a variable length array on the stack * since we have very limited stack space. */ pcell_t arr[len/sizeof(cell_t)]; res = OF_getencprop(node, "ibm,segment-page-sizes", arr, sizeof(arr)); len /= 4; idx = 0; while (len > 0) { shift = arr[idx]; slb_encoding = arr[idx + 1]; nptlp = arr[idx + 2]; idx += 3; len -= 3; while (len > 0 && nptlp) { lp_size = arr[idx]; lp_encoding = arr[idx+1]; if (slb_encoding == SLBV_L && lp_encoding == 0) break; idx += 2; len -= 2; nptlp--; } if (nptlp && slb_encoding == SLBV_L && lp_encoding == 0) break; } if (len == 0) panic("Standard large pages (SLB[L] = 1, PTE[LP] = 0) " "not supported by this system. Please enable huge " "page backing if running under PowerKVM."); moea64_large_page_shift = shift; moea64_large_page_size = 1ULL << lp_size; } moea64_mid_bootstrap(mmup, kernelstart, kernelend); moea64_late_bootstrap(mmup, kernelstart, kernelend); + + /* Test for broken versions of KVM that don't conform to the spec */ + if (phyp_hcall(H_CLEAR_MOD, 0, 0) == H_FUNCTION) + brokenkvm = 1; } static void mphyp_cpu_bootstrap(mmu_t mmup, int ap) { struct slb *slb = PCPU_GET(slb); register_t seg0; int i; /* * Install kernel SLB entries */ __asm __volatile ("slbia"); __asm __volatile ("slbmfee %0,%1; slbie %0;" : "=r"(seg0) : "r"(0)); for (i = 0; i < 64; i++) { if (!(slb[i].slbe & SLBE_VALID)) continue; __asm __volatile ("slbmte %0, %1" :: "r"(slb[i].slbv), "r"(slb[i].slbe)); } } static int64_t mphyp_pte_synch(mmu_t mmu, struct pvo_entry *pvo) { struct lpte pte; uint64_t junk; __asm __volatile("ptesync"); phyp_pft_hcall(H_READ, 0, pvo->pvo_pte.slot, 0, 0, &pte.pte_hi, &pte.pte_lo, &junk); if ((pte.pte_hi & LPTE_AVPN_MASK) != ((pvo->pvo_vpn >> (ADDR_API_SHFT64 - ADDR_PIDX_SHFT)) & LPTE_AVPN_MASK)) return (-1); if (!(pte.pte_hi & LPTE_VALID)) return (-1); return (pte.pte_lo & (LPTE_CHG | LPTE_REF)); } static int64_t mphyp_pte_clear(mmu_t mmu, struct pvo_entry *pvo, uint64_t ptebit) { int64_t refchg; uint64_t ptelo, junk; + int err; /* * This involves two steps (synch and clear) so we need the entry * not to change in the middle. We are protected against deliberate * unset by virtue of holding the pmap lock. Protection against * incidental unset (page table eviction) comes from holding the * shared eviction lock. */ PMAP_LOCK_ASSERT(pvo->pvo_pmap, MA_OWNED); rw_rlock(&mphyp_eviction_lock); refchg = mphyp_pte_synch(mmu, pvo); if (refchg < 0) { rw_runlock(&mphyp_eviction_lock); return (refchg); } + if (brokenkvm) { + /* + * No way to clear either bit, which is total madness. + * Pessimistically claim that, once modified, it stays so + * forever and that it is never referenced. + */ + rw_runlock(&mphyp_eviction_lock); + return (refchg & ~LPTE_REF); + } + if (ptebit & LPTE_CHG) { - phyp_pft_hcall(H_CLEAR_MOD, 0, pvo->pvo_pte.slot, 0, 0, &ptelo, - &junk, &junk); + err = phyp_pft_hcall(H_CLEAR_MOD, 0, pvo->pvo_pte.slot, 0, 0, + &ptelo, &junk, &junk); + KASSERT(err == H_SUCCESS, + ("Error clearing page change bit: %d", err)); refchg |= (ptelo & LPTE_CHG); } if (ptebit & LPTE_REF) { - phyp_pft_hcall(H_CLEAR_REF, 0, pvo->pvo_pte.slot, 0, 0, &ptelo, - &junk, &junk); + err = phyp_pft_hcall(H_CLEAR_REF, 0, pvo->pvo_pte.slot, 0, 0, + &ptelo, &junk, &junk); + KASSERT(err == H_SUCCESS, + ("Error clearing page reference bit: %d", err)); refchg |= (ptelo & LPTE_REF); } rw_runlock(&mphyp_eviction_lock); return (refchg); } static void mphyp_pte_unset(mmu_t mmu, struct pvo_entry *pvo) { struct lpte pte; uint64_t junk; int err; PMAP_LOCK_ASSERT(pvo->pvo_pmap, MA_OWNED); moea64_pte_from_pvo(pvo, &pte); err = phyp_pft_hcall(H_REMOVE, H_AVPN, pvo->pvo_pte.slot, pte.pte_hi & LPTE_AVPN_MASK, 0, &pte.pte_hi, &pte.pte_lo, &junk); KASSERT(err == H_SUCCESS || err == H_NOT_FOUND, ("Error removing page: %d", err)); if (err == H_SUCCESS) moea64_sync_refchg((pvo->pvo_pte.pa & LPTE_RPGN) | (pte.pte_lo & (LPTE_REF | LPTE_CHG))); if (err == H_NOT_FOUND) moea64_pte_overflow--; } static void mphyp_pte_replace(mmu_t mmu, struct pvo_entry *pvo, int flags) { PMAP_LOCK_ASSERT(pvo->pvo_pmap, MA_OWNED); /* * For anything other than a simple page protection update, we have to * reinsert the page. H_PROTECT is somehow slower than this, so just do * unset followed by insert unconditionally. */ mphyp_pte_unset(mmu, pvo); mphyp_pte_insert(mmu, pvo); } static uintptr_t mphyp_pte_spillable_ident(uintptr_t ptegbase, struct lpte *to_evict) { uint64_t slot, junk, k; struct lpte pt; int i, j; /* Start at a random slot */ i = mftb() % 8; k = -1; for (j = 0; j < 8; j++) { slot = ptegbase + (i + j) % 8; phyp_pft_hcall(H_READ, H_R_XLATE, slot, 0, 0, &pt.pte_hi, &pt.pte_lo, &junk); if (pt.pte_hi & LPTE_WIRED) continue; /* This is a candidate, so remember it */ k = slot; /* Try to get a page that has not been used lately */ if (!(pt.pte_lo & LPTE_REF)) { memcpy(to_evict, &pt, sizeof(struct lpte)); return (k); } } if (k == -1) return (k); phyp_pft_hcall(H_READ, H_R_XLATE, k, 0, 0, &to_evict->pte_hi, &to_evict->pte_lo, &junk); return (k); } static int mphyp_pte_insert(mmu_t mmu, struct pvo_entry *pvo) { int64_t result; struct lpte evicted, pte; uint64_t index, junk, lastptelo; PMAP_LOCK_ASSERT(pvo->pvo_pmap, MA_OWNED); /* Initialize PTE */ moea64_pte_from_pvo(pvo, &pte); evicted.pte_hi = 0; /* Make sure further insertion is locked out during evictions */ rw_rlock(&mphyp_eviction_lock); /* * First try primary hash. */ pvo->pvo_pte.slot &= ~7UL; /* Base slot address */ result = phyp_pft_hcall(H_ENTER, 0, pvo->pvo_pte.slot, pte.pte_hi, pte.pte_lo, &index, &evicted.pte_lo, &junk); if (result == H_SUCCESS) { rw_runlock(&mphyp_eviction_lock); pvo->pvo_pte.slot = index; return (0); } KASSERT(result == H_PTEG_FULL, ("Page insertion error: %ld " "(ptegidx: %#zx/%#x, PTE %#lx/%#lx", result, pvo->pvo_pte.slot, moea64_pteg_count, pte.pte_hi, pte.pte_lo)); /* * Next try secondary hash. */ pvo->pvo_vaddr ^= PVO_HID; pte.pte_hi ^= LPTE_HID; pvo->pvo_pte.slot ^= (moea64_pteg_mask << 3); result = phyp_pft_hcall(H_ENTER, 0, pvo->pvo_pte.slot, pte.pte_hi, pte.pte_lo, &index, &evicted.pte_lo, &junk); if (result == H_SUCCESS) { rw_runlock(&mphyp_eviction_lock); pvo->pvo_pte.slot = index; return (0); } KASSERT(result == H_PTEG_FULL, ("Secondary page insertion error: %ld", result)); /* * Out of luck. Find a PTE to sacrifice. */ /* Lock out all insertions for a bit */ if (!rw_try_upgrade(&mphyp_eviction_lock)) { rw_runlock(&mphyp_eviction_lock); rw_wlock(&mphyp_eviction_lock); } index = mphyp_pte_spillable_ident(pvo->pvo_pte.slot, &evicted); if (index == -1L) { /* Try other hash table? */ pvo->pvo_vaddr ^= PVO_HID; pte.pte_hi ^= LPTE_HID; pvo->pvo_pte.slot ^= (moea64_pteg_mask << 3); index = mphyp_pte_spillable_ident(pvo->pvo_pte.slot, &evicted); } if (index == -1L) { /* No freeable slots in either PTEG? We're hosed. */ rw_wunlock(&mphyp_eviction_lock); panic("mphyp_pte_insert: overflow"); return (-1); } /* Victim acquired: update page before waving goodbye */ if (evicted.pte_hi & LPTE_VALID) { result = phyp_pft_hcall(H_REMOVE, H_AVPN, index, evicted.pte_hi & LPTE_AVPN_MASK, 0, &junk, &lastptelo, &junk); moea64_pte_overflow++; KASSERT(result == H_SUCCESS, ("Error evicting page: %d", (int)result)); /* * Update VM system on final disposition of the old entry. The * RPN we get from H_REMOVE is not necessarily meaningful, so * combine the one from H_READ with the RC bits from H_REMOVE */ moea64_sync_refchg((evicted.pte_lo & LPTE_RPGN) | (lastptelo & (LPTE_REF | LPTE_CHG))); } /* * Set the new PTE. */ result = phyp_pft_hcall(H_ENTER, H_EXACT, index, pte.pte_hi, pte.pte_lo, &index, &evicted.pte_lo, &junk); rw_wunlock(&mphyp_eviction_lock); /* All clear */ pvo->pvo_pte.slot = index; if (result == H_SUCCESS) return (0); panic("Page replacement error: %ld", result); return (result); }