xref: /onnv-gate/usr/src/uts/i86pc/os/mlsetup.c (revision 10175:dd9708d1f561)
10Sstevel@tonic-gate /*
20Sstevel@tonic-gate  * CDDL HEADER START
30Sstevel@tonic-gate  *
40Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
52006Sandrei  * Common Development and Distribution License (the "License").
62006Sandrei  * You may not use this file except in compliance with the License.
70Sstevel@tonic-gate  *
80Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
90Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
100Sstevel@tonic-gate  * See the License for the specific language governing permissions
110Sstevel@tonic-gate  * and limitations under the License.
120Sstevel@tonic-gate  *
130Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
140Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
150Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
160Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
170Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
180Sstevel@tonic-gate  *
190Sstevel@tonic-gate  * CDDL HEADER END
200Sstevel@tonic-gate  */
210Sstevel@tonic-gate /*
228906SEric.Saxe@Sun.COM  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
230Sstevel@tonic-gate  * Use is subject to license terms.
240Sstevel@tonic-gate  */
250Sstevel@tonic-gate 
260Sstevel@tonic-gate #include <sys/types.h>
273446Smrj #include <sys/sysmacros.h>
280Sstevel@tonic-gate #include <sys/disp.h>
290Sstevel@tonic-gate #include <sys/promif.h>
300Sstevel@tonic-gate #include <sys/clock.h>
310Sstevel@tonic-gate #include <sys/cpuvar.h>
320Sstevel@tonic-gate #include <sys/stack.h>
330Sstevel@tonic-gate #include <vm/as.h>
340Sstevel@tonic-gate #include <vm/hat.h>
350Sstevel@tonic-gate #include <sys/reboot.h>
360Sstevel@tonic-gate #include <sys/avintr.h>
370Sstevel@tonic-gate #include <sys/vtrace.h>
380Sstevel@tonic-gate #include <sys/proc.h>
390Sstevel@tonic-gate #include <sys/thread.h>
400Sstevel@tonic-gate #include <sys/cpupart.h>
410Sstevel@tonic-gate #include <sys/pset.h>
420Sstevel@tonic-gate #include <sys/copyops.h>
433434Sesaxe #include <sys/pg.h>
440Sstevel@tonic-gate #include <sys/disp.h>
450Sstevel@tonic-gate #include <sys/debug.h>
460Sstevel@tonic-gate #include <sys/sunddi.h>
470Sstevel@tonic-gate #include <sys/x86_archext.h>
480Sstevel@tonic-gate #include <sys/privregs.h>
490Sstevel@tonic-gate #include <sys/machsystm.h>
500Sstevel@tonic-gate #include <sys/ontrap.h>
510Sstevel@tonic-gate #include <sys/bootconf.h>
523446Smrj #include <sys/kdi_machimpl.h>
530Sstevel@tonic-gate #include <sys/archsystm.h>
540Sstevel@tonic-gate #include <sys/promif.h>
550Sstevel@tonic-gate #include <sys/bootconf.h>
56748Sdmick #include <sys/pci_cfgspace.h>
575084Sjohnlev #ifdef __xpv
585084Sjohnlev #include <sys/hypervisor.h>
59*10175SStuart.Maybee@Sun.COM #else
60*10175SStuart.Maybee@Sun.COM #include <sys/xpv_support.h>
615084Sjohnlev #endif
620Sstevel@tonic-gate 
630Sstevel@tonic-gate /*
640Sstevel@tonic-gate  * some globals for patching the result of cpuid
650Sstevel@tonic-gate  * to solve problems w/ creative cpu vendors
660Sstevel@tonic-gate  */
670Sstevel@tonic-gate 
680Sstevel@tonic-gate extern uint32_t cpuid_feature_ecx_include;
690Sstevel@tonic-gate extern uint32_t cpuid_feature_ecx_exclude;
700Sstevel@tonic-gate extern uint32_t cpuid_feature_edx_include;
710Sstevel@tonic-gate extern uint32_t cpuid_feature_edx_exclude;
720Sstevel@tonic-gate 
730Sstevel@tonic-gate /*
74783Sdmick  * Dummy spl priority masks
75783Sdmick  */
763446Smrj static unsigned char dummy_cpu_pri[MAXIPL + 1] = {
77783Sdmick 	0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf,
78783Sdmick 	0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf
79783Sdmick };
80783Sdmick 
810Sstevel@tonic-gate 
820Sstevel@tonic-gate /*
830Sstevel@tonic-gate  * Setup routine called right before main(). Interposing this function
840Sstevel@tonic-gate  * before main() allows us to call it in a machine-independent fashion.
850Sstevel@tonic-gate  */
860Sstevel@tonic-gate void
870Sstevel@tonic-gate mlsetup(struct regs *rp)
880Sstevel@tonic-gate {
899053Sjonathan.chew@sun.com 	u_longlong_t prop_value;
900Sstevel@tonic-gate 	extern struct classfuncs sys_classfuncs;
910Sstevel@tonic-gate 	extern disp_t cpu0_disp;
920Sstevel@tonic-gate 	extern char t0stack[];
930Sstevel@tonic-gate 
940Sstevel@tonic-gate 	ASSERT_STACK_ALIGNED();
950Sstevel@tonic-gate 
960Sstevel@tonic-gate 	/*
970Sstevel@tonic-gate 	 * initialize cpu_self
980Sstevel@tonic-gate 	 */
990Sstevel@tonic-gate 	cpu[0]->cpu_self = cpu[0];
1000Sstevel@tonic-gate 
1015084Sjohnlev #if defined(__xpv)
1025084Sjohnlev 	/*
1035084Sjohnlev 	 * Point at the hypervisor's virtual cpu structure
1045084Sjohnlev 	 */
1055084Sjohnlev 	cpu[0]->cpu_m.mcpu_vcpu_info = &HYPERVISOR_shared_info->vcpu_info[0];
1065084Sjohnlev #endif
1075084Sjohnlev 
1080Sstevel@tonic-gate 	/*
109783Sdmick 	 * Set up dummy cpu_pri_data values till psm spl code is
110783Sdmick 	 * installed.  This allows splx() to work on amd64.
111783Sdmick 	 */
112783Sdmick 
113783Sdmick 	cpu[0]->cpu_pri_data = dummy_cpu_pri;
114783Sdmick 
115783Sdmick 	/*
1160Sstevel@tonic-gate 	 * check if we've got special bits to clear or set
1170Sstevel@tonic-gate 	 * when checking cpu features
1180Sstevel@tonic-gate 	 */
1190Sstevel@tonic-gate 
1209053Sjonathan.chew@sun.com 	if (bootprop_getval("cpuid_feature_ecx_include", &prop_value) != 0)
1219053Sjonathan.chew@sun.com 		cpuid_feature_ecx_include = 0;
1229053Sjonathan.chew@sun.com 	else
1239053Sjonathan.chew@sun.com 		cpuid_feature_ecx_include = (uint32_t)prop_value;
1249053Sjonathan.chew@sun.com 
1259053Sjonathan.chew@sun.com 	if (bootprop_getval("cpuid_feature_ecx_exclude", &prop_value) != 0)
1269053Sjonathan.chew@sun.com 		cpuid_feature_ecx_exclude = 0;
1279053Sjonathan.chew@sun.com 	else
1289053Sjonathan.chew@sun.com 		cpuid_feature_ecx_exclude = (uint32_t)prop_value;
1299053Sjonathan.chew@sun.com 
1309053Sjonathan.chew@sun.com 	if (bootprop_getval("cpuid_feature_edx_include", &prop_value) != 0)
1319053Sjonathan.chew@sun.com 		cpuid_feature_edx_include = 0;
1329053Sjonathan.chew@sun.com 	else
1339053Sjonathan.chew@sun.com 		cpuid_feature_edx_include = (uint32_t)prop_value;
1349053Sjonathan.chew@sun.com 
1359053Sjonathan.chew@sun.com 	if (bootprop_getval("cpuid_feature_edx_exclude", &prop_value) != 0)
1369053Sjonathan.chew@sun.com 		cpuid_feature_edx_exclude = 0;
1379053Sjonathan.chew@sun.com 	else
1389053Sjonathan.chew@sun.com 		cpuid_feature_edx_exclude = (uint32_t)prop_value;
1390Sstevel@tonic-gate 
1400Sstevel@tonic-gate 	/*
1410Sstevel@tonic-gate 	 * The first lightweight pass (pass0) through the cpuid data
1420Sstevel@tonic-gate 	 * was done in locore before mlsetup was called.  Do the next
1430Sstevel@tonic-gate 	 * pass in C code.
1440Sstevel@tonic-gate 	 *
1450Sstevel@tonic-gate 	 * The x86_feature bits are set here on the basis of the capabilities
1460Sstevel@tonic-gate 	 * of the boot CPU.  Note that if we choose to support CPUs that have
1470Sstevel@tonic-gate 	 * different feature sets (at which point we would almost certainly
1480Sstevel@tonic-gate 	 * want to set the feature bits to correspond to the feature
1490Sstevel@tonic-gate 	 * minimum) this value may be altered.
1500Sstevel@tonic-gate 	 */
1510Sstevel@tonic-gate 	x86_feature = cpuid_pass1(cpu[0]);
1520Sstevel@tonic-gate 
1530Sstevel@tonic-gate 	/*
1540Sstevel@tonic-gate 	 * Initialize idt0, gdt0, ldt0_default, ktss0 and dftss.
1550Sstevel@tonic-gate 	 */
1563446Smrj 	init_desctbls();
1570Sstevel@tonic-gate 
1585322Ssudheer #if !defined(__xpv)
1595322Ssudheer 
160*10175SStuart.Maybee@Sun.COM 	if (get_hwenv() == HW_XEN_HVM)
161*10175SStuart.Maybee@Sun.COM 		xen_hvm_init();
162*10175SStuart.Maybee@Sun.COM 
1635322Ssudheer 	/*
1645322Ssudheer 	 * Patch the tsc_read routine with appropriate set of instructions,
1655322Ssudheer 	 * depending on the processor family and architecure, to read the
1665322Ssudheer 	 * time-stamp counter while ensuring no out-of-order execution.
1675322Ssudheer 	 * Patch it while the kernel text is still writable.
1685322Ssudheer 	 *
1695322Ssudheer 	 * Note: tsc_read is not patched for intel processors whose family
1705322Ssudheer 	 * is >6 and for amd whose family >f (in case they don't support rdtscp
1715322Ssudheer 	 * instruction, unlikely). By default tsc_read will use cpuid for
1725322Ssudheer 	 * serialization in such cases. The following code needs to be
1735322Ssudheer 	 * revisited if intel processors of family >= f retains the
1745322Ssudheer 	 * instruction serialization nature of mfence instruction.
1755338Ssudheer 	 * Note: tsc_read is not patched for x86 processors which do
1765338Ssudheer 	 * not support "mfence". By default tsc_read will use cpuid for
1775338Ssudheer 	 * serialization in such cases.
1785741Smrj 	 *
1795741Smrj 	 * The Xen hypervisor does not correctly report whether rdtscp is
1805741Smrj 	 * supported or not, so we must assume that it is not.
1815322Ssudheer 	 */
1829000SStuart.Maybee@Sun.COM 	if (get_hwenv() != HW_XEN_HVM && (x86_feature & X86_TSCP))
1835322Ssudheer 		patch_tsc_read(X86_HAVE_TSCP);
1845322Ssudheer 	else if (cpuid_getvendor(CPU) == X86_VENDOR_AMD &&
1855338Ssudheer 	    cpuid_getfamily(CPU) <= 0xf && (x86_feature & X86_SSE2) != 0)
1865322Ssudheer 		patch_tsc_read(X86_TSC_MFENCE);
1875322Ssudheer 	else if (cpuid_getvendor(CPU) == X86_VENDOR_Intel &&
1885338Ssudheer 	    cpuid_getfamily(CPU) <= 6 && (x86_feature & X86_SSE2) != 0)
1896642Ssudheer 		patch_tsc_read(X86_TSC_LFENCE);
1905322Ssudheer 
1915322Ssudheer #endif	/* !__xpv */
1920Sstevel@tonic-gate 
1935084Sjohnlev #if defined(__i386) && !defined(__xpv)
1940Sstevel@tonic-gate 	/*
1950Sstevel@tonic-gate 	 * Some i386 processors do not implement the rdtsc instruction,
1965322Ssudheer 	 * or at least they do not implement it correctly. Patch them to
1975322Ssudheer 	 * return 0.
1980Sstevel@tonic-gate 	 */
1995322Ssudheer 	if ((x86_feature & X86_TSC) == 0)
2005322Ssudheer 		patch_tsc_read(X86_NO_TSC);
2015084Sjohnlev #endif	/* __i386 && !__xpv */
2025084Sjohnlev 
2038377SBill.Holler@Sun.COM #if defined(__amd64) && !defined(__xpv)
2048377SBill.Holler@Sun.COM 	patch_memops(cpuid_getvendor(CPU));
2058377SBill.Holler@Sun.COM #endif	/* __amd64 && !__xpv */
2068377SBill.Holler@Sun.COM 
2075084Sjohnlev #if !defined(__xpv)
2085084Sjohnlev 	/* XXPV	what, if anything, should be dorked with here under xen? */
2093446Smrj 
2103446Smrj 	/*
2113446Smrj 	 * While we're thinking about the TSC, let's set up %cr4 so that
2123446Smrj 	 * userland can issue rdtsc, and initialize the TSC_AUX value
2133446Smrj 	 * (the cpuid) for the rdtscp instruction on appropriately
2143446Smrj 	 * capable hardware.
2153446Smrj 	 */
2163446Smrj 	if (x86_feature & X86_TSC)
2173446Smrj 		setcr4(getcr4() & ~CR4_TSD);
2183446Smrj 
2193446Smrj 	if (x86_feature & X86_TSCP)
2203446Smrj 		(void) wrmsr(MSR_AMD_TSCAUX, 0);
2213446Smrj 
2223446Smrj 	if (x86_feature & X86_DE)
2233446Smrj 		setcr4(getcr4() | CR4_DE);
2245084Sjohnlev #endif /* __xpv */
2250Sstevel@tonic-gate 
2260Sstevel@tonic-gate 	/*
2270Sstevel@tonic-gate 	 * initialize t0
2280Sstevel@tonic-gate 	 */
2290Sstevel@tonic-gate 	t0.t_stk = (caddr_t)rp - MINFRAME;
2300Sstevel@tonic-gate 	t0.t_stkbase = t0stack;
2310Sstevel@tonic-gate 	t0.t_pri = maxclsyspri - 3;
2320Sstevel@tonic-gate 	t0.t_schedflag = TS_LOAD | TS_DONT_SWAP;
2330Sstevel@tonic-gate 	t0.t_procp = &p0;
2340Sstevel@tonic-gate 	t0.t_plockp = &p0lock.pl_lock;
2350Sstevel@tonic-gate 	t0.t_lwp = &lwp0;
2360Sstevel@tonic-gate 	t0.t_forw = &t0;
2370Sstevel@tonic-gate 	t0.t_back = &t0;
2380Sstevel@tonic-gate 	t0.t_next = &t0;
2390Sstevel@tonic-gate 	t0.t_prev = &t0;
2400Sstevel@tonic-gate 	t0.t_cpu = cpu[0];
2410Sstevel@tonic-gate 	t0.t_disp_queue = &cpu0_disp;
2420Sstevel@tonic-gate 	t0.t_bind_cpu = PBIND_NONE;
2430Sstevel@tonic-gate 	t0.t_bind_pset = PS_NONE;
2446298Sakolb 	t0.t_bindflag = (uchar_t)default_binding_mode;
2450Sstevel@tonic-gate 	t0.t_cpupart = &cp_default;
2460Sstevel@tonic-gate 	t0.t_clfuncs = &sys_classfuncs.thread;
2470Sstevel@tonic-gate 	t0.t_copyops = NULL;
2480Sstevel@tonic-gate 	THREAD_ONPROC(&t0, CPU);
2490Sstevel@tonic-gate 
2500Sstevel@tonic-gate 	lwp0.lwp_thread = &t0;
2513446Smrj 	lwp0.lwp_regs = (void *)rp;
2520Sstevel@tonic-gate 	lwp0.lwp_procp = &p0;
2530Sstevel@tonic-gate 	t0.t_tid = p0.p_lwpcnt = p0.p_lwprcnt = p0.p_lwpid = 1;
2540Sstevel@tonic-gate 
2550Sstevel@tonic-gate 	p0.p_exec = NULL;
2560Sstevel@tonic-gate 	p0.p_stat = SRUN;
2570Sstevel@tonic-gate 	p0.p_flag = SSYS;
2580Sstevel@tonic-gate 	p0.p_tlist = &t0;
2590Sstevel@tonic-gate 	p0.p_stksize = 2*PAGESIZE;
2600Sstevel@tonic-gate 	p0.p_stkpageszc = 0;
2610Sstevel@tonic-gate 	p0.p_as = &kas;
2620Sstevel@tonic-gate 	p0.p_lockp = &p0lock;
2630Sstevel@tonic-gate 	p0.p_brkpageszc = 0;
2644426Saguzovsk 	p0.p_t1_lgrpid = LGRP_NONE;
2654426Saguzovsk 	p0.p_tr_lgrpid = LGRP_NONE;
2660Sstevel@tonic-gate 	sigorset(&p0.p_ignore, &ignoredefault);
2670Sstevel@tonic-gate 
2680Sstevel@tonic-gate 	CPU->cpu_thread = &t0;
2690Sstevel@tonic-gate 	bzero(&cpu0_disp, sizeof (disp_t));
2700Sstevel@tonic-gate 	CPU->cpu_disp = &cpu0_disp;
2710Sstevel@tonic-gate 	CPU->cpu_disp->disp_cpu = CPU;
2720Sstevel@tonic-gate 	CPU->cpu_dispthread = &t0;
2730Sstevel@tonic-gate 	CPU->cpu_idle_thread = &t0;
2740Sstevel@tonic-gate 	CPU->cpu_flags = CPU_READY | CPU_RUNNING | CPU_EXISTS | CPU_ENABLE;
2750Sstevel@tonic-gate 	CPU->cpu_dispatch_pri = t0.t_pri;
2760Sstevel@tonic-gate 
2770Sstevel@tonic-gate 	CPU->cpu_id = 0;
2780Sstevel@tonic-gate 
2790Sstevel@tonic-gate 	CPU->cpu_pri = 12;		/* initial PIL for the boot CPU */
2800Sstevel@tonic-gate 
2810Sstevel@tonic-gate 	/*
2821217Srab 	 * The kernel doesn't use LDTs unless a process explicitly requests one.
2830Sstevel@tonic-gate 	 */
2845084Sjohnlev 	p0.p_ldt_desc = null_sdesc;
2850Sstevel@tonic-gate 
2860Sstevel@tonic-gate 	/*
2873446Smrj 	 * Initialize thread/cpu microstate accounting
2880Sstevel@tonic-gate 	 */
2890Sstevel@tonic-gate 	init_mstate(&t0, LMS_SYSTEM);
2900Sstevel@tonic-gate 	init_cpu_mstate(CPU, CMS_SYSTEM);
2910Sstevel@tonic-gate 
2920Sstevel@tonic-gate 	/*
2930Sstevel@tonic-gate 	 * Initialize lists of available and active CPUs.
2940Sstevel@tonic-gate 	 */
2950Sstevel@tonic-gate 	cpu_list_init(CPU);
2960Sstevel@tonic-gate 
2978906SEric.Saxe@Sun.COM 	pg_cpu_bootstrap(CPU);
2988906SEric.Saxe@Sun.COM 
2993446Smrj 	/*
3003446Smrj 	 * Now that we have taken over the GDT, IDT and have initialized
3013446Smrj 	 * active CPU list it's time to inform kmdb if present.
3023446Smrj 	 */
3033446Smrj 	if (boothowto & RB_DEBUG)
3043446Smrj 		kdi_idt_sync();
3053446Smrj 
3063446Smrj 	/*
3073446Smrj 	 * If requested (boot -d) drop into kmdb.
3083446Smrj 	 *
3093446Smrj 	 * This must be done after cpu_list_init() on the 64-bit kernel
3103446Smrj 	 * since taking a trap requires that we re-compute gsbase based
3113446Smrj 	 * on the cpu list.
3123446Smrj 	 */
3133446Smrj 	if (boothowto & RB_DEBUGENTER)
3143446Smrj 		kmdb_enter();
3153446Smrj 
316414Skchow 	cpu_vm_data_init(CPU);
317414Skchow 
318748Sdmick 	/* lgrp_init() needs PCI config space access */
3195084Sjohnlev #if defined(__xpv)
3205084Sjohnlev 	if (DOMAIN_IS_INITDOMAIN(xen_info))
3215084Sjohnlev 		pci_cfgspace_init();
3225084Sjohnlev #else
323748Sdmick 	pci_cfgspace_init();
3245084Sjohnlev #endif
325748Sdmick 
3260Sstevel@tonic-gate 	rp->r_fp = 0;	/* terminate kernel stack traces! */
3270Sstevel@tonic-gate 
3280Sstevel@tonic-gate 	prom_init("kernel", (void *)NULL);
3290Sstevel@tonic-gate 
3309053Sjonathan.chew@sun.com 	if (bootprop_getval("boot-ncpus", &prop_value) != 0)
3313446Smrj 		boot_ncpus = NCPU;
3329053Sjonathan.chew@sun.com 	else {
3339053Sjonathan.chew@sun.com 		boot_ncpus = (int)prop_value;
3349053Sjonathan.chew@sun.com 		if (boot_ncpus <= 0 || boot_ncpus > NCPU)
3359053Sjonathan.chew@sun.com 			boot_ncpus = NCPU;
3369053Sjonathan.chew@sun.com 	}
3372006Sandrei 
3382006Sandrei 	max_ncpus = boot_max_ncpus = boot_ncpus;
3392006Sandrei 
3406445Sjjc 	/*
3416445Sjjc 	 * Initialize the lgrp framework
3426445Sjjc 	 */
3436445Sjjc 	lgrp_init();
3446445Sjjc 
3450Sstevel@tonic-gate 	if (boothowto & RB_HALT) {
3460Sstevel@tonic-gate 		prom_printf("unix: kernel halted by -h flag\n");
3470Sstevel@tonic-gate 		prom_enter_mon();
3480Sstevel@tonic-gate 	}
3490Sstevel@tonic-gate 
3500Sstevel@tonic-gate 	ASSERT_STACK_ALIGNED();
3510Sstevel@tonic-gate 
3524581Ssherrym 	/*
3534581Ssherrym 	 * Fill out cpu_ucode_info.  Update microcode if necessary.
3544581Ssherrym 	 */
3554581Ssherrym 	ucode_check(CPU);
3564581Ssherrym 
3570Sstevel@tonic-gate 	if (workaround_errata(CPU) != 0)
3580Sstevel@tonic-gate 		panic("critical workaround(s) missing for boot cpu");
3590Sstevel@tonic-gate }
3605648Ssetje 
3615648Ssetje 
3625648Ssetje void
3635648Ssetje mach_modpath(char *path, const char *filename)
3645648Ssetje {
3655648Ssetje 	/*
3665648Ssetje 	 * Construct the directory path from the filename.
3675648Ssetje 	 */
3685648Ssetje 
3695648Ssetje 	int len;
3705648Ssetje 	char *p;
3715648Ssetje 	const char isastr[] = "/amd64";
3725648Ssetje 	size_t isalen = strlen(isastr);
3735648Ssetje 
3745648Ssetje 	if ((p = strrchr(filename, '/')) == NULL)
3755648Ssetje 		return;
3765648Ssetje 
3775648Ssetje 	while (p > filename && *(p - 1) == '/')
3785648Ssetje 		p--;	/* remove trailing '/' characters */
3795648Ssetje 	if (p == filename)
3805648Ssetje 		p++;	/* so "/" -is- the modpath in this case */
3815648Ssetje 
3825648Ssetje 	/*
3835648Ssetje 	 * Remove optional isa-dependent directory name - the module
3845648Ssetje 	 * subsystem will put this back again (!)
3855648Ssetje 	 */
3865648Ssetje 	len = p - filename;
3875648Ssetje 	if (len > isalen &&
3885648Ssetje 	    strncmp(&filename[len - isalen], isastr, isalen) == 0)
3895648Ssetje 		p -= isalen;
3905648Ssetje 
3915648Ssetje 	/*
3925648Ssetje 	 * "/platform/mumblefrotz" + " " + MOD_DEFPATH
3935648Ssetje 	 */
3945648Ssetje 	len += (p - filename) + 1 + strlen(MOD_DEFPATH) + 1;
3955648Ssetje 	(void) strncpy(path, filename, p - filename);
3965648Ssetje }
397