/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (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 (c) 1992, 2010, Oracle and/or its affiliates. All rights reserved. * Copyright 2021 Joyent, Inc. * Copyright 2021 Oxide Computer Company */ /* Copyright (c) 1990, 1991 UNIX System Laboratories, Inc. */ /* Copyright (c) 1984, 1986, 1987, 1988, 1989, 1990 AT&T */ /* All Rights Reserved */ #include <sys/types.h> #include <sys/stdbool.h> #include <sys/param.h> #include <sys/sysmacros.h> #include <sys/signal.h> #include <sys/systm.h> #include <sys/user.h> #include <sys/mman.h> #include <sys/class.h> #include <sys/proc.h> #include <sys/procfs.h> #include <sys/buf.h> #include <sys/kmem.h> #include <sys/cred.h> #include <sys/archsystm.h> #include <sys/vmparam.h> #include <sys/prsystm.h> #include <sys/reboot.h> #include <sys/uadmin.h> #include <sys/vfs.h> #include <sys/vnode.h> #include <sys/file.h> #include <sys/session.h> #include <sys/ucontext.h> #include <sys/dnlc.h> #include <sys/var.h> #include <sys/cmn_err.h> #include <sys/debugreg.h> #include <sys/thread.h> #include <sys/vtrace.h> #include <sys/consdev.h> #include <sys/psw.h> #include <sys/regset.h> #include <sys/privregs.h> #include <sys/cpu.h> #include <sys/stack.h> #include <sys/swap.h> #include <vm/hat.h> #include <vm/anon.h> #include <vm/as.h> #include <vm/page.h> #include <vm/seg.h> #include <vm/seg_kmem.h> #include <vm/seg_map.h> #include <vm/seg_vn.h> #include <sys/exec.h> #include <sys/acct.h> #include <sys/core.h> #include <sys/corectl.h> #include <sys/modctl.h> #include <sys/tuneable.h> #include <c2/audit.h> #include <sys/bootconf.h> #include <sys/brand.h> #include <sys/dumphdr.h> #include <sys/promif.h> #include <sys/systeminfo.h> #include <sys/kdi.h> #include <sys/contract_impl.h> #include <sys/x86_archext.h> #include <sys/segments.h> #include <sys/ontrap.h> #include <sys/cpu.h> #ifdef __xpv #include <sys/hypervisor.h> #endif /* * Compare the version of boot that boot says it is against * the version of boot the kernel expects. */ int check_boot_version(int boots_version) { if (boots_version == BO_VERSION) return (0); prom_printf("Wrong boot interface - kernel needs v%d found v%d\n", BO_VERSION, boots_version); prom_panic("halting"); /*NOTREACHED*/ } /* * Process the physical installed list for boot. * Finds: * 1) the pfn of the highest installed physical page, * 2) the number of pages installed * 3) the number of distinct contiguous regions these pages fall into. * 4) the number of contiguous memory ranges */ void installed_top_size_ex( struct memlist *list, /* pointer to start of installed list */ pfn_t *high_pfn, /* return ptr for top value */ pgcnt_t *pgcnt, /* return ptr for sum of installed pages */ int *ranges) /* return ptr for the count of contig. ranges */ { pfn_t top = 0; pgcnt_t sumpages = 0; pfn_t highp; /* high page in a chunk */ int cnt = 0; for (; list; list = list->ml_next) { ++cnt; highp = (list->ml_address + list->ml_size - 1) >> PAGESHIFT; if (top < highp) top = highp; sumpages += btop(list->ml_size); } *high_pfn = top; *pgcnt = sumpages; *ranges = cnt; } void installed_top_size( struct memlist *list, /* pointer to start of installed list */ pfn_t *high_pfn, /* return ptr for top value */ pgcnt_t *pgcnt) /* return ptr for sum of installed pages */ { int ranges; installed_top_size_ex(list, high_pfn, pgcnt, &ranges); } void phys_install_has_changed(void) {} /* * Copy in a memory list from boot to kernel, with a filter function * to remove pages. The filter function can increase the address and/or * decrease the size to filter out pages. It will also align addresses and * sizes to PAGESIZE. */ void copy_memlist_filter( struct memlist *src, struct memlist **dstp, void (*filter)(uint64_t *, uint64_t *)) { struct memlist *dst, *prev; uint64_t addr; uint64_t size; uint64_t eaddr; dst = *dstp; prev = dst; /* * Move through the memlist applying a filter against * each range of memory. Note that we may apply the * filter multiple times against each memlist entry. */ for (; src; src = src->ml_next) { addr = P2ROUNDUP(src->ml_address, PAGESIZE); eaddr = P2ALIGN(src->ml_address + src->ml_size, PAGESIZE); while (addr < eaddr) { size = eaddr - addr; if (filter != NULL) filter(&addr, &size); if (size == 0) break; dst->ml_address = addr; dst->ml_size = size; dst->ml_next = 0; if (prev == dst) { dst->ml_prev = 0; dst++; } else { dst->ml_prev = prev; prev->ml_next = dst; dst++; prev++; } addr += size; } } *dstp = dst; } /* * Kernel setup code, called from startup(). */ void kern_setup1(void) { proc_t *pp; pp = &p0; proc_sched = pp; /* * Initialize process 0 data structures */ pp->p_stat = SRUN; pp->p_flag = SSYS; pp->p_pidp = &pid0; pp->p_pgidp = &pid0; pp->p_sessp = &session0; pp->p_tlist = &t0; pid0.pid_pglink = pp; pid0.pid_pgtail = pp; /* * XXX - we asssume that the u-area is zeroed out except for * ttolwp(curthread)->lwp_regs. */ PTOU(curproc)->u_cmask = (mode_t)CMASK; thread_init(); /* init thread_free list */ pid_init(); /* initialize pid (proc) table */ contract_init(); /* initialize contracts */ init_pages_pp_maximum(); } /* * Load a procedure into a thread. */ void thread_load(kthread_t *t, void (*start)(), caddr_t arg, size_t len) { caddr_t sp; size_t framesz; caddr_t argp; long *p; extern void thread_start(); /* * Push a "c" call frame onto the stack to represent * the caller of "start". */ sp = t->t_stk; ASSERT(((uintptr_t)t->t_stk & (STACK_ENTRY_ALIGN - 1)) == 0); if (len != 0) { /* * the object that arg points at is copied into the * caller's frame. */ framesz = SA(len); sp -= framesz; ASSERT(sp > t->t_stkbase); argp = sp + SA(MINFRAME); bcopy(arg, argp, len); arg = argp; } /* * Set up arguments (arg and len) on the caller's stack frame. */ p = (long *)sp; *--p = 0; /* fake call */ *--p = 0; /* null frame pointer terminates stack trace */ *--p = (long)len; *--p = (intptr_t)arg; *--p = (intptr_t)start; /* * initialize thread to resume at thread_start() which will * turn around and invoke (*start)(arg, len). */ t->t_pc = (uintptr_t)thread_start; t->t_sp = (uintptr_t)p; ASSERT((t->t_sp & (STACK_ENTRY_ALIGN - 1)) == 0); } /* * load user registers into lwp. */ /*ARGSUSED2*/ void lwp_load(klwp_t *lwp, gregset_t grp, uintptr_t thrptr) { struct regs *rp = lwptoregs(lwp); setgregs(lwp, grp); rp->r_ps = PSL_USER; /* * For 64-bit lwps, we allow one magic %fs selector value, and one * magic %gs selector to point anywhere in the address space using * %fsbase and %gsbase behind the scenes. libc uses %fs to point * at the ulwp_t structure. * * For 32-bit lwps, libc wedges its lwp thread pointer into the * ucontext ESP slot (which is otherwise irrelevant to setting a * ucontext) and LWPGS_SEL value into gregs[REG_GS]. This is so * syslwp_create() can atomically setup %gs. * * See setup_context() in libc. */ #ifdef _SYSCALL32_IMPL if (lwp_getdatamodel(lwp) == DATAMODEL_ILP32) { if (grp[REG_GS] == LWPGS_SEL) (void) lwp_setprivate(lwp, _LWP_GSBASE, thrptr); } else { /* * See lwp_setprivate in kernel and setup_context in libc. * * Currently libc constructs a ucontext from whole cloth for * every new (not main) lwp created. For 64 bit processes * %fsbase is directly set to point to current thread pointer. * In the past (solaris 10) %fs was also set LWPFS_SEL to * indicate %fsbase. Now we use the null GDT selector for * this purpose. LWP[FS|GS]_SEL are only intended for 32 bit * processes. To ease transition we support older libcs in * the newer kernel by forcing %fs or %gs selector to null * by calling lwp_setprivate if LWP[FS|GS]_SEL is passed in * the ucontext. This is should be ripped out at some future * date. Another fix would be for libc to do a getcontext * and inherit the null %fs/%gs from the current context but * that means an extra system call and could hurt performance. */ if (grp[REG_FS] == 0x1bb) /* hard code legacy LWPFS_SEL */ (void) lwp_setprivate(lwp, _LWP_FSBASE, (uintptr_t)grp[REG_FSBASE]); if (grp[REG_GS] == 0x1c3) /* hard code legacy LWPGS_SEL */ (void) lwp_setprivate(lwp, _LWP_GSBASE, (uintptr_t)grp[REG_GSBASE]); } #else if (grp[GS] == LWPGS_SEL) (void) lwp_setprivate(lwp, _LWP_GSBASE, thrptr); #endif lwp->lwp_eosys = JUSTRETURN; lwptot(lwp)->t_post_sys = 1; } /* * set syscall()'s return values for a lwp. */ void lwp_setrval(klwp_t *lwp, int v1, int v2) { lwptoregs(lwp)->r_ps &= ~PS_C; lwptoregs(lwp)->r_r0 = v1; lwptoregs(lwp)->r_r1 = v2; } /* * set syscall()'s return values for a lwp. */ void lwp_setsp(klwp_t *lwp, caddr_t sp) { lwptoregs(lwp)->r_sp = (intptr_t)sp; } /* * Copy regs from parent to child. */ void lwp_forkregs(klwp_t *lwp, klwp_t *clwp) { struct pcb *pcb = &clwp->lwp_pcb; struct regs *rp = lwptoregs(lwp); if (!PCB_NEED_UPDATE_SEGS(pcb)) { pcb->pcb_ds = rp->r_ds; pcb->pcb_es = rp->r_es; pcb->pcb_fs = rp->r_fs; pcb->pcb_gs = rp->r_gs; PCB_SET_UPDATE_SEGS(pcb); lwptot(clwp)->t_post_sys = 1; } ASSERT(lwptot(clwp)->t_post_sys); fp_lwp_dup(clwp); bcopy(lwp->lwp_regs, clwp->lwp_regs, sizeof (struct regs)); } /* * This function is currently unused on x86. */ /*ARGSUSED*/ void lwp_freeregs(klwp_t *lwp, int isexec) {} /* * This function is currently unused on x86. */ void lwp_pcb_exit(void) {} /* * Lwp context ops for segment registers. */ /* * Every time we come into the kernel (syscall, interrupt or trap * but not fast-traps) we capture the current values of the user's * segment registers into the lwp's reg structure. This includes * lcall for i386 generic system call support since it is handled * as a segment-not-present trap. * * Here we save the current values from the lwp regs into the pcb * and or PCB_UPDATE_SEGS (1) in pcb->pcb_rupdate to tell the rest * of the kernel that the pcb copy of the segment registers is the * current one. This ensures the lwp's next trip to user land via * update_sregs. Finally we set t_post_sys to ensure that no * system call fast-path's its way out of the kernel via sysret. * * (This means that we need to have interrupts disabled when we * test t->t_post_sys in the syscall handlers; if the test fails, * we need to keep interrupts disabled until we return to userland * so we can't be switched away.) * * As a result of all this, we don't really have to do a whole lot * if the thread is just mucking about in the kernel, switching on * and off the cpu for whatever reason it feels like. And yet we * still preserve fast syscalls, cause if we -don't- get * descheduled, we never come here either. */ #define VALID_LWP_DESC(udp) ((udp)->usd_type == SDT_MEMRWA && \ (udp)->usd_p == 1 && (udp)->usd_dpl == SEL_UPL) /*ARGSUSED*/ void lwp_segregs_save(void *arg) { klwp_t *lwp = arg; pcb_t *pcb = &lwp->lwp_pcb; struct regs *rp; ASSERT(VALID_LWP_DESC(&pcb->pcb_fsdesc)); ASSERT(VALID_LWP_DESC(&pcb->pcb_gsdesc)); if (!PCB_NEED_UPDATE_SEGS(pcb)) { rp = lwptoregs(lwp); /* * If there's no update already pending, capture the current * %ds/%es/%fs/%gs values from lwp's regs in case the user * changed them; %fsbase and %gsbase are privileged so the * kernel versions of these registers in pcb_fsbase and * pcb_gsbase are always up-to-date. */ pcb->pcb_ds = rp->r_ds; pcb->pcb_es = rp->r_es; pcb->pcb_fs = rp->r_fs; pcb->pcb_gs = rp->r_gs; PCB_SET_UPDATE_SEGS(pcb); lwp->lwp_thread->t_post_sys = 1; } #if !defined(__xpv) /* XXPV not sure if we can re-read gdt? */ ASSERT(bcmp(&CPU->cpu_gdt[GDT_LWPFS], &lwp->lwp_pcb.pcb_fsdesc, sizeof (lwp->lwp_pcb.pcb_fsdesc)) == 0); ASSERT(bcmp(&CPU->cpu_gdt[GDT_LWPGS], &lwp->lwp_pcb.pcb_gsdesc, sizeof (lwp->lwp_pcb.pcb_gsdesc)) == 0); #endif } /* * Update the segment registers with new values from the pcb. * * We have to do this carefully, and in the following order, * in case any of the selectors points at a bogus descriptor. * If they do, we'll catch trap with on_trap and return 1. * returns 0 on success. * * This is particularly tricky for %gs. * This routine must be executed under a cli. */ int update_sregs(struct regs *rp, klwp_t *lwp) { pcb_t *pcb = &lwp->lwp_pcb; ulong_t kgsbase; on_trap_data_t otd; int rc; if (!on_trap(&otd, OT_SEGMENT_ACCESS)) { rc = 0; #if defined(__xpv) /* * On the hyervisor this is easy. The hypercall below will * swapgs and load %gs with the user selector. If the user * selector is bad the hypervisor will catch the fault and * load %gs with the null selector instead. Either way the * kernel's gsbase is not damaged. */ kgsbase = (ulong_t)CPU; if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, pcb->pcb_gs) != 0) { no_trap(); return (1); } rp->r_gs = pcb->pcb_gs; ASSERT((cpu_t *)kgsbase == CPU); #else /* __xpv */ /* * A little more complicated running native. */ kgsbase = (ulong_t)CPU; __set_gs(pcb->pcb_gs); /* * If __set_gs fails it's because the new %gs is a bad %gs, * we'll be taking a trap but with the original %gs and %gsbase * undamaged (i.e. pointing at curcpu). * * We've just mucked up the kernel's gsbase. Oops. In * particular we can't take any traps at all. Make the newly * computed gsbase be the hidden gs via swapgs, and fix * the kernel's gsbase back again. Later, when we return to * userland we'll swapgs again restoring gsbase just loaded * above. */ __asm__ __volatile__("mfence; swapgs"); rp->r_gs = pcb->pcb_gs; /* * Restore kernel's gsbase. Note that this also serializes any * attempted speculation from loading the user-controlled * %gsbase. */ wrmsr(MSR_AMD_GSBASE, kgsbase); #endif /* __xpv */ /* * Only override the descriptor base address if * r_gs == LWPGS_SEL or if r_gs == NULL. A note on * NULL descriptors -- 32-bit programs take faults * if they deference NULL descriptors; however, * when 64-bit programs load them into %fs or %gs, * they DONT fault -- only the base address remains * whatever it was from the last load. Urk. * * XXX - note that lwp_setprivate now sets %fs/%gs to the * null selector for 64 bit processes. Whereas before * %fs/%gs were set to LWP(FS|GS)_SEL regardless of * the process's data model. For now we check for both * values so that the kernel can also support the older * libc. This should be ripped out at some point in the * future. */ if (pcb->pcb_gs == LWPGS_SEL || pcb->pcb_gs == 0) { #if defined(__xpv) if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER, pcb->pcb_gsbase)) { no_trap(); return (1); } #else wrmsr(MSR_AMD_KGSBASE, pcb->pcb_gsbase); #endif } __set_ds(pcb->pcb_ds); rp->r_ds = pcb->pcb_ds; __set_es(pcb->pcb_es); rp->r_es = pcb->pcb_es; __set_fs(pcb->pcb_fs); rp->r_fs = pcb->pcb_fs; /* * Same as for %gs */ if (pcb->pcb_fs == LWPFS_SEL || pcb->pcb_fs == 0) { #if defined(__xpv) if (HYPERVISOR_set_segment_base(SEGBASE_FS, pcb->pcb_fsbase)) { no_trap(); return (1); } #else wrmsr(MSR_AMD_FSBASE, pcb->pcb_fsbase); #endif } } else { cli(); rc = 1; } no_trap(); return (rc); } /* * Make sure any stale selectors are cleared from the segment registers * by putting KDS_SEL (the kernel's default %ds gdt selector) into them. * This is necessary because the kernel itself does not use %es, %fs, nor * %ds. (%cs and %ss are necessary, and are set up by the kernel - along with * %gs - to point to the current cpu struct.) If we enter kmdb while in the * kernel and resume with a stale ldt or brandz selector sitting there in a * segment register, kmdb will #gp fault if the stale selector points to, * for example, an ldt in the context of another process. * * WARNING: Intel and AMD chips behave differently when storing * the null selector into %fs and %gs while in long mode. On AMD * chips fsbase and gsbase are not cleared. But on Intel chips, storing * a null selector into %fs or %gs has the side effect of clearing * fsbase or gsbase. For that reason we use KDS_SEL, which has * consistent behavor between AMD and Intel. * * Caller responsible for preventing cpu migration. */ void reset_sregs(void) { ulong_t kgsbase = (ulong_t)CPU; ASSERT(curthread->t_preempt != 0 || getpil() >= DISP_LEVEL); cli(); __set_gs(KGS_SEL); /* * restore kernel gsbase */ #if defined(__xpv) xen_set_segment_base(SEGBASE_GS_KERNEL, kgsbase); #else wrmsr(MSR_AMD_GSBASE, kgsbase); #endif sti(); __set_ds(KDS_SEL); __set_es(0 | SEL_KPL); /* selector RPL not ring 0 on hypervisor */ __set_fs(KFS_SEL); } #ifdef _SYSCALL32_IMPL /* * Make it impossible for a process to change its data model. * We do this by toggling the present bits for the 32 and * 64-bit user code descriptors. That way if a user lwp attempts * to change its data model (by using the wrong code descriptor in * %cs) it will fault immediately. This also allows us to simplify * assertions and checks in the kernel. */ static void gdt_ucode_model(model_t model) { kpreempt_disable(); if (model == DATAMODEL_NATIVE) { gdt_update_usegd(GDT_UCODE, &ucs_on); gdt_update_usegd(GDT_U32CODE, &ucs32_off); } else { gdt_update_usegd(GDT_U32CODE, &ucs32_on); gdt_update_usegd(GDT_UCODE, &ucs_off); } kpreempt_enable(); } #endif /* _SYSCALL32_IMPL */ /* * Restore lwp private fs and gs segment descriptors * on current cpu's GDT. */ static void lwp_segregs_restore(void *arg) { klwp_t *lwp = arg; pcb_t *pcb = &lwp->lwp_pcb; ASSERT(VALID_LWP_DESC(&pcb->pcb_fsdesc)); ASSERT(VALID_LWP_DESC(&pcb->pcb_gsdesc)); #ifdef _SYSCALL32_IMPL gdt_ucode_model(DATAMODEL_NATIVE); #endif gdt_update_usegd(GDT_LWPFS, &pcb->pcb_fsdesc); gdt_update_usegd(GDT_LWPGS, &pcb->pcb_gsdesc); } #ifdef _SYSCALL32_IMPL static void lwp_segregs_restore32(void *arg) { klwp_t *lwp = arg; pcb_t *pcb = &lwp->lwp_pcb; ASSERT(VALID_LWP_DESC(&lwp->lwp_pcb.pcb_fsdesc)); ASSERT(VALID_LWP_DESC(&lwp->lwp_pcb.pcb_gsdesc)); gdt_ucode_model(DATAMODEL_ILP32); gdt_update_usegd(GDT_LWPFS, &pcb->pcb_fsdesc); gdt_update_usegd(GDT_LWPGS, &pcb->pcb_gsdesc); } #endif /* _SYSCALL32_IMPL */ static const struct ctxop_template brand_interpose_ctxop_tpl = { .ct_rev = CTXOP_TPL_REV, .ct_save = brand_interpositioning_disable, .ct_restore = brand_interpositioning_enable, .ct_exit = brand_interpositioning_disable, }; /* * If this is a process in a branded zone, then we want it to use the brand * syscall entry points instead of the standard Solaris entry points. This * routine must be called when a new lwp is created within a branded zone * or when an existing lwp moves into a branded zone via a zone_enter() * operation. */ void lwp_attach_brand_hdlrs(klwp_t *lwp) { kthread_t *t = lwptot(lwp); ASSERT(PROC_IS_BRANDED(lwptoproc(lwp))); /* Confirm that brand interposition ctxop is not already present */ ASSERT0(ctxop_remove(t, &brand_interpose_ctxop_tpl, NULL)); ctxop_install(t, &brand_interpose_ctxop_tpl, NULL); if (t == curthread) { kpreempt_disable(); brand_interpositioning_enable(NULL); kpreempt_enable(); } } /* * If this is a process in a branded zone, then we want it to disable the * brand syscall entry points. This routine must be called when the last * lwp in a process is exiting in proc_exit(). */ void lwp_detach_brand_hdlrs(klwp_t *lwp) { kthread_t *t = lwptot(lwp); ASSERT(PROC_IS_BRANDED(lwptoproc(lwp))); if (t == curthread) kpreempt_disable(); /* Remove the original context handlers */ ctxop_remove(t, &brand_interpose_ctxop_tpl, NULL); if (t == curthread) { /* Cleanup our MSR and IDT entries. */ brand_interpositioning_disable(NULL); kpreempt_enable(); } } static const struct ctxop_template sep_tpl = { .ct_rev = CTXOP_TPL_REV, .ct_save = sep_save, .ct_restore = sep_restore, }; /* * Add any lwp-associated context handlers to the lwp at the beginning * of the lwp's useful life. * * All paths which create lwp's invoke lwp_create(); lwp_create() * invokes lwp_stk_init() which initializes the stack, sets up * lwp_regs, and invokes this routine. * * All paths which destroy lwp's invoke lwp_exit() to rip the lwp * apart and put it on 'lwp_deathrow'; if the lwp is destroyed it * ends up in thread_free() which invokes freectx(t, 0) before * invoking lwp_stk_fini(). When the lwp is recycled from death * row, lwp_stk_fini() is invoked, then thread_free(), and thus * freectx(t, 0) as before. * * In the case of exec, the surviving lwp is thoroughly scrubbed * clean; exec invokes freectx(t, 1) to destroy associated contexts. * On the way back to the new image, it invokes setregs() which * in turn invokes this routine. */ void lwp_installctx(klwp_t *lwp) { kthread_t *t = lwptot(lwp); bool thisthread = (t == curthread); struct ctxop *ctx; const struct ctxop_template segreg_tpl = { .ct_rev = CTXOP_TPL_REV, .ct_save = lwp_segregs_save, #ifdef _SYSCALL32_IMPL .ct_restore = lwp_getdatamodel(lwp) == DATAMODEL_NATIVE ? lwp_segregs_restore : lwp_segregs_restore32 #else .ct_restore = lwp_segregs_restore; #endif }; /* * Install the basic lwp context handlers on each lwp. * * On the amd64 kernel, the context handlers are responsible for * virtualizing %ds, %es, %fs, and %gs to the lwp. The register * values are only ever changed via sys_rtt when the * PCB_UPDATE_SEGS bit (1) is set in pcb->pcb_rupdate. Only * sys_rtt gets to clear the bit. * * On the i386 kernel, the context handlers are responsible for * virtualizing %gs/%fs to the lwp by updating the per-cpu GDTs */ ASSERT0(ctxop_remove(t, &segreg_tpl, lwp)); ctx = ctxop_allocate(&segreg_tpl, lwp); if (thisthread) { kpreempt_disable(); } ctxop_attach(t, ctx); if (thisthread) { /* * Since we're the right thread, set the values in the GDT */ segreg_tpl.ct_restore(lwp); kpreempt_enable(); } /* * If we have sysenter/sysexit instructions enabled, we need * to ensure that the hardware mechanism is kept up-to-date with the * lwp's kernel stack pointer across context switches. * * sep_save zeros the sysenter stack pointer msr; sep_restore sets * it to the lwp's kernel stack pointer (kstktop). */ if (is_x86_feature(x86_featureset, X86FSET_SEP)) { caddr_t kstktop = (caddr_t)lwp->lwp_regs; ASSERT0(ctxop_remove(t, &sep_tpl, kstktop)); ctx = ctxop_allocate(&sep_tpl, kstktop); if (thisthread) { kpreempt_disable(); } ctxop_attach(t, ctx); if (thisthread) { /* * We're the right thread, so set the stack pointer * for the first sysenter instruction to use */ sep_restore(kstktop); kpreempt_enable(); } } if (PROC_IS_BRANDED(ttoproc(t))) lwp_attach_brand_hdlrs(lwp); } /* * Clear registers on exec(2). */ void setregs(uarg_t *args) { struct regs *rp; kthread_t *t = curthread; klwp_t *lwp = ttolwp(t); pcb_t *pcb = &lwp->lwp_pcb; greg_t sp; /* * Initialize user registers */ (void) save_syscall_args(); /* copy args from registers first */ rp = lwptoregs(lwp); sp = rp->r_sp; bzero(rp, sizeof (*rp)); rp->r_ss = UDS_SEL; rp->r_sp = sp; rp->r_pc = args->entry; rp->r_ps = PSL_USER; pcb->pcb_fs = pcb->pcb_gs = 0; pcb->pcb_fsbase = pcb->pcb_gsbase = 0; if (ttoproc(t)->p_model == DATAMODEL_NATIVE) { rp->r_cs = UCS_SEL; /* * Only allow 64-bit user code descriptor to be present. */ gdt_ucode_model(DATAMODEL_NATIVE); /* * Arrange that the virtualized %fs and %gs GDT descriptors * have a well-defined initial state (present, ring 3 * and of type data). */ pcb->pcb_fsdesc = pcb->pcb_gsdesc = zero_udesc; /* * thrptr is either NULL or a value used by DTrace. * 64-bit processes use %fs as their "thread" register. */ if (args->thrptr) (void) lwp_setprivate(lwp, _LWP_FSBASE, args->thrptr); } else { rp->r_cs = U32CS_SEL; rp->r_ds = rp->r_es = UDS_SEL; /* * only allow 32-bit user code selector to be present. */ gdt_ucode_model(DATAMODEL_ILP32); pcb->pcb_fsdesc = pcb->pcb_gsdesc = zero_u32desc; /* * thrptr is either NULL or a value used by DTrace. * 32-bit processes use %gs as their "thread" register. */ if (args->thrptr) (void) lwp_setprivate(lwp, _LWP_GSBASE, args->thrptr); } pcb->pcb_ds = rp->r_ds; pcb->pcb_es = rp->r_es; PCB_SET_UPDATE_SEGS(pcb); lwp->lwp_eosys = JUSTRETURN; t->t_post_sys = 1; /* * Add the lwp context handlers that virtualize segment registers, * and/or system call stacks etc. */ lwp_installctx(lwp); /* * Reset the FPU flags and then initialize the FPU for this lwp. */ fp_exec(); } user_desc_t * cpu_get_gdt(void) { return (CPU->cpu_gdt); } #if !defined(lwp_getdatamodel) /* * Return the datamodel of the given lwp. */ /*ARGSUSED*/ model_t lwp_getdatamodel(klwp_t *lwp) { return (lwp->lwp_procp->p_model); } #endif /* !lwp_getdatamodel */ #if !defined(get_udatamodel) model_t get_udatamodel(void) { return (curproc->p_model); } #endif /* !get_udatamodel */
