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Diffstat (limited to 'arch/x86/kernel/vsyscall_64.c')
-rw-r--r--arch/x86/kernel/vsyscall_64.c402
1 files changed, 0 insertions, 402 deletions
diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
deleted file mode 100644
index 9a907a67be8f..000000000000
--- a/arch/x86/kernel/vsyscall_64.c
+++ /dev/null
@@ -1,402 +0,0 @@
-/*
- * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
- * Copyright 2003 Andi Kleen, SuSE Labs.
- *
- * [ NOTE: this mechanism is now deprecated in favor of the vDSO. ]
- *
- * Thanks to hpa@transmeta.com for some useful hint.
- * Special thanks to Ingo Molnar for his early experience with
- * a different vsyscall implementation for Linux/IA32 and for the name.
- *
- * vsyscall 1 is located at -10Mbyte, vsyscall 2 is located
- * at virtual address -10Mbyte+1024bytes etc... There are at max 4
- * vsyscalls. One vsyscall can reserve more than 1 slot to avoid
- * jumping out of line if necessary. We cannot add more with this
- * mechanism because older kernels won't return -ENOSYS.
- *
- * Note: the concept clashes with user mode linux. UML users should
- * use the vDSO.
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/time.h>
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/timer.h>
-#include <linux/seqlock.h>
-#include <linux/jiffies.h>
-#include <linux/sysctl.h>
-#include <linux/topology.h>
-#include <linux/timekeeper_internal.h>
-#include <linux/getcpu.h>
-#include <linux/cpu.h>
-#include <linux/smp.h>
-#include <linux/notifier.h>
-#include <linux/syscalls.h>
-#include <linux/ratelimit.h>
-
-#include <asm/vsyscall.h>
-#include <asm/pgtable.h>
-#include <asm/compat.h>
-#include <asm/page.h>
-#include <asm/unistd.h>
-#include <asm/fixmap.h>
-#include <asm/errno.h>
-#include <asm/io.h>
-#include <asm/segment.h>
-#include <asm/desc.h>
-#include <asm/topology.h>
-#include <asm/vgtod.h>
-#include <asm/traps.h>
-
-#define CREATE_TRACE_POINTS
-#include "vsyscall_trace.h"
-
-DEFINE_VVAR(int, vgetcpu_mode);
-DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data);
-
-static enum { EMULATE, NATIVE, NONE } vsyscall_mode = EMULATE;
-
-static int __init vsyscall_setup(char *str)
-{
- if (str) {
- if (!strcmp("emulate", str))
- vsyscall_mode = EMULATE;
- else if (!strcmp("native", str))
- vsyscall_mode = NATIVE;
- else if (!strcmp("none", str))
- vsyscall_mode = NONE;
- else
- return -EINVAL;
-
- return 0;
- }
-
- return -EINVAL;
-}
-early_param("vsyscall", vsyscall_setup);
-
-void update_vsyscall_tz(void)
-{
- vsyscall_gtod_data.sys_tz = sys_tz;
-}
-
-void update_vsyscall(struct timekeeper *tk)
-{
- struct vsyscall_gtod_data *vdata = &vsyscall_gtod_data;
-
- write_seqcount_begin(&vdata->seq);
-
- /* copy vsyscall data */
- vdata->clock.vclock_mode = tk->clock->archdata.vclock_mode;
- vdata->clock.cycle_last = tk->clock->cycle_last;
- vdata->clock.mask = tk->clock->mask;
- vdata->clock.mult = tk->mult;
- vdata->clock.shift = tk->shift;
-
- vdata->wall_time_sec = tk->xtime_sec;
- vdata->wall_time_snsec = tk->xtime_nsec;
-
- vdata->monotonic_time_sec = tk->xtime_sec
- + tk->wall_to_monotonic.tv_sec;
- vdata->monotonic_time_snsec = tk->xtime_nsec
- + (tk->wall_to_monotonic.tv_nsec
- << tk->shift);
- while (vdata->monotonic_time_snsec >=
- (((u64)NSEC_PER_SEC) << tk->shift)) {
- vdata->monotonic_time_snsec -=
- ((u64)NSEC_PER_SEC) << tk->shift;
- vdata->monotonic_time_sec++;
- }
-
- vdata->wall_time_coarse.tv_sec = tk->xtime_sec;
- vdata->wall_time_coarse.tv_nsec = (long)(tk->xtime_nsec >> tk->shift);
-
- vdata->monotonic_time_coarse = timespec_add(vdata->wall_time_coarse,
- tk->wall_to_monotonic);
-
- write_seqcount_end(&vdata->seq);
-}
-
-static void warn_bad_vsyscall(const char *level, struct pt_regs *regs,
- const char *message)
-{
- if (!show_unhandled_signals)
- return;
-
- pr_notice_ratelimited("%s%s[%d] %s ip:%lx cs:%lx sp:%lx ax:%lx si:%lx di:%lx\n",
- level, current->comm, task_pid_nr(current),
- message, regs->ip, regs->cs,
- regs->sp, regs->ax, regs->si, regs->di);
-}
-
-static int addr_to_vsyscall_nr(unsigned long addr)
-{
- int nr;
-
- if ((addr & ~0xC00UL) != VSYSCALL_START)
- return -EINVAL;
-
- nr = (addr & 0xC00UL) >> 10;
- if (nr >= 3)
- return -EINVAL;
-
- return nr;
-}
-
-static bool write_ok_or_segv(unsigned long ptr, size_t size)
-{
- /*
- * XXX: if access_ok, get_user, and put_user handled
- * sig_on_uaccess_error, this could go away.
- */
-
- if (!access_ok(VERIFY_WRITE, (void __user *)ptr, size)) {
- siginfo_t info;
- struct thread_struct *thread = &current->thread;
-
- thread->error_code = 6; /* user fault, no page, write */
- thread->cr2 = ptr;
- thread->trap_nr = X86_TRAP_PF;
-
- memset(&info, 0, sizeof(info));
- info.si_signo = SIGSEGV;
- info.si_errno = 0;
- info.si_code = SEGV_MAPERR;
- info.si_addr = (void __user *)ptr;
-
- force_sig_info(SIGSEGV, &info, current);
- return false;
- } else {
- return true;
- }
-}
-
-bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
-{
- struct task_struct *tsk;
- unsigned long caller;
- int vsyscall_nr, syscall_nr, tmp;
- int prev_sig_on_uaccess_error;
- long ret;
-
- /*
- * No point in checking CS -- the only way to get here is a user mode
- * trap to a high address, which means that we're in 64-bit user code.
- */
-
- WARN_ON_ONCE(address != regs->ip);
-
- if (vsyscall_mode == NONE) {
- warn_bad_vsyscall(KERN_INFO, regs,
- "vsyscall attempted with vsyscall=none");
- return false;
- }
-
- vsyscall_nr = addr_to_vsyscall_nr(address);
-
- trace_emulate_vsyscall(vsyscall_nr);
-
- if (vsyscall_nr < 0) {
- warn_bad_vsyscall(KERN_WARNING, regs,
- "misaligned vsyscall (exploit attempt or buggy program) -- look up the vsyscall kernel parameter if you need a workaround");
- goto sigsegv;
- }
-
- if (get_user(caller, (unsigned long __user *)regs->sp) != 0) {
- warn_bad_vsyscall(KERN_WARNING, regs,
- "vsyscall with bad stack (exploit attempt?)");
- goto sigsegv;
- }
-
- tsk = current;
-
- /*
- * Check for access_ok violations and find the syscall nr.
- *
- * NULL is a valid user pointer (in the access_ok sense) on 32-bit and
- * 64-bit, so we don't need to special-case it here. For all the
- * vsyscalls, NULL means "don't write anything" not "write it at
- * address 0".
- */
- switch (vsyscall_nr) {
- case 0:
- if (!write_ok_or_segv(regs->di, sizeof(struct timeval)) ||
- !write_ok_or_segv(regs->si, sizeof(struct timezone))) {
- ret = -EFAULT;
- goto check_fault;
- }
-
- syscall_nr = __NR_gettimeofday;
- break;
-
- case 1:
- if (!write_ok_or_segv(regs->di, sizeof(time_t))) {
- ret = -EFAULT;
- goto check_fault;
- }
-
- syscall_nr = __NR_time;
- break;
-
- case 2:
- if (!write_ok_or_segv(regs->di, sizeof(unsigned)) ||
- !write_ok_or_segv(regs->si, sizeof(unsigned))) {
- ret = -EFAULT;
- goto check_fault;
- }
-
- syscall_nr = __NR_getcpu;
- break;
- }
-
- /*
- * Handle seccomp. regs->ip must be the original value.
- * See seccomp_send_sigsys and Documentation/prctl/seccomp_filter.txt.
- *
- * We could optimize the seccomp disabled case, but performance
- * here doesn't matter.
- */
- regs->orig_ax = syscall_nr;
- regs->ax = -ENOSYS;
- tmp = secure_computing(syscall_nr);
- if ((!tmp && regs->orig_ax != syscall_nr) || regs->ip != address) {
- warn_bad_vsyscall(KERN_DEBUG, regs,
- "seccomp tried to change syscall nr or ip");
- do_exit(SIGSYS);
- }
- if (tmp)
- goto do_ret; /* skip requested */
-
- /*
- * With a real vsyscall, page faults cause SIGSEGV. We want to
- * preserve that behavior to make writing exploits harder.
- */
- prev_sig_on_uaccess_error = current_thread_info()->sig_on_uaccess_error;
- current_thread_info()->sig_on_uaccess_error = 1;
-
- ret = -EFAULT;
- switch (vsyscall_nr) {
- case 0:
- ret = sys_gettimeofday(
- (struct timeval __user *)regs->di,
- (struct timezone __user *)regs->si);
- break;
-
- case 1:
- ret = sys_time((time_t __user *)regs->di);
- break;
-
- case 2:
- ret = sys_getcpu((unsigned __user *)regs->di,
- (unsigned __user *)regs->si,
- NULL);
- break;
- }
-
- current_thread_info()->sig_on_uaccess_error = prev_sig_on_uaccess_error;
-
-check_fault:
- if (ret == -EFAULT) {
- /* Bad news -- userspace fed a bad pointer to a vsyscall. */
- warn_bad_vsyscall(KERN_INFO, regs,
- "vsyscall fault (exploit attempt?)");
-
- /*
- * If we failed to generate a signal for any reason,
- * generate one here. (This should be impossible.)
- */
- if (WARN_ON_ONCE(!sigismember(&tsk->pending.signal, SIGBUS) &&
- !sigismember(&tsk->pending.signal, SIGSEGV)))
- goto sigsegv;
-
- return true; /* Don't emulate the ret. */
- }
-
- regs->ax = ret;
-
-do_ret:
- /* Emulate a ret instruction. */
- regs->ip = caller;
- regs->sp += 8;
- return true;
-
-sigsegv:
- force_sig(SIGSEGV, current);
- return true;
-}
-
-/*
- * Assume __initcall executes before all user space. Hopefully kmod
- * doesn't violate that. We'll find out if it does.
- */
-static void __cpuinit vsyscall_set_cpu(int cpu)
-{
- unsigned long d;
- unsigned long node = 0;
-#ifdef CONFIG_NUMA
- node = cpu_to_node(cpu);
-#endif
- if (cpu_has(&cpu_data(cpu), X86_FEATURE_RDTSCP))
- write_rdtscp_aux((node << 12) | cpu);
-
- /*
- * Store cpu number in limit so that it can be loaded quickly
- * in user space in vgetcpu. (12 bits for the CPU and 8 bits for the node)
- */
- d = 0x0f40000000000ULL;
- d |= cpu;
- d |= (node & 0xf) << 12;
- d |= (node >> 4) << 48;
-
- write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_PER_CPU, &d, DESCTYPE_S);
-}
-
-static void __cpuinit cpu_vsyscall_init(void *arg)
-{
- /* preemption should be already off */
- vsyscall_set_cpu(raw_smp_processor_id());
-}
-
-static int __cpuinit
-cpu_vsyscall_notifier(struct notifier_block *n, unsigned long action, void *arg)
-{
- long cpu = (long)arg;
-
- if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN)
- smp_call_function_single(cpu, cpu_vsyscall_init, NULL, 1);
-
- return NOTIFY_DONE;
-}
-
-void __init map_vsyscall(void)
-{
- extern char __vsyscall_page;
- unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page);
- extern char __vvar_page;
- unsigned long physaddr_vvar_page = __pa_symbol(&__vvar_page);
-
- __set_fixmap(VSYSCALL_FIRST_PAGE, physaddr_vsyscall,
- vsyscall_mode == NATIVE
- ? PAGE_KERNEL_VSYSCALL
- : PAGE_KERNEL_VVAR);
- BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_FIRST_PAGE) !=
- (unsigned long)VSYSCALL_START);
-
- __set_fixmap(VVAR_PAGE, physaddr_vvar_page, PAGE_KERNEL_VVAR);
- BUILD_BUG_ON((unsigned long)__fix_to_virt(VVAR_PAGE) !=
- (unsigned long)VVAR_ADDRESS);
-}
-
-static int __init vsyscall_init(void)
-{
- BUG_ON(VSYSCALL_ADDR(0) != __fix_to_virt(VSYSCALL_FIRST_PAGE));
-
- on_each_cpu(cpu_vsyscall_init, NULL, 1);
- /* notifier priority > KVM */
- hotcpu_notifier(cpu_vsyscall_notifier, 30);
-
- return 0;
-}
-__initcall(vsyscall_init);
generated by cgit (git 2.34.1) at 2025-12-25 16:00:24 +0000