diff options
Diffstat (limited to 'arch/um/sys-i386')
| -rw-r--r-- | arch/um/sys-i386/Makefile | 3 | ||||
| -rw-r--r-- | arch/um/sys-i386/ptrace.c | 2 | ||||
| -rw-r--r-- | arch/um/sys-i386/sys_call_table.S | 2 | ||||
| -rw-r--r-- | arch/um/sys-i386/syscalls.c | 14 | ||||
| -rw-r--r-- | arch/um/sys-i386/tls.c | 326 |
5 files changed, 340 insertions, 7 deletions
diff --git a/arch/um/sys-i386/Makefile b/arch/um/sys-i386/Makefile index 2c06a07a1bdbd..98b20b7bba4f9 100644 --- a/arch/um/sys-i386/Makefile +++ b/arch/um/sys-i386/Makefile @@ -1,5 +1,6 @@ obj-y = bugs.o checksum.o delay.o fault.o ksyms.o ldt.o ptrace.o \ - ptrace_user.o signal.o sigcontext.o syscalls.o sysrq.o sys_call_table.o + ptrace_user.o signal.o sigcontext.o syscalls.o sysrq.o \ + sys_call_table.o tls.o obj-$(CONFIG_MODE_SKAS) += stub.o stub_segv.o diff --git a/arch/um/sys-i386/ptrace.c b/arch/um/sys-i386/ptrace.c index 927fcd9556513..6a23cc6947c3c 100644 --- a/arch/um/sys-i386/ptrace.c +++ b/arch/um/sys-i386/ptrace.c @@ -18,10 +18,12 @@ void arch_switch_to_tt(struct task_struct *from, struct task_struct *to) { update_debugregs(to->thread.arch.debugregs_seq); + arch_switch_tls_tt(from, to); } void arch_switch_to_skas(struct task_struct *from, struct task_struct *to) { + arch_switch_tls_skas(from, to); } int is_syscall(unsigned long addr) diff --git a/arch/um/sys-i386/sys_call_table.S b/arch/um/sys-i386/sys_call_table.S index ad75c27afe38a..1ff61474b25c6 100644 --- a/arch/um/sys-i386/sys_call_table.S +++ b/arch/um/sys-i386/sys_call_table.S @@ -6,8 +6,6 @@ #define sys_vm86old sys_ni_syscall #define sys_vm86 sys_ni_syscall -#define sys_set_thread_area sys_ni_syscall -#define sys_get_thread_area sys_ni_syscall #define sys_stime um_stime #define sys_time um_time diff --git a/arch/um/sys-i386/syscalls.c b/arch/um/sys-i386/syscalls.c index 1845123ed1249..749dd1bfe60f9 100644 --- a/arch/um/sys-i386/syscalls.c +++ b/arch/um/sys-i386/syscalls.c @@ -61,21 +61,27 @@ long old_select(struct sel_arg_struct __user *arg) return sys_select(a.n, a.inp, a.outp, a.exp, a.tvp); } -/* The i386 version skips reading from %esi, the fourth argument. So we must do - * this, too. +/* + * The prototype on i386 is: + * + * int clone(int flags, void * child_stack, int * parent_tidptr, struct user_desc * newtls, int * child_tidptr) + * + * and the "newtls" arg. on i386 is read by copy_thread directly from the + * register saved on the stack. */ long sys_clone(unsigned long clone_flags, unsigned long newsp, - int __user *parent_tid, int unused, int __user *child_tid) + int __user *parent_tid, void *newtls, int __user *child_tid) { long ret; if (!newsp) newsp = UPT_SP(¤t->thread.regs.regs); + current->thread.forking = 1; ret = do_fork(clone_flags, newsp, ¤t->thread.regs, 0, parent_tid, child_tid); current->thread.forking = 0; - return(ret); + return ret; } /* diff --git a/arch/um/sys-i386/tls.c b/arch/um/sys-i386/tls.c new file mode 100644 index 0000000000000..e3c5bc593faea --- /dev/null +++ b/arch/um/sys-i386/tls.c @@ -0,0 +1,326 @@ +/* + * Copyright (C) 2005 Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> + * Licensed under the GPL + */ + +#include "linux/config.h" +#include "linux/kernel.h" +#include "linux/sched.h" +#include "linux/slab.h" +#include "linux/types.h" +#include "asm/uaccess.h" +#include "asm/ptrace.h" +#include "asm/segment.h" +#include "asm/smp.h" +#include "asm/desc.h" +#include "choose-mode.h" +#include "kern.h" +#include "kern_util.h" +#include "mode_kern.h" +#include "os.h" +#include "mode.h" + +#ifdef CONFIG_MODE_SKAS +#include "skas.h" +#endif + +#ifdef CONFIG_MODE_SKAS +int do_set_thread_area_skas(struct user_desc *info) +{ + int ret; + u32 cpu; + + cpu = get_cpu(); + ret = os_set_thread_area(info, userspace_pid[cpu]); + put_cpu(); + return ret; +} + +int do_get_thread_area_skas(struct user_desc *info) +{ + int ret; + u32 cpu; + + cpu = get_cpu(); + ret = os_get_thread_area(info, userspace_pid[cpu]); + put_cpu(); + return ret; +} +#endif + +/* + * sys_get_thread_area: get a yet unused TLS descriptor index. + * XXX: Consider leaving one free slot for glibc usage at first place. This must + * be done here (and by changing GDT_ENTRY_TLS_* macros) and nowhere else. + * + * Also, this must be tested when compiling in SKAS mode with dinamic linking + * and running against NPTL. + */ +static int get_free_idx(struct task_struct* task) +{ + struct thread_struct *t = &task->thread; + int idx; + + if (!t->arch.tls_array) + return GDT_ENTRY_TLS_MIN; + + for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++) + if (!t->arch.tls_array[idx].present) + return idx + GDT_ENTRY_TLS_MIN; + return -ESRCH; +} + +#define O_FORCE 1 + +static inline void clear_user_desc(struct user_desc* info) +{ + /* Postcondition: LDT_empty(info) returns true. */ + memset(info, 0, sizeof(*info)); + + /* Check the LDT_empty or the i386 sys_get_thread_area code - we obtain + * indeed an empty user_desc. + */ + info->read_exec_only = 1; + info->seg_not_present = 1; +} + +static int load_TLS(int flags, struct task_struct *to) +{ + int ret = 0; + int idx; + + for (idx = GDT_ENTRY_TLS_MIN; idx < GDT_ENTRY_TLS_MAX; idx++) { + struct uml_tls_struct* curr = &to->thread.arch.tls_array[idx - GDT_ENTRY_TLS_MIN]; + + /* Actually, now if it wasn't flushed it gets cleared and + * flushed to the host, which will clear it.*/ + if (!curr->present) { + if (!curr->flushed) { + clear_user_desc(&curr->tls); + curr->tls.entry_number = idx; + } else { + WARN_ON(!LDT_empty(&curr->tls)); + continue; + } + } + + if (!(flags & O_FORCE) && curr->flushed) + continue; + + ret = do_set_thread_area(&curr->tls); + if (ret) + goto out; + + curr->flushed = 1; + } +out: + return ret; +} + +/* Verify if we need to do a flush for the new process, i.e. if there are any + * present desc's, only if they haven't been flushed. + */ +static inline int needs_TLS_update(struct task_struct *task) +{ + int i; + int ret = 0; + + for (i = GDT_ENTRY_TLS_MIN; i < GDT_ENTRY_TLS_MAX; i++) { + struct uml_tls_struct* curr = &task->thread.arch.tls_array[i - GDT_ENTRY_TLS_MIN]; + + /* Can't test curr->present, we may need to clear a descriptor + * which had a value. */ + if (curr->flushed) + continue; + ret = 1; + break; + } + return ret; +} + +/* On a newly forked process, the TLS descriptors haven't yet been flushed. So + * we mark them as such and the first switch_to will do the job. + */ +void clear_flushed_tls(struct task_struct *task) +{ + int i; + + for (i = GDT_ENTRY_TLS_MIN; i < GDT_ENTRY_TLS_MAX; i++) { + struct uml_tls_struct* curr = &task->thread.arch.tls_array[i - GDT_ENTRY_TLS_MIN]; + + /* Still correct to do this, if it wasn't present on the host it + * will remain as flushed as it was. */ + if (!curr->present) + continue; + + curr->flushed = 0; + } +} + +/* This in SKAS0 does not need to be used, since we have different host + * processes. Nor will this need to be used when we'll add support to the host + * SKAS patch. */ +int arch_switch_tls_skas(struct task_struct *from, struct task_struct *to) +{ + return load_TLS(O_FORCE, to); +} + +int arch_switch_tls_tt(struct task_struct *from, struct task_struct *to) +{ + if (needs_TLS_update(to)) + return load_TLS(0, to); + + return 0; +} + +static int set_tls_entry(struct task_struct* task, struct user_desc *info, + int idx, int flushed) +{ + struct thread_struct *t = &task->thread; + + if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX) + return -EINVAL; + + t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].tls = *info; + t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].present = 1; + t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].flushed = flushed; + + return 0; +} + +int arch_copy_tls(struct task_struct *new) +{ + struct user_desc info; + int idx, ret = -EFAULT; + + if (copy_from_user(&info, + (void __user *) UPT_ESI(&new->thread.regs.regs), + sizeof(info))) + goto out; + + ret = -EINVAL; + if (LDT_empty(&info)) + goto out; + + idx = info.entry_number; + + ret = set_tls_entry(new, &info, idx, 0); +out: + return ret; +} + +/* XXX: use do_get_thread_area to read the host value? I'm not at all sure! */ +static int get_tls_entry(struct task_struct* task, struct user_desc *info, int idx) +{ + struct thread_struct *t = &task->thread; + + if (!t->arch.tls_array) + goto clear; + + if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX) + return -EINVAL; + + if (!t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].present) + goto clear; + + *info = t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].tls; + +out: + /* Temporary debugging check, to make sure that things have been + * flushed. This could be triggered if load_TLS() failed. + */ + if (unlikely(task == current && !t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].flushed)) { + printk(KERN_ERR "get_tls_entry: task with pid %d got here " + "without flushed TLS.", current->pid); + } + + return 0; +clear: + /* When the TLS entry has not been set, the values read to user in the + * tls_array are 0 (because it's cleared at boot, see + * arch/i386/kernel/head.S:cpu_gdt_table). Emulate that. + */ + clear_user_desc(info); + info->entry_number = idx; + goto out; +} + +asmlinkage int sys_set_thread_area(struct user_desc __user *user_desc) +{ + struct user_desc info; + int idx, ret; + + if (copy_from_user(&info, user_desc, sizeof(info))) + return -EFAULT; + + idx = info.entry_number; + + if (idx == -1) { + idx = get_free_idx(current); + if (idx < 0) + return idx; + info.entry_number = idx; + /* Tell the user which slot we chose for him.*/ + if (put_user(idx, &user_desc->entry_number)) + return -EFAULT; + } + + ret = CHOOSE_MODE_PROC(do_set_thread_area_tt, do_set_thread_area_skas, &info); + if (ret) + return ret; + return set_tls_entry(current, &info, idx, 1); +} + +/* + * Perform set_thread_area on behalf of the traced child. + * Note: error handling is not done on the deferred load, and this differ from + * i386. However the only possible error are caused by bugs. + */ +int ptrace_set_thread_area(struct task_struct *child, int idx, + struct user_desc __user *user_desc) +{ + struct user_desc info; + + if (copy_from_user(&info, user_desc, sizeof(info))) + return -EFAULT; + + return set_tls_entry(child, &info, idx, 0); +} + +asmlinkage int sys_get_thread_area(struct user_desc __user *user_desc) +{ + struct user_desc info; + int idx, ret; + + if (get_user(idx, &user_desc->entry_number)) + return -EFAULT; + + ret = get_tls_entry(current, &info, idx); + if (ret < 0) + goto out; + + if (copy_to_user(user_desc, &info, sizeof(info))) + ret = -EFAULT; + +out: + return ret; +} + +/* + * Perform get_thread_area on behalf of the traced child. + */ +int ptrace_get_thread_area(struct task_struct *child, int idx, + struct user_desc __user *user_desc) +{ + struct user_desc info; + int ret; + + ret = get_tls_entry(child, &info, idx); + if (ret < 0) + goto out; + + if (copy_to_user(user_desc, &info, sizeof(info))) + ret = -EFAULT; +out: + return ret; +} |