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author | Greg KH <greg@press.(none)> | 2005-06-28 09:07:56 +0400 |
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committer | Greg Kroah-Hartman <gregkh@suse.de> | 2005-06-28 09:07:56 +0400 |
commit | 8644d2a42bdba2d513f71c07eaf1b6f9b718b8eb (patch) | |
tree | c43b6c2fdf1b68b66906a2de69446dcec0f9af6b /arch/i386 | |
parent | 1cde8a16815bd85c8137d1ea556398983c597c11 (diff) | |
parent | 99f95e5286df2f69edab8a04c7080d986ee4233b (diff) | |
download | linux-8644d2a42bdba2d513f71c07eaf1b6f9b718b8eb.tar.xz |
Merge rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Diffstat (limited to 'arch/i386')
-rw-r--r-- | arch/i386/kernel/kprobes.c | 133 | ||||
-rw-r--r-- | arch/i386/kernel/process.c | 29 | ||||
-rw-r--r-- | arch/i386/kernel/syscall_table.S | 2 |
3 files changed, 101 insertions, 63 deletions
diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c index 3762f6b35ab2..fc8b17521761 100644 --- a/arch/i386/kernel/kprobes.c +++ b/arch/i386/kernel/kprobes.c @@ -127,48 +127,23 @@ static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs) regs->eip = (unsigned long)&p->ainsn.insn; } -struct task_struct *arch_get_kprobe_task(void *ptr) -{ - return ((struct thread_info *) (((unsigned long) ptr) & - (~(THREAD_SIZE -1))))->task; -} - void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs) { unsigned long *sara = (unsigned long *)®s->esp; - struct kretprobe_instance *ri; - static void *orig_ret_addr; + struct kretprobe_instance *ri; + + if ((ri = get_free_rp_inst(rp)) != NULL) { + ri->rp = rp; + ri->task = current; + ri->ret_addr = (kprobe_opcode_t *) *sara; - /* - * Save the return address when the return probe hits - * the first time, and use it to populate the (krprobe - * instance)->ret_addr for subsequent return probes at - * the same addrress since stack address would have - * the kretprobe_trampoline by then. - */ - if (((void*) *sara) != kretprobe_trampoline) - orig_ret_addr = (void*) *sara; - - if ((ri = get_free_rp_inst(rp)) != NULL) { - ri->rp = rp; - ri->stack_addr = sara; - ri->ret_addr = orig_ret_addr; - add_rp_inst(ri); /* Replace the return addr with trampoline addr */ *sara = (unsigned long) &kretprobe_trampoline; - } else { - rp->nmissed++; - } -} -void arch_kprobe_flush_task(struct task_struct *tk) -{ - struct kretprobe_instance *ri; - while ((ri = get_rp_inst_tsk(tk)) != NULL) { - *((unsigned long *)(ri->stack_addr)) = - (unsigned long) ri->ret_addr; - recycle_rp_inst(ri); - } + add_rp_inst(ri); + } else { + rp->nmissed++; + } } /* @@ -286,36 +261,59 @@ no_kprobe: */ int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) { - struct task_struct *tsk; - struct kretprobe_instance *ri; - struct hlist_head *head; - struct hlist_node *node; - unsigned long *sara = ((unsigned long *) ®s->esp) - 1; - - tsk = arch_get_kprobe_task(sara); - head = kretprobe_inst_table_head(tsk); - - hlist_for_each_entry(ri, node, head, hlist) { - if (ri->stack_addr == sara && ri->rp) { - if (ri->rp->handler) - ri->rp->handler(ri, regs); - } - } - return 0; -} + struct kretprobe_instance *ri = NULL; + struct hlist_head *head; + struct hlist_node *node, *tmp; + unsigned long orig_ret_address = 0; + unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline; -void trampoline_post_handler(struct kprobe *p, struct pt_regs *regs, - unsigned long flags) -{ - struct kretprobe_instance *ri; - /* RA already popped */ - unsigned long *sara = ((unsigned long *)®s->esp) - 1; + head = kretprobe_inst_table_head(current); - while ((ri = get_rp_inst(sara))) { - regs->eip = (unsigned long)ri->ret_addr; + /* + * It is possible to have multiple instances associated with a given + * task either because an multiple functions in the call path + * have a return probe installed on them, and/or more then one return + * return probe was registered for a target function. + * + * We can handle this because: + * - instances are always inserted at the head of the list + * - when multiple return probes are registered for the same + * function, the first instance's ret_addr will point to the + * real return address, and all the rest will point to + * kretprobe_trampoline + */ + hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { + if (ri->task != current) + /* another task is sharing our hash bucket */ + continue; + + if (ri->rp && ri->rp->handler) + ri->rp->handler(ri, regs); + + orig_ret_address = (unsigned long)ri->ret_addr; recycle_rp_inst(ri); + + if (orig_ret_address != trampoline_address) + /* + * This is the real return address. Any other + * instances associated with this task are for + * other calls deeper on the call stack + */ + break; } - regs->eflags &= ~TF_MASK; + + BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address)); + regs->eip = orig_ret_address; + + unlock_kprobes(); + preempt_enable_no_resched(); + + /* + * By returning a non-zero value, we are telling + * kprobe_handler() that we have handled unlocking + * and re-enabling preemption. + */ + return 1; } /* @@ -403,8 +401,7 @@ static inline int post_kprobe_handler(struct pt_regs *regs) current_kprobe->post_handler(current_kprobe, regs, 0); } - if (current_kprobe->post_handler != trampoline_post_handler) - resume_execution(current_kprobe, regs); + resume_execution(current_kprobe, regs); regs->eflags |= kprobe_saved_eflags; /*Restore back the original saved kprobes variables and continue. */ @@ -534,3 +531,13 @@ int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) } return 0; } + +static struct kprobe trampoline_p = { + .addr = (kprobe_opcode_t *) &kretprobe_trampoline, + .pre_handler = trampoline_probe_handler +}; + +int __init arch_init(void) +{ + return register_kprobe(&trampoline_p); +} diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c index 5f8cfa6b7940..ba243a4cc119 100644 --- a/arch/i386/kernel/process.c +++ b/arch/i386/kernel/process.c @@ -617,6 +617,33 @@ handle_io_bitmap(struct thread_struct *next, struct tss_struct *tss) } /* + * This function selects if the context switch from prev to next + * has to tweak the TSC disable bit in the cr4. + */ +static inline void disable_tsc(struct task_struct *prev_p, + struct task_struct *next_p) +{ + struct thread_info *prev, *next; + + /* + * gcc should eliminate the ->thread_info dereference if + * has_secure_computing returns 0 at compile time (SECCOMP=n). + */ + prev = prev_p->thread_info; + next = next_p->thread_info; + + if (has_secure_computing(prev) || has_secure_computing(next)) { + /* slow path here */ + if (has_secure_computing(prev) && + !has_secure_computing(next)) { + write_cr4(read_cr4() & ~X86_CR4_TSD); + } else if (!has_secure_computing(prev) && + has_secure_computing(next)) + write_cr4(read_cr4() | X86_CR4_TSD); + } +} + +/* * switch_to(x,yn) should switch tasks from x to y. * * We fsave/fwait so that an exception goes off at the right time @@ -695,6 +722,8 @@ struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct tas if (unlikely(prev->io_bitmap_ptr || next->io_bitmap_ptr)) handle_io_bitmap(next, tss); + disable_tsc(prev_p, next_p); + return prev_p; } diff --git a/arch/i386/kernel/syscall_table.S b/arch/i386/kernel/syscall_table.S index 442a6e937b19..3db9a04aec6e 100644 --- a/arch/i386/kernel/syscall_table.S +++ b/arch/i386/kernel/syscall_table.S @@ -289,3 +289,5 @@ ENTRY(sys_call_table) .long sys_add_key .long sys_request_key .long sys_keyctl + .long sys_ioprio_set + .long sys_ioprio_get /* 290 */ |