diff options
author | Greg KH <greg@press.(none)> | 2005-06-27 22:07:56 -0700 |
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committer | Greg Kroah-Hartman <gregkh@suse.de> | 2005-06-27 22:07:56 -0700 |
commit | 8644d2a42bdba2d513f71c07eaf1b6f9b718b8eb (patch) | |
tree | c43b6c2fdf1b68b66906a2de69446dcec0f9af6b /arch/x86_64 | |
parent | 1cde8a16815bd85c8137d1ea556398983c597c11 (diff) | |
parent | 99f95e5286df2f69edab8a04c7080d986ee4233b (diff) |
Merge rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Diffstat (limited to 'arch/x86_64')
-rw-r--r-- | arch/x86_64/kernel/kprobes.c | 236 | ||||
-rw-r--r-- | arch/x86_64/kernel/process.c | 29 |
2 files changed, 95 insertions, 170 deletions
diff --git a/arch/x86_64/kernel/kprobes.c b/arch/x86_64/kernel/kprobes.c index 4e680f87a75f..acd2a778ebe6 100644 --- a/arch/x86_64/kernel/kprobes.c +++ b/arch/x86_64/kernel/kprobes.c @@ -38,7 +38,7 @@ #include <linux/string.h> #include <linux/slab.h> #include <linux/preempt.h> -#include <linux/moduleloader.h> + #include <asm/cacheflush.h> #include <asm/pgtable.h> #include <asm/kdebug.h> @@ -51,8 +51,6 @@ static struct kprobe *kprobe_prev; static unsigned long kprobe_status_prev, kprobe_old_rflags_prev, kprobe_saved_rflags_prev; static struct pt_regs jprobe_saved_regs; static long *jprobe_saved_rsp; -static kprobe_opcode_t *get_insn_slot(void); -static void free_insn_slot(kprobe_opcode_t *slot); void jprobe_return_end(void); /* copy of the kernel stack at the probe fire time */ @@ -274,48 +272,23 @@ static void prepare_singlestep(struct kprobe *p, struct pt_regs *regs) regs->rip = (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 *)regs->rsp; - 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++; + } } /* @@ -428,36 +401,59 @@ 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 *)regs->rsp - 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 *)regs->rsp) - 1; + head = kretprobe_inst_table_head(current); - while ((ri = get_rp_inst(sara))) { - regs->rip = (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->rip = 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; } /* @@ -550,8 +546,7 @@ 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_rflags; /* Restore the original saved kprobes variables and continue. */ @@ -682,111 +677,12 @@ int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) return 0; } -/* - * kprobe->ainsn.insn points to the copy of the instruction to be single-stepped. - * By default on x86_64, pages we get from kmalloc or vmalloc are not - * executable. Single-stepping an instruction on such a page yields an - * oops. So instead of storing the instruction copies in their respective - * kprobe objects, we allocate a page, map it executable, and store all the - * instruction copies there. (We can allocate additional pages if somebody - * inserts a huge number of probes.) Each page can hold up to INSNS_PER_PAGE - * instruction slots, each of which is MAX_INSN_SIZE*sizeof(kprobe_opcode_t) - * bytes. - */ -#define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE*sizeof(kprobe_opcode_t))) -struct kprobe_insn_page { - struct hlist_node hlist; - kprobe_opcode_t *insns; /* page of instruction slots */ - char slot_used[INSNS_PER_PAGE]; - int nused; +static struct kprobe trampoline_p = { + .addr = (kprobe_opcode_t *) &kretprobe_trampoline, + .pre_handler = trampoline_probe_handler }; -static struct hlist_head kprobe_insn_pages; - -/** - * get_insn_slot() - Find a slot on an executable page for an instruction. - * We allocate an executable page if there's no room on existing ones. - */ -static kprobe_opcode_t *get_insn_slot(void) -{ - struct kprobe_insn_page *kip; - struct hlist_node *pos; - - hlist_for_each(pos, &kprobe_insn_pages) { - kip = hlist_entry(pos, struct kprobe_insn_page, hlist); - if (kip->nused < INSNS_PER_PAGE) { - int i; - for (i = 0; i < INSNS_PER_PAGE; i++) { - if (!kip->slot_used[i]) { - kip->slot_used[i] = 1; - kip->nused++; - return kip->insns + (i*MAX_INSN_SIZE); - } - } - /* Surprise! No unused slots. Fix kip->nused. */ - kip->nused = INSNS_PER_PAGE; - } - } - - /* All out of space. Need to allocate a new page. Use slot 0.*/ - kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL); - if (!kip) { - return NULL; - } - - /* - * For the %rip-relative displacement fixups to be doable, we - * need our instruction copy to be within +/- 2GB of any data it - * might access via %rip. That is, within 2GB of where the - * kernel image and loaded module images reside. So we allocate - * a page in the module loading area. - */ - kip->insns = module_alloc(PAGE_SIZE); - if (!kip->insns) { - kfree(kip); - return NULL; - } - INIT_HLIST_NODE(&kip->hlist); - hlist_add_head(&kip->hlist, &kprobe_insn_pages); - memset(kip->slot_used, 0, INSNS_PER_PAGE); - kip->slot_used[0] = 1; - kip->nused = 1; - return kip->insns; -} - -/** - * free_insn_slot() - Free instruction slot obtained from get_insn_slot(). - */ -static void free_insn_slot(kprobe_opcode_t *slot) +int __init arch_init(void) { - struct kprobe_insn_page *kip; - struct hlist_node *pos; - - hlist_for_each(pos, &kprobe_insn_pages) { - kip = hlist_entry(pos, struct kprobe_insn_page, hlist); - if (kip->insns <= slot - && slot < kip->insns+(INSNS_PER_PAGE*MAX_INSN_SIZE)) { - int i = (slot - kip->insns) / MAX_INSN_SIZE; - kip->slot_used[i] = 0; - kip->nused--; - if (kip->nused == 0) { - /* - * Page is no longer in use. Free it unless - * it's the last one. We keep the last one - * so as not to have to set it up again the - * next time somebody inserts a probe. - */ - hlist_del(&kip->hlist); - if (hlist_empty(&kprobe_insn_pages)) { - INIT_HLIST_NODE(&kip->hlist); - hlist_add_head(&kip->hlist, - &kprobe_insn_pages); - } else { - module_free(NULL, kip->insns); - kfree(kip); - } - } - return; - } - } + return register_kprobe(&trampoline_p); } diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c index 1d91271796e5..7577f9d7a75d 100644 --- a/arch/x86_64/kernel/process.c +++ b/arch/x86_64/kernel/process.c @@ -482,6 +482,33 @@ out: } /* + * 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); + } +} + +/* * This special macro can be used to load a debugging register */ #define loaddebug(thread,r) set_debug(thread->debugreg ## r, r) @@ -599,6 +626,8 @@ struct task_struct *__switch_to(struct task_struct *prev_p, struct task_struct * } } + disable_tsc(prev_p, next_p); + return prev_p; } |