diff options
Diffstat (limited to 'arch/s390/kernel/kprobes.c')
| -rw-r--r-- | arch/s390/kernel/kprobes.c | 138 |
1 files changed, 41 insertions, 97 deletions
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c index d2a71d872638..aae24dc75df6 100644 --- a/arch/s390/kernel/kprobes.c +++ b/arch/s390/kernel/kprobes.c @@ -7,6 +7,7 @@ * s390 port, used ppc64 as template. Mike Grundy <grundym@us.ibm.com> */ +#include <linux/moduleloader.h> #include <linux/kprobes.h> #include <linux/ptrace.h> #include <linux/preempt.h> @@ -21,6 +22,7 @@ #include <asm/set_memory.h> #include <asm/sections.h> #include <asm/dis.h> +#include "entry.h" DEFINE_PER_CPU(struct kprobe *, current_kprobe); DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); @@ -30,19 +32,32 @@ struct kretprobe_blackpoint kretprobe_blacklist[] = { }; DEFINE_INSN_CACHE_OPS(s390_insn); static int insn_page_in_use; -static char insn_page[PAGE_SIZE] __aligned(PAGE_SIZE); + +void *alloc_insn_page(void) +{ + void *page; + + page = module_alloc(PAGE_SIZE); + if (!page) + return NULL; + __set_memory((unsigned long) page, 1, SET_MEMORY_RO | SET_MEMORY_X); + return page; +} + +void free_insn_page(void *page) +{ + module_memfree(page); +} static void *alloc_s390_insn_page(void) { if (xchg(&insn_page_in_use, 1) == 1) return NULL; - set_memory_x((unsigned long) &insn_page, 1); - return &insn_page; + return &kprobes_insn_page; } static void free_s390_insn_page(void *page) { - set_memory_nx((unsigned long) page, 1); xchg(&insn_page_in_use, 0); } @@ -56,25 +71,29 @@ struct kprobe_insn_cache kprobe_s390_insn_slots = { static void copy_instruction(struct kprobe *p) { + kprobe_opcode_t insn[MAX_INSN_SIZE]; s64 disp, new_disp; u64 addr, new_addr; + unsigned int len; - memcpy(p->ainsn.insn, p->addr, insn_length(*p->addr >> 8)); - p->opcode = p->ainsn.insn[0]; - if (!probe_is_insn_relative_long(p->ainsn.insn)) - return; - /* - * For pc-relative instructions in RIL-b or RIL-c format patch the - * RI2 displacement field. We have already made sure that the insn - * slot for the patched instruction is within the same 2GB area - * as the original instruction (either kernel image or module area). - * Therefore the new displacement will always fit. - */ - disp = *(s32 *)&p->ainsn.insn[1]; - addr = (u64)(unsigned long)p->addr; - new_addr = (u64)(unsigned long)p->ainsn.insn; - new_disp = ((addr + (disp * 2)) - new_addr) / 2; - *(s32 *)&p->ainsn.insn[1] = new_disp; + len = insn_length(*p->addr >> 8); + memcpy(&insn, p->addr, len); + p->opcode = insn[0]; + if (probe_is_insn_relative_long(&insn[0])) { + /* + * For pc-relative instructions in RIL-b or RIL-c format patch + * the RI2 displacement field. We have already made sure that + * the insn slot for the patched instruction is within the same + * 2GB area as the original instruction (either kernel image or + * module area). Therefore the new displacement will always fit. + */ + disp = *(s32 *)&insn[1]; + addr = (u64)(unsigned long)p->addr; + new_addr = (u64)(unsigned long)p->ainsn.insn; + new_disp = ((addr + (disp * 2)) - new_addr) / 2; + *(s32 *)&insn[1] = new_disp; + } + s390_kernel_write(p->ainsn.insn, &insn, len); } NOKPROBE_SYMBOL(copy_instruction); @@ -228,6 +247,7 @@ NOKPROBE_SYMBOL(pop_kprobe); void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs) { ri->ret_addr = (kprobe_opcode_t *) regs->gprs[14]; + ri->fp = NULL; /* Replace the return addr with trampoline addr */ regs->gprs[14] = (unsigned long) &kretprobe_trampoline; @@ -331,83 +351,7 @@ static void __used kretprobe_trampoline_holder(void) */ static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) { - struct kretprobe_instance *ri; - struct hlist_head *head, empty_rp; - struct hlist_node *tmp; - unsigned long flags, orig_ret_address; - unsigned long trampoline_address; - kprobe_opcode_t *correct_ret_addr; - - INIT_HLIST_HEAD(&empty_rp); - kretprobe_hash_lock(current, &head, &flags); - - /* - * 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 than 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 - */ - ri = NULL; - orig_ret_address = 0; - correct_ret_addr = NULL; - trampoline_address = (unsigned long) &kretprobe_trampoline; - hlist_for_each_entry_safe(ri, tmp, head, hlist) { - if (ri->task != current) - /* another task is sharing our hash bucket */ - continue; - - orig_ret_address = (unsigned long) ri->ret_addr; - - 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; - } - - kretprobe_assert(ri, orig_ret_address, trampoline_address); - - correct_ret_addr = ri->ret_addr; - hlist_for_each_entry_safe(ri, tmp, head, hlist) { - if (ri->task != current) - /* another task is sharing our hash bucket */ - continue; - - orig_ret_address = (unsigned long) ri->ret_addr; - - if (ri->rp && ri->rp->handler) { - ri->ret_addr = correct_ret_addr; - ri->rp->handler(ri, regs); - } - - recycle_rp_inst(ri, &empty_rp); - - 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->psw.addr = orig_ret_address; - - kretprobe_hash_unlock(current, &flags); - - hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { - hlist_del(&ri->hlist); - kfree(ri); - } + regs->psw.addr = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL); /* * By returning a non-zero value, we are telling * kprobe_handler() that we don't want the post_handler |