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linux-2.6-s390-kprobes.patch
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File linux-2.6-s390-kprobes.patch of Package kernel
Signed-off-by: Michael Grundy <grundym@us.ibm.com> Signed-off-by: David Wilder <dwilder@us.ibm.com> diff -Naur linux-2.6.18-rc1/arch/s390/Kconfig linux-2.6.18-rc1.s390-kprob/arch/s390/Kconfig --- linux-2.6.18-rc1/arch/s390/Kconfig 2006-07-06 11:05:42.000000000 -0700 +++ linux-2.6.18-rc1.s390-kprob/arch/s390/Kconfig 2006-07-11 15:16:24.000000000 -0700 @@ -490,8 +490,22 @@ source "fs/Kconfig" +menu "Instrumentation Support" + depends on EXPERIMENTAL + source "arch/s390/oprofile/Kconfig" +config KPROBES + bool "Kprobes (EXPERIMENTAL)" + depends on EXPERIMENTAL && MODULES + help + Kprobes allows you to trap at almost any kernel address and + execute a callback function. register_kprobe() establishes + a probepoint and specifies the callback. Kprobes is useful + for kernel debugging, non-intrusive instrumentation and testing. + If in doubt, say "N". +endmenu + source "arch/s390/Kconfig.debug" source "security/Kconfig" diff -Naur linux-2.6.18-rc1/arch/s390/kernel/entry64.S linux-2.6.18-rc1.s390-kprob/arch/s390/kernel/entry64.S --- linux-2.6.18-rc1/arch/s390/kernel/entry64.S 2006-07-06 11:05:42.000000000 -0700 +++ linux-2.6.18-rc1.s390-kprob/arch/s390/kernel/entry64.S 2006-07-11 15:16:24.000000000 -0700 @@ -518,6 +518,8 @@ #endif lg %r9,__LC_THREAD_INFO # load pointer to thread_info struct lg %r1,__TI_task(%r9) + tm __LC_PGM_OLD_PSW+1(%r15),0x01 # kernel per event ? + jz kernel_per mvc __THREAD_per+__PER_atmid(2,%r1),__LC_PER_ATMID mvc __THREAD_per+__PER_address(8,%r1),__LC_PER_ADDRESS mvc __THREAD_per+__PER_access_id(1,%r1),__LC_PER_ACCESS_ID @@ -553,6 +555,16 @@ stosm __SF_EMPTY(%r15),0x03 # reenable interrupts j sysc_do_svc +# +# per was called from kernel, must be kprobes +# +kernel_per: + lhi %r0,__LC_PGM_OLD_PSW + sth %r0,SP_TRAP(%r15) # set trap indication to pgm check + la %r2,SP_PTREGS(%r15) # address of register-save area + larl %r14,sysc_leave # load adr. of system ret, no work + jg do_single_step # branch to do_single_step + /* * IO interrupt handler routine */ diff -Naur linux-2.6.18-rc1/arch/s390/kernel/entry.S linux-2.6.18-rc1.s390-kprob/arch/s390/kernel/entry.S --- linux-2.6.18-rc1/arch/s390/kernel/entry.S 2006-07-06 11:05:42.000000000 -0700 +++ linux-2.6.18-rc1.s390-kprob/arch/s390/kernel/entry.S 2006-07-11 15:16:24.000000000 -0700 @@ -505,6 +505,8 @@ mvc __THREAD_per+__PER_address(4,%r1),__LC_PER_ADDRESS mvc __THREAD_per+__PER_access_id(1,%r1),__LC_PER_ACCESS_ID oi __TI_flags+3(%r9),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP + tm __LC_PGM_OLD_PSW+1(%r15),0x01 # kernel per event ? + bz BASED(kernel_per) l %r3,__LC_PGM_ILC # load program interruption code la %r8,0x7f nr %r8,%r3 # clear per-event-bit and ilc @@ -536,6 +538,16 @@ stosm __SF_EMPTY(%r15),0x03 # reenable interrupts b BASED(sysc_do_svc) +# +# per was called from kernel, must be kprobes +# +kernel_per: + mvi SP_TRAP+1(%r15),0x28 # set trap indication to pgm check + la %r2,SP_PTREGS(%r15) # address of register-save area + l %r1,BASED(.Lhandle_per) # load adr. of per handler + la %r14,BASED(sysc_leave) # load adr. of system return + br %r1 # branch to do_single_step + /* * IO interrupt handler routine */ diff -Naur linux-2.6.18-rc1/arch/s390/kernel/kprobes.c linux-2.6.18-rc1.s390-kprob/arch/s390/kernel/kprobes.c --- linux-2.6.18-rc1/arch/s390/kernel/kprobes.c 1969-12-31 16:00:00.000000000 -0800 +++ linux-2.6.18-rc1.s390-kprob/arch/s390/kernel/kprobes.c 2006-07-11 15:16:24.000000000 -0700 @@ -0,0 +1,682 @@ +/* + * Kernel Probes (KProbes) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright (C) IBM Corporation, 2002, 2006 + * + * s390 port, used ppc64 as template. Mike Grundy <grundym@us.ibm.com> + */ + +#include <linux/kprobes.h> +#include <linux/ptrace.h> +#include <linux/preempt.h> +#include <linux/stop_machine.h> +#include <asm/cacheflush.h> +#include <asm/kdebug.h> +#include <asm/sections.h> +#include <asm/uaccess.h> +#include <linux/module.h> + +DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; +DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); + +int __kprobes arch_prepare_kprobe(struct kprobe *p) +{ + /* Make sure the probe isn't going on a difficult instruction */ + if (is_prohibited_opcode((kprobe_opcode_t *) p->addr)) + return -EINVAL; + + if ((unsigned long)p->addr & 0x01) { + printk("Attempt to register kprobe at an unaligned address\n"); + return -EINVAL; + } + + /* Use the get_insn_slot() facility for correctness */ + if (!(p->ainsn.insn = get_insn_slot())) + return -ENOMEM; + + memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); + + get_instruction_type(&p->ainsn); + p->opcode = *p->addr; + return 0; +} + +int __kprobes is_prohibited_opcode(kprobe_opcode_t *instruction) +{ + switch (*(__u8 *) instruction) { + case 0x0c: /* bassm */ + case 0x0b: /* bsm */ + case 0x83: /* diag */ + case 0x44: /* ex */ + return -EINVAL; + } + switch (*(__u16 *) instruction) { + case 0x0101: /* pr */ + case 0xb25a: /* bsa */ + case 0xb240: /* bakr */ + case 0xb258: /* bsg */ + case 0xb218: /* pc */ + case 0xb228: /* pt */ + return -EINVAL; + } + return 0; +} + +void __kprobes get_instruction_type(struct arch_specific_insn *ainsn) +{ + /* default fixup method */ + ainsn->fixup = FIXUP_PSW_NORMAL; + + /* save r1 operand */ + ainsn->reg = (*ainsn->insn & 0xf0) >> 4; + + /* save the instruction length (pop 5-5) in bytes */ + switch (*(__u8 *) (ainsn->insn) >> 4) { + case 0: + ainsn->ilen = 2; + break; + case 1: + case 2: + ainsn->ilen = 4; + break; + case 3: + ainsn->ilen = 6; + break; + } + + switch (*(__u8 *) ainsn->insn) { + case 0x05: /* balr */ + case 0x0d: /* basr */ + ainsn->fixup = FIXUP_RETURN_REGISTER; + /* if r2 = 0, no branch will be taken */ + if ((*ainsn->insn & 0x0f) == 0) + ainsn->fixup |= FIXUP_BRANCH_NOT_TAKEN; + break; + case 0x06: /* bctr */ + case 0x07: /* bcr */ + ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN; + break; + case 0x45: /* bal */ + case 0x4d: /* bas */ + ainsn->fixup = FIXUP_RETURN_REGISTER; + break; + case 0x47: /* bc */ + case 0x46: /* bct */ + case 0x86: /* bxh */ + case 0x87: /* bxle */ + ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN; + break; + case 0x82: /* lpsw */ + ainsn->fixup = FIXUP_NOT_REQUIRED; + break; + case 0xb2: /* lpswe */ + if (*(((__u8 *) ainsn->insn) + 1) == 0xb2) { + ainsn->fixup = FIXUP_NOT_REQUIRED; + } + break; + case 0xa7: /* bras */ + if ((*ainsn->insn & 0x0f) == 0x05) { + ainsn->fixup |= FIXUP_RETURN_REGISTER; + } + break; + case 0xc0: + if ((*ainsn->insn & 0x0f) == 0x00) /* larl */ + ainsn->fixup = FIXUP_RETURN_REGISTER; + if ((*ainsn->insn & 0x0f) == 0x05) /* brasl*/ + ainsn->fixup |= FIXUP_RETURN_REGISTER; + break; + case 0xeb: + if (*(((__u8 *) ainsn->insn) + 5 ) == 0x44 || /* bxhg */ + *(((__u8 *) ainsn->insn) + 5) == 0x45) {/* bxleg */ + ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN; + } + break; + case 0xe3: /* bctg */ + if (*(((__u8 *) ainsn->insn) + 5) == 0x46) { + ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN; + } + break; + } +} + +static int __kprobes swap_instruction(void *aref) +{ + struct ins_replace_args *args = aref; + int err = 0; + asm volatile( + "0: mvc 0(2,%1),0(%2)\n" + "1:\n" +#ifndef __s390x__ + ".section .fixup,\"ax\"\n" + "2: lhi %0,%3\n" + " bras 1,3f\n" + " .long 1b\n" + "3: l 1,0(1)\n" + " br 1\n" + ".previous\n" + ".section __ex_table,\"a\"\n" + " .align 4\n" + " .long 0b,2b\n" + ".previous" +#else /* __s390x__ */ + ".section .fixup,\"ax\"\n" + "2: lghi %0,%3\n" + " jg 1b\n" + ".previous\n" + ".section __ex_table,\"a\"\n" + " .align 8\n" + " .quad 0b,2b\n" + ".previous" +#endif /* __s390x__ */ + : "+&d" (err) + : "a" (args->ptr), "a" (&(args->new)), + "K" (-EFAULT), "m" (args->new) + : "cc" +#ifndef __s390x__ + ,"1" +#endif + ); + + return err; +} +void __kprobes arch_arm_kprobe(struct kprobe *p) +{ + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + unsigned long status = kcb->kprobe_status; + struct ins_replace_args args; + + args.ptr = p->addr; + args.old = p->opcode; + args.new = BREAKPOINT_INSTRUCTION; + + kcb->kprobe_status = KPROBE_SWAP_INST; + stop_machine_run(swap_instruction, &args, NR_CPUS); + kcb->kprobe_status = status; +} + +void __kprobes arch_disarm_kprobe(struct kprobe *p) +{ + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + unsigned long status = kcb->kprobe_status; + struct ins_replace_args args; + + args.ptr = p->addr; + args.old = BREAKPOINT_INSTRUCTION; + args.new = p->opcode; + + kcb->kprobe_status = KPROBE_SWAP_INST; + stop_machine_run(swap_instruction, &args, NR_CPUS); + kcb->kprobe_status = status; +} + +void __kprobes arch_remove_kprobe(struct kprobe *p) +{ + mutex_lock(&kprobe_mutex); + free_insn_slot(p->ainsn.insn); + mutex_unlock(&kprobe_mutex); +} + +static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) +{ + per_cr_bits kprobe_per_regs[1]; + + memset(kprobe_per_regs, 0, sizeof(per_cr_bits)); + regs->psw.addr = (unsigned long)p->ainsn.insn | PSW_ADDR_AMODE; + + /* Set up the per control reg info, will pass to lctl */ + kprobe_per_regs[0].em_instruction_fetch = 1; + kprobe_per_regs[0].starting_addr = (unsigned long)p->ainsn.insn; + kprobe_per_regs[0].ending_addr = (unsigned long)p->ainsn.insn + 1; + + /* Set the PER control regs, turns on single step for this address */ + __ctl_load(kprobe_per_regs, 9, 11); + regs->psw.mask |= PSW_MASK_PER; + regs->psw.mask &= ~(PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK); +} + +static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) +{ + kcb->prev_kprobe.kp = kprobe_running(); + kcb->prev_kprobe.status = kcb->kprobe_status; + kcb->prev_kprobe.kprobe_saved_imask = kcb->kprobe_saved_imask; + memcpy(kcb->prev_kprobe.kprobe_saved_ctl, kcb->kprobe_saved_ctl, + sizeof(kcb->kprobe_saved_ctl)); +} + +static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) +{ + __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp; + kcb->kprobe_status = kcb->prev_kprobe.status; + kcb->kprobe_saved_imask = kcb->prev_kprobe.kprobe_saved_imask; + memcpy(kcb->kprobe_saved_ctl, kcb->prev_kprobe.kprobe_saved_ctl, + sizeof(kcb->kprobe_saved_ctl)); +} + +static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, + struct kprobe_ctlblk *kcb) +{ + __get_cpu_var(current_kprobe) = p; + /* Save the interrupt and per flags */ + kcb->kprobe_saved_imask = regs->psw.mask & + (PSW_MASK_PER | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK); + /* Save the control regs that govern PER */ + __ctl_store(kcb->kprobe_saved_ctl, 9, 11); +} + +/* Called with kretprobe_lock held */ +void __kprobes arch_prepare_kretprobe(struct kretprobe *rp, + struct pt_regs *regs) +{ + struct kretprobe_instance *ri; + + if ((ri = get_free_rp_inst(rp)) != NULL) { + ri->rp = rp; + ri->task = current; + ri->ret_addr = (kprobe_opcode_t *) regs->gprs[14]; + + /* Replace the return addr with trampoline addr */ + regs->gprs[14] = (unsigned long)&kretprobe_trampoline; + + add_rp_inst(ri); + } else { + rp->nmissed++; + } +} + +static int __kprobes kprobe_handler(struct pt_regs *regs) +{ + struct kprobe *p; + int ret = 0; + unsigned long *addr = (unsigned long *) + ((regs->psw.addr & PSW_ADDR_INSN) - 2); + struct kprobe_ctlblk *kcb; + + /* + * We don't want to be preempted for the entire + * duration of kprobe processing + */ + preempt_disable(); + kcb = get_kprobe_ctlblk(); + + /* Check we're not actually recursing */ + if (kprobe_running()) { + p = get_kprobe(addr); + if (p) { + if (kcb->kprobe_status == KPROBE_HIT_SS && + *p->ainsn.insn == BREAKPOINT_INSTRUCTION) { + regs->psw.mask &= ~PSW_MASK_PER; + regs->psw.mask |= kcb->kprobe_saved_imask; + goto no_kprobe; + } + /* We have reentered the kprobe_handler(), since + * another probe was hit while within the handler. + * We here save the original kprobes variables and + * just single step on the instruction of the new probe + * without calling any user handlers. + */ + save_previous_kprobe(kcb); + set_current_kprobe(p, regs, kcb); + kprobes_inc_nmissed_count(p); + prepare_singlestep(p, regs); + kcb->kprobe_status = KPROBE_REENTER; + return 1; + } else { + p = __get_cpu_var(current_kprobe); + if (p->break_handler && p->break_handler(p, regs)) { + goto ss_probe; + } + } + goto no_kprobe; + } + + p = get_kprobe(addr); + if (!p) { + if (*addr != BREAKPOINT_INSTRUCTION) { + /* + * The breakpoint instruction was removed right + * after we hit it. Another cpu has removed + * either a probepoint or a debugger breakpoint + * at this address. In either case, no further + * handling of this interrupt is appropriate. + * + */ + ret = 1; + } + /* Not one of ours: let kernel handle it */ + goto no_kprobe; + } + + kcb->kprobe_status = KPROBE_HIT_ACTIVE; + set_current_kprobe(p, regs, kcb); + if (p->pre_handler && p->pre_handler(p, regs)) + /* handler has already set things up, so skip ss setup */ + return 1; + +ss_probe: + prepare_singlestep(p, regs); + kcb->kprobe_status = KPROBE_HIT_SS; + return 1; + +no_kprobe: + preempt_enable_no_resched(); + return ret; +} + +/* + * Function return probe trampoline: + * - init_kprobes() establishes a probepoint here + * - When the probed function returns, this probe + * causes the handlers to fire + */ +void kretprobe_trampoline_holder(void) +{ + asm volatile (".global kretprobe_trampoline\n" + "kretprobe_trampoline:\n" "bcr 0,0\n"); +} + +/* + * Called when the probe at kretprobe trampoline is hit + */ +int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) +{ + struct kretprobe_instance *ri = NULL; + struct hlist_head *head; + struct hlist_node *node, *tmp; + unsigned long flags, orig_ret_address = 0; + unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline; + + spin_lock_irqsave(&kretprobe_lock, flags); + head = kretprobe_inst_table_head(current); + + /* + * 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; + } + } + BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address)); + regs->psw.addr = orig_ret_address | PSW_ADDR_AMODE; + + reset_current_kprobe(); + spin_unlock_irqrestore(&kretprobe_lock, flags); + preempt_enable_no_resched(); + + /* + * By returning a non-zero value, we are telling + * kprobe_handler() that we don't want the post_handler + * to run (and have re-enabled preemption) + */ + return 1; +} + +/* + * Called after single-stepping. p->addr is the address of the + * instruction whose first byte has been replaced by the "breakpoint" + * instruction. To avoid the SMP problems that can occur when we + * temporarily put back the original opcode to single-step, we + * single-stepped a copy of the instruction. The address of this + * copy is p->ainsn.insn. + */ +static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs) +{ + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + + regs->psw.addr &= PSW_ADDR_INSN; + + if (p->ainsn.fixup & FIXUP_PSW_NORMAL) + regs->psw.addr = (unsigned long)p->addr + + ((unsigned long)regs->psw.addr - + (unsigned long)p->ainsn.insn); + + if (p->ainsn.fixup & FIXUP_BRANCH_NOT_TAKEN) + if ((unsigned long)regs->psw.addr - + (unsigned long)p->ainsn.insn == p->ainsn.ilen) + regs->psw.addr = (unsigned long)p->addr + p->ainsn.ilen; + + if (p->ainsn.fixup & FIXUP_RETURN_REGISTER) + regs->gprs[p->ainsn.reg] = ((unsigned long)p->addr + + (regs->gprs[p->ainsn.reg] - + (unsigned long)p->ainsn.insn)) + | PSW_ADDR_AMODE; + + regs->psw.addr |= PSW_ADDR_AMODE; + /* turn off PER mode */ + regs->psw.mask &= ~PSW_MASK_PER; + /* Restore the original per control regs */ + __ctl_load(kcb->kprobe_saved_ctl, 9, 11); + regs->psw.mask |= kcb->kprobe_saved_imask; +} + +static int __kprobes post_kprobe_handler(struct pt_regs *regs) +{ + struct kprobe *cur = kprobe_running(); + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + + if (!cur) + return 0; + + if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { + kcb->kprobe_status = KPROBE_HIT_SSDONE; + cur->post_handler(cur, regs, 0); + } + + resume_execution(cur, regs); + + /*Restore back the original saved kprobes variables and continue. */ + if (kcb->kprobe_status == KPROBE_REENTER) { + restore_previous_kprobe(kcb); + goto out; + } + reset_current_kprobe(); +out: + preempt_enable_no_resched(); + + /* + * if somebody else is singlestepping across a probe point, psw mask + * will have PER set, in which case, continue the remaining processing + * of do_single_step, as if this is not a probe hit. + */ + if (regs->psw.mask & PSW_MASK_PER) { + return 0; + } + + return 1; +} + +static int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) +{ + struct kprobe *cur = kprobe_running(); + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + const struct exception_table_entry *entry; + + switch(kcb->kprobe_status) { + case KPROBE_SWAP_INST: + /* We are here because the instruction replacement failed */ + return 0; + case KPROBE_HIT_SS: + case KPROBE_REENTER: + /* + * We are here because the instruction being single + * stepped caused a page fault. We reset the current + * kprobe and the nip points back to the probe address + * and allow the page fault handler to continue as a + * normal page fault. + */ + regs->psw.addr = (unsigned long)cur->addr | PSW_ADDR_AMODE; + regs->psw.mask &= ~PSW_MASK_PER; + regs->psw.mask |= kcb->kprobe_saved_imask; + if (kcb->kprobe_status == KPROBE_REENTER) + restore_previous_kprobe(kcb); + else + reset_current_kprobe(); + preempt_enable_no_resched(); + break; + case KPROBE_HIT_ACTIVE: + case KPROBE_HIT_SSDONE: + /* + * We increment the nmissed count for accounting, + * we can also use npre/npostfault count for accouting + * these specific fault cases. + */ + kprobes_inc_nmissed_count(cur); + + /* + * We come here because instructions in the pre/post + * handler caused the page_fault, this could happen + * if handler tries to access user space by + * copy_from_user(), get_user() etc. Let the + * user-specified handler try to fix it first. + */ + if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) + return 1; + + /* + * In case the user-specified fault handler returned + * zero, try to fix up. + */ + entry = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN); + if (entry) { + regs->psw.addr = entry->fixup | PSW_ADDR_AMODE; + return 1; + } + + /* + * fixup_exception() could not handle it, + * Let do_page_fault() fix it. + */ + break; + default: + break; + } + return 0; +} + +/* + * Wrapper routine to for handling exceptions. + */ +int __kprobes kprobe_exceptions_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + struct die_args *args = (struct die_args *)data; + int ret = NOTIFY_DONE; + + switch (val) { + case DIE_BPT: + if (kprobe_handler(args->regs)) + ret = NOTIFY_STOP; + break; + case DIE_SSTEP: + if (post_kprobe_handler(args->regs)) + ret = NOTIFY_STOP; + break; + case DIE_TRAP: + case DIE_PAGE_FAULT: + /* kprobe_running() needs smp_processor_id() */ + preempt_disable(); + if (kprobe_running() && + kprobe_fault_handler(args->regs, args->trapnr)) + ret = NOTIFY_STOP; + preempt_enable(); + break; + default: + break; + } + return ret; +} + +int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) +{ + struct jprobe *jp = container_of(p, struct jprobe, kp); + unsigned long addr; + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + + memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs)); + + /* setup return addr to the jprobe handler routine */ + regs->psw.addr = (unsigned long)(jp->entry) | PSW_ADDR_AMODE; + + /* r14 is the function return address */ + kcb->jprobe_saved_r14 = (unsigned long)regs->gprs[14]; + /* r15 is the stack pointer */ + kcb->jprobe_saved_r15 = (unsigned long)regs->gprs[15]; + addr = (unsigned long)kcb->jprobe_saved_r15; + + memcpy(kcb->jprobes_stack, (kprobe_opcode_t *) addr, + MIN_STACK_SIZE(addr)); + return 1; +} + +void __kprobes jprobe_return(void) +{ + asm volatile (".word 0x0002"); +} + +void __kprobes jprobe_return_end(void) +{ + asm volatile ("bcr 0,0"); +} + +int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) +{ + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_r15); + + /* Put the regs back */ + memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs)); + /* put the stack back */ + memcpy((kprobe_opcode_t *) stack_addr, kcb->jprobes_stack, + MIN_STACK_SIZE(stack_addr)); + preempt_enable_no_resched(); + return 1; +} + +static struct kprobe trampoline_p = { + .addr = (kprobe_opcode_t *) & kretprobe_trampoline, + .pre_handler = trampoline_probe_handler +}; + +int __init arch_init_kprobes(void) +{ + return register_kprobe(&trampoline_p); +} diff -Naur linux-2.6.18-rc1/arch/s390/kernel/Makefile linux-2.6.18-rc1.s390-kprob/arch/s390/kernel/Makefile --- linux-2.6.18-rc1/arch/s390/kernel/Makefile 2006-07-06 11:05:42.000000000 -0700 +++ linux-2.6.18-rc1.s390-kprob/arch/s390/kernel/Makefile 2006-07-11 15:16:24.000000000 -0700 @@ -22,6 +22,7 @@ obj-$(CONFIG_VIRT_TIMER) += vtime.o obj-$(CONFIG_STACKTRACE) += stacktrace.o +obj-$(CONFIG_KPROBES) += kprobes.o # Kexec part S390_KEXEC_OBJS := machine_kexec.o crash.o diff -Naur linux-2.6.18-rc1/arch/s390/kernel/traps.c linux-2.6.18-rc1.s390-kprob/arch/s390/kernel/traps.c --- linux-2.6.18-rc1/arch/s390/kernel/traps.c 2006-07-06 11:05:42.000000000 -0700 +++ linux-2.6.18-rc1.s390-kprob/arch/s390/kernel/traps.c 2006-07-11 15:16:24.000000000 -0700 @@ -29,6 +29,7 @@ #include <linux/module.h> #include <linux/kallsyms.h> #include <linux/reboot.h> +#include <linux/kprobes.h> #include <asm/system.h> #include <asm/uaccess.h> @@ -39,6 +40,7 @@ #include <asm/s390_ext.h> #include <asm/lowcore.h> #include <asm/debug.h> +#include <asm/kdebug.h> /* Called from entry.S only */ extern void handle_per_exception(struct pt_regs *regs); @@ -74,6 +76,20 @@ static int kstack_depth_to_print = 20; #endif /* CONFIG_64BIT */ +ATOMIC_NOTIFIER_HEAD(s390die_chain); + +int register_die_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_register(&s390die_chain, nb); +} +EXPORT_SYMBOL(register_die_notifier); + +int unregister_die_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_unregister(&s390die_chain, nb); +} +EXPORT_SYMBOL(unregister_die_notifier); + /* * For show_trace we have tree different stack to consider: * - the panic stack which is used if the kernel stack has overflown @@ -305,8 +321,9 @@ #endif } -static void inline do_trap(long interruption_code, int signr, char *str, - struct pt_regs *regs, siginfo_t *info) +static void __kprobes inline do_trap(long interruption_code, int signr, + char *str, struct pt_regs *regs, + siginfo_t *info) { /* * We got all needed information from the lowcore and can @@ -315,6 +332,10 @@ if (regs->psw.mask & PSW_MASK_PSTATE) local_irq_enable(); + if (notify_die(DIE_TRAP, str, regs, interruption_code, + interruption_code, signr) == NOTIFY_STOP) + return; + if (regs->psw.mask & PSW_MASK_PSTATE) { struct task_struct *tsk = current; @@ -357,8 +357,11 @@ static inline void __user *get_check_add return (void __user *)((regs->psw.addr-S390_lowcore.pgm_ilc) & PSW_ADDR_INSN); } -void do_single_step(struct pt_regs *regs) +void __kprobes do_single_step(struct pt_regs *regs) { + if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP) + return; + if (tracehook_consider_fatal_signal(current, SIGTRAP)) force_sig(SIGTRAP, current); } @@ -463,8 +488,15 @@ #endif } else signal = SIGILL; - } else - signal = SIGILL; + } else { + /* + * If we get an illegal op in kernel mode, send it through the + * kprobes notifier. If kprobes doesn't pick it up, SIGILL + */ + if (notify_die(DIE_BPT, "bpt", regs, interruption_code, + 3, SIGTRAP) != NOTIFY_STOP) + signal = SIGILL; + } #ifdef CONFIG_MATHEMU if (signal == SIGFPE) diff -Naur linux-2.6.18-rc1/arch/s390/kernel/vmlinux.lds.S linux-2.6.18-rc1.s390-kprob/arch/s390/kernel/vmlinux.lds.S --- linux-2.6.18-rc1/arch/s390/kernel/vmlinux.lds.S 2006-07-06 11:05:42.000000000 -0700 +++ linux-2.6.18-rc1.s390-kprob/arch/s390/kernel/vmlinux.lds.S 2006-07-11 15:16:24.000000000 -0700 @@ -24,6 +24,7 @@ *(.text) SCHED_TEXT LOCK_TEXT + KPROBES_TEXT *(.fixup) *(.gnu.warning) } = 0x0700 diff -Naur linux-2.6.18-rc1/arch/s390/mm/fault.c linux-2.6.18-rc1.s390-kprob/arch/s390/mm/fault.c --- linux-2.6.18-rc1/arch/s390/mm/fault.c 2006-07-06 11:05:42.000000000 -0700 +++ linux-2.6.18-rc1.s390-kprob/arch/s390/mm/fault.c 2006-07-11 15:16:24.000000000 -0700 @@ -25,10 +25,12 @@ #include <linux/console.h> #include <linux/module.h> #include <linux/hardirq.h> +#include <linux/kprobes.h> #include <asm/system.h> #include <asm/uaccess.h> #include <asm/pgtable.h> +#include <asm/kdebug.h> #ifndef CONFIG_64BIT #define __FAIL_ADDR_MASK 0x7ffff000 @@ -48,6 +50,38 @@ extern void die(const char *,struct pt_regs *,long); +#ifdef CONFIG_KPROBES +ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain); +int register_page_fault_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_register(¬ify_page_fault_chain, nb); +} + +int unregister_page_fault_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_unregister(¬ify_page_fault_chain, nb); +} + +static inline int notify_page_fault(enum die_val val, const char *str, + struct pt_regs *regs, long err, int trap, int sig) +{ + struct die_args args = { + .regs = regs, + .str = str, + .err = err, + .trapnr = trap, + .signr = sig + }; + return atomic_notifier_call_chain(¬ify_page_fault_chain, val, &args); +} +#else +static inline int notify_page_fault(enum die_val val, const char *str, + struct pt_regs *regs, long err, int trap, int sig) +{ + return NOTIFY_DONE; +} +#endif + extern spinlock_t timerlist_lock; /* @@ -159,7 +193,7 @@ * 11 Page translation -> Not present (nullification) * 3b Region third trans. -> Not present (nullification) */ -static inline void +static inline void __kprobes do_exception(struct pt_regs *regs, unsigned long error_code, int is_protection) { struct task_struct *tsk; @@ -173,6 +207,10 @@ tsk = current; mm = tsk->mm; + if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, error_code, 14, + SIGSEGV) == NOTIFY_STOP) + return; + /* * Check for low-address protection. This needs to be treated * as a special case because the translation exception code diff -Naur linux-2.6.18-rc1/include/asm-s390/kdebug.h linux-2.6.18-rc1.s390-kprob/include/asm-s390/kdebug.h --- linux-2.6.18-rc1/include/asm-s390/kdebug.h 1969-12-31 16:00:00.000000000 -0800 +++ linux-2.6.18-rc1.s390-kprob/include/asm-s390/kdebug.h 2006-07-11 15:17:19.314860992 -0700 @@ -0,0 +1,59 @@ +#ifndef _S390_KDEBUG_H +#define _S390_KDEBUG_H + +/* + * Feb 2006 Ported to s390 <grundym@us.ibm.com> + */ +#include <linux/notifier.h> + +struct pt_regs; + +struct die_args { + struct pt_regs *regs; + const char *str; + long err; + int trapnr; + int signr; +}; + +/* Note - you should never unregister because that can race with NMIs. + * If you really want to do it first unregister - then synchronize_sched + * - then free. + */ +extern int register_die_notifier(struct notifier_block *); +extern int unregister_die_notifier(struct notifier_block *); +extern int register_page_fault_notifier(struct notifier_block *); +extern int unregister_page_fault_notifier(struct notifier_block *); +extern struct atomic_notifier_head s390die_chain; + + +enum die_val { + DIE_OOPS = 1, + DIE_BPT, + DIE_SSTEP, + DIE_PANIC, + DIE_NMI, + DIE_DIE, + DIE_NMIWATCHDOG, + DIE_KERNELDEBUG, + DIE_TRAP, + DIE_GPF, + DIE_CALL, + DIE_NMI_IPI, + DIE_PAGE_FAULT, +}; + +static inline int notify_die(enum die_val val, const char *str, + struct pt_regs *regs, long err, int trap, int sig) +{ + struct die_args args = { + .regs = regs, + .str = str, + .err = err, + .trapnr = trap, + .signr = sig + }; + return atomic_notifier_call_chain(&s390die_chain, val, &args); +} + +#endif diff -Naur linux-2.6.18-rc1/include/asm-s390/kprobes.h linux-2.6.18-rc1.s390-kprob/include/asm-s390/kprobes.h --- linux-2.6.18-rc1/include/asm-s390/kprobes.h 1969-12-31 16:00:00.000000000 -0800 +++ linux-2.6.18-rc1.s390-kprob/include/asm-s390/kprobes.h 2006-07-11 15:16:24.985120368 -0700 @@ -0,0 +1,111 @@ +#ifndef _ASM_S390_KPROBES_H +#define _ASM_S390_KPROBES_H +/* + * Kernel Probes (KProbes) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright (C) IBM Corporation, 2002, 2006 + * + * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel + * Probes initial implementation ( includes suggestions from + * Rusty Russell). + * 2004-Nov Modified for PPC64 by Ananth N Mavinakayanahalli + * <ananth@in.ibm.com> + * 2005-Dec Used as a template for s390 by Mike Grundy + * <grundym@us.ibm.com> + */ +#include <linux/types.h> +#include <linux/ptrace.h> +#include <linux/percpu.h> + +#define __ARCH_WANT_KPROBES_INSN_SLOT +struct pt_regs; +struct kprobe; + +typedef u16 kprobe_opcode_t; +#define BREAKPOINT_INSTRUCTION 0x0002 + +/* Maximum instruction size is 3 (16bit) halfwords: */ +#define MAX_INSN_SIZE 0x0003 +#define MAX_STACK_SIZE 64 +#define MIN_STACK_SIZE(ADDR) (((MAX_STACK_SIZE) < \ + (((unsigned long)current_thread_info()) + THREAD_SIZE - (ADDR))) \ + ? (MAX_STACK_SIZE) \ + : (((unsigned long)current_thread_info()) + THREAD_SIZE - (ADDR))) + +#define JPROBE_ENTRY(pentry) (kprobe_opcode_t *)((func_descr_t *)pentry) + +#define ARCH_SUPPORTS_KRETPROBES +#define ARCH_INACTIVE_KPROBE_COUNT 0 + +#define KPROBE_SWAP_INST 0x10 + +#define FIXUP_PSW_NORMAL 0x08 +#define FIXUP_BRANCH_NOT_TAKEN 0x04 +#define FIXUP_RETURN_REGISTER 0x02 +#define FIXUP_NOT_REQUIRED 0x01 + +/* Architecture specific copy of original instruction */ +struct arch_specific_insn { + /* copy of original instruction */ + kprobe_opcode_t *insn; + int fixup; + int ilen; + int reg; +}; + +struct ins_replace_args { + kprobe_opcode_t *ptr; + kprobe_opcode_t old; + kprobe_opcode_t new; +}; +struct prev_kprobe { + struct kprobe *kp; + unsigned long status; + unsigned long saved_psw; + unsigned long kprobe_saved_imask; + unsigned long kprobe_saved_ctl[3]; +}; + +/* per-cpu kprobe control block */ +struct kprobe_ctlblk { + unsigned long kprobe_status; + unsigned long kprobe_saved_imask; + unsigned long kprobe_saved_ctl[3]; + struct pt_regs jprobe_saved_regs; + unsigned long jprobe_saved_r14; + unsigned long jprobe_saved_r15; + struct prev_kprobe prev_kprobe; + kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE]; +}; + +void arch_remove_kprobe(struct kprobe *p); +void kretprobe_trampoline(void); +int is_prohibited_opcode(kprobe_opcode_t *instruction); +void get_instruction_type(struct arch_specific_insn *ainsn); +#endif /* _ASM_S390_KPROBES_H */ + +#ifdef CONFIG_KPROBES + +extern int kprobe_exceptions_notify(struct notifier_block *self, + unsigned long val, void *data); +#else /* !CONFIG_KPROBES */ +static inline int kprobe_exceptions_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + return 0; +} +#endif --- linux-2.6.17.noarch/include/asm-s390/kprobes.h~ 2006-08-01 19:44:20.000000000 -0400 +++ linux-2.6.17.noarch/include/asm-s390/kprobes.h 2006-08-01 19:44:25.000000000 -0400 @@ -50,6 +50,7 @@ typedef u16 kprobe_opcode_t; #define ARCH_SUPPORTS_KRETPROBES #define ARCH_INACTIVE_KPROBE_COUNT 0 +#define flush_insn_slot(p) do { } while (0) #define KPROBE_SWAP_INST 0x10
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