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![Masami Hiramatsu](/assets/img/avatar_default.png)
Clear current_kprobe and enable preemption in kprobe even if pre_handler returns !0. This simplifies function override using kprobes. Jprobe used to require to keep the preemption disabled and keep current_kprobe until it returned to original function entry. For this reason kprobe_int3_handler() and similar arch dependent kprobe handers checks pre_handler result and exit without enabling preemption if the result is !0. After removing the jprobe, Kprobes does not need to keep preempt disabled even if user handler returns !0 anymore. But since the function override handler in error-inject and bpf is also returns !0 if it overrides a function, to balancing the preempt count, it enables preemption and reset current kprobe by itself. That is a bad design that is very buggy. This fixes such unbalanced preempt-count and current_kprobes setting in kprobes, bpf and error-inject. Note: for powerpc and x86, this removes all preempt_disable from kprobe_ftrace_handler because ftrace callbacks are called under preempt disabled. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David S. Miller <davem@davemloft.net> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: James Hogan <jhogan@kernel.org> Cc: Josef Bacik <jbacik@fb.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: linux-arch@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-ia64@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: linux-s390@vger.kernel.org Cc: linux-sh@vger.kernel.org Cc: linux-snps-arc@lists.infradead.org Cc: linuxppc-dev@lists.ozlabs.org Cc: sparclinux@vger.kernel.org Link: https://lore.kernel.org/lkml/152942494574.15209.12323837825873032258.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
658 lines
18 KiB
C
658 lines
18 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Kernel Probes (KProbes)
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*
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* Copyright IBM Corp. 2002, 2006
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*
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* s390 port, used ppc64 as template. Mike Grundy <grundym@us.ibm.com>
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*/
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#include <linux/kprobes.h>
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#include <linux/ptrace.h>
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#include <linux/preempt.h>
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#include <linux/stop_machine.h>
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#include <linux/kdebug.h>
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#include <linux/uaccess.h>
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#include <linux/extable.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/hardirq.h>
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#include <linux/ftrace.h>
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#include <asm/set_memory.h>
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#include <asm/sections.h>
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#include <asm/dis.h>
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DEFINE_PER_CPU(struct kprobe *, current_kprobe);
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DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
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struct kretprobe_blackpoint kretprobe_blacklist[] = { };
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DEFINE_INSN_CACHE_OPS(dmainsn);
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static void *alloc_dmainsn_page(void)
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{
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void *page;
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page = (void *) __get_free_page(GFP_KERNEL | GFP_DMA);
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if (page)
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set_memory_x((unsigned long) page, 1);
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return page;
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}
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static void free_dmainsn_page(void *page)
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{
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set_memory_nx((unsigned long) page, 1);
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free_page((unsigned long)page);
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}
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struct kprobe_insn_cache kprobe_dmainsn_slots = {
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.mutex = __MUTEX_INITIALIZER(kprobe_dmainsn_slots.mutex),
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.alloc = alloc_dmainsn_page,
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.free = free_dmainsn_page,
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.pages = LIST_HEAD_INIT(kprobe_dmainsn_slots.pages),
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.insn_size = MAX_INSN_SIZE,
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};
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static void copy_instruction(struct kprobe *p)
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{
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unsigned long ip = (unsigned long) p->addr;
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s64 disp, new_disp;
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u64 addr, new_addr;
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if (ftrace_location(ip) == ip) {
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/*
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* If kprobes patches the instruction that is morphed by
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* ftrace make sure that kprobes always sees the branch
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* "jg .+24" that skips the mcount block or the "brcl 0,0"
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* in case of hotpatch.
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*/
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ftrace_generate_nop_insn((struct ftrace_insn *)p->ainsn.insn);
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p->ainsn.is_ftrace_insn = 1;
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} else
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memcpy(p->ainsn.insn, p->addr, insn_length(*p->addr >> 8));
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p->opcode = p->ainsn.insn[0];
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if (!probe_is_insn_relative_long(p->ainsn.insn))
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return;
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/*
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* For pc-relative instructions in RIL-b or RIL-c format patch the
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* RI2 displacement field. We have already made sure that the insn
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* slot for the patched instruction is within the same 2GB area
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* as the original instruction (either kernel image or module area).
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* Therefore the new displacement will always fit.
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*/
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disp = *(s32 *)&p->ainsn.insn[1];
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addr = (u64)(unsigned long)p->addr;
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new_addr = (u64)(unsigned long)p->ainsn.insn;
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new_disp = ((addr + (disp * 2)) - new_addr) / 2;
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*(s32 *)&p->ainsn.insn[1] = new_disp;
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}
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NOKPROBE_SYMBOL(copy_instruction);
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static inline int is_kernel_addr(void *addr)
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{
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return addr < (void *)_end;
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}
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static int s390_get_insn_slot(struct kprobe *p)
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{
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/*
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* Get an insn slot that is within the same 2GB area like the original
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* instruction. That way instructions with a 32bit signed displacement
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* field can be patched and executed within the insn slot.
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*/
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p->ainsn.insn = NULL;
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if (is_kernel_addr(p->addr))
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p->ainsn.insn = get_dmainsn_slot();
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else if (is_module_addr(p->addr))
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p->ainsn.insn = get_insn_slot();
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return p->ainsn.insn ? 0 : -ENOMEM;
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}
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NOKPROBE_SYMBOL(s390_get_insn_slot);
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static void s390_free_insn_slot(struct kprobe *p)
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{
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if (!p->ainsn.insn)
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return;
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if (is_kernel_addr(p->addr))
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free_dmainsn_slot(p->ainsn.insn, 0);
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else
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free_insn_slot(p->ainsn.insn, 0);
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p->ainsn.insn = NULL;
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}
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NOKPROBE_SYMBOL(s390_free_insn_slot);
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int arch_prepare_kprobe(struct kprobe *p)
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{
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if ((unsigned long) p->addr & 0x01)
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return -EINVAL;
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/* Make sure the probe isn't going on a difficult instruction */
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if (probe_is_prohibited_opcode(p->addr))
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return -EINVAL;
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if (s390_get_insn_slot(p))
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return -ENOMEM;
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copy_instruction(p);
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return 0;
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}
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NOKPROBE_SYMBOL(arch_prepare_kprobe);
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int arch_check_ftrace_location(struct kprobe *p)
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{
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return 0;
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}
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struct swap_insn_args {
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struct kprobe *p;
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unsigned int arm_kprobe : 1;
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};
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static int swap_instruction(void *data)
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{
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struct swap_insn_args *args = data;
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struct ftrace_insn new_insn, *insn;
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struct kprobe *p = args->p;
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size_t len;
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new_insn.opc = args->arm_kprobe ? BREAKPOINT_INSTRUCTION : p->opcode;
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len = sizeof(new_insn.opc);
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if (!p->ainsn.is_ftrace_insn)
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goto skip_ftrace;
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len = sizeof(new_insn);
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insn = (struct ftrace_insn *) p->addr;
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if (args->arm_kprobe) {
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if (is_ftrace_nop(insn))
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new_insn.disp = KPROBE_ON_FTRACE_NOP;
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else
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new_insn.disp = KPROBE_ON_FTRACE_CALL;
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} else {
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ftrace_generate_call_insn(&new_insn, (unsigned long)p->addr);
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if (insn->disp == KPROBE_ON_FTRACE_NOP)
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ftrace_generate_nop_insn(&new_insn);
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}
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skip_ftrace:
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s390_kernel_write(p->addr, &new_insn, len);
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return 0;
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}
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NOKPROBE_SYMBOL(swap_instruction);
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void arch_arm_kprobe(struct kprobe *p)
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{
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struct swap_insn_args args = {.p = p, .arm_kprobe = 1};
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stop_machine_cpuslocked(swap_instruction, &args, NULL);
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}
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NOKPROBE_SYMBOL(arch_arm_kprobe);
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void arch_disarm_kprobe(struct kprobe *p)
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{
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struct swap_insn_args args = {.p = p, .arm_kprobe = 0};
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stop_machine_cpuslocked(swap_instruction, &args, NULL);
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}
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NOKPROBE_SYMBOL(arch_disarm_kprobe);
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void arch_remove_kprobe(struct kprobe *p)
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{
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s390_free_insn_slot(p);
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}
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NOKPROBE_SYMBOL(arch_remove_kprobe);
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static void enable_singlestep(struct kprobe_ctlblk *kcb,
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struct pt_regs *regs,
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unsigned long ip)
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{
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struct per_regs per_kprobe;
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/* Set up the PER control registers %cr9-%cr11 */
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per_kprobe.control = PER_EVENT_IFETCH;
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per_kprobe.start = ip;
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per_kprobe.end = ip;
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/* Save control regs and psw mask */
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__ctl_store(kcb->kprobe_saved_ctl, 9, 11);
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kcb->kprobe_saved_imask = regs->psw.mask &
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(PSW_MASK_PER | PSW_MASK_IO | PSW_MASK_EXT);
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/* Set PER control regs, turns on single step for the given address */
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__ctl_load(per_kprobe, 9, 11);
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regs->psw.mask |= PSW_MASK_PER;
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regs->psw.mask &= ~(PSW_MASK_IO | PSW_MASK_EXT);
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regs->psw.addr = ip;
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}
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NOKPROBE_SYMBOL(enable_singlestep);
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static void disable_singlestep(struct kprobe_ctlblk *kcb,
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struct pt_regs *regs,
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unsigned long ip)
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{
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/* Restore control regs and psw mask, set new psw address */
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__ctl_load(kcb->kprobe_saved_ctl, 9, 11);
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regs->psw.mask &= ~PSW_MASK_PER;
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regs->psw.mask |= kcb->kprobe_saved_imask;
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regs->psw.addr = ip;
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}
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NOKPROBE_SYMBOL(disable_singlestep);
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/*
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* Activate a kprobe by storing its pointer to current_kprobe. The
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* previous kprobe is stored in kcb->prev_kprobe. A stack of up to
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* two kprobes can be active, see KPROBE_REENTER.
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*/
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static void push_kprobe(struct kprobe_ctlblk *kcb, struct kprobe *p)
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{
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kcb->prev_kprobe.kp = __this_cpu_read(current_kprobe);
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kcb->prev_kprobe.status = kcb->kprobe_status;
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__this_cpu_write(current_kprobe, p);
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}
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NOKPROBE_SYMBOL(push_kprobe);
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/*
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* Deactivate a kprobe by backing up to the previous state. If the
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* current state is KPROBE_REENTER prev_kprobe.kp will be non-NULL,
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* for any other state prev_kprobe.kp will be NULL.
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*/
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static void pop_kprobe(struct kprobe_ctlblk *kcb)
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{
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__this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
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kcb->kprobe_status = kcb->prev_kprobe.status;
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}
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NOKPROBE_SYMBOL(pop_kprobe);
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void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs)
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{
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ri->ret_addr = (kprobe_opcode_t *) regs->gprs[14];
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/* Replace the return addr with trampoline addr */
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regs->gprs[14] = (unsigned long) &kretprobe_trampoline;
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}
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NOKPROBE_SYMBOL(arch_prepare_kretprobe);
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static void kprobe_reenter_check(struct kprobe_ctlblk *kcb, struct kprobe *p)
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{
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switch (kcb->kprobe_status) {
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case KPROBE_HIT_SSDONE:
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case KPROBE_HIT_ACTIVE:
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kprobes_inc_nmissed_count(p);
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break;
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case KPROBE_HIT_SS:
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case KPROBE_REENTER:
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default:
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/*
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* A kprobe on the code path to single step an instruction
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* is a BUG. The code path resides in the .kprobes.text
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* section and is executed with interrupts disabled.
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*/
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pr_err("Invalid kprobe detected.\n");
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dump_kprobe(p);
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BUG();
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}
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}
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NOKPROBE_SYMBOL(kprobe_reenter_check);
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static int kprobe_handler(struct pt_regs *regs)
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{
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struct kprobe_ctlblk *kcb;
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struct kprobe *p;
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/*
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* We want to disable preemption for the entire duration of kprobe
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* processing. That includes the calls to the pre/post handlers
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* and single stepping the kprobe instruction.
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*/
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preempt_disable();
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kcb = get_kprobe_ctlblk();
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p = get_kprobe((void *)(regs->psw.addr - 2));
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if (p) {
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if (kprobe_running()) {
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/*
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* We have hit a kprobe while another is still
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* active. This can happen in the pre and post
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* handler. Single step the instruction of the
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* new probe but do not call any handler function
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* of this secondary kprobe.
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* push_kprobe and pop_kprobe saves and restores
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* the currently active kprobe.
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*/
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kprobe_reenter_check(kcb, p);
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push_kprobe(kcb, p);
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kcb->kprobe_status = KPROBE_REENTER;
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} else {
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/*
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* If we have no pre-handler or it returned 0, we
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* continue with single stepping. If we have a
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* pre-handler and it returned non-zero, it prepped
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* for changing execution path, so get out doing
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* nothing more here.
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*/
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push_kprobe(kcb, p);
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kcb->kprobe_status = KPROBE_HIT_ACTIVE;
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if (p->pre_handler && p->pre_handler(p, regs)) {
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pop_kprobe(kcb);
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preempt_enable_no_resched();
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return 1;
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}
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kcb->kprobe_status = KPROBE_HIT_SS;
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}
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enable_singlestep(kcb, regs, (unsigned long) p->ainsn.insn);
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return 1;
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} /* else:
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* No kprobe at this address and no active kprobe. The trap has
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* not been caused by a kprobe breakpoint. The race of breakpoint
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* vs. kprobe remove does not exist because on s390 as we use
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* stop_machine to arm/disarm the breakpoints.
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*/
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preempt_enable_no_resched();
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return 0;
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}
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NOKPROBE_SYMBOL(kprobe_handler);
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/*
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* Function return probe trampoline:
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* - init_kprobes() establishes a probepoint here
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* - When the probed function returns, this probe
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* causes the handlers to fire
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*/
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static void __used kretprobe_trampoline_holder(void)
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{
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asm volatile(".global kretprobe_trampoline\n"
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"kretprobe_trampoline: bcr 0,0\n");
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}
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/*
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* Called when the probe at kretprobe trampoline is hit
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*/
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static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
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{
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struct kretprobe_instance *ri;
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struct hlist_head *head, empty_rp;
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struct hlist_node *tmp;
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unsigned long flags, orig_ret_address;
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unsigned long trampoline_address;
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kprobe_opcode_t *correct_ret_addr;
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INIT_HLIST_HEAD(&empty_rp);
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kretprobe_hash_lock(current, &head, &flags);
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/*
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* It is possible to have multiple instances associated with a given
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* task either because an multiple functions in the call path
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* have a return probe installed on them, and/or more than one return
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* return probe was registered for a target function.
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*
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* We can handle this because:
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* - instances are always inserted at the head of the list
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* - when multiple return probes are registered for the same
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* function, the first instance's ret_addr will point to the
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* real return address, and all the rest will point to
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* kretprobe_trampoline
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*/
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ri = NULL;
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orig_ret_address = 0;
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correct_ret_addr = NULL;
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trampoline_address = (unsigned long) &kretprobe_trampoline;
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hlist_for_each_entry_safe(ri, tmp, head, hlist) {
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if (ri->task != current)
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/* another task is sharing our hash bucket */
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continue;
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orig_ret_address = (unsigned long) ri->ret_addr;
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if (orig_ret_address != trampoline_address)
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/*
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* This is the real return address. Any other
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* instances associated with this task are for
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* other calls deeper on the call stack
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*/
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break;
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}
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kretprobe_assert(ri, orig_ret_address, trampoline_address);
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correct_ret_addr = ri->ret_addr;
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hlist_for_each_entry_safe(ri, tmp, head, hlist) {
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if (ri->task != current)
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/* another task is sharing our hash bucket */
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continue;
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orig_ret_address = (unsigned long) ri->ret_addr;
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if (ri->rp && ri->rp->handler) {
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ri->ret_addr = correct_ret_addr;
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ri->rp->handler(ri, regs);
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}
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recycle_rp_inst(ri, &empty_rp);
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if (orig_ret_address != trampoline_address)
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/*
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* This is the real return address. Any other
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* instances associated with this task are for
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* other calls deeper on the call stack
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*/
|
|
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);
|
|
}
|
|
/*
|
|
* 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;
|
|
}
|
|
NOKPROBE_SYMBOL(trampoline_probe_handler);
|
|
|
|
/*
|
|
* 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 resume_execution(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
|
|
unsigned long ip = regs->psw.addr;
|
|
int fixup = probe_get_fixup_type(p->ainsn.insn);
|
|
|
|
/* Check if the kprobes location is an enabled ftrace caller */
|
|
if (p->ainsn.is_ftrace_insn) {
|
|
struct ftrace_insn *insn = (struct ftrace_insn *) p->addr;
|
|
struct ftrace_insn call_insn;
|
|
|
|
ftrace_generate_call_insn(&call_insn, (unsigned long) p->addr);
|
|
/*
|
|
* A kprobe on an enabled ftrace call site actually single
|
|
* stepped an unconditional branch (ftrace nop equivalent).
|
|
* Now we need to fixup things and pretend that a brasl r0,...
|
|
* was executed instead.
|
|
*/
|
|
if (insn->disp == KPROBE_ON_FTRACE_CALL) {
|
|
ip += call_insn.disp * 2 - MCOUNT_INSN_SIZE;
|
|
regs->gprs[0] = (unsigned long)p->addr + sizeof(*insn);
|
|
}
|
|
}
|
|
|
|
if (fixup & FIXUP_PSW_NORMAL)
|
|
ip += (unsigned long) p->addr - (unsigned long) p->ainsn.insn;
|
|
|
|
if (fixup & FIXUP_BRANCH_NOT_TAKEN) {
|
|
int ilen = insn_length(p->ainsn.insn[0] >> 8);
|
|
if (ip - (unsigned long) p->ainsn.insn == ilen)
|
|
ip = (unsigned long) p->addr + ilen;
|
|
}
|
|
|
|
if (fixup & FIXUP_RETURN_REGISTER) {
|
|
int reg = (p->ainsn.insn[0] & 0xf0) >> 4;
|
|
regs->gprs[reg] += (unsigned long) p->addr -
|
|
(unsigned long) p->ainsn.insn;
|
|
}
|
|
|
|
disable_singlestep(kcb, regs, ip);
|
|
}
|
|
NOKPROBE_SYMBOL(resume_execution);
|
|
|
|
static int post_kprobe_handler(struct pt_regs *regs)
|
|
{
|
|
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
|
|
struct kprobe *p = kprobe_running();
|
|
|
|
if (!p)
|
|
return 0;
|
|
|
|
if (kcb->kprobe_status != KPROBE_REENTER && p->post_handler) {
|
|
kcb->kprobe_status = KPROBE_HIT_SSDONE;
|
|
p->post_handler(p, regs, 0);
|
|
}
|
|
|
|
resume_execution(p, regs);
|
|
pop_kprobe(kcb);
|
|
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;
|
|
}
|
|
NOKPROBE_SYMBOL(post_kprobe_handler);
|
|
|
|
static int kprobe_trap_handler(struct pt_regs *regs, int trapnr)
|
|
{
|
|
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
|
|
struct kprobe *p = kprobe_running();
|
|
const struct exception_table_entry *entry;
|
|
|
|
switch(kcb->kprobe_status) {
|
|
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.
|
|
*/
|
|
disable_singlestep(kcb, regs, (unsigned long) p->addr);
|
|
pop_kprobe(kcb);
|
|
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 accounting
|
|
* these specific fault cases.
|
|
*/
|
|
kprobes_inc_nmissed_count(p);
|
|
|
|
/*
|
|
* 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 (p->fault_handler && p->fault_handler(p, regs, trapnr))
|
|
return 1;
|
|
|
|
/*
|
|
* In case the user-specified fault handler returned
|
|
* zero, try to fix up.
|
|
*/
|
|
entry = search_exception_tables(regs->psw.addr);
|
|
if (entry) {
|
|
regs->psw.addr = extable_fixup(entry);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* fixup_exception() could not handle it,
|
|
* Let do_page_fault() fix it.
|
|
*/
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
return 0;
|
|
}
|
|
NOKPROBE_SYMBOL(kprobe_trap_handler);
|
|
|
|
int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
|
|
{
|
|
int ret;
|
|
|
|
if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT))
|
|
local_irq_disable();
|
|
ret = kprobe_trap_handler(regs, trapnr);
|
|
if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT))
|
|
local_irq_restore(regs->psw.mask & ~PSW_MASK_PER);
|
|
return ret;
|
|
}
|
|
NOKPROBE_SYMBOL(kprobe_fault_handler);
|
|
|
|
/*
|
|
* Wrapper routine to for handling exceptions.
|
|
*/
|
|
int kprobe_exceptions_notify(struct notifier_block *self,
|
|
unsigned long val, void *data)
|
|
{
|
|
struct die_args *args = (struct die_args *) data;
|
|
struct pt_regs *regs = args->regs;
|
|
int ret = NOTIFY_DONE;
|
|
|
|
if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT))
|
|
local_irq_disable();
|
|
|
|
switch (val) {
|
|
case DIE_BPT:
|
|
if (kprobe_handler(regs))
|
|
ret = NOTIFY_STOP;
|
|
break;
|
|
case DIE_SSTEP:
|
|
if (post_kprobe_handler(regs))
|
|
ret = NOTIFY_STOP;
|
|
break;
|
|
case DIE_TRAP:
|
|
if (!preemptible() && kprobe_running() &&
|
|
kprobe_trap_handler(regs, args->trapnr))
|
|
ret = NOTIFY_STOP;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
|
|
if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT))
|
|
local_irq_restore(regs->psw.mask & ~PSW_MASK_PER);
|
|
|
|
return ret;
|
|
}
|
|
NOKPROBE_SYMBOL(kprobe_exceptions_notify);
|
|
|
|
static struct kprobe trampoline = {
|
|
.addr = (kprobe_opcode_t *) &kretprobe_trampoline,
|
|
.pre_handler = trampoline_probe_handler
|
|
};
|
|
|
|
int __init arch_init_kprobes(void)
|
|
{
|
|
return register_kprobe(&trampoline);
|
|
}
|
|
|
|
int arch_trampoline_kprobe(struct kprobe *p)
|
|
{
|
|
return p->addr == (kprobe_opcode_t *) &kretprobe_trampoline;
|
|
}
|
|
NOKPROBE_SYMBOL(arch_trampoline_kprobe);
|