![Linus Torvalds](/assets/img/avatar_default.png)
Pull trivial tree updates from Jiri Kosina: "Usual earth-shaking, news-breaking, rocket science pile from trivial.git" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (23 commits) doc: usb: Fix typo in Documentation/usb/gadget_configs.txt doc: add missing files to timers/00-INDEX timekeeping: Fix some trivial typos in comments mm: Fix some trivial typos in comments irq: Fix some trivial typos in comments NUMA: fix typos in Kconfig help text mm: update 00-INDEX doc: Documentation/DMA-attributes.txt fix typo DRM: comment: `halve' -> `half' Docs: Kconfig: `devlopers' -> `developers' doc: typo on word accounting in kprobes.c in mutliple architectures treewide: fix "usefull" typo treewide: fix "distingush" typo mm/Kconfig: Grammar s/an/a/ kexec: Typo s/the/then/ Documentation/kvm: Update cpuid documentation for steal time and pv eoi treewide: Fix common typo in "identify" __page_to_pfn: Fix typo in comment Correct some typos for word frequency clk: fixed-factor: Fix a trivial typo ...
826 lines
22 KiB
C
826 lines
22 KiB
C
/*
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* Kernel Probes (KProbes)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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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/module.h>
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#include <linux/slab.h>
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#include <linux/hardirq.h>
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#include <asm/cacheflush.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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return (void *)__get_free_page(GFP_KERNEL | GFP_DMA);
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}
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static void free_dmainsn_page(void *page)
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{
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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 int __kprobes is_prohibited_opcode(kprobe_opcode_t *insn)
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{
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if (!is_known_insn((unsigned char *)insn))
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return -EINVAL;
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switch (insn[0] >> 8) {
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case 0x0c: /* bassm */
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case 0x0b: /* bsm */
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case 0x83: /* diag */
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case 0x44: /* ex */
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case 0xac: /* stnsm */
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case 0xad: /* stosm */
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return -EINVAL;
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case 0xc6:
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switch (insn[0] & 0x0f) {
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case 0x00: /* exrl */
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return -EINVAL;
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}
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}
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switch (insn[0]) {
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case 0x0101: /* pr */
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case 0xb25a: /* bsa */
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case 0xb240: /* bakr */
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case 0xb258: /* bsg */
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case 0xb218: /* pc */
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case 0xb228: /* pt */
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case 0xb98d: /* epsw */
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return -EINVAL;
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}
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return 0;
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}
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static int __kprobes get_fixup_type(kprobe_opcode_t *insn)
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{
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/* default fixup method */
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int fixup = FIXUP_PSW_NORMAL;
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switch (insn[0] >> 8) {
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case 0x05: /* balr */
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case 0x0d: /* basr */
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fixup = FIXUP_RETURN_REGISTER;
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/* if r2 = 0, no branch will be taken */
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if ((insn[0] & 0x0f) == 0)
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fixup |= FIXUP_BRANCH_NOT_TAKEN;
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break;
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case 0x06: /* bctr */
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case 0x07: /* bcr */
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fixup = FIXUP_BRANCH_NOT_TAKEN;
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break;
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case 0x45: /* bal */
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case 0x4d: /* bas */
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fixup = FIXUP_RETURN_REGISTER;
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break;
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case 0x47: /* bc */
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case 0x46: /* bct */
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case 0x86: /* bxh */
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case 0x87: /* bxle */
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fixup = FIXUP_BRANCH_NOT_TAKEN;
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break;
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case 0x82: /* lpsw */
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fixup = FIXUP_NOT_REQUIRED;
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break;
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case 0xb2: /* lpswe */
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if ((insn[0] & 0xff) == 0xb2)
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fixup = FIXUP_NOT_REQUIRED;
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break;
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case 0xa7: /* bras */
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if ((insn[0] & 0x0f) == 0x05)
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fixup |= FIXUP_RETURN_REGISTER;
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break;
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case 0xc0:
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if ((insn[0] & 0x0f) == 0x05) /* brasl */
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fixup |= FIXUP_RETURN_REGISTER;
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break;
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case 0xeb:
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switch (insn[2] & 0xff) {
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case 0x44: /* bxhg */
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case 0x45: /* bxleg */
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fixup = FIXUP_BRANCH_NOT_TAKEN;
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break;
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}
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break;
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case 0xe3: /* bctg */
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if ((insn[2] & 0xff) == 0x46)
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fixup = FIXUP_BRANCH_NOT_TAKEN;
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break;
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case 0xec:
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switch (insn[2] & 0xff) {
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case 0xe5: /* clgrb */
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case 0xe6: /* cgrb */
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case 0xf6: /* crb */
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case 0xf7: /* clrb */
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case 0xfc: /* cgib */
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case 0xfd: /* cglib */
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case 0xfe: /* cib */
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case 0xff: /* clib */
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fixup = FIXUP_BRANCH_NOT_TAKEN;
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break;
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}
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break;
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}
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return fixup;
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}
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static int __kprobes is_insn_relative_long(kprobe_opcode_t *insn)
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{
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/* Check if we have a RIL-b or RIL-c format instruction which
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* we need to modify in order to avoid instruction emulation. */
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switch (insn[0] >> 8) {
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case 0xc0:
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if ((insn[0] & 0x0f) == 0x00) /* larl */
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return true;
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break;
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case 0xc4:
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switch (insn[0] & 0x0f) {
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case 0x02: /* llhrl */
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case 0x04: /* lghrl */
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case 0x05: /* lhrl */
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case 0x06: /* llghrl */
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case 0x07: /* sthrl */
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case 0x08: /* lgrl */
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case 0x0b: /* stgrl */
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case 0x0c: /* lgfrl */
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case 0x0d: /* lrl */
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case 0x0e: /* llgfrl */
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case 0x0f: /* strl */
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return true;
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}
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break;
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case 0xc6:
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switch (insn[0] & 0x0f) {
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case 0x02: /* pfdrl */
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case 0x04: /* cghrl */
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case 0x05: /* chrl */
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case 0x06: /* clghrl */
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case 0x07: /* clhrl */
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case 0x08: /* cgrl */
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case 0x0a: /* clgrl */
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case 0x0c: /* cgfrl */
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case 0x0d: /* crl */
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case 0x0e: /* clgfrl */
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case 0x0f: /* clrl */
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return true;
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}
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break;
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}
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return false;
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}
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static void __kprobes copy_instruction(struct kprobe *p)
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{
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s64 disp, new_disp;
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u64 addr, new_addr;
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memcpy(p->ainsn.insn, p->addr, insn_length(p->opcode >> 8));
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if (!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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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 inline int is_module_addr(void *addr)
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{
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#ifdef CONFIG_64BIT
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BUILD_BUG_ON(MODULES_LEN > (1UL << 31));
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if (addr < (void *)MODULES_VADDR)
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return 0;
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if (addr > (void *)MODULES_END)
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return 0;
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#endif
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return 1;
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}
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static int __kprobes 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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static void __kprobes 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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int __kprobes 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 (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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p->opcode = *p->addr;
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copy_instruction(p);
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return 0;
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}
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struct ins_replace_args {
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kprobe_opcode_t *ptr;
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kprobe_opcode_t opcode;
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};
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static int __kprobes swap_instruction(void *aref)
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{
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struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
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unsigned long status = kcb->kprobe_status;
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struct ins_replace_args *args = aref;
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kcb->kprobe_status = KPROBE_SWAP_INST;
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probe_kernel_write(args->ptr, &args->opcode, sizeof(args->opcode));
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kcb->kprobe_status = status;
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return 0;
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}
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void __kprobes arch_arm_kprobe(struct kprobe *p)
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{
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struct ins_replace_args args;
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args.ptr = p->addr;
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args.opcode = BREAKPOINT_INSTRUCTION;
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stop_machine(swap_instruction, &args, NULL);
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}
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void __kprobes arch_disarm_kprobe(struct kprobe *p)
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{
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struct ins_replace_args args;
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args.ptr = p->addr;
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args.opcode = p->opcode;
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stop_machine(swap_instruction, &args, NULL);
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}
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void __kprobes 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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static void __kprobes 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 | PSW_ADDR_AMODE;
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}
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static void __kprobes 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 | PSW_ADDR_AMODE;
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}
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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 __kprobes push_kprobe(struct kprobe_ctlblk *kcb, struct kprobe *p)
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{
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kcb->prev_kprobe.kp = __get_cpu_var(current_kprobe);
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kcb->prev_kprobe.status = kcb->kprobe_status;
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__get_cpu_var(current_kprobe) = p;
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}
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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 __kprobes pop_kprobe(struct kprobe_ctlblk *kcb)
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{
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__get_cpu_var(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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void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
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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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static void __kprobes kprobe_reenter_check(struct kprobe_ctlblk *kcb,
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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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printk(KERN_EMERG "Invalid kprobe detected at %p.\n", p->addr);
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dump_kprobe(p);
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BUG();
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}
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}
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static int __kprobes 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 & PSW_ADDR_INSN) - 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 calling the break_handler below on re-entry
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* for jprobe processing, so get out doing nothing
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* 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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return 1;
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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 if (kprobe_running()) {
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p = __get_cpu_var(current_kprobe);
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if (p->break_handler && p->break_handler(p, regs)) {
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/*
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* Continuation after the jprobe completed and
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* caused the jprobe_return trap. The jprobe
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* break_handler "returns" to the original
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* function that still has the kprobe breakpoint
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|
* installed. We continue with single stepping.
|
|
*/
|
|
kcb->kprobe_status = KPROBE_HIT_SS;
|
|
enable_singlestep(kcb, regs,
|
|
(unsigned long) p->ainsn.insn);
|
|
return 1;
|
|
} /* else:
|
|
* No kprobe at this address and the current kprobe
|
|
* has no break handler (no jprobe!). The kernel just
|
|
* exploded, let the standard trap handler pick up the
|
|
* pieces.
|
|
*/
|
|
} /* else:
|
|
* No kprobe at this address and no active kprobe. The trap has
|
|
* not been caused by a kprobe breakpoint. The race of breakpoint
|
|
* vs. kprobe remove does not exist because on s390 as we use
|
|
* stop_machine to arm/disarm the breakpoints.
|
|
*/
|
|
preempt_enable_no_resched();
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Function return probe trampoline:
|
|
* - init_kprobes() establishes a probepoint here
|
|
* - When the probed function returns, this probe
|
|
* causes the handlers to fire
|
|
*/
|
|
static void __used kretprobe_trampoline_holder(void)
|
|
{
|
|
asm volatile(".global kretprobe_trampoline\n"
|
|
"kretprobe_trampoline: bcr 0,0\n");
|
|
}
|
|
|
|
/*
|
|
* Called when the probe at kretprobe trampoline is hit
|
|
*/
|
|
static int __kprobes 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 | PSW_ADDR_AMODE;
|
|
|
|
pop_kprobe(get_kprobe_ctlblk());
|
|
kretprobe_hash_unlock(current, &flags);
|
|
preempt_enable_no_resched();
|
|
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* 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();
|
|
unsigned long ip = regs->psw.addr & PSW_ADDR_INSN;
|
|
int fixup = get_fixup_type(p->ainsn.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);
|
|
}
|
|
|
|
static int __kprobes 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;
|
|
}
|
|
|
|
static int __kprobes 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_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.
|
|
*/
|
|
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 & PSW_ADDR_INSN);
|
|
if (entry) {
|
|
regs->psw.addr = extable_fixup(entry) | PSW_ADDR_AMODE;
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* fixup_exception() could not handle it,
|
|
* Let do_page_fault() fix it.
|
|
*/
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int __kprobes 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;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
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;
|
|
}
|
|
|
|
int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
struct jprobe *jp = container_of(p, struct jprobe, kp);
|
|
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
|
|
unsigned long stack;
|
|
|
|
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;
|
|
regs->psw.mask &= ~(PSW_MASK_IO | PSW_MASK_EXT);
|
|
|
|
/* r15 is the stack pointer */
|
|
stack = (unsigned long) regs->gprs[15];
|
|
|
|
memcpy(kcb->jprobes_stack, (void *) stack, MIN_STACK_SIZE(stack));
|
|
return 1;
|
|
}
|
|
|
|
void __kprobes jprobe_return(void)
|
|
{
|
|
asm volatile(".word 0x0002");
|
|
}
|
|
|
|
static void __used __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;
|
|
|
|
stack = (unsigned long) kcb->jprobe_saved_regs.gprs[15];
|
|
|
|
/* Put the regs back */
|
|
memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs));
|
|
/* put the stack back */
|
|
memcpy((void *) stack, kcb->jprobes_stack, MIN_STACK_SIZE(stack));
|
|
preempt_enable_no_resched();
|
|
return 1;
|
|
}
|
|
|
|
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 __kprobes arch_trampoline_kprobe(struct kprobe *p)
|
|
{
|
|
return p->addr == (kprobe_opcode_t *) &kretprobe_trampoline;
|
|
}
|