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systemtap
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linux
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uprobes
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Filename :
uprobes_s390.c
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/* * Userspace Probes (UProbes) * arch/s390/uprobes/uprobes_s390.c * * 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, see <http://www.gnu.org/licenses/>. * * Copyright (C) IBM Corporation, 2006 */ /* * In versions of uprobes built in the SystemTap runtime, this file * is #included at the end of uprobes.c. */ #include <linux/uaccess.h> /* adapted from s390/kernel/kprobes.c is_prohibited_opcode() */ /* TODO More instructions?? Should floating point inst be added?? */ static int prohibited_opcode(uprobe_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; } static int arch_validate_probed_insn(struct uprobe_probept *ppt, struct task_struct *tsk) { if (ppt->vaddr & 0x01) { printk("Attempt to register uprobe at an unaligned address\n"); return -EPERM; } /* Make sure the probe isn't going on a difficult instruction */ if (prohibited_opcode((uprobe_opcode_t *) ppt->insn)) return -EPERM; return 0; } /* * Get an instruction slot from the process's SSOL area, containing the * instruction at ppt's probepoint. Point the psw.addr at that slot, in * preparation for single-stepping out of line. */ static void uprobe_pre_ssout(struct uprobe_task *utask, struct uprobe_probept *ppt, struct pt_regs *regs) { struct uprobe_ssol_slot *slot; slot = uprobe_get_insn_slot(ppt); if (!slot) { utask->doomed = 1; return; } regs->psw.addr = (long)slot->insn; utask->singlestep_addr = regs->psw.addr; } static void uprobe_post_ssout(struct uprobe_task *utask, struct uprobe_probept *ppt, struct pt_regs *regs) { int ilen, fixup, reg; unsigned long copy_ins_addr = utask->singlestep_addr; unsigned long orig_ins_addr = ppt->vaddr; up_read(&ppt->slot->rwsem); /* default fixup method */ fixup = FIXUP_PSW_NORMAL;; /* get r1 operand */ reg = (*ppt->insn & 0xf0) >> 4; /* save the instruction length (pop 5-5) in bytes */ switch (*(__u8 *) (ppt->insn) >> 6) { case 0: ilen = 2; break; case 1: case 2: ilen = 4; break; case 3: ilen = 6; break; default: ilen = 0; BUG(); } switch (*(__u8 *) ppt->insn) { case 0x05: /* balr */ case 0x0d: /* basr */ fixup = FIXUP_RETURN_REGISTER; /* if r2 = 0, no branch will be taken */ if ((*ppt->insn & 0x0f) == 0) fixup |= FIXUP_BRANCH_NOT_TAKEN; break; case 0x06: /* bctr */ case 0x07: /* bcr */ fixup = FIXUP_BRANCH_NOT_TAKEN; break; case 0x45: /* bal */ case 0x4d: /* bas */ fixup = FIXUP_RETURN_REGISTER; break; case 0x47: /* bc */ case 0x46: /* bct */ case 0x86: /* bxh */ case 0x87: /* bxle */ fixup = FIXUP_BRANCH_NOT_TAKEN; break; case 0x82: /* lpsw */ fixup = FIXUP_NOT_REQUIRED; break; case 0xb2: /* lpswe */ if (*(((__u8 *) ppt->insn) + 1) == 0xb2) { fixup = FIXUP_NOT_REQUIRED; } break; case 0xa7: /* bras */ if ((*ppt->insn & 0x0f) == 0x05) { fixup |= FIXUP_RETURN_REGISTER; } break; case 0xc0: if ((*ppt->insn & 0x0f) == 0x00 /* larl */ || (*ppt->insn & 0x0f) == 0x05) /* brasl */ fixup |= FIXUP_RETURN_REGISTER; break; case 0xeb: if (*(((__u8 *) ppt->insn) + 5 ) == 0x44 || /* bxhg */ *(((__u8 *) ppt->insn) + 5) == 0x45) {/* bxleg */ fixup = FIXUP_BRANCH_NOT_TAKEN; } break; case 0xe3: /* bctg */ if (*(((__u8 *) ppt->insn) + 5) == 0x46) { fixup = FIXUP_BRANCH_NOT_TAKEN; } break; } /* do the fixup and adjust psw as needed */ regs->psw.addr &= PSW_ADDR_INSN; if (fixup & FIXUP_PSW_NORMAL) regs->psw.addr = orig_ins_addr + regs->psw.addr - copy_ins_addr; if (fixup & FIXUP_BRANCH_NOT_TAKEN) if (regs->psw.addr - copy_ins_addr == ilen) regs->psw.addr = orig_ins_addr + ilen; if (fixup & FIXUP_RETURN_REGISTER) regs->gprs[reg] = (orig_ins_addr + (regs->gprs[reg] - copy_ins_addr)) | PSW_ADDR_AMODE; regs->psw.addr |= PSW_ADDR_AMODE; } /* * Replace the return address with the trampoline address. Returns * the original return address. */ static unsigned long arch_hijack_uret_addr(unsigned long trampoline_address, struct pt_regs *regs, struct uprobe_task *utask) { unsigned long orig_ret_addr; #ifdef CONFIG_COMPAT if (test_tsk_thread_flag(utask->tsk, TIF_31BIT)) orig_ret_addr = regs->gprs[14]&0x7FFFFFFFUL; else #endif orig_ret_addr = regs->gprs[14]; regs->gprs[14] = trampoline_address; return orig_ret_addr; } /* Check if instruction is nop and return true. */ static int uprobe_emulate_insn(struct pt_regs *regs, struct uprobe_probept *ppt) { unsigned int insn = *ppt->insn; if (insn == 0x47000000) /* ip already points to the insn after the nop/bkpt insn. */ return 1; return 0; }