From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- arch/arm/probes/uprobes/Makefile | 1 + arch/arm/probes/uprobes/actions-arm.c | 232 ++++++++++++++++++++++++++++++++++ arch/arm/probes/uprobes/core.c | 230 +++++++++++++++++++++++++++++++++ arch/arm/probes/uprobes/core.h | 35 +++++ 4 files changed, 498 insertions(+) create mode 100644 arch/arm/probes/uprobes/Makefile create mode 100644 arch/arm/probes/uprobes/actions-arm.c create mode 100644 arch/arm/probes/uprobes/core.c create mode 100644 arch/arm/probes/uprobes/core.h (limited to 'arch/arm/probes/uprobes') diff --git a/arch/arm/probes/uprobes/Makefile b/arch/arm/probes/uprobes/Makefile new file mode 100644 index 000000000..e1dc3d0f6 --- /dev/null +++ b/arch/arm/probes/uprobes/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_UPROBES) += core.o actions-arm.o diff --git a/arch/arm/probes/uprobes/actions-arm.c b/arch/arm/probes/uprobes/actions-arm.c new file mode 100644 index 000000000..76eb44972 --- /dev/null +++ b/arch/arm/probes/uprobes/actions-arm.c @@ -0,0 +1,232 @@ +/* + * Copyright (C) 2012 Rabin Vincent + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include + +#include "../decode.h" +#include "../decode-arm.h" +#include "core.h" + +static int uprobes_substitute_pc(unsigned long *pinsn, u32 oregs) +{ + probes_opcode_t insn = __mem_to_opcode_arm(*pinsn); + probes_opcode_t temp; + probes_opcode_t mask; + int freereg; + u32 free = 0xffff; + u32 regs; + + for (regs = oregs; regs; regs >>= 4, insn >>= 4) { + if ((regs & 0xf) == REG_TYPE_NONE) + continue; + + free &= ~(1 << (insn & 0xf)); + } + + /* No PC, no problem */ + if (free & (1 << 15)) + return 15; + + if (!free) + return -1; + + /* + * fls instead of ffs ensures that for "ldrd r0, r1, [pc]" we would + * pick LR instead of R1. + */ + freereg = free = fls(free) - 1; + + temp = __mem_to_opcode_arm(*pinsn); + insn = temp; + regs = oregs; + mask = 0xf; + + for (; regs; regs >>= 4, mask <<= 4, free <<= 4, temp >>= 4) { + if ((regs & 0xf) == REG_TYPE_NONE) + continue; + + if ((temp & 0xf) != 15) + continue; + + insn &= ~mask; + insn |= free & mask; + } + + *pinsn = __opcode_to_mem_arm(insn); + return freereg; +} + +static void uprobe_set_pc(struct arch_uprobe *auprobe, + struct arch_uprobe_task *autask, + struct pt_regs *regs) +{ + u32 pcreg = auprobe->pcreg; + + autask->backup = regs->uregs[pcreg]; + regs->uregs[pcreg] = regs->ARM_pc + 8; +} + +static void uprobe_unset_pc(struct arch_uprobe *auprobe, + struct arch_uprobe_task *autask, + struct pt_regs *regs) +{ + /* PC will be taken care of by common code */ + regs->uregs[auprobe->pcreg] = autask->backup; +} + +static void uprobe_aluwrite_pc(struct arch_uprobe *auprobe, + struct arch_uprobe_task *autask, + struct pt_regs *regs) +{ + u32 pcreg = auprobe->pcreg; + + alu_write_pc(regs->uregs[pcreg], regs); + regs->uregs[pcreg] = autask->backup; +} + +static void uprobe_write_pc(struct arch_uprobe *auprobe, + struct arch_uprobe_task *autask, + struct pt_regs *regs) +{ + u32 pcreg = auprobe->pcreg; + + load_write_pc(regs->uregs[pcreg], regs); + regs->uregs[pcreg] = autask->backup; +} + +enum probes_insn +decode_pc_ro(probes_opcode_t insn, struct arch_probes_insn *asi, + const struct decode_header *d) +{ + struct arch_uprobe *auprobe = container_of(asi, struct arch_uprobe, + asi); + struct decode_emulate *decode = (struct decode_emulate *) d; + u32 regs = decode->header.type_regs.bits >> DECODE_TYPE_BITS; + int reg; + + reg = uprobes_substitute_pc(&auprobe->ixol[0], regs); + if (reg == 15) + return INSN_GOOD; + + if (reg == -1) + return INSN_REJECTED; + + auprobe->pcreg = reg; + auprobe->prehandler = uprobe_set_pc; + auprobe->posthandler = uprobe_unset_pc; + + return INSN_GOOD; +} + +enum probes_insn +decode_wb_pc(probes_opcode_t insn, struct arch_probes_insn *asi, + const struct decode_header *d, bool alu) +{ + struct arch_uprobe *auprobe = container_of(asi, struct arch_uprobe, + asi); + enum probes_insn ret = decode_pc_ro(insn, asi, d); + + if (((insn >> 12) & 0xf) == 15) + auprobe->posthandler = alu ? uprobe_aluwrite_pc + : uprobe_write_pc; + + return ret; +} + +enum probes_insn +decode_rd12rn16rm0rs8_rwflags(probes_opcode_t insn, + struct arch_probes_insn *asi, + const struct decode_header *d) +{ + return decode_wb_pc(insn, asi, d, true); +} + +enum probes_insn +decode_ldr(probes_opcode_t insn, struct arch_probes_insn *asi, + const struct decode_header *d) +{ + return decode_wb_pc(insn, asi, d, false); +} + +enum probes_insn +uprobe_decode_ldmstm(probes_opcode_t insn, + struct arch_probes_insn *asi, + const struct decode_header *d) +{ + struct arch_uprobe *auprobe = container_of(asi, struct arch_uprobe, + asi); + unsigned reglist = insn & 0xffff; + int rn = (insn >> 16) & 0xf; + int lbit = insn & (1 << 20); + unsigned used = reglist | (1 << rn); + + if (rn == 15) + return INSN_REJECTED; + + if (!(used & (1 << 15))) + return INSN_GOOD; + + if (used & (1 << 14)) + return INSN_REJECTED; + + /* Use LR instead of PC */ + insn ^= 0xc000; + + auprobe->pcreg = 14; + auprobe->ixol[0] = __opcode_to_mem_arm(insn); + + auprobe->prehandler = uprobe_set_pc; + if (lbit) + auprobe->posthandler = uprobe_write_pc; + else + auprobe->posthandler = uprobe_unset_pc; + + return INSN_GOOD; +} + +const union decode_action uprobes_probes_actions[] = { + [PROBES_PRELOAD_IMM] = {.handler = probes_simulate_nop}, + [PROBES_PRELOAD_REG] = {.handler = probes_simulate_nop}, + [PROBES_BRANCH_IMM] = {.handler = simulate_blx1}, + [PROBES_MRS] = {.handler = simulate_mrs}, + [PROBES_BRANCH_REG] = {.handler = simulate_blx2bx}, + [PROBES_CLZ] = {.handler = probes_simulate_nop}, + [PROBES_SATURATING_ARITHMETIC] = {.handler = probes_simulate_nop}, + [PROBES_MUL1] = {.handler = probes_simulate_nop}, + [PROBES_MUL2] = {.handler = probes_simulate_nop}, + [PROBES_SWP] = {.handler = probes_simulate_nop}, + [PROBES_LDRSTRD] = {.decoder = decode_pc_ro}, + [PROBES_LOAD_EXTRA] = {.decoder = decode_pc_ro}, + [PROBES_LOAD] = {.decoder = decode_ldr}, + [PROBES_STORE_EXTRA] = {.decoder = decode_pc_ro}, + [PROBES_STORE] = {.decoder = decode_pc_ro}, + [PROBES_MOV_IP_SP] = {.handler = simulate_mov_ipsp}, + [PROBES_DATA_PROCESSING_REG] = { + .decoder = decode_rd12rn16rm0rs8_rwflags}, + [PROBES_DATA_PROCESSING_IMM] = { + .decoder = decode_rd12rn16rm0rs8_rwflags}, + [PROBES_MOV_HALFWORD] = {.handler = probes_simulate_nop}, + [PROBES_SEV] = {.handler = probes_simulate_nop}, + [PROBES_WFE] = {.handler = probes_simulate_nop}, + [PROBES_SATURATE] = {.handler = probes_simulate_nop}, + [PROBES_REV] = {.handler = probes_simulate_nop}, + [PROBES_MMI] = {.handler = probes_simulate_nop}, + [PROBES_PACK] = {.handler = probes_simulate_nop}, + [PROBES_EXTEND] = {.handler = probes_simulate_nop}, + [PROBES_EXTEND_ADD] = {.handler = probes_simulate_nop}, + [PROBES_MUL_ADD_LONG] = {.handler = probes_simulate_nop}, + [PROBES_MUL_ADD] = {.handler = probes_simulate_nop}, + [PROBES_BITFIELD] = {.handler = probes_simulate_nop}, + [PROBES_BRANCH] = {.handler = simulate_bbl}, + [PROBES_LDMSTM] = {.decoder = uprobe_decode_ldmstm} +}; diff --git a/arch/arm/probes/uprobes/core.c b/arch/arm/probes/uprobes/core.c new file mode 100644 index 000000000..d1329f1ba --- /dev/null +++ b/arch/arm/probes/uprobes/core.c @@ -0,0 +1,230 @@ +/* + * Copyright (C) 2012 Rabin Vincent + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "../decode.h" +#include "../decode-arm.h" +#include "core.h" + +#define UPROBE_TRAP_NR UINT_MAX + +bool is_swbp_insn(uprobe_opcode_t *insn) +{ + return (__mem_to_opcode_arm(*insn) & 0x0fffffff) == + (UPROBE_SWBP_ARM_INSN & 0x0fffffff); +} + +int set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, + unsigned long vaddr) +{ + return uprobe_write_opcode(mm, vaddr, + __opcode_to_mem_arm(auprobe->bpinsn)); +} + +bool arch_uprobe_ignore(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + if (!auprobe->asi.insn_check_cc(regs->ARM_cpsr)) { + regs->ARM_pc += 4; + return true; + } + + return false; +} + +bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + probes_opcode_t opcode; + + if (!auprobe->simulate) + return false; + + opcode = __mem_to_opcode_arm(*(unsigned int *) auprobe->insn); + + auprobe->asi.insn_singlestep(opcode, &auprobe->asi, regs); + + return true; +} + +unsigned long +arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, + struct pt_regs *regs) +{ + unsigned long orig_ret_vaddr; + + orig_ret_vaddr = regs->ARM_lr; + /* Replace the return addr with trampoline addr */ + regs->ARM_lr = trampoline_vaddr; + return orig_ret_vaddr; +} + +int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, + unsigned long addr) +{ + unsigned int insn; + unsigned int bpinsn; + enum probes_insn ret; + + /* Thumb not yet support */ + if (addr & 0x3) + return -EINVAL; + + insn = __mem_to_opcode_arm(*(unsigned int *)auprobe->insn); + auprobe->ixol[0] = __opcode_to_mem_arm(insn); + auprobe->ixol[1] = __opcode_to_mem_arm(UPROBE_SS_ARM_INSN); + + ret = arm_probes_decode_insn(insn, &auprobe->asi, false, + uprobes_probes_actions, NULL); + switch (ret) { + case INSN_REJECTED: + return -EINVAL; + + case INSN_GOOD_NO_SLOT: + auprobe->simulate = true; + break; + + case INSN_GOOD: + default: + break; + } + + bpinsn = UPROBE_SWBP_ARM_INSN & 0x0fffffff; + if (insn >= 0xe0000000) + bpinsn |= 0xe0000000; /* Unconditional instruction */ + else + bpinsn |= insn & 0xf0000000; /* Copy condition from insn */ + + auprobe->bpinsn = bpinsn; + + return 0; +} + +void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr, + void *src, unsigned long len) +{ + void *xol_page_kaddr = kmap_atomic(page); + void *dst = xol_page_kaddr + (vaddr & ~PAGE_MASK); + + preempt_disable(); + + /* Initialize the slot */ + memcpy(dst, src, len); + + /* flush caches (dcache/icache) */ + flush_uprobe_xol_access(page, vaddr, dst, len); + + preempt_enable(); + + kunmap_atomic(xol_page_kaddr); +} + + +int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + struct uprobe_task *utask = current->utask; + + if (auprobe->prehandler) + auprobe->prehandler(auprobe, &utask->autask, regs); + + utask->autask.saved_trap_no = current->thread.trap_no; + current->thread.trap_no = UPROBE_TRAP_NR; + regs->ARM_pc = utask->xol_vaddr; + + return 0; +} + +int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + struct uprobe_task *utask = current->utask; + + WARN_ON_ONCE(current->thread.trap_no != UPROBE_TRAP_NR); + + current->thread.trap_no = utask->autask.saved_trap_no; + regs->ARM_pc = utask->vaddr + 4; + + if (auprobe->posthandler) + auprobe->posthandler(auprobe, &utask->autask, regs); + + return 0; +} + +bool arch_uprobe_xol_was_trapped(struct task_struct *t) +{ + if (t->thread.trap_no != UPROBE_TRAP_NR) + return true; + + return false; +} + +void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + struct uprobe_task *utask = current->utask; + + current->thread.trap_no = utask->autask.saved_trap_no; + instruction_pointer_set(regs, utask->vaddr); +} + +int arch_uprobe_exception_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + return NOTIFY_DONE; +} + +static int uprobe_trap_handler(struct pt_regs *regs, unsigned int instr) +{ + unsigned long flags; + + local_irq_save(flags); + instr &= 0x0fffffff; + if (instr == (UPROBE_SWBP_ARM_INSN & 0x0fffffff)) + uprobe_pre_sstep_notifier(regs); + else if (instr == (UPROBE_SS_ARM_INSN & 0x0fffffff)) + uprobe_post_sstep_notifier(regs); + local_irq_restore(flags); + + return 0; +} + +unsigned long uprobe_get_swbp_addr(struct pt_regs *regs) +{ + return instruction_pointer(regs); +} + +static struct undef_hook uprobes_arm_break_hook = { + .instr_mask = 0x0fffffff, + .instr_val = (UPROBE_SWBP_ARM_INSN & 0x0fffffff), + .cpsr_mask = MODE_MASK, + .cpsr_val = USR_MODE, + .fn = uprobe_trap_handler, +}; + +static struct undef_hook uprobes_arm_ss_hook = { + .instr_mask = 0x0fffffff, + .instr_val = (UPROBE_SS_ARM_INSN & 0x0fffffff), + .cpsr_mask = MODE_MASK, + .cpsr_val = USR_MODE, + .fn = uprobe_trap_handler, +}; + +static int arch_uprobes_init(void) +{ + register_undef_hook(&uprobes_arm_break_hook); + register_undef_hook(&uprobes_arm_ss_hook); + + return 0; +} +device_initcall(arch_uprobes_init); diff --git a/arch/arm/probes/uprobes/core.h b/arch/arm/probes/uprobes/core.h new file mode 100644 index 000000000..1d0c12dfb --- /dev/null +++ b/arch/arm/probes/uprobes/core.h @@ -0,0 +1,35 @@ +/* + * Copyright (C) 2012 Rabin Vincent + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef __ARM_KERNEL_UPROBES_H +#define __ARM_KERNEL_UPROBES_H + +enum probes_insn uprobe_decode_ldmstm(probes_opcode_t insn, + struct arch_probes_insn *asi, + const struct decode_header *d); + +enum probes_insn decode_ldr(probes_opcode_t insn, + struct arch_probes_insn *asi, + const struct decode_header *d); + +enum probes_insn +decode_rd12rn16rm0rs8_rwflags(probes_opcode_t insn, + struct arch_probes_insn *asi, + const struct decode_header *d); + +enum probes_insn +decode_wb_pc(probes_opcode_t insn, struct arch_probes_insn *asi, + const struct decode_header *d, bool alu); + +enum probes_insn +decode_pc_ro(probes_opcode_t insn, struct arch_probes_insn *asi, + const struct decode_header *d); + +extern const union decode_action uprobes_probes_actions[]; + +#endif -- cgit v1.2.3-54-g00ecf