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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/arm/probes/kprobes/actions-common.c
Initial import
Diffstat (limited to 'arch/arm/probes/kprobes/actions-common.c')
-rw-r--r--arch/arm/probes/kprobes/actions-common.c171
1 files changed, 171 insertions, 0 deletions
diff --git a/arch/arm/probes/kprobes/actions-common.c b/arch/arm/probes/kprobes/actions-common.c
new file mode 100644
index 000000000..bd20a71cd
--- /dev/null
+++ b/arch/arm/probes/kprobes/actions-common.c
@@ -0,0 +1,171 @@
+/*
+ * arch/arm/probes/kprobes/actions-common.c
+ *
+ * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
+ *
+ * Some contents moved here from arch/arm/include/asm/kprobes-arm.c which is
+ * Copyright (C) 2006, 2007 Motorola Inc.
+ *
+ * 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 <linux/kernel.h>
+#include <linux/kprobes.h>
+#include <asm/opcodes.h>
+
+#include "core.h"
+
+
+static void __kprobes simulate_ldm1stm1(probes_opcode_t insn,
+ struct arch_probes_insn *asi,
+ struct pt_regs *regs)
+{
+ int rn = (insn >> 16) & 0xf;
+ int lbit = insn & (1 << 20);
+ int wbit = insn & (1 << 21);
+ int ubit = insn & (1 << 23);
+ int pbit = insn & (1 << 24);
+ long *addr = (long *)regs->uregs[rn];
+ int reg_bit_vector;
+ int reg_count;
+
+ reg_count = 0;
+ reg_bit_vector = insn & 0xffff;
+ while (reg_bit_vector) {
+ reg_bit_vector &= (reg_bit_vector - 1);
+ ++reg_count;
+ }
+
+ if (!ubit)
+ addr -= reg_count;
+ addr += (!pbit == !ubit);
+
+ reg_bit_vector = insn & 0xffff;
+ while (reg_bit_vector) {
+ int reg = __ffs(reg_bit_vector);
+ reg_bit_vector &= (reg_bit_vector - 1);
+ if (lbit)
+ regs->uregs[reg] = *addr++;
+ else
+ *addr++ = regs->uregs[reg];
+ }
+
+ if (wbit) {
+ if (!ubit)
+ addr -= reg_count;
+ addr -= (!pbit == !ubit);
+ regs->uregs[rn] = (long)addr;
+ }
+}
+
+static void __kprobes simulate_stm1_pc(probes_opcode_t insn,
+ struct arch_probes_insn *asi,
+ struct pt_regs *regs)
+{
+ unsigned long addr = regs->ARM_pc - 4;
+
+ regs->ARM_pc = (long)addr + str_pc_offset;
+ simulate_ldm1stm1(insn, asi, regs);
+ regs->ARM_pc = (long)addr + 4;
+}
+
+static void __kprobes simulate_ldm1_pc(probes_opcode_t insn,
+ struct arch_probes_insn *asi,
+ struct pt_regs *regs)
+{
+ simulate_ldm1stm1(insn, asi, regs);
+ load_write_pc(regs->ARM_pc, regs);
+}
+
+static void __kprobes
+emulate_generic_r0_12_noflags(probes_opcode_t insn,
+ struct arch_probes_insn *asi, struct pt_regs *regs)
+{
+ register void *rregs asm("r1") = regs;
+ register void *rfn asm("lr") = asi->insn_fn;
+
+ __asm__ __volatile__ (
+ "stmdb sp!, {%[regs], r11} \n\t"
+ "ldmia %[regs], {r0-r12} \n\t"
+#if __LINUX_ARM_ARCH__ >= 6
+ "blx %[fn] \n\t"
+#else
+ "str %[fn], [sp, #-4]! \n\t"
+ "adr lr, 1f \n\t"
+ "ldr pc, [sp], #4 \n\t"
+ "1: \n\t"
+#endif
+ "ldr lr, [sp], #4 \n\t" /* lr = regs */
+ "stmia lr, {r0-r12} \n\t"
+ "ldr r11, [sp], #4 \n\t"
+ : [regs] "=r" (rregs), [fn] "=r" (rfn)
+ : "0" (rregs), "1" (rfn)
+ : "r0", "r2", "r3", "r4", "r5", "r6", "r7",
+ "r8", "r9", "r10", "r12", "memory", "cc"
+ );
+}
+
+static void __kprobes
+emulate_generic_r2_14_noflags(probes_opcode_t insn,
+ struct arch_probes_insn *asi, struct pt_regs *regs)
+{
+ emulate_generic_r0_12_noflags(insn, asi,
+ (struct pt_regs *)(regs->uregs+2));
+}
+
+static void __kprobes
+emulate_ldm_r3_15(probes_opcode_t insn,
+ struct arch_probes_insn *asi, struct pt_regs *regs)
+{
+ emulate_generic_r0_12_noflags(insn, asi,
+ (struct pt_regs *)(regs->uregs+3));
+ load_write_pc(regs->ARM_pc, regs);
+}
+
+enum probes_insn __kprobes
+kprobe_decode_ldmstm(probes_opcode_t insn, struct arch_probes_insn *asi,
+ const struct decode_header *h)
+{
+ probes_insn_handler_t *handler = 0;
+ unsigned reglist = insn & 0xffff;
+ int is_ldm = insn & 0x100000;
+ int rn = (insn >> 16) & 0xf;
+
+ if (rn <= 12 && (reglist & 0xe000) == 0) {
+ /* Instruction only uses registers in the range R0..R12 */
+ handler = emulate_generic_r0_12_noflags;
+
+ } else if (rn >= 2 && (reglist & 0x8003) == 0) {
+ /* Instruction only uses registers in the range R2..R14 */
+ rn -= 2;
+ reglist >>= 2;
+ handler = emulate_generic_r2_14_noflags;
+
+ } else if (rn >= 3 && (reglist & 0x0007) == 0) {
+ /* Instruction only uses registers in the range R3..R15 */
+ if (is_ldm && (reglist & 0x8000)) {
+ rn -= 3;
+ reglist >>= 3;
+ handler = emulate_ldm_r3_15;
+ }
+ }
+
+ if (handler) {
+ /* We can emulate the instruction in (possibly) modified form */
+ asi->insn[0] = __opcode_to_mem_arm((insn & 0xfff00000) |
+ (rn << 16) | reglist);
+ asi->insn_handler = handler;
+ return INSN_GOOD;
+ }
+
+ /* Fallback to slower simulation... */
+ if (reglist & 0x8000)
+ handler = is_ldm ? simulate_ldm1_pc : simulate_stm1_pc;
+ else
+ handler = simulate_ldm1stm1;
+ asi->insn_handler = handler;
+ return INSN_GOOD_NO_SLOT;
+}
+