From: Anil S Keshavamurthy arch_prepare_kprobes() was doing lots of functionality in just one single function. This patch attempts to clean up arch_prepare_kprobes() by moving specific sub task to the following (new)functions 1)valid_kprobe_addr() -->> validate the given kprobe address 2)get_kprobe_inst(slot..)->> Retrives the instruction for a given slot from the bundle 3)prepare_break_inst() -->> Prepares break instruction within the bundle 3a)update_kprobe_inst_flag()-->>Updates the internal flags, required for proper emulation of the instruction at later point in time. Signed-off-by: Anil S Keshavamurthy Signed-off-by: Andrew Morton --- arch/ia64/kernel/kprobes.c | 195 ++++++++++++++++++++++++++++----------------- 1 files changed, 123 insertions(+), 72 deletions(-) diff -puN arch/ia64/kernel/kprobes.c~kprobes-ia64-cleanup-2 arch/ia64/kernel/kprobes.c --- 25/arch/ia64/kernel/kprobes.c~kprobes-ia64-cleanup-2 Mon Jun 6 14:52:23 2005 +++ 25-akpm/arch/ia64/kernel/kprobes.c Mon Jun 6 14:52:23 2005 @@ -81,90 +81,141 @@ static enum instruction_type bundle_enco { u, u, u }, /* 1F */ }; -int arch_prepare_kprobe(struct kprobe *p) +/* + * In this function we check to see if the instruction + * is IP relative instruction and update the kprobe + * inst flag accordingly + */ +static void update_kprobe_inst_flag(uint template, uint slot, uint major_opcode, + unsigned long kprobe_inst, struct kprobe *p) { - unsigned long addr = (unsigned long) p->addr; - unsigned long *bundle_addr = (unsigned long *)(addr & ~0xFULL); - unsigned long slot = addr & 0xf; - unsigned long template; - unsigned long major_opcode = 0; - unsigned long lx_type_inst = 0; - unsigned long kprobe_inst = 0; - bundle_t *bundle = &p->ainsn.insn.bundle; - - memcpy(&p->opcode.bundle, bundle_addr, sizeof(bundle_t)); - memcpy(&p->ainsn.insn.bundle, bundle_addr, sizeof(bundle_t)); - p->ainsn.inst_flag = 0; p->ainsn.target_br_reg = 0; - template = bundle->quad0.template; + if (bundle_encoding[template][slot] == B) { + switch (major_opcode) { + case INDIRECT_CALL_OPCODE: + p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG; + p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7); + break; + case IP_RELATIVE_PREDICT_OPCODE: + case IP_RELATIVE_BRANCH_OPCODE: + p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR; + break; + case IP_RELATIVE_CALL_OPCODE: + p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR; + p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG; + p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7); + break; + } + } else if (bundle_encoding[template][slot] == X) { + switch (major_opcode) { + case LONG_CALL_OPCODE: + p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG; + p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7); + break; + } + } + return; +} - if (((bundle_encoding[template][1] == L) && slot > 1) || (slot > 2)) { - printk(KERN_WARNING "Attempting to insert unaligned kprobe at 0x%lx\n", - addr); - return -EINVAL; +/* + * In this function we override the bundle with + * the break instruction at the given slot. + */ +static void prepare_break_inst(uint template, uint slot, uint major_opcode, + unsigned long kprobe_inst, struct kprobe *p) +{ + unsigned long break_inst = BREAK_INST; + bundle_t *bundle = &p->ainsn.insn.bundle; + + /* + * Copy the original kprobe_inst qualifying predicate(qp) + * to the break instruction + */ + break_inst |= (0x3f & kprobe_inst); + + switch (slot) { + case 0: + bundle->quad0.slot0 = break_inst; + break; + case 1: + bundle->quad0.slot1_p0 = break_inst; + bundle->quad1.slot1_p1 = break_inst >> (64-46); + break; + case 2: + bundle->quad1.slot2 = break_inst; + break; } - if (slot == 1 && bundle_encoding[template][1] == L) { - lx_type_inst = 1; - slot = 2; - } + /* + * Update the instruction flag, so that we can + * emulate the instruction properly after we + * single step on original instruction + */ + update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p); +} + +static inline void get_kprobe_inst(bundle_t *bundle, uint slot, + unsigned long *kprobe_inst, uint *major_opcode) +{ + unsigned long kprobe_inst_p0, kprobe_inst_p1; + unsigned int template; + + template = bundle->quad0.template; switch (slot) { - case 0: - major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT); - kprobe_inst = bundle->quad0.slot0; - bundle->quad0.slot0 = BREAK_INST | (0x3f & kprobe_inst); - break; - case 1: - major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT); - kprobe_inst = (bundle->quad0.slot1_p0 | - (bundle->quad1.slot1_p1 << (64-46))); - bundle->quad0.slot1_p0 = BREAK_INST | (0x3f & kprobe_inst); - bundle->quad1.slot1_p1 = (BREAK_INST >> (64-46)); - break; - case 2: - major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT); - kprobe_inst = bundle->quad1.slot2; - bundle->quad1.slot2 = BREAK_INST | (0x3f & kprobe_inst); + case 0: + *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT); + *kprobe_inst = bundle->quad0.slot0; + break; + case 1: + *major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT); + kprobe_inst_p0 = bundle->quad0.slot1_p0; + kprobe_inst_p1 = bundle->quad1.slot1_p1; + *kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46)); + break; + case 2: + *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT); + *kprobe_inst = bundle->quad1.slot2; break; } +} - /* - * Look for IP relative Branches, IP relative call or - * IP relative predicate instructions - */ - if (bundle_encoding[template][slot] == B) { - switch (major_opcode) { - case INDIRECT_CALL_OPCODE: - p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG; - p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7); - break; - case IP_RELATIVE_PREDICT_OPCODE: - case IP_RELATIVE_BRANCH_OPCODE: - p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR; - break; - case IP_RELATIVE_CALL_OPCODE: - p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR; - p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG; - p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7); - break; - default: - /* Do nothing */ - break; - } - } else if (lx_type_inst) { - switch (major_opcode) { - case LONG_CALL_OPCODE: - p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG; - p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7); - break; - default: - /* Do nothing */ - break; - } +static int valid_kprobe_addr(int template, int slot, unsigned long addr) +{ + if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) { + printk(KERN_WARNING "Attempting to insert unaligned kprobe at 0x%lx\n", + addr); + return -EINVAL; } + return 0; +} + +int arch_prepare_kprobe(struct kprobe *p) +{ + unsigned long addr = (unsigned long) p->addr; + unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL); + unsigned long kprobe_inst=0; + unsigned int slot = addr & 0xf, template, major_opcode = 0; + bundle_t *bundle = &p->ainsn.insn.bundle; + + memcpy(&p->opcode.bundle, kprobe_addr, sizeof(bundle_t)); + memcpy(&p->ainsn.insn.bundle, kprobe_addr, sizeof(bundle_t)); + + template = bundle->quad0.template; + + if(valid_kprobe_addr(template, slot, addr)) + return -EINVAL; + + /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */ + if (slot == 1 && bundle_encoding[template][1] == L) + slot++; + + /* Get kprobe_inst and major_opcode from the bundle */ + get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode); + + prepare_break_inst(template, slot, major_opcode, kprobe_inst, p); return 0; } @@ -260,7 +311,7 @@ static void resume_execution(struct kpro if (regs->cr_iip == bundle_addr) { regs->cr_iip = resume_addr; } - } + } turn_ss_off: /* Turn off Single Step bit */ _