diff options
Diffstat (limited to 'arch/arm/probes/uprobes/core.c')
| -rw-r--r-- | arch/arm/probes/uprobes/core.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/arch/arm/probes/uprobes/core.c b/arch/arm/probes/uprobes/core.c new file mode 100644 index 000000000..f5f790c6e --- /dev/null +++ b/arch/arm/probes/uprobes/core.c @@ -0,0 +1,227 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2012 Rabin Vincent <rabin at rab.in> + */ + +#include <linux/kernel.h> +#include <linux/stddef.h> +#include <linux/errno.h> +#include <linux/highmem.h> +#include <linux/sched.h> +#include <linux/uprobes.h> +#include <linux/notifier.h> + +#include <asm/opcodes.h> +#include <asm/traps.h> + +#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(auprobe, 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 = (PSR_T_BIT | 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 = (PSR_T_BIT | 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); |