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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /arch/arc/kernel/kprobes.c | |
parent | Initial commit. (diff) | |
download | linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.tar.xz linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.zip |
Adding upstream version 5.10.209.upstream/5.10.209
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | arch/arc/kernel/kprobes.c | 430 |
1 files changed, 430 insertions, 0 deletions
diff --git a/arch/arc/kernel/kprobes.c b/arch/arc/kernel/kprobes.c new file mode 100644 index 000000000..cabef45f1 --- /dev/null +++ b/arch/arc/kernel/kprobes.c @@ -0,0 +1,430 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + */ + +#include <linux/types.h> +#include <linux/kprobes.h> +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/kdebug.h> +#include <linux/sched.h> +#include <linux/uaccess.h> +#include <asm/cacheflush.h> +#include <asm/current.h> +#include <asm/disasm.h> + +#define MIN_STACK_SIZE(addr) min((unsigned long)MAX_STACK_SIZE, \ + (unsigned long)current_thread_info() + THREAD_SIZE - (addr)) + +DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; +DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); + +int __kprobes arch_prepare_kprobe(struct kprobe *p) +{ + /* Attempt to probe at unaligned address */ + if ((unsigned long)p->addr & 0x01) + return -EINVAL; + + /* Address should not be in exception handling code */ + + p->ainsn.is_short = is_short_instr((unsigned long)p->addr); + p->opcode = *p->addr; + + return 0; +} + +void __kprobes arch_arm_kprobe(struct kprobe *p) +{ + *p->addr = UNIMP_S_INSTRUCTION; + + flush_icache_range((unsigned long)p->addr, + (unsigned long)p->addr + sizeof(kprobe_opcode_t)); +} + +void __kprobes arch_disarm_kprobe(struct kprobe *p) +{ + *p->addr = p->opcode; + + flush_icache_range((unsigned long)p->addr, + (unsigned long)p->addr + sizeof(kprobe_opcode_t)); +} + +void __kprobes arch_remove_kprobe(struct kprobe *p) +{ + arch_disarm_kprobe(p); + + /* Can we remove the kprobe in the middle of kprobe handling? */ + if (p->ainsn.t1_addr) { + *(p->ainsn.t1_addr) = p->ainsn.t1_opcode; + + flush_icache_range((unsigned long)p->ainsn.t1_addr, + (unsigned long)p->ainsn.t1_addr + + sizeof(kprobe_opcode_t)); + + p->ainsn.t1_addr = NULL; + } + + if (p->ainsn.t2_addr) { + *(p->ainsn.t2_addr) = p->ainsn.t2_opcode; + + flush_icache_range((unsigned long)p->ainsn.t2_addr, + (unsigned long)p->ainsn.t2_addr + + sizeof(kprobe_opcode_t)); + + p->ainsn.t2_addr = NULL; + } +} + +static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) +{ + kcb->prev_kprobe.kp = kprobe_running(); + kcb->prev_kprobe.status = kcb->kprobe_status; +} + +static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) +{ + __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp); + kcb->kprobe_status = kcb->prev_kprobe.status; +} + +static inline void __kprobes set_current_kprobe(struct kprobe *p) +{ + __this_cpu_write(current_kprobe, p); +} + +static void __kprobes resume_execution(struct kprobe *p, unsigned long addr, + struct pt_regs *regs) +{ + /* Remove the trap instructions inserted for single step and + * restore the original instructions + */ + if (p->ainsn.t1_addr) { + *(p->ainsn.t1_addr) = p->ainsn.t1_opcode; + + flush_icache_range((unsigned long)p->ainsn.t1_addr, + (unsigned long)p->ainsn.t1_addr + + sizeof(kprobe_opcode_t)); + + p->ainsn.t1_addr = NULL; + } + + if (p->ainsn.t2_addr) { + *(p->ainsn.t2_addr) = p->ainsn.t2_opcode; + + flush_icache_range((unsigned long)p->ainsn.t2_addr, + (unsigned long)p->ainsn.t2_addr + + sizeof(kprobe_opcode_t)); + + p->ainsn.t2_addr = NULL; + } + + return; +} + +static void __kprobes setup_singlestep(struct kprobe *p, struct pt_regs *regs) +{ + unsigned long next_pc; + unsigned long tgt_if_br = 0; + int is_branch; + unsigned long bta; + + /* Copy the opcode back to the kprobe location and execute the + * instruction. Because of this we will not be able to get into the + * same kprobe until this kprobe is done + */ + *(p->addr) = p->opcode; + + flush_icache_range((unsigned long)p->addr, + (unsigned long)p->addr + sizeof(kprobe_opcode_t)); + + /* Now we insert the trap at the next location after this instruction to + * single step. If it is a branch we insert the trap at possible branch + * targets + */ + + bta = regs->bta; + + if (regs->status32 & 0x40) { + /* We are in a delay slot with the branch taken */ + + next_pc = bta & ~0x01; + + if (!p->ainsn.is_short) { + if (bta & 0x01) + regs->blink += 2; + else { + /* Branch not taken */ + next_pc += 2; + + /* next pc is taken from bta after executing the + * delay slot instruction + */ + regs->bta += 2; + } + } + + is_branch = 0; + } else + is_branch = + disasm_next_pc((unsigned long)p->addr, regs, + (struct callee_regs *) current->thread.callee_reg, + &next_pc, &tgt_if_br); + + p->ainsn.t1_addr = (kprobe_opcode_t *) next_pc; + p->ainsn.t1_opcode = *(p->ainsn.t1_addr); + *(p->ainsn.t1_addr) = TRAP_S_2_INSTRUCTION; + + flush_icache_range((unsigned long)p->ainsn.t1_addr, + (unsigned long)p->ainsn.t1_addr + + sizeof(kprobe_opcode_t)); + + if (is_branch) { + p->ainsn.t2_addr = (kprobe_opcode_t *) tgt_if_br; + p->ainsn.t2_opcode = *(p->ainsn.t2_addr); + *(p->ainsn.t2_addr) = TRAP_S_2_INSTRUCTION; + + flush_icache_range((unsigned long)p->ainsn.t2_addr, + (unsigned long)p->ainsn.t2_addr + + sizeof(kprobe_opcode_t)); + } +} + +int __kprobes arc_kprobe_handler(unsigned long addr, struct pt_regs *regs) +{ + struct kprobe *p; + struct kprobe_ctlblk *kcb; + + preempt_disable(); + + kcb = get_kprobe_ctlblk(); + p = get_kprobe((unsigned long *)addr); + + if (p) { + /* + * We have reentered the kprobe_handler, since another kprobe + * was hit while within the handler, we save the original + * kprobes and single step on the instruction of the new probe + * without calling any user handlers to avoid recursive + * kprobes. + */ + if (kprobe_running()) { + save_previous_kprobe(kcb); + set_current_kprobe(p); + kprobes_inc_nmissed_count(p); + setup_singlestep(p, regs); + kcb->kprobe_status = KPROBE_REENTER; + return 1; + } + + set_current_kprobe(p); + kcb->kprobe_status = KPROBE_HIT_ACTIVE; + + /* If we have no pre-handler or it returned 0, we continue with + * normal processing. If we have a pre-handler and it returned + * non-zero - which means user handler setup registers to exit + * to another instruction, we must skip the single stepping. + */ + if (!p->pre_handler || !p->pre_handler(p, regs)) { + setup_singlestep(p, regs); + kcb->kprobe_status = KPROBE_HIT_SS; + } else { + reset_current_kprobe(); + preempt_enable_no_resched(); + } + + return 1; + } + + /* no_kprobe: */ + preempt_enable_no_resched(); + return 0; +} + +static int __kprobes arc_post_kprobe_handler(unsigned long addr, + struct pt_regs *regs) +{ + struct kprobe *cur = kprobe_running(); + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + + if (!cur) + return 0; + + resume_execution(cur, addr, regs); + + /* Rearm the kprobe */ + arch_arm_kprobe(cur); + + /* + * When we return from trap instruction we go to the next instruction + * We restored the actual instruction in resume_exectuiont and we to + * return to the same address and execute it + */ + regs->ret = addr; + + if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { + kcb->kprobe_status = KPROBE_HIT_SSDONE; + cur->post_handler(cur, regs, 0); + } + + if (kcb->kprobe_status == KPROBE_REENTER) { + restore_previous_kprobe(kcb); + goto out; + } + + reset_current_kprobe(); + +out: + preempt_enable_no_resched(); + return 1; +} + +/* + * Fault can be for the instruction being single stepped or for the + * pre/post handlers in the module. + * This is applicable for applications like user probes, where we have the + * probe in user space and the handlers in the kernel + */ + +int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned long trapnr) +{ + struct kprobe *cur = kprobe_running(); + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + + switch (kcb->kprobe_status) { + case KPROBE_HIT_SS: + case KPROBE_REENTER: + /* + * We are here because the instruction being single stepped + * caused the fault. We reset the current kprobe and allow the + * exception handler as if it is regular exception. In our + * case it doesn't matter because the system will be halted + */ + resume_execution(cur, (unsigned long)cur->addr, regs); + + if (kcb->kprobe_status == KPROBE_REENTER) + restore_previous_kprobe(kcb); + else + reset_current_kprobe(); + + preempt_enable_no_resched(); + break; + + case KPROBE_HIT_ACTIVE: + case KPROBE_HIT_SSDONE: + /* + * We are here because the instructions in the pre/post handler + * caused the fault. + */ + + /* We increment the nmissed count for accounting, + * we can also use npre/npostfault count for accounting + * these specific fault cases. + */ + kprobes_inc_nmissed_count(cur); + + /* + * We come here because instructions in the pre/post + * handler caused the page_fault, this could happen + * if handler tries to access user space by + * copy_from_user(), get_user() etc. Let the + * user-specified handler try to fix it first. + */ + if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) + return 1; + + /* + * In case the user-specified fault handler returned zero, + * try to fix up. + */ + if (fixup_exception(regs)) + return 1; + + /* + * fixup_exception() could not handle it, + * Let do_page_fault() fix it. + */ + break; + + default: + break; + } + return 0; +} + +int __kprobes kprobe_exceptions_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + struct die_args *args = data; + unsigned long addr = args->err; + int ret = NOTIFY_DONE; + + switch (val) { + case DIE_IERR: + if (arc_kprobe_handler(addr, args->regs)) + return NOTIFY_STOP; + break; + + case DIE_TRAP: + if (arc_post_kprobe_handler(addr, args->regs)) + return NOTIFY_STOP; + break; + + default: + break; + } + + return ret; +} + +static void __used kretprobe_trampoline_holder(void) +{ + __asm__ __volatile__(".global kretprobe_trampoline\n" + "kretprobe_trampoline:\n" "nop\n"); +} + +void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, + struct pt_regs *regs) +{ + + ri->ret_addr = (kprobe_opcode_t *) regs->blink; + ri->fp = NULL; + + /* Replace the return addr with trampoline addr */ + regs->blink = (unsigned long)&kretprobe_trampoline; +} + +static int __kprobes trampoline_probe_handler(struct kprobe *p, + struct pt_regs *regs) +{ + regs->ret = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL); + + /* By returning a non zero value, we are telling the kprobe handler + * that we don't want the post_handler to run + */ + return 1; +} + +static struct kprobe trampoline_p = { + .addr = (kprobe_opcode_t *) &kretprobe_trampoline, + .pre_handler = trampoline_probe_handler +}; + +int __init arch_init_kprobes(void) +{ + /* Registering the trampoline code for the kret probe */ + return register_kprobe(&trampoline_p); +} + +int __kprobes arch_trampoline_kprobe(struct kprobe *p) +{ + if (p->addr == (kprobe_opcode_t *) &kretprobe_trampoline) + return 1; + + return 0; +} + +void trap_is_kprobe(unsigned long address, struct pt_regs *regs) +{ + notify_die(DIE_TRAP, "kprobe_trap", regs, address, 0, SIGTRAP); +} |