cregit-Linux how code gets into the kernel

Release 4.14 arch/m32r/kernel/ptrace.c

Directory: arch/m32r/kernel
// SPDX-License-Identifier: GPL-2.0
/*
 * linux/arch/m32r/kernel/ptrace.c
 *
 * Copyright (C) 2002  Hirokazu Takata, Takeo Takahashi
 * Copyright (C) 2004  Hirokazu Takata, Kei Sakamoto
 *
 * Original x86 implementation:
 *      By Ross Biro 1/23/92
 *      edited by Linus Torvalds
 *
 * Some code taken from sh version:
 *   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
 * Some code taken from arm version:
 *   Copyright (C) 2000 Russell King
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/mm.h>
#include <linux/err.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/string.h>
#include <linux/signal.h>

#include <asm/cacheflush.h>
#include <asm/io.h>
#include <linux/uaccess.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/mmu_context.h>

/*
 * This routine will get a word off of the process kernel stack.
 */

static inline unsigned long int get_stack_long(struct task_struct *task, int offset) { unsigned long *stack; stack = (unsigned long *)task_pt_regs(task); return stack[offset]; }

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Hirokazu Takata3997.50%266.67%
Al Viro12.50%133.33%
Total40100.00%3100.00%

/* * This routine will put a word on the process kernel stack. */
static inline int put_stack_long(struct task_struct *task, int offset, unsigned long data) { unsigned long *stack; stack = (unsigned long *)task_pt_regs(task); stack[offset] = data; return 0; }

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Hirokazu Takata4597.83%266.67%
Al Viro12.17%133.33%
Total46100.00%3100.00%

static int reg_offset[] = { PT_R0, PT_R1, PT_R2, PT_R3, PT_R4, PT_R5, PT_R6, PT_R7, PT_R8, PT_R9, PT_R10, PT_R11, PT_R12, PT_FP, PT_LR, PT_SPU, }; /* * Read the word at offset "off" into the "struct user". We * actually access the pt_regs stored on the kernel stack. */
static int ptrace_read_user(struct task_struct *tsk, unsigned long off, unsigned long __user *data) { unsigned long tmp; #ifndef NO_FPU struct user * dummy = NULL; #endif if ((off & 3) || off > sizeof(struct user) - 3) return -EIO; off >>= 2; switch (off) { case PT_EVB: __asm__ __volatile__ ( "mvfc %0, cr5 \n\t" : "=r" (tmp) ); break; case PT_CBR: { unsigned long psw; psw = get_stack_long(tsk, PT_PSW); tmp = ((psw >> 8) & 1); } break; case PT_PSW: { unsigned long psw, bbpsw; psw = get_stack_long(tsk, PT_PSW); bbpsw = get_stack_long(tsk, PT_BBPSW); tmp = ((psw >> 8) & 0xff) | ((bbpsw & 0xff) << 8); } break; case PT_PC: tmp = get_stack_long(tsk, PT_BPC); break; case PT_BPC: off = PT_BBPC; /* fall through */ default: if (off < (sizeof(struct pt_regs) >> 2)) tmp = get_stack_long(tsk, off); #ifndef NO_FPU else if (off >= (long)(&dummy->fpu >> 2) && off < (long)(&dummy->u_fpvalid >> 2)) { if (!tsk_used_math(tsk)) { if (off == (long)(&dummy->fpu.fpscr >> 2)) tmp = FPSCR_INIT; else tmp = 0; } else tmp = ((long *)(&tsk->thread.fpu >> 2)) [off - (long)&dummy->fpu]; } else if (off == (long)(&dummy->u_fpvalid >> 2)) tmp = !!tsk_used_math(tsk); #endif /* not NO_FPU */ else tmp = 0; } return put_user(tmp, data); }

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Hirokazu Takata34297.71%266.67%
Andrea Arcangeli82.29%133.33%
Total350100.00%3100.00%


static int ptrace_write_user(struct task_struct *tsk, unsigned long off, unsigned long data) { int ret = -EIO; #ifndef NO_FPU struct user * dummy = NULL; #endif if ((off & 3) || off > sizeof(struct user) - 3) return -EIO; off >>= 2; switch (off) { case PT_EVB: case PT_BPC: case PT_SPI: /* We don't allow to modify evb. */ ret = 0; break; case PT_PSW: case PT_CBR: { /* We allow to modify only cbr in psw */ unsigned long psw; psw = get_stack_long(tsk, PT_PSW); psw = (psw & ~0x100) | ((data & 1) << 8); ret = put_stack_long(tsk, PT_PSW, psw); } break; case PT_PC: off = PT_BPC; data &= ~1; /* fall through */ default: if (off < (sizeof(struct pt_regs) >> 2)) ret = put_stack_long(tsk, off, data); #ifndef NO_FPU else if (off >= (long)(&dummy->fpu >> 2) && off < (long)(&dummy->u_fpvalid >> 2)) { set_stopped_child_used_math(tsk); ((long *)&tsk->thread.fpu) [off - (long)&dummy->fpu] = data; ret = 0; } else if (off == (long)(&dummy->u_fpvalid >> 2)) { conditional_stopped_child_used_math(data, tsk); ret = 0; } #endif /* not NO_FPU */ break; } return ret; }

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Hirokazu Takata27697.18%266.67%
Andrea Arcangeli82.82%133.33%
Total284100.00%3100.00%

/* * Get all user integer registers. */
static int ptrace_getregs(struct task_struct *tsk, void __user *uregs) { struct pt_regs *regs = task_pt_regs(tsk); return copy_to_user(uregs, regs, sizeof(struct pt_regs)) ? -EFAULT : 0; }

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Hirokazu Takata4497.78%266.67%
Al Viro12.22%133.33%
Total45100.00%3100.00%

/* * Set all user integer registers. */
static int ptrace_setregs(struct task_struct *tsk, void __user *uregs) { struct pt_regs newregs; int ret; ret = -EFAULT; if (copy_from_user(&newregs, uregs, sizeof(struct pt_regs)) == 0) { struct pt_regs *regs = task_pt_regs(tsk); *regs = newregs; ret = 0; } return ret; }

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Hirokazu Takata6998.57%266.67%
Al Viro11.43%133.33%
Total70100.00%3100.00%


static inline int check_condition_bit(struct task_struct *child) { return (int)((get_stack_long(child, PT_PSW) >> 8) & 1); }

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Hirokazu Takata31100.00%2100.00%
Total31100.00%2100.00%


static int check_condition_src(unsigned long op, unsigned long regno1, unsigned long regno2, struct task_struct *child) { unsigned long reg1, reg2; reg2 = get_stack_long(child, reg_offset[regno2]); switch (op) { case 0x0: /* BEQ */ reg1 = get_stack_long(child, reg_offset[regno1]); return reg1 == reg2; case 0x1: /* BNE */ reg1 = get_stack_long(child, reg_offset[regno1]); return reg1 != reg2; case 0x8: /* BEQZ */ return reg2 == 0; case 0x9: /* BNEZ */ return reg2 != 0; case 0xa: /* BLTZ */ return (int)reg2 < 0; case 0xb: /* BGEZ */ return (int)reg2 >= 0; case 0xc: /* BLEZ */ return (int)reg2 <= 0; case 0xd: /* BGTZ */ return (int)reg2 > 0; default: /* never reached */ return 0; } }

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Hirokazu Takata160100.00%2100.00%
Total160100.00%2100.00%


static void compute_next_pc_for_16bit_insn(unsigned long insn, unsigned long pc, unsigned long *next_pc, struct task_struct *child) { unsigned long op, op2, op3; unsigned long disp; unsigned long regno; int parallel = 0; if (insn & 0x00008000) parallel = 1; if (pc & 3) insn &= 0x7fff; /* right slot */ else insn >>= 16; /* left slot */ op = (insn >> 12) & 0xf; op2 = (insn >> 8) & 0xf; op3 = (insn >> 4) & 0xf; if (op == 0x7) { switch (op2) { case 0xd: /* BNC */ case 0x9: /* BNCL */ if (!check_condition_bit(child)) { disp = (long)(insn << 24) >> 22; *next_pc = (pc & ~0x3) + disp; return; } break; case 0x8: /* BCL */ case 0xc: /* BC */ if (check_condition_bit(child)) { disp = (long)(insn << 24) >> 22; *next_pc = (pc & ~0x3) + disp; return; } break; case 0xe: /* BL */ case 0xf: /* BRA */ disp = (long)(insn << 24) >> 22; *next_pc = (pc & ~0x3) + disp; return; break; } } else if (op == 0x1) { switch (op2) { case 0x0: if (op3 == 0xf) { /* TRAP */ #if 1 /* pass through */ #else /* kernel space is not allowed as next_pc */ unsigned long evb; unsigned long trapno; trapno = insn & 0xf; __asm__ __volatile__ ( "mvfc %0, cr5\n" :"=r"(evb) : ); *next_pc = evb + (trapno << 2); return; #endif } else if (op3 == 0xd) { /* RTE */ *next_pc = get_stack_long(child, PT_BPC); return; } break; case 0xc: /* JC */ if (op3 == 0xc && check_condition_bit(child)) { regno = insn & 0xf; *next_pc = get_stack_long(child, reg_offset[regno]); return; } break; case 0xd: /* JNC */ if (op3 == 0xc && !check_condition_bit(child)) { regno = insn & 0xf; *next_pc = get_stack_long(child, reg_offset[regno]); return; } break; case 0xe: /* JL */ case 0xf: /* JMP */ if (op3 == 0xc) { /* JMP */ regno = insn & 0xf; *next_pc = get_stack_long(child, reg_offset[regno]); return; } break; } } if (parallel) *next_pc = pc + 4; else *next_pc = pc + 2; }

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Hirokazu Takata461100.00%2100.00%
Total461100.00%2100.00%


static void compute_next_pc_for_32bit_insn(unsigned long insn, unsigned long pc, unsigned long *next_pc, struct task_struct *child) { unsigned long op; unsigned long op2; unsigned long disp; unsigned long regno1, regno2; op = (insn >> 28) & 0xf; if (op == 0xf) { /* branch 24-bit relative */ op2 = (insn >> 24) & 0xf; switch (op2) { case 0xd: /* BNC */ case 0x9: /* BNCL */ if (!check_condition_bit(child)) { disp = (long)(insn << 8) >> 6; *next_pc = (pc & ~0x3) + disp; return; } break; case 0x8: /* BCL */ case 0xc: /* BC */ if (check_condition_bit(child)) { disp = (long)(insn << 8) >> 6; *next_pc = (pc & ~0x3) + disp; return; } break; case 0xe: /* BL */ case 0xf: /* BRA */ disp = (long)(insn << 8) >> 6; *next_pc = (pc & ~0x3) + disp; return; } } else if (op == 0xb) { /* branch 16-bit relative */ op2 = (insn >> 20) & 0xf; switch (op2) { case 0x0: /* BEQ */ case 0x1: /* BNE */ case 0x8: /* BEQZ */ case 0x9: /* BNEZ */ case 0xa: /* BLTZ */ case 0xb: /* BGEZ */ case 0xc: /* BLEZ */ case 0xd: /* BGTZ */ regno1 = ((insn >> 24) & 0xf); regno2 = ((insn >> 16) & 0xf); if (check_condition_src(op2, regno1, regno2, child)) { disp = (long)(insn << 16) >> 14; *next_pc = (pc & ~0x3) + disp; return; } break; } } *next_pc = pc + 4; }

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Hirokazu Takata331100.00%2100.00%
Total331100.00%2100.00%


static inline void compute_next_pc(unsigned long insn, unsigned long pc, unsigned long *next_pc, struct task_struct *child) { if (insn & 0x80000000) compute_next_pc_for_32bit_insn(insn, pc, next_pc, child); else compute_next_pc_for_16bit_insn(insn, pc, next_pc, child); }

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Hirokazu Takata54100.00%2100.00%
Total54100.00%2100.00%


static int register_debug_trap(struct task_struct *child, unsigned long next_pc, unsigned long next_insn, unsigned long *code) { struct debug_trap *p = &child->thread.debug_trap; unsigned long addr = next_pc & ~3; if (p->nr_trap == MAX_TRAPS) { printk("kernel BUG at %s %d: p->nr_trap = %d\n", __FILE__, __LINE__, p->nr_trap); return -1; } p->addr[p->nr_trap] = addr; p->insn[p->nr_trap] = next_insn; p->nr_trap++; if (next_pc & 3) { *code = (next_insn & 0xffff0000) | 0x10f1; /* xxx --> TRAP1 */ } else { if ((next_insn & 0x80000000) || (next_insn & 0x8000)) { *code = 0x10f17000; /* TRAP1 --> NOP */ } else { *code = (next_insn & 0xffff) | 0x10f10000; /* TRAP1 --> xxx */ } } return 0; }

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Hirokazu Takata162100.00%3100.00%
Total162100.00%3100.00%


static int unregister_debug_trap(struct task_struct *child, unsigned long addr, unsigned long *code) { struct debug_trap *p = &child->thread.debug_trap; int i; /* Search debug trap entry. */ for (i = 0; i < p->nr_trap; i++) { if (p->addr[i] == addr) break; } if (i >= p->nr_trap) { /* The trap may be requested from debugger. * ptrace should do nothing in this case. */ return 0; } /* Recover original instruction code. */ *code = p->insn[i]; /* Shift debug trap entries. */ while (i < p->nr_trap - 1) { p->insn[i] = p->insn[i + 1]; p->addr[i] = p->addr[i + 1]; i++; } p->nr_trap--; return 1; }

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Hirokazu Takata14599.32%375.00%
Joe Perches10.68%125.00%
Total146100.00%4100.00%


static void unregister_all_debug_traps(struct task_struct *child) { struct debug_trap *p = &child->thread.debug_trap; int i; for (i = 0; i < p->nr_trap; i++) access_process_vm(child, p->addr[i], &p->insn[i], sizeof(p->insn[i]), FOLL_FORCE | FOLL_WRITE); p->nr_trap = 0; }

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Hirokazu Takata7896.30%375.00%
Lorenzo Stoakes33.70%125.00%
Total81100.00%4100.00%


static inline void invalidate_cache(void) { #if defined(CONFIG_CHIP_M32700) || defined(CONFIG_CHIP_OPSP) _flush_cache_copyback_all(); #else /* ! CONFIG_CHIP_M32700 */ /* Invalidate cache */ __asm__ __volatile__ ( "ldi r0, #-1 \n\t" "ldi r1, #0 \n\t" "stb r1, @r0 ; cache off \n\t" "; \n\t" "ldi r0, #-2 \n\t" "ldi r1, #1 \n\t" "stb r1, @r0 ; cache invalidate \n\t" ".fillinsn \n" "0: \n\t" "ldb r1, @r0 ; invalidate check \n\t" "bnez r1, 0b \n\t" "; \n\t" "ldi r0, #-1 \n\t" "ldi r1, #1 \n\t" "stb r1, @r0 ; cache on \n\t" : : : "r0", "r1", "memory" ); /* FIXME: copying-back d-cache and invalidating i-cache are needed. */ #endif /* CONFIG_CHIP_M32700 */ }

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Hirokazu Takata34100.00%2100.00%
Total34100.00%2100.00%

/* Embed a debug trap (TRAP1) code */
static int embed_debug_trap(struct task_struct *child, unsigned long next_pc) { unsigned long next_insn, code; unsigned long addr = next_pc & ~3; if (access_process_vm(child, addr, &next_insn, sizeof(next_insn), FOLL_FORCE) != sizeof(next_insn)) { return -1; /* error */ } /* Set a trap code. */ if (register_debug_trap(child, next_pc, next_insn, &code)) { return -1; /* error */ } if (access_process_vm(child, addr, &code, sizeof(code), FOLL_FORCE | FOLL_WRITE) != sizeof(code)) { return -1; /* error */ } return 0; /* success */ }

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Hirokazu Takata11696.67%266.67%
Lorenzo Stoakes43.33%133.33%
Total120100.00%3100.00%


void withdraw_debug_trap(struct pt_regs *regs) { unsigned long addr; unsigned long code; addr = (regs->bpc - 2) & ~3; regs->bpc -= 2; if (unregister_debug_trap(current, addr, &code)) { access_process_vm(current, addr, &code, sizeof(code), FOLL_FORCE | FOLL_WRITE); invalidate_cache(); } }

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Hirokazu Takata7095.89%266.67%
Lorenzo Stoakes34.11%133.33%
Total73100.00%3100.00%


void init_debug_traps(struct task_struct *child) { struct debug_trap *p = &child->thread.debug_trap; int i; p->nr_trap = 0; for (i = 0; i < MAX_TRAPS; i++) { p->addr[i] = 0; p->insn[i] = 0; } }

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Hirokazu Takata64100.00%3100.00%
Total64100.00%3100.00%


void user_enable_single_step(struct task_struct *child) { unsigned long next_pc; unsigned long pc, insn; clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); /* Compute next pc. */ pc = get_stack_long(child, PT_BPC); if (access_process_vm(child, pc&~3, &insn, sizeof(insn), FOLL_FORCE) != sizeof(insn)) return; compute_next_pc(insn, pc, &next_pc, child); if (next_pc & 0x80000000) return; if (embed_debug_trap(child, next_pc)) return; invalidate_cache(); }

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Christoph Hellwig9395.88%133.33%
Geert Uytterhoeven33.09%133.33%
Lorenzo Stoakes11.03%133.33%
Total97100.00%3100.00%


void user_disable_single_step(struct task_struct *child) { unregister_all_debug_traps(child); invalidate_cache(); }

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Christoph Hellwig18100.00%1100.00%
Total18100.00%1100.00%

/* * Called by kernel/ptrace.c when detaching.. * * Make sure single step bits etc are not set. */
void ptrace_disable(struct task_struct *child) { /* nothing to do.. */ }

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Hirokazu Takata11100.00%1100.00%
Total11100.00%1100.00%


long arch_ptrace(struct task_struct *child, long request, unsigned long addr, unsigned long data) { int ret; unsigned long __user *datap = (unsigned long __user *) data; switch (request) { /* * read word at location "addr" in the child process. */ case PTRACE_PEEKTEXT: case PTRACE_PEEKDATA: ret = generic_ptrace_peekdata(child, addr, data); break; /* * read the word at location addr in the USER area. */ case PTRACE_PEEKUSR: ret = ptrace_read_user(child, addr, datap); break; /* * write the word at location addr. */ case PTRACE_POKETEXT: case PTRACE_POKEDATA: ret = generic_ptrace_pokedata(child, addr, data); if (ret == 0 && request == PTRACE_POKETEXT) invalidate_cache(); break; /* * write the word at location addr in the USER area. */ case PTRACE_POKEUSR: ret = ptrace_write_user(child, addr, data); break; case PTRACE_GETREGS: ret = ptrace_getregs(child, datap); break; case PTRACE_SETREGS: ret = ptrace_setregs(child, datap); break; default: ret = ptrace_request(child, request, addr, data); break; } return ret; }

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Hirokazu Takata14484.21%228.57%
Namhyung Kim1911.11%228.57%
Christoph Hellwig52.92%114.29%
Alexey Dobriyan31.75%228.57%
Total171100.00%7100.00%

/* notification of system call entry/exit * - triggered by current->work.syscall_trace */
void do_syscall_trace(void) { if (!test_thread_flag(TIF_SYSCALL_TRACE)) return; if (!(current->ptrace & PT_PTRACED)) return; /* the 0x80 provides a way for the tracing parent to distinguish between a syscall stop and SIGTRAP delivery */ ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0)); /* * this isn't the same as continuing with a signal, but it will do * for normal use. strace only continues with a signal if the * stopping signal is not SIGTRAP. -brl */ if (current->exit_code) { send_sig(current->exit_code, current, 1); current->exit_code = 0; } }

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Hirokazu Takata74100.00%1100.00%
Total74100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Hirokazu Takata284294.01%421.05%
Christoph Hellwig1163.84%210.53%
Namhyung Kim190.63%210.53%
Andrea Arcangeli160.53%15.26%
Lorenzo Stoakes110.36%15.26%
Al Viro40.13%15.26%
Alexey Dobriyan30.10%210.53%
Geert Uytterhoeven30.10%15.26%
Jesper Juhl30.10%15.26%
Ingo Molnar30.10%15.26%
Joe Perches10.03%15.26%
Linus Torvalds10.03%15.26%
Greg Kroah-Hartman10.03%15.26%
Total3023100.00%19100.00%
Directory: arch/m32r/kernel
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