cregit-Linux how code gets into the kernel

Release 4.7 tools/testing/selftests/x86/check_initial_reg_state.c

/*
 * check_initial_reg_state.c - check that execve sets the correct state
 * Copyright (c) 2014-2016 Andrew Lutomirski
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 */


#define _GNU_SOURCE

#include <stdio.h>










unsigned long ax, bx, cx, dx, si, di, bp, sp, flags;








unsigned long r8, r9, r10, r11, r12, r13, r14, r15;

asm (
        ".pushsection .text\n\t"
        ".type real_start, @function\n\t"
        ".global real_start\n\t"
        "real_start:\n\t"
#ifdef __x86_64__
	"mov %rax, ax\n\t"
        "mov %rbx, bx\n\t"
        "mov %rcx, cx\n\t"
        "mov %rdx, dx\n\t"
        "mov %rsi, si\n\t"
        "mov %rdi, di\n\t"
        "mov %rbp, bp\n\t"
        "mov %rsp, sp\n\t"
        "mov %r8, r8\n\t"
        "mov %r9, r9\n\t"
        "mov %r10, r10\n\t"
        "mov %r11, r11\n\t"
        "mov %r12, r12\n\t"
        "mov %r13, r13\n\t"
        "mov %r14, r14\n\t"
        "mov %r15, r15\n\t"
        "pushfq\n\t"
        "popq flags\n\t"
#else
	"mov %eax, ax\n\t"
        "mov %ebx, bx\n\t"
        "mov %ecx, cx\n\t"
        "mov %edx, dx\n\t"
        "mov %esi, si\n\t"
        "mov %edi, di\n\t"
        "mov %ebp, bp\n\t"
        "mov %esp, sp\n\t"
        "pushfl\n\t"
        "popl flags\n\t"
#endif
	"jmp _start\n\t"
        ".size real_start, . - real_start\n\t"
        ".popsection");


int main() { int nerrs = 0; if (sp == 0) { printf("[FAIL]\tTest was built incorrectly\n"); return 1; } if (ax || bx || cx || dx || si || di || bp #ifdef __x86_64__ || r8 || r9 || r10 || r11 || r12 || r13 || r14 || r15 #endif ) { printf("[FAIL]\tAll GPRs except SP should be 0\n"); #define SHOW(x) printf("\t" #x " = 0x%lx\n", x); SHOW(ax); SHOW(bx); SHOW(cx); SHOW(dx); SHOW(si); SHOW(di); SHOW(bp); SHOW(sp); #ifdef __x86_64__ SHOW(r8); SHOW(r9); SHOW(r10); SHOW(r11); SHOW(r12); SHOW(r13); SHOW(r14); SHOW(r15); #endif nerrs++; } else { printf("[OK]\tAll GPRs except SP are 0\n"); } if (flags != 0x202) { printf("[FAIL]\tFLAGS is 0x%lx, but it should be 0x202\n", flags); nerrs++; } else { printf("[OK]\tFLAGS is 0x202\n"); } return nerrs ? 1 : 0; }

Contributors

PersonTokensPropCommitsCommitProp
andy lutomirskiandy lutomirski206100.00%1100.00%
Total206100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
andy lutomirskiandy lutomirski262100.00%1100.00%
Total262100.00%1100.00%
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