mirror of
https://github.com/cirosantilli/linux-kernel-module-cheat.git
synced 2026-01-13 20:12:26 +00:00
26b890f42f
This allows add.c to run unmodified on both! For that to work, use int main on baremetal, and pass the return value to the final exit.
89 lines
2.1 KiB
C
89 lines
2.1 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <sys/stat.h>
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enum {
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UART_FR_RXFE = 0x10,
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};
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#define UART_DR(baseaddr) (*(unsigned int *)(baseaddr))
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#define UART_FR(baseaddr) (*(((unsigned int *)(baseaddr))+6))
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int _close(int file) { return -1; }
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int _fstat(int file, struct stat *st) {
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st->st_mode = S_IFCHR;
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return 0;
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}
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int _isatty(int file) { return 1; }
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int _lseek(int file, int ptr, int dir) { return 0; }
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int _open(const char *name, int flags, int mode) { return -1; }
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int _read(int file, char *ptr, int len) {
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int todo;
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if (len == 0)
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return 0;
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while (UART_FR(UART0_ADDR) & UART_FR_RXFE);
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*ptr++ = UART_DR(UART0_ADDR);
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for (todo = 1; todo < len; todo++) {
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if (UART_FR(UART0_ADDR) & UART_FR_RXFE) {
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break;
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}
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*ptr++ = UART_DR(UART0_ADDR);
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}
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return todo;
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}
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char *heap_end = 0;
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caddr_t _sbrk(int incr) {
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extern char heap_low;
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extern char heap_top;
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char *prev_heap_end;
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if (heap_end == 0) {
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heap_end = &heap_low;
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}
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prev_heap_end = heap_end;
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if (heap_end + incr > &heap_top) {
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/* Heap and stack collision */
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return (caddr_t)0;
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}
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heap_end += incr;
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return (caddr_t)prev_heap_end;
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}
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int _write(int file, char *ptr, int len) {
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int todo;
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for (todo = 0; todo < len; todo++) {
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UART_DR(UART0_ADDR) = *ptr++;
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}
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return len;
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}
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/* Only 0 is supported for now, arm semihosting cannot handle other values. */
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void _exit(int status) {
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#if defined(GEM5)
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#if defined(__arm__)
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__asm__ __volatile__ ("mov r0, #0; mov r1, #0; .inst 0xEE000110 | (0x21 << 16);");
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#elif defined(__aarch64__)
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__asm__ __volatile__ ("mov x0, #0; .inst 0XFF000110 | (0x21 << 16);");
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#endif
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#else
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#if defined(__arm__)
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__asm__ __volatile__ ("mov r0, #0x18; ldr r1, =#0x20026; svc 0x00123456");
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#elif defined(__aarch64__)
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/* TODO actually use the exit value here, just for fun. */
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__asm__ __volatile__ (
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"mov x1, #0x26\n" \
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"movk x1, #2, lsl #16\n" \
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"str x1, [sp,#0]\n" \
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"mov x0, #0\n" \
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"str x0, [sp,#8]\n" \
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"mov x1, sp\n" \
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"mov w0, #0x18\n" \
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"hlt 0xf000\n"
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);
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#endif
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#endif
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}
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