From 22a4424b0b32a898950b917af834967c2672fb9e Mon Sep 17 00:00:00 2001 From: Khem Raj Date: Tue, 15 May 2007 00:37:02 +0000 Subject: Fix arm mmap when using mmap2 syscall. Fixes bug #1303 --- test/mmap/mmap2.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 test/mmap/mmap2.c (limited to 'test/mmap') diff --git a/test/mmap/mmap2.c b/test/mmap/mmap2.c new file mode 100644 index 000000000..b9a8f9ac4 --- /dev/null +++ b/test/mmap/mmap2.c @@ -0,0 +1,41 @@ +/* When trying to map /dev/mem with offset 0xFFFFF000 on the ARM platform, mmap + * returns -EOVERFLOW. + * + * Since off_t is defined as a long int and the sign bit is set in the address, + * the shift operation shifts in ones instead of zeroes + * from the left. This results the offset sent to the kernel function becomes + * 0xFFFFFFFF instead of 0x000FFFFF with MMAP2_PAGE_SHIFT set to 12. + */ + +#include +#include +#include +#include +#include +#include +#include + +#define FATAL do { fprintf(stderr, "Error at line %d, file %s (%d) [%s]\n", \ + __LINE__, __FILE__, errno, strerror(errno)); exit(1); } while(0) + +#define MAP_SIZE 4096UL +#define MAP_MASK (MAP_SIZE - 1) + +int main(int argc, char **argv) { + void* map_base = 0; + int fd; + off_t target = 0xfffff000; + if((fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1) FATAL; + printf("/dev/mem opened.\n"); + fflush(stdout); + + /* Map one page */ + map_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, + fd, target & ~MAP_MASK); + if(map_base == (void *) -1) FATAL; + printf("Memory mapped at address %p.\n", map_base); + fflush(stdout); + if(munmap(map_base, MAP_SIZE) == -1) FATAL; + close(fd); + return 0; +} -- cgit v1.2.3