92 lines
2.8 KiB
Diff
92 lines
2.8 KiB
Diff
--- /dev/null
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+++ b/test/mmap/mmap2.c
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@@ -0,0 +1,41 @@
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+/* When trying to map /dev/mem with offset 0xFFFFF000 on the ARM platform, mmap
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+ * returns -EOVERFLOW.
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+ *
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+ * Since off_t is defined as a long int and the sign bit is set in the address,
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+ * the shift operation shifts in ones instead of zeroes
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+ * from the left. This results the offset sent to the kernel function becomes
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+ * 0xFFFFFFFF instead of 0x000FFFFF with MMAP2_PAGE_SHIFT set to 12.
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+ */
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+
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+#include <unistd.h>
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+#include <stdio.h>
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+#include <stdlib.h>
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+#include <string.h>
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+#include <errno.h>
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+#include <fcntl.h>
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+#include <sys/mman.h>
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+
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+#define FATAL do { fprintf(stderr, "Error at line %d, file %s (%d) [%s]\n", \
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+ __LINE__, __FILE__, errno, strerror(errno)); exit(1); } while(0)
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+
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+#define MAP_SIZE 4096UL
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+#define MAP_MASK (MAP_SIZE - 1)
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+
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+int main(int argc, char **argv) {
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+ void* map_base = 0;
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+ int fd;
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+ off_t target = 0xfffff000;
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+ if((fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1) FATAL;
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+ printf("/dev/mem opened.\n");
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+ fflush(stdout);
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+
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+ /* Map one page */
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+ map_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,
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+ fd, target & ~MAP_MASK);
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+ if(map_base == (void *) -1) FATAL;
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+ printf("Memory mapped at address %p.\n", map_base);
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+ fflush(stdout);
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+ if(munmap(map_base, MAP_SIZE) == -1) FATAL;
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+ close(fd);
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+ return 0;
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+}
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--- a/libc/sysdeps/linux/arm/mmap.c
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+++ b/libc/sysdeps/linux/arm/mmap.c
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@@ -27,7 +27,6 @@ __ptr_t mmap(__ptr_t addr, size_t len, i
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#elif defined (__NR_mmap2)
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#define __NR__mmap __NR_mmap2
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-
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#ifndef MMAP2_PAGE_SHIFT
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# define MMAP2_PAGE_SHIFT 12
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#endif
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@@ -39,9 +38,17 @@ __ptr_t mmap(__ptr_t addr, size_t len, i
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{
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/* check if offset is page aligned */
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if (offset & ((1 << MMAP2_PAGE_SHIFT) - 1))
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+ {
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+ __set_errno(EINVAL);
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return MAP_FAILED;
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+ }
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+#ifdef __USE_FILE_OFFSET64
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+ return (__ptr_t) _mmap (addr, len, prot, flags,
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+ fd,((__u_quad_t) offset >> MMAP2_PAGE_SHIFT));
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+#else
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return (__ptr_t) _mmap (addr, len, prot, flags,
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- fd,(off_t) (offset >> MMAP2_PAGE_SHIFT));
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+ fd,((__u_long) offset >> MMAP2_PAGE_SHIFT));
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+#endif
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}
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#elif defined (__NR_mmap)
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# define __NR__mmap __NR_mmap
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--- a/libc/sysdeps/linux/common/mmap64.c
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+++ b/libc/sysdeps/linux/common/mmap64.c
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@@ -58,8 +58,13 @@ __ptr_t mmap64(__ptr_t addr, size_t len,
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__set_errno(EINVAL);
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return MAP_FAILED;
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}
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-
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- return __syscall_mmap2(addr, len, prot, flags, fd, (off_t) (offset >> MMAP2_PAGE_SHIFT));
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+#ifdef __USE_FILE_OFFSET64
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+ return __syscall_mmap2(addr, len, prot, flags,
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+ fd,((__u_quad_t)offset >> MMAP2_PAGE_SHIFT));
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+#else
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+ return __syscall_mmap2(addr, len, prot, flags,
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+ fd,((__u_long)offset >> MMAP2_PAGE_SHIFT));
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+#endif
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}
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# endif
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