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The fix for BZ#21270 (commit 158d5fa0e1) added a mask to avoid offset larger
than 1^44 to be used along __NR_mmap2. However mips64n32 users __NR_mmap,
as mips64n64, but still defines off_t as old non-LFS type (other ILP32, such
x32, defines off_t being equal to off64_t). This leads to use the same
mask meant only for __NR_mmap2 call for __NR_mmap, thus limiting the maximum
offset it can use with mmap64.
This patch fixes by setting the high mask only for __NR_mmap2 usage. The
posix/tst-mmap-offset.c already tests it and also fails for mips64n32. The
patch also change the test to check for an arch-specific header that defines
the maximum supported offset.
Checked on x86_64-linux-gnu, i686-linux-gnu, and I also tests tst-mmap-offset
on qemu simulated mips64 with kernel 3.2.0 kernel for both mips-linux-gnu and
mips64-n32-linux-gnu.
[BZ #24699]
* posix/tst-mmap-offset.c: Mention BZ #24699.
(do_test_bz21270): Rename to do_test_large_offset and use
mmap64_maximum_offset to check for maximum expected offset value.
* sysdeps/generic/mmap_info.h: New file.
* sysdeps/unix/sysv/linux/mips/mmap_info.h: Likewise.
* sysdeps/unix/sysv/linux/mmap64.c (MMAP_OFF_HIGH_MASK): Define iff
__NR_mmap2 is used.
17 lines
705 B
C
17 lines
705 B
C
/* As default architectures with sizeof (off_t) < sizeof (off64_t) the mmap is
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implemented with __SYS_mmap2 syscall and the offset is represented in
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multiples of page size. For offset larger than
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'1 << (page_shift + 8 * sizeof (off_t))' (that is, 1<<44 on system with
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page size of 4096 bytes) the system call silently truncates the offset.
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For this case, glibc mmap implementation returns EINVAL. */
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/* Return the maximum value expected as offset argument in mmap64 call. */
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static inline uint64_t
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mmap64_maximum_offset (long int page_shift)
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{
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if (sizeof (off_t) < sizeof (off64_t))
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return (UINT64_C(1) << (page_shift + (8 * sizeof (off_t)))) - 1;
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else
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return UINT64_MAX;
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}
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