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| author | Alex Suykov <alex.suykov@gmail.com> | 2016-08-15 20:32:48 +0300 |
|---|---|---|
| committer | Andrew Waterman <waterman@eecs.berkeley.edu> | 2016-08-15 10:32:48 -0700 |
| commit | 006846161cc2f3de5a34f57d77fd8999f183fe48 (patch) | |
| tree | 159561404d08dac1b77395162e8271b7999b7d2d /newlib | |
| parent | bfbfdec43fc89a6bed4e3b823badcc1414e73740 (diff) | |
| download | riscv-gnu-toolchain-006846161cc2f3de5a34f57d77fd8999f183fe48.zip riscv-gnu-toolchain-006846161cc2f3de5a34f57d77fd8999f183fe48.tar.gz riscv-gnu-toolchain-006846161cc2f3de5a34f57d77fd8999f183fe48.tar.bz2 | |
newlib: use brk(0) to get initial program break (#172)
There are no guarantees that the break going to be located exactly
at the _end, but brk(0) is guaranteed to return its current value.
QEMU ELF loader moves the initial break up to the next page boundary,
disabling sbrk-based malloc for any allocations smaller than
the adjustment made. And ASLR may do even worse.
Diffstat (limited to 'newlib')
| -rw-r--r-- | newlib/libgloss/riscv/syscalls.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/newlib/libgloss/riscv/syscalls.c b/newlib/libgloss/riscv/syscalls.c index 50203d6..ae1edc5 100644 --- a/newlib/libgloss/riscv/syscalls.c +++ b/newlib/libgloss/riscv/syscalls.c @@ -436,11 +436,15 @@ long sysconf(int name) void* sbrk(ptrdiff_t incr) { - extern unsigned char _end[]; // Defined by linker static unsigned long heap_end; - if (heap_end == 0) - heap_end = (long)_end; + if (heap_end == 0) { + long brk = syscall_errno(SYS_brk, 0, 0, 0, 0); + if(brk == -1) + return (void*)-1; + heap_end = brk; + } + if (syscall_errno(SYS_brk, heap_end + incr, 0, 0, 0) != heap_end + incr) return (void*)-1; |