[libc] riscv32 sysconf cannot get page size properly

[SchrodingerZhu]

[1474/1621] Running unit test libc.test.src.unistd.sysconf_test
FAILED: libc/test/src/unistd/CMakeFiles/libc.test.src.unistd.sysconf_test /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/build/libc/test/src/unistd/CMakeFiles/libc.test.src.unistd.sysconf_test 
cd /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/build/libc/test/src/unistd && /home/libcrv32buildbot/cross.sh /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/build/libc/test/src/unistd/libc.test.src.unistd.sysconf_test.__build__
sh: line 1: /timer.24741: Permission denied
[==========] Running 1 test from 1 test suite.
[ RUN      ] LlvmLibcSysconfTest.PagesizeTest
/home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/test/src/unistd/sysconf_test.cpp:16: FAILURE
          Expected: pagesize
          Which is: -1
To be greater than: 0l
          Which is: 0
[  FAILED  ] LlvmLibcSysconfTest.PagesizeTest

This is also reproduced with toybox (https://landley.net/toybox/) after mounting the binary and interpreter.

[llvmbot]

@llvm/issue-subscribers-libc

Author: Schrodinger ZHU Yifan (SchrodingerZhu)

``` [1474/1621] Running unit test libc.test.src.unistd.sysconf_test FAILED: libc/test/src/unistd/CMakeFiles/libc.test.src.unistd.sysconf_test /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/build/libc/test/src/unistd/CMakeFiles/libc.test.src.unistd.sysconf_test cd /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/build/libc/test/src/unistd && /home/libcrv32buildbot/cross.sh /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/build/libc/test/src/unistd/libc.test.src.unistd.sysconf_test.__build__ sh: line 1: /timer.24741: Permission denied [==========] Running 1 test from 1 test suite. [ RUN ] LlvmLibcSysconfTest.PagesizeTest /home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/test/src/unistd/sysconf_test.cpp:16: FAILURE Expected: pagesize Which is: -1 To be greater than: 0l Which is: 0 [ FAILED ] LlvmLibcSysconfTest.PagesizeTest ```

This is also reproduced with toybox (https://landley.net/toybox/) after mounting the binary and interpreter.