Message ID | cover.1684949267.git.falcon@tinylab.org (mailing list archive) |
---|---|
Headers | show |
Series | tools/nolibc: riscv: Add full rv32 support | expand |
Hi, Just to mention, the 3rd one is missing in the riscv-linux mailing list [1], but it is ok in the other two [2], [3], it was sent with the same command ;-( [1]: https://lore.kernel.org/linux-riscv/cover.1684949267.git.falcon@tinylab.org/T/#m1c2c31ec2f5dfafc7d0067a1e5fe430d591d74b8 [2]: https://lore.kernel.org/lkml/cover.1684949267.git.falcon@tinylab.org/T/#m1c2c31ec2f5dfafc7d0067a1e5fe430d591d74b8 [3]: https://lore.kernel.org/linux-kselftest/cover.1684949267.git.falcon@tinylab.org/T/#t If required, do we need to resend the 3rd to riscv-linux only? Thanks, Zhangjin > Hi, Willy > > Thanks very mush for your kindly review, discuss and suggestion, now we > get full rv32 support ;-) > > In the first series [1], we have fixed up the compile errors about > _start and __NR_llseek for rv32, but left compile errors about tons of > time32 syscalls (removed after kernel commit d4c08b9776b3 ("riscv: Use > latest system call ABI")) and the missing fstat in nolibc-test.c [2], > now we have fixed up all of them. > > Introduction > ============ > > This series is based on the 20230524-nolibc-rv32+stkp4 branch of [3], it > includes 3 parts, they work together to add full rv32 support: > > * Reverts two old out-of-day patches > * Revert "tools/nolibc: riscv: Support __NR_llseek for rv32" > * Revert "selftests/nolibc: Fix up compile error for rv32" > > (these two and the reverted ones: > > * commit 606343b7478c ("selftests/nolibc: Fix up compile error for rv32") > * commit d2c3acba6d66 ("tools/nolibc: riscv: Support __NR_llseek for rv32") > > can be removed from the git repo completely, there are two new ones to replace > them) > > * Compile and test support patches > * selftests/nolibc: print name instead of number for EOVERFLOW > * selftests/nolibc: syscall_args: use __NR_statx for rv32 > * --> replace the old one 606343b7478, use statx instead of read > * selftests/nolibc: riscv: customize makefile for rv32 > * selftests/nolibc: allow specify a bios for qemu > * selftests/nolibc: remove the duplicated gettimeofday_bad2 > > * Fix up some missing syscalls, mainly time32 syscalls > * tools/nolibc: sys_lseek: riscv: use __NR_llseek for rv32 > * --> replace the old one d2c3acba6d66, cleaned up > * tools/nolibc: sys_poll: riscv: use __NR_ppoll_time64 for rv32 > * tools/nolibc: ppoll/ppoll_time64: Add a missing argument > * tools/nolibc: sys_select: riscv: use __NR_pselect6_time64 for rv32 > * tools/nolibc: sys_wait4: riscv: use __NR_waitid for rv32 > * tools/nolibc: sys_gettimeofday: riscv: use __NR_clock_gettime64 for rv32 > > Compile > ======= > > For rv64: > > $ make ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- nolibc-test > $ file nolibc-test > nolibc-test: ELF 64-bit LSB executable, UCB RISC-V ... > > $ make ARCH=riscv64 CROSS_COMPILE=riscv64-linux-gnu- nolibc-test > $ file nolibc-test > nolibc-test: ELF 64-bit LSB executable, UCB RISC-V ... > > For rv32: > > $ make ARCH=riscv CONFIG_32BIT=1 CROSS_COMPILE=riscv64-linux-gnu- nolibc-test > $ file nolibc-test > nolibc-test: ELF 32-bit LSB executable, UCB RISC-V ... > > $ make ARCH=riscv32 CROSS_COMPILE=riscv64-linux-gnu- nolibc-test > $ file nolibc-test > nolibc-test: ELF 32-bit LSB executable, UCB RISC-V ... > > Testing > ======= > > Environment: > > // gcc toolchain > $ riscv64-linux-gnu-gcc --version > riscv64-linux-gnu-gcc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0 > Copyright (C) 2019 Free Software Foundation, Inc. > This is free software; see the source for copying conditions. There is NO > warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. > > // glibc >= 2.33 required, for older glibc, must upgrade include/bits/wordsize.h > $ dpkg -l | grep libc6-dev | grep riscv > ii libc6-dev-riscv64-cross 2.31-0ubuntu7cross1 > > // glibc include/bits/wordsize.h: manually upgraded to >= 2.33 > // without this, can not build tools/testing/selftests/nolibc/nolibc-test.c > $ cat /usr/riscv64-linux-gnu/include/bits/wordsize.h > #if __riscv_xlen == (__SIZEOF_POINTER__ * 8) > # define __WORDSIZE __riscv_xlen > #else > # error unsupported ABI > #endif > > # define __WORDSIZE_TIME64_COMPAT32 1 > > #if __WORDSIZE == 32 > # define __WORDSIZE32_SIZE_ULONG 0 > # define __WORDSIZE32_PTRDIFF_LONG 0 > #endif > > // higher qemu version is better, latest version is v8.0.0+ > $ qemu-system-riscv64 --version > QEMU emulator version 4.2.1 (Debian 1:4.2-3ubuntu6.18) > Copyright (c) 2003-2019 Fabrice Bellard and the QEMU Project developers > > // opensbi version, higher is better, must match kernel version and qemu version > // rv64: used version is 1.2, latest is 1.2 > $ head -2 /labs/linux-lab/src/linux-stable/tools/testing/selftests/nolibc/run.out | tail -1 > OpenSBI v1.2-116-g7919530 > // rv32: used version is v0.9, latest is 1.2 > $ head -2 /labs/linux-lab/src/linux-stable/tools/testing/selftests/nolibc/run.out | tail -1 > OpenSBI v0.9-152-g754d511 > > For rv64: > > $ pwd > /labs/linux-lab/src/linux-stable/tools/testing/selftests/nolibc > $ make ARCH=riscv64 CROSS_COMPILE=riscv64-linux-gnu- defconfig > $ make ARCH=riscv64 CROSS_COMPILE=riscv64-linux-gnu- BIOS=/labs/linux-lab/boards/riscv64/virt/bsp/bios/opensbi/generic/fw_jump.elf run > MKDIR sysroot/riscv/include > make[1]: Entering directory '/labs/linux-lab/src/linux-stable/tools/include/nolibc' > make[2]: Entering directory '/labs/linux-lab/src/linux-stable' > make[2]: Leaving directory '/labs/linux-lab/src/linux-stable' > make[2]: Entering directory '/labs/linux-lab/src/linux-stable' > INSTALL /labs/linux-lab/src/linux-stable/tools/testing/selftests/nolibc/sysroot/sysroot/include > make[2]: Leaving directory '/labs/linux-lab/src/linux-stable' > make[1]: Leaving directory '/labs/linux-lab/src/linux-stable/tools/include/nolibc' > CC nolibc-test > MKDIR initramfs > INSTALL initramfs/init > make[1]: Entering directory '/labs/linux-lab/src/linux-stable' > ... > LD vmlinux > NM System.map > SORTTAB vmlinux > OBJCOPY arch/riscv/boot/Image > Kernel: arch/riscv/boot/Image is ready > make[1]: Leaving directory '/labs/linux-lab/src/linux-stable' > 135 test(s) passed. > $ file ../../../../vmlinux > ../../../../vmlinux: ELF 64-bit LSB executable, UCB RISC-V, version 1 (SYSV), statically linked, BuildID[sha1]=b8e1cea5122b04bce540b4022f0d6f171ffe615a, not stripped > > For rv32: > > $ pwd > /labs/linux-lab/src/linux-stable/tools/testing/selftests/nolibc > $ make ARCH=riscv32 CROSS_COMPILE=riscv64-linux-gnu- defconfig > $ make ARCH=riscv32 CROSS_COMPILE=riscv64-linux-gnu- BIOS=/labs/linux-lab/boards/riscv32/virt/bsp/bios/opensbi/generic/fw_jump.elf run > MKDIR sysroot/riscv/include > make[1]: Entering directory '/labs/linux-lab/src/linux-stable/tools/include/nolibc' > make[2]: Entering directory '/labs/linux-lab/src/linux-stable' > make[2]: Leaving directory '/labs/linux-lab/src/linux-stable' > make[2]: Entering directory '/labs/linux-lab/src/linux-stable' > INSTALL /labs/linux-lab/src/linux-stable/tools/testing/selftests/nolibc/sysroot/sysroot/include > make[2]: Leaving directory '/labs/linux-lab/src/linux-stable' > make[1]: Leaving directory '/labs/linux-lab/src/linux-stable/tools/include/nolibc' > CC nolibc-test > MKDIR initramfs > INSTALL initramfs/init > make[1]: Entering directory '/labs/linux-lab/src/linux-stable' > CALL scripts/checksyscalls.sh > GEN usr/initramfs_data.cpio > COPY usr/initramfs_inc_data > AS usr/initramfs_data.o > AR usr/built-in.a > GEN security/selinux/flask.h security/selinux/av_permissions.h > CC security/selinux/avc.o > CC security/selinux/hooks.o > CC security/selinux/selinuxfs.o > CC security/selinux/nlmsgtab.o > CC security/selinux/netif.o > CC security/selinux/netnode.o > CC security/selinux/netport.o > CC security/selinux/status.o > CC security/selinux/ss/services.o > AR security/selinux/built-in.a > AR security/built-in.a > AR built-in.a > AR vmlinux.a > LD vmlinux.o > OBJCOPY modules.builtin.modinfo > GEN modules.builtin > MODPOST vmlinux.symvers > UPD include/generated/utsversion.h > CC init/version-timestamp.o > LD .tmp_vmlinux.kallsyms1 > NM .tmp_vmlinux.kallsyms1.syms > KSYMS .tmp_vmlinux.kallsyms1.S > AS .tmp_vmlinux.kallsyms1.S > LD .tmp_vmlinux.kallsyms2 > NM .tmp_vmlinux.kallsyms2.syms > KSYMS .tmp_vmlinux.kallsyms2.S > AS .tmp_vmlinux.kallsyms2.S > LD vmlinux > NM System.map > SORTTAB vmlinux > OBJCOPY arch/riscv/boot/Image > Kernel: arch/riscv/boot/Image is ready > make[1]: Leaving directory '/labs/linux-lab/src/linux-stable' > 135 test(s) passed. > $ file ../../../../vmlinux > ../../../../vmlinux: ELF 32-bit LSB executable, UCB RISC-V, version 1 (SYSV), statically linked, BuildID[sha1]=bad4c1f3899f47355d2a2010bade56972fd94b9d, not stripped > > The full rv64 testing result (run.out) is uploaded at [4]. > The full rv32 testing result (run.out) is uploaded at [5]. > > That's all, thanks! > > Best regards, > Zhangjin Wu > --- > > [1]: https://lore.kernel.org/linux-riscv/20230520143154.68663-1-falcon@tinylab.org/T/#mf0e54ee19bd3f94dadbb4420ed9dffa316d1719d > [2]: https://lore.kernel.org/linux-riscv/20230520135235.68155-1-falcon@tinylab.org/T/#u > [3]: https://git.kernel.org/pub/scm/linux/kernel/git/wtarreau/nolibc.git > [4]: https://pastebin.com/3L0nV78u > [5]: https://pastebin.com/RadrXdta > > > > Zhangjin Wu (13): > Revert "tools/nolibc: riscv: Support __NR_llseek for rv32" > Revert "selftests/nolibc: Fix up compile error for rv32" > selftests/nolibc: print name instead of number for EOVERFLOW > selftests/nolibc: syscall_args: use __NR_statx for rv32 > selftests/nolibc: riscv: customize makefile for rv32 > selftests/nolibc: allow specify a bios for qemu > selftests/nolibc: remove the duplicated gettimeofday_bad2 > tools/nolibc: sys_lseek: riscv: use __NR_llseek for rv32 > tools/nolibc: sys_poll: riscv: use __NR_ppoll_time64 for rv32 > tools/nolibc: ppoll/ppoll_time64: Add a missing argument > tools/nolibc: sys_select: riscv: use __NR_pselect6_time64 for rv32 > tools/nolibc: sys_wait4: riscv: use __NR_waitid for rv32 > tools/nolibc: sys_gettimeofday: riscv: use __NR_clock_gettime64 for > rv32 > > tools/include/nolibc/std.h | 1 + > tools/include/nolibc/sys.h | 135 +++++++++++++++++-- > tools/include/nolibc/types.h | 21 ++- > tools/testing/selftests/nolibc/Makefile | 14 +- > tools/testing/selftests/nolibc/nolibc-test.c | 15 ++- > 5 files changed, 167 insertions(+), 19 deletions(-) > > -- > 2.25.1
Hi Zhangjin, On Thu, May 25, 2023 at 01:33:14AM +0800, Zhangjin Wu wrote: > Hi, Willy > > Thanks very mush for your kindly review, discuss and suggestion, now we > get full rv32 support ;-) > > In the first series [1], we have fixed up the compile errors about > _start and __NR_llseek for rv32, but left compile errors about tons of > time32 syscalls (removed after kernel commit d4c08b9776b3 ("riscv: Use > latest system call ABI")) and the missing fstat in nolibc-test.c [2], > now we have fixed up all of them. (...) I have read the comments that others made on the series and overall agree. I've seen that you intend to prepare a v2. I think we must first decide how to better deal with emulated syscalls as I said in an earlier message. Probably that we should just add a specific test case for EFAULT in nolibc-test since it's the only one (I think) that risks to trigger crashes with emulated syscalls. We could also imagine dealing with the signal ourselves but I'm not that keen on going to implement signal() & longjmp() for now :-/ Regardless, in order to clean the things up and relieve you from the non-rv32 stuff, I've just reverted the two patches that your series reverts (1 & 2), and added the EOVERFLOW one (3). I'm pushing this to branch 20230528-nolibc-rv32+stkp5. Regards, Willy
On 2023-05-28 09:59:55+0200, Willy Tarreau wrote: > On Thu, May 25, 2023 at 01:33:14AM +0800, Zhangjin Wu wrote: > > Thanks very mush for your kindly review, discuss and suggestion, now we > > get full rv32 support ;-) > > > > In the first series [1], we have fixed up the compile errors about > > _start and __NR_llseek for rv32, but left compile errors about tons of > > time32 syscalls (removed after kernel commit d4c08b9776b3 ("riscv: Use > > latest system call ABI")) and the missing fstat in nolibc-test.c [2], > > now we have fixed up all of them. > > (...) > > I have read the comments that others made on the series and overall > agree. I've seen that you intend to prepare a v2. I think we must > first decide how to better deal with emulated syscalls as I said in > an earlier message. Probably that we should just add a specific test > case for EFAULT in nolibc-test since it's the only one (I think) that > risks to trigger crashes with emulated syscalls. We could also imagine > dealing with the signal ourselves but I'm not that keen on going to > implement signal() & longjmp() for now :-/ > > Regardless, in order to clean the things up and relieve you from the > non-rv32 stuff, I've just reverted the two patches that your series > reverts (1 & 2), and added the EOVERFLOW one (3). I'm pushing this to > branch 20230528-nolibc-rv32+stkp5. If you are fine with pushing more stuff to this branch, picking up the fix for the duplicated test gettimeofday_bad2 (7) would be nice, too. Thomas
On 2023-05-28 10:42:39+0200, Thomas Weißschuh wrote: > On 2023-05-28 09:59:55+0200, Willy Tarreau wrote: > > On Thu, May 25, 2023 at 01:33:14AM +0800, Zhangjin Wu wrote: > > > Thanks very mush for your kindly review, discuss and suggestion, now we > > > get full rv32 support ;-) > > > > > > In the first series [1], we have fixed up the compile errors about > > > _start and __NR_llseek for rv32, but left compile errors about tons of > > > time32 syscalls (removed after kernel commit d4c08b9776b3 ("riscv: Use > > > latest system call ABI")) and the missing fstat in nolibc-test.c [2], > > > now we have fixed up all of them. > > > > (...) > > > > I have read the comments that others made on the series and overall > > agree. I've seen that you intend to prepare a v2. I think we must > > first decide how to better deal with emulated syscalls as I said in > > an earlier message. Probably that we should just add a specific test > > case for EFAULT in nolibc-test since it's the only one (I think) that > > risks to trigger crashes with emulated syscalls. We could also imagine > > dealing with the signal ourselves but I'm not that keen on going to > > implement signal() & longjmp() for now :-/ > > > > Regardless, in order to clean the things up and relieve you from the > > non-rv32 stuff, I've just reverted the two patches that your series > > reverts (1 & 2), and added the EOVERFLOW one (3). I'm pushing this to > > branch 20230528-nolibc-rv32+stkp5. > > If you are fine with pushing more stuff to this branch, picking up > the fix for the duplicated test gettimeofday_bad2 (7) would be nice, too. And the ppoll() argument cleanup (10) for that matter. Zhangjin: IMO it would be more convenient to move generic cleanup patches to the beginning of the series. When the reviewers are focussing on the real changes they won't be interrupted by the cleanups. Also the maintainer can more easily pick them up independently, so they are dealt with and nobody has to worry about them anymore. Thomas
On Sun, May 28, 2023 at 11:41:53AM +0200, Thomas Weißschuh wrote: > > If you are fine with pushing more stuff to this branch, picking up > > the fix for the duplicated test gettimeofday_bad2 (7) would be nice, too. > > And the ppoll() argument cleanup (10) for that matter. OK now both done, thank you. > IMO it would be more convenient to move generic cleanup patches to the > beginning of the series. > When the reviewers are focussing on the real changes they won't be > interrupted by the cleanups. Also the maintainer can more easily pick > them up independently, so they are dealt with and nobody has to worry > about them anymore. Agreed! Thanks! Willy
Hi, Willy > Hi Zhangjin, > > On Thu, May 25, 2023 at 01:33:14AM +0800, Zhangjin Wu wrote: > > Hi, Willy > > > > Thanks very mush for your kindly review, discuss and suggestion, now we > > get full rv32 support ;-) > > > > In the first series [1], we have fixed up the compile errors about > > _start and __NR_llseek for rv32, but left compile errors about tons of > > time32 syscalls (removed after kernel commit d4c08b9776b3 ("riscv: Use > > latest system call ABI")) and the missing fstat in nolibc-test.c [2], > > now we have fixed up all of them. > > (...) > > I have read the comments that others made on the series and overall > agree. I've seen that you intend to prepare a v2. I think we must > first decide how to better deal with emulated syscalls as I said in > an earlier message. Probably that we should just add a specific test > case for EFAULT in nolibc-test since it's the only one (I think) that > risks to trigger crashes with emulated syscalls. We could also imagine > dealing with the signal ourselves but I'm not that keen on going to > implement signal() & longjmp() for now :-/ > Yes, user-space signal() may be the right direction, we just need to let user-space not crash the kernel, what about this 'solution' for current stage (consider the pure time64 support too): #if defined(NOLIBC) && defined(__NR_gettimeofday) && __SIZEOF_LONG__ == 8 CASE_TEST(gettimeofday_bad1); EXPECT_SYSER(1, gettimeofday((void *)1, NULL), -1, EFAULT); break; CASE_TEST(gettimeofday_bad2); EXPECT_SYSER(1, gettimeofday(NULL, (void *)1), -1, EFAULT); break; #endif This idea is from your commit 1da02f51088 ("selftests/nolibc: support glibc as well") for glibc, but the difference is of course glibc not crashes the kernel. Btw, since the gettimeofday_null case may be optimized by compiler and not trigger such errors: // rv32 nolibc-test.c:(.text.run_syscall+0x8c0): undefined reference to `__divdi3' // arm32 nolibc-test.c:(.text.run_syscall+0x820): undefined reference to `__aeabi_ldivmod' The above errors have been hidden after the disabling of the gettimeofday_bad1 test case, so, still need to solve it before sending v2. The method used by musl may work, but the high bits may be lost (from long long to int)? tv->tv_usec = (int)ts.tv_nsec / 1000; Perhaps we really need to add the missing __divdi3 and __aeabi_ldivmod and the ones for the other architectures, or get one from lib/math/div64.c. Will add such new test cases to detect the above issues: CASE_TEST(gettimeofday_tv); EXPECT_SYSZR(1, gettimeofday(&tv, NULL)); break; CASE_TEST(gettimeofday_tz); EXPECT_SYSZR(1, gettimeofday(NULL, &tz)); break; CASE_TEST(gettimeofday_tv_tz);EXPECT_SYSZR(1, gettimeofday(&tv, &tz)); break; May still require to add 'used' attribute to 'struct timeval tv' and 'struct timeval tz' to let compiler not optimize them away. For the waitid syscall based waitpid INT_MIN test case, I have prepared such code: #define IF_TEST(name) \ if (strcmp(test, #name) == 0) const int _errorno(const char *test) { #ifdef __NR_wait4 IF_TEST(waitpid_min); return ESRCH; #else /* __NR_waitid */ IF_TEST(waitpid_min); return EINVAL; #endif return 0; } #define errorno(test) _errorno(#test) CASE_TEST(waitpid_min); EXPECT_SYSER(1, waitpid(INT_MIN, &tmp, WNOHANG), -1, errorno(waitpid_min)); break; Instead of simply disabling this case, the above code allows to return different values for different syscalls. is a standalone errorno_waitpid_min() better? I just want to let future test cases share some code, but it may be slower ;-) > Regardless, in order to clean the things up and relieve you from the > non-rv32 stuff, I've just reverted the two patches that your series > reverts (1 & 2), and added the EOVERFLOW one (3). I'm pushing this to > branch 20230528-nolibc-rv32+stkp5. > Thanks very much and I have seen another two have been pushed too, will rebase everything on this new branch. Based on the other suggestions from you and Thomas, I plan to send some generic and independent changes at first, and then the left hard parts, It may simplify the whole progress. Best regards, Zhangjin > Regards, > Willy
On Sun, May 28, 2023 at 06:39:57PM +0800, Zhangjin Wu wrote: > > I have read the comments that others made on the series and overall > > agree. I've seen that you intend to prepare a v2. I think we must > > first decide how to better deal with emulated syscalls as I said in > > an earlier message. Probably that we should just add a specific test > > case for EFAULT in nolibc-test since it's the only one (I think) that > > risks to trigger crashes with emulated syscalls. We could also imagine > > dealing with the signal ourselves but I'm not that keen on going to > > implement signal() & longjmp() for now :-/ > > > > Yes, user-space signal() may be the right direction, we just need to let > user-space not crash the kernel, what about this 'solution' for current stage > (consider the pure time64 support too): > > #if defined(NOLIBC) && defined(__NR_gettimeofday) && __SIZEOF_LONG__ == 8 > CASE_TEST(gettimeofday_bad1); EXPECT_SYSER(1, gettimeofday((void *)1, NULL), -1, EFAULT); break; > CASE_TEST(gettimeofday_bad2); EXPECT_SYSER(1, gettimeofday(NULL, (void *)1), -1, EFAULT); break; > #endif > > This idea is from your commit 1da02f51088 ("selftests/nolibc: support glibc as > well") for glibc, but the difference is of course glibc not crashes the kernel. Well, I was imagining implementing an EXPECT_EFAULT() macro that would rely on whatever other macros we'd set to indicate that a syscall got remapped. But I had another check grepping for EFAULT: CASE_TEST(gettimeofday_bad1); EXPECT_SYSER(1, gettimeofday((void *)1, NULL), -1, EFAULT); break; CASE_TEST(gettimeofday_bad2); EXPECT_SYSER(1, gettimeofday(NULL, (void *)1), -1, EFAULT); break; CASE_TEST(poll_fault); EXPECT_SYSER(1, poll((void *)1, 1, 0), -1, EFAULT); break; CASE_TEST(prctl); EXPECT_SYSER(1, prctl(PR_SET_NAME, (unsigned long)NULL, 0, 0, 0), -1, EFAULT); break; CASE_TEST(select_fault); EXPECT_SYSER(1, select(1, (void *)1, NULL, NULL, 0), -1, EFAULT); break; CASE_TEST(stat_fault); EXPECT_SYSER(1, stat(NULL, &stat_buf), -1, EFAULT); break; CASE_TEST(syscall_args); EXPECT_SYSER(1, syscall(__NR_fstat, 0, NULL), -1, EFAULT); break; In short, they're very few, and several of these could simply be dropped as irrelevant once we know that the libc is able to remap them and dereference the arguments itself. I'd be fine with dropping the two gettimeofday_bad ones, poll_fault, select_fault and stat_fault. These ones already have at least one or two other tests. These ones were initially added because they were easy to implement, but if they're not relevant we can drop them and stop wondering how to hack around the tests. If that's OK for you as well I can do that. > Btw, since the gettimeofday_null case may be optimized by compiler and not > trigger such errors: > > // rv32 > nolibc-test.c:(.text.run_syscall+0x8c0): undefined reference to `__divdi3' > > // arm32 > nolibc-test.c:(.text.run_syscall+0x820): undefined reference to `__aeabi_ldivmod' > > The above errors have been hidden after the disabling of the gettimeofday_bad1 > test case, so, still need to solve it before sending v2. Sorry, I don't understand what you mean, I'm not seeing such a divide in the code. Or maybe you're speaking about what you got after some of your proposed changes ? > The method used by musl may work, but the high bits may be lost (from long long > to int)? > > tv->tv_usec = (int)ts.tv_nsec / 1000; Yes, and it would be even cleaner to use a uint here since tv_nsec is always positive. This will simply result in a multiplication and a shift on most platforms. Of course that's the type of thing you normally don't want on a fast path for some small systems but here code compacity counts more and that's fine. > Perhaps we really need to add the missing __divdi3 and __aeabi_ldivmod and the > ones for the other architectures, or get one from lib/math/div64.c. No, these ones come from the compiler via libgcc_s, we must not try to reimplement them. And we should do our best to avoid depending on them to avoid the error you got above. > Will add such new test cases to detect the above issues: > > CASE_TEST(gettimeofday_tv); EXPECT_SYSZR(1, gettimeofday(&tv, NULL)); break; > CASE_TEST(gettimeofday_tz); EXPECT_SYSZR(1, gettimeofday(NULL, &tz)); break; > CASE_TEST(gettimeofday_tv_tz);EXPECT_SYSZR(1, gettimeofday(&tv, &tz)); break; > > May still require to add 'used' attribute to 'struct timeval tv' and 'struct > timeval tz' to let compiler not optimize them away. Maybe, or turn them to volatile as well. > For the waitid syscall based waitpid INT_MIN test case, I have prepared such > code: > > #define IF_TEST(name) \ > if (strcmp(test, #name) == 0) > > const int _errorno(const char *test) > { > #ifdef __NR_wait4 > IF_TEST(waitpid_min); return ESRCH; > #else /* __NR_waitid */ > IF_TEST(waitpid_min); return EINVAL; > #endif > return 0; > } > > #define errorno(test) _errorno(#test) > > CASE_TEST(waitpid_min); EXPECT_SYSER(1, waitpid(INT_MIN, &tmp, WNOHANG), -1, errorno(waitpid_min)); break; > > Instead of simply disabling this case, the above code allows to return > different values for different syscalls. I don't like this, it gets particularly complicated to follow, especially since it doesn't rely on the underlying syscall but on which ones are defined, and supposes that the underlying implementation will use exactly these ones. Do not forget that we're not trying to verify that the tests provoke a specific syscall return, but that our syscall implementation returns the errno the application expects. If we see that one of them breaks, it means either that our test is wrong or undefined, or that our mapping of the syscall is incorrect. But in either case it indicates that an application relying on a specific errno would see a different value. Many syscalls can return various values among a set, depending on which error is tested first. If that's the case for the ones above, I'd largely prefer to have EXPECT_SYSER2() that accepts any errno among a set of two (and maybe layer EXPECT_SYSER3() if 3 errno are possible). Also there's something to keep in mind: nolibc-test is just one userland application among others. This means that every time you need to modify it to shut up an error that pops up after a change to nolibc, it means that you're possibly breaking one application living on an edge case and explicitly checking for that errno value. It is not necessarily dramatic but that's still something to keep in mind. We've all seen some of our code fail after a syscall started to report a new errno value we didn't expect, so it's important to still be cautious here and not to rely too much on the ease of adapting error handling in nolibc-test. > Thanks very much and I have seen another two have been pushed too, will rebase > everything on this new branch. OK. > Based on the other suggestions from you and Thomas, I plan to send some generic > and independent changes at first, and then the left hard parts, It may simplify > the whole progress. Yes, thank you! As a general rule of thumb (which makes the handling easier for everyone including you), the least controversial changes should be proposed first. This often allows to merge the first half of the patches at once and saves you from having to reorder what's left. Willy
> On Sun, May 28, 2023 at 06:39:57PM +0800, Zhangjin Wu wrote: > > > I have read the comments that others made on the series and overall > > > agree. I've seen that you intend to prepare a v2. I think we must > > > first decide how to better deal with emulated syscalls as I said in > > > an earlier message. Probably that we should just add a specific test > > > case for EFAULT in nolibc-test since it's the only one (I think) that > > > risks to trigger crashes with emulated syscalls. We could also imagine > > > dealing with the signal ourselves but I'm not that keen on going to > > > implement signal() & longjmp() for now :-/ > > > > > > > Yes, user-space signal() may be the right direction, we just need to let > > user-space not crash the kernel, what about this 'solution' for current stage > > (consider the pure time64 support too): > > > > #if defined(NOLIBC) && defined(__NR_gettimeofday) && __SIZEOF_LONG__ == 8 > > CASE_TEST(gettimeofday_bad1); EXPECT_SYSER(1, gettimeofday((void *)1, NULL), -1, EFAULT); break; > > CASE_TEST(gettimeofday_bad2); EXPECT_SYSER(1, gettimeofday(NULL, (void *)1), -1, EFAULT); break; > > #endif > > > > This idea is from your commit 1da02f51088 ("selftests/nolibc: support glibc as > > well") for glibc, but the difference is of course glibc not crashes the kernel. > > Well, I was imagining implementing an EXPECT_EFAULT() macro that would > rely on whatever other macros we'd set to indicate that a syscall got > remapped. But I had another check grepping for EFAULT: > > CASE_TEST(gettimeofday_bad1); EXPECT_SYSER(1, gettimeofday((void *)1, NULL), -1, EFAULT); break; > CASE_TEST(gettimeofday_bad2); EXPECT_SYSER(1, gettimeofday(NULL, (void *)1), -1, EFAULT); break; > CASE_TEST(poll_fault); EXPECT_SYSER(1, poll((void *)1, 1, 0), -1, EFAULT); break; > CASE_TEST(prctl); EXPECT_SYSER(1, prctl(PR_SET_NAME, (unsigned long)NULL, 0, 0, 0), -1, EFAULT); break; > CASE_TEST(select_fault); EXPECT_SYSER(1, select(1, (void *)1, NULL, NULL, 0), -1, EFAULT); break; > CASE_TEST(stat_fault); EXPECT_SYSER(1, stat(NULL, &stat_buf), -1, EFAULT); break; > CASE_TEST(syscall_args); EXPECT_SYSER(1, syscall(__NR_fstat, 0, NULL), -1, EFAULT); break; > > In short, they're very few, and several of these could simply be dropped > as irrelevant once we know that the libc is able to remap them and > dereference the arguments itself. > > I'd be fine with dropping the two gettimeofday_bad ones, poll_fault, > select_fault and stat_fault. These ones already have at least one or > two other tests. These ones were initially added because they were > easy to implement, but if they're not relevant we can drop them and > stop wondering how to hack around the tests. > > If that's OK for you as well I can do that. > The dropping of the others is not required, since currently, we only found these two gettimeofday test cases have such issues when we implement them with clock_gettime/time64, because there is a "timespec to timeval" conversion in user-space, if the data pointer could be passed to kernel space, there would be no such issues (kernel will transfer data via put_user() helpers). > > Btw, since the gettimeofday_null case may be optimized by compiler and not > > trigger such errors: > > > > // rv32 > > nolibc-test.c:(.text.run_syscall+0x8c0): undefined reference to `__divdi3' > > > > // arm32 > > nolibc-test.c:(.text.run_syscall+0x820): undefined reference to `__aeabi_ldivmod' > > > > The above errors have been hidden after the disabling of the gettimeofday_bad1 > > test case, so, still need to solve it before sending v2. > > Sorry, I don't understand what you mean, I'm not seeing such a divide in > the code. Or maybe you're speaking about what you got after some of your > proposed changes ? > > > The method used by musl may work, but the high bits may be lost (from long long > > to int)? > > > > tv->tv_usec = (int)ts.tv_nsec / 1000; > > Yes, and it would be even cleaner to use a uint here since tv_nsec is > always positive. This will simply result in a multiplication and a > shift on most platforms. Of course that's the type of thing you normally > don't want on a fast path for some small systems but here code compacity > counts more and that's fine. > Ok, will use uint here. > > Perhaps we really need to add the missing __divdi3 and __aeabi_ldivmod and the > > ones for the other architectures, or get one from lib/math/div64.c. > > No, these ones come from the compiler via libgcc_s, we must not try to > reimplement them. And we should do our best to avoid depending on them > to avoid the error you got above. > > > Will add such new test cases to detect the above issues: > > > > CASE_TEST(gettimeofday_tv); EXPECT_SYSZR(1, gettimeofday(&tv, NULL)); break; > > CASE_TEST(gettimeofday_tz); EXPECT_SYSZR(1, gettimeofday(NULL, &tz)); break; > > CASE_TEST(gettimeofday_tv_tz);EXPECT_SYSZR(1, gettimeofday(&tv, &tz)); break; > > > > May still require to add 'used' attribute to 'struct timeval tv' and 'struct > > timeval tz' to let compiler not optimize them away. > > Maybe, or turn them to volatile as well. > Yeah, volatile is better. > > For the waitid syscall based waitpid INT_MIN test case, I have prepared such > > code: > > > > #define IF_TEST(name) \ > > if (strcmp(test, #name) == 0) > > > > const int _errorno(const char *test) > > { > > #ifdef __NR_wait4 > > IF_TEST(waitpid_min); return ESRCH; > > #else /* __NR_waitid */ > > IF_TEST(waitpid_min); return EINVAL; > > #endif > > return 0; > > } > > > > #define errorno(test) _errorno(#test) > > > > CASE_TEST(waitpid_min); EXPECT_SYSER(1, waitpid(INT_MIN, &tmp, WNOHANG), -1, errorno(waitpid_min)); break; > > > > Instead of simply disabling this case, the above code allows to return > > different values for different syscalls. > > I don't like this, it gets particularly complicated to follow, especially > since it doesn't rely on the underlying syscall but on which ones are > defined, and supposes that the underlying implementation will use exactly > these ones. Do not forget that we're not trying to verify that the tests > provoke a specific syscall return, but that our syscall implementation > returns the errno the application expects. If we see that one of them > breaks, it means either that our test is wrong or undefined, or that our > mapping of the syscall is incorrect. But in either case it indicates that > an application relying on a specific errno would see a different value. > > Many syscalls can return various values among a set, depending on which > error is tested first. If that's the case for the ones above, I'd largely > prefer to have EXPECT_SYSER2() that accepts any errno among a set of two > (and maybe layer EXPECT_SYSER3() if 3 errno are possible). > Ok. > Also there's something to keep in mind: nolibc-test is just one userland > application among others. This means that every time you need to modify > it to shut up an error that pops up after a change to nolibc, it means > that you're possibly breaking one application living on an edge case and > explicitly checking for that errno value. It is not necessarily dramatic > but that's still something to keep in mind. We've all seen some of our > code fail after a syscall started to report a new errno value we didn't > expect, so it's important to still be cautious here and not to rely too > much on the ease of adapting error handling in nolibc-test. > > > Thanks very much and I have seen another two have been pushed too, will rebase > > everything on this new branch. > > OK. > > > Based on the other suggestions from you and Thomas, I plan to send some generic > > and independent changes at first, and then the left hard parts, It may simplify > > the whole progress. > > Yes, thank you! As a general rule of thumb (which makes the handling > easier for everyone including you), the least controversial changes should > be proposed first. This often allows to merge the first half of the patches > at once and saves you from having to reorder what's left. > That's true. Thanks, Zhangjin > Willy
Hi Zhangjin, May 28, 2023 12:40:31 Zhangjin Wu <falcon@tinylab.org>: > Hi, Willy > >> Hi Zhangjin, >> >> On Thu, May 25, 2023 at 01:33:14AM +0800, Zhangjin Wu wrote: >>> Hi, Willy >>> >>> Thanks very mush for your kindly review, discuss and suggestion, now we >>> get full rv32 support ;-) >>> >>> In the first series [1], we have fixed up the compile errors about >>> _start and __NR_llseek for rv32, but left compile errors about tons of >>> time32 syscalls (removed after kernel commit d4c08b9776b3 ("riscv: Use >>> latest system call ABI")) and the missing fstat in nolibc-test.c [2], >>> now we have fixed up all of them. >> >> (...) >> >> I have read the comments that others made on the series and overall >> agree. I've seen that you intend to prepare a v2. I think we must >> first decide how to better deal with emulated syscalls as I said in >> an earlier message. Probably that we should just add a specific test >> case for EFAULT in nolibc-test since it's the only one (I think) that >> risks to trigger crashes with emulated syscalls. We could also imagine >> dealing with the signal ourselves but I'm not that keen on going to >> implement signal() & longjmp() for now :-/ >> > > Yes, user-space signal() may be the right direction, we just need to let > user-space not crash the kernel, what about this 'solution' for current stage > (consider the pure time64 support too): If you did manage to crash the actual kernel than that would be a bug in the kernel that needs to be fixed. Feel free to describe how it happened and I'll take a look. Thomas
> May 28, 2023 12:40:31 Zhangjin Wu <falcon@tinylab.org>: > > > Hi, Willy > > > >> Hi Zhangjin, > >> > >> On Thu, May 25, 2023 at 01:33:14AM +0800, Zhangjin Wu wrote: > >>> Hi, Willy > >>> > >>> Thanks very mush for your kindly review, discuss and suggestion, now we > >>> get full rv32 support ;-) > >>> > >>> In the first series [1], we have fixed up the compile errors about > >>> _start and __NR_llseek for rv32, but left compile errors about tons of > >>> time32 syscalls (removed after kernel commit d4c08b9776b3 ("riscv: Use > >>> latest system call ABI")) and the missing fstat in nolibc-test.c [2], > >>> now we have fixed up all of them. > >> > >> (...) > >> > >> I have read the comments that others made on the series and overall > >> agree. I've seen that you intend to prepare a v2. I think we must > >> first decide how to better deal with emulated syscalls as I said in > >> an earlier message. Probably that we should just add a specific test > >> case for EFAULT in nolibc-test since it's the only one (I think) that > >> risks to trigger crashes with emulated syscalls. We could also imagine > >> dealing with the signal ourselves but I'm not that keen on going to > >> implement signal() & longjmp() for now :-/ > >> > > > > Yes, user-space signal() may be the right direction, we just need to let > > user-space not crash the kernel, what about this 'solution' for current stage > > (consider the pure time64 support too): > > If you did manage to crash the actual kernel than that would be a bug in the kernel that needs to be fixed. > Feel free to describe how it happened and I'll take a look. > Sorry, my description above is not really right, the sigsegv (11) signal will be sent to our program when it tries to write something to the address: (void *)1 for this test case tries to do/test so: CASE_TEST(gettimeofday_bad1); EXPECT_SYSER(1, gettimeofday((void *)1, NULL), -1, EFAULT); break; In the original gettimeofday syscall based implementation, the kernel side tries to use put_user to copy timespec data to user space timeval: kernel/time/time.c: if (put_user(ts.tv_sec, &tv->tv_sec) || put_user(ts.tv_nsec / 1000, &tv->tv_usec)) return -EFAULT; The put_user() in arch/riscv/include/asm/uaccess.h will trigger the 'fixup' logic and return -EFAULT and let the other test cases continue. But if add our clock_gettime/time64 syscalls based implementation, we must get timespec from kernel space and then convert them to timeval in user space, the address of timespec can be handled by kernel space too, but we must write them to the address of timeval in user-space: tv->tv_sec = ts.tv_sec; tv->tv_usec = (unsigned int)ts.tv_nsec / 1000; In above test case, tv above is something like (void *)1, it is invalid, kernel will prevent writing and force send a sigsegv and stop the program: 35 gettimeofday_bad1init[1]: unhandled signal 11 code 0x1 at 0x00000002 in init[10000+5000] CPU: 0 PID: 1 Comm: init Not tainted 6.4.0-rc1-00137-gfdc311fa22ed-dirty #60 Hardware name: riscv-virtio,qemu (DT) epc : 00012c90 ra : 00012c6c sp : 9d097d90 gp : 00016800 tp : 00000000 t0 : 00000000 t1 : 0000000a t2 : 00000000 s0 : 00000001 s1 : 00016008 a0 : 00000000 a1 : 9d097da8 a2 : 00000014 a3 : 00000000 a4 : 00000000 a5 : 00000000 a6 : 00000001 a7 : 00000193 s2 : 00000023 s3 : 00000000 s4 : 9d097da4 s5 : 00000000 s6 : 0000541b s7 : 00000007 s8 : 9d097dcc s9 : 00014474 s10: 00016000 s11: 00000006 t3 : 00000000 t4 : ffffffff t5 : 00000000 t6 : 00000000 status: 00000020 badaddr: 00000002 cause: 0000000f Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b Because our test run nolibc-test as init of initramfs on qemu, when init exit but not reboot as normally, then it 'crashes' the kernel (kernel panic above). If we have sigaction()/sigsetjmp/siglongjump support, then, we can call 'reboot()' in sigsegv signal handler, and event let it continue the other test cases. sigaction seems only work to trigger when to call siglongjump, siglongjump ask sigsetjmp to do the real recover action. I did find some useful urls, and wrote such an exception restore logic, not completely, not support NOLIBC_TEST environment variables yet. diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index 001ea789fa39..e7d488722e14 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -110,6 +110,47 @@ const char *errorname(int err) } } +#if !defined(NOLIBC) +#include <setjmp.h> +int test_base = 0; +int test_number = 0; +int test_llen = 0; +sigjmp_buf mark; +typedef int (*func_t)(int min, int max); +func_t test_func = NULL; +int test_idx = 0; + +static int pad_spc(int llen, int cnt, const char *fmt, ...); +static const struct test test_names[]; + +void continue_run(void) +{ + int idx; + int err; + int ret; + int min = 0; + int max = INT_MAX; + + test_llen += printf(" = %d ", -1); + pad_spc(test_llen, 64, "[FAIL] (continued by sigaction/siglongjmp/sigsetjmp)\n"); + test_func = test_names[test_idx].func; + test_func(test_number - test_base + 1, 1000); + + for (idx = test_idx + 1; test_names[idx].name; idx++) { + printf("Running test '%s'\n", test_names[idx].name); + err = test_names[idx].func(min, max); + ret += err; + printf("Errors during this test: %d\n\n", err); + } +} + +void action(int sig, siginfo_t *si, void *p) +{ + if (sig != SIGKILL) + siglongjmp(mark, -1); +} +#endif + #define IF_TEST(name) \ if (strcmp(test, #name) == 0) @@ -447,8 +488,13 @@ static int expect_strne(const char *expr, int llen, const char *cmp) /* declare tests based on line numbers. There must be exactly one test per line. */ +#if !defined(NOLIBC) +#define CASE_TEST(name) \ + case __LINE__: test_number = __LINE__; if (strcmp(#name, "getpid") == 0) { test_base = test_number; } llen += printf("%d %s", test, #name); test_llen = llen; +#else #define CASE_TEST(name) \ case __LINE__: llen += printf("%d %s", test, #name); +#endif /* used by some syscall tests below */ int test_getdents64(const char *dir) @@ -582,7 +628,7 @@ int run_syscall(int min, int max) CASE_TEST(gettimeofday_tv); EXPECT_SYSZR(1, gettimeofday(&tv, NULL)); break; CASE_TEST(gettimeofday_tz); EXPECT_SYSZR(1, gettimeofday(NULL, &tz)); break; CASE_TEST(gettimeofday_tv_tz);EXPECT_SYSZR(1, gettimeofday(&tv, &tz)); break; -#ifdef NOLIBC +#if 1 CASE_TEST(gettimeofday_bad1); EXPECT_SYSER(1, gettimeofday((void *)1, NULL), -1, EFAULT); break; CASE_TEST(gettimeofday_bad2); EXPECT_SYSER(1, gettimeofday(NULL, (void *)1), -1, EFAULT); break; #endif @@ -952,6 +998,22 @@ int main(int argc, char **argv, char **envp) if (getpid() == 1) prepare(); +#if !defined(NOLIBC) + struct sigaction sa = {0}; + sa.sa_sigaction = action; + sa.sa_flags = SA_SIGINFO; + ret = sigaction(SIGSEGV, &sa, NULL); + if (ret == -1) { + perror("sigaction"); + exit(1); + } + + if (sigsetjmp(mark, 1) != 0) { + continue_run(); + exit(0); + } +#endif + /* the definition of a series of tests comes from either argv[1] or the * "NOLIBC_TEST" environment variable. It's made of a comma-delimited * series of test names and optional ranges: @@ -1008,6 +1070,9 @@ int main(int argc, char **argv, char **envp) /* now's time to call the test */ printf("Running test '%s'\n", test_names[idx].name); +#if !defined(NOLIBC) + test_idx = idx; +#endif err = test_names[idx].func(min, max); ret += err; printf("Errors during this test: %d\n\n", err); @@ -1021,6 +1086,9 @@ int main(int argc, char **argv, char **envp) /* no test mentioned, run everything */ for (idx = 0; test_names[idx].name; idx++) { printf("Running test '%s'\n", test_names[idx].name); +#if !defined(NOLIBC) + test_idx = idx; +#endif err = test_names[idx].func(min, max); ret += err; printf("Errors during this test: %d\n\n", err); usage: $ gcc -o nolibc-test tools/testing/selftests/nolibc/nolibc-test.c $ ./nolibc-test ... 35 gettimeofday_tz = 0 [OK] 36 gettimeofday_tv_tz = 0 [OK] 37 gettimeofday_bad1 = -1 [FAIL] (continued by sigaction/siglongjmp/sigsetjmp) 38 gettimeofday_bad2 = -1 [FAIL] (continued by sigaction/siglongjmp/sigsetjmp) 39 getpagesize = 0 [OK] 40 ioctl_tiocinq = 0 [OK] 41 ioctl_tiocinq = 0 [OK] ... It did work as expected, but for nolibc, we still need to add sigaction/siglongjump/sigsetjmp support. Will send a patch based on Willy's latest branch, perhaps this may help us to verify the future sigaction/siglongjump/sigsetjmp for nolibc. ref: https://www.ibm.com/docs/en/i/7.1?topic=ssw_ibm_i_71/apis/sigsetj.html https://www.ibm.com/docs/en/zos/2.1.0?topic=functions-siglongjmp-restore-stack-environment-signal-mask Best regards, Zhangjin > Thomas
Hi Zhangjin, On 2023-05-29 02:39:06+0800, Zhangjin Wu wrote: > > May 28, 2023 12:40:31 Zhangjin Wu <falcon@tinylab.org>: > > >> On Thu, May 25, 2023 at 01:33:14AM +0800, Zhangjin Wu wrote: > > >>> Hi, Willy > > >>> > > >>> Thanks very mush for your kindly review, discuss and suggestion, now we > > >>> get full rv32 support ;-) > > >>> > > >>> In the first series [1], we have fixed up the compile errors about > > >>> _start and __NR_llseek for rv32, but left compile errors about tons of > > >>> time32 syscalls (removed after kernel commit d4c08b9776b3 ("riscv: Use > > >>> latest system call ABI")) and the missing fstat in nolibc-test.c [2], > > >>> now we have fixed up all of them. > > >> > > >> (...) > > >> > > >> I have read the comments that others made on the series and overall > > >> agree. I've seen that you intend to prepare a v2. I think we must > > >> first decide how to better deal with emulated syscalls as I said in > > >> an earlier message. Probably that we should just add a specific test > > >> case for EFAULT in nolibc-test since it's the only one (I think) that > > >> risks to trigger crashes with emulated syscalls. We could also imagine > > >> dealing with the signal ourselves but I'm not that keen on going to > > >> implement signal() & longjmp() for now :-/ > > >> > > > > > > Yes, user-space signal() may be the right direction, we just need to let > > > user-space not crash the kernel, what about this 'solution' for current stage > > > (consider the pure time64 support too): > > > > If you did manage to crash the actual kernel than that would be a bug in the kernel that needs to be fixed. > > Feel free to describe how it happened and I'll take a look. > > > > Sorry, my description above is not really right, the sigsegv (11) signal will > be sent to our program when it tries to write something to the address: (void > *)1 for this test case tries to do/test so: > > CASE_TEST(gettimeofday_bad1); EXPECT_SYSER(1, gettimeofday((void *)1, NULL), -1, EFAULT); break; <snip> > 35 gettimeofday_bad1init[1]: unhandled signal 11 code 0x1 at 0x00000002 in init[10000+5000] > CPU: 0 PID: 1 Comm: init Not tainted 6.4.0-rc1-00137-gfdc311fa22ed-dirty #60 > Hardware name: riscv-virtio,qemu (DT) > epc : 00012c90 ra : 00012c6c sp : 9d097d90 > gp : 00016800 tp : 00000000 t0 : 00000000 > t1 : 0000000a t2 : 00000000 s0 : 00000001 > s1 : 00016008 a0 : 00000000 a1 : 9d097da8 > a2 : 00000014 a3 : 00000000 a4 : 00000000 > a5 : 00000000 a6 : 00000001 a7 : 00000193 > s2 : 00000023 s3 : 00000000 s4 : 9d097da4 > s5 : 00000000 s6 : 0000541b s7 : 00000007 > s8 : 9d097dcc s9 : 00014474 s10: 00016000 > s11: 00000006 t3 : 00000000 t4 : ffffffff > t5 : 00000000 t6 : 00000000 > status: 00000020 badaddr: 00000002 cause: 0000000f > Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b > > Because our test run nolibc-test as init of initramfs on qemu, when init exit > but not reboot as normally, then it 'crashes' the kernel (kernel panic above). This makes sense, thanks. I just wanted to make sure no kernel bugs were going unhandeld. > If we have sigaction()/sigsetjmp/siglongjump support, then, we can call > 'reboot()' in sigsegv signal handler, and event let it continue the other test > cases. sigaction seems only work to trigger when to call siglongjump, > siglongjump ask sigsetjmp to do the real recover action. > > I did find some useful urls, and wrote such an exception restore logic, not > completely, not support NOLIBC_TEST environment variables yet. <lots of implementation> > usage: > > $ gcc -o nolibc-test tools/testing/selftests/nolibc/nolibc-test.c > $ ./nolibc-test > ... > 35 gettimeofday_tz = 0 [OK] > 36 gettimeofday_tv_tz = 0 [OK] > 37 gettimeofday_bad1 = -1 [FAIL] (continued by sigaction/siglongjmp/sigsetjmp) > 38 gettimeofday_bad2 = -1 [FAIL] (continued by sigaction/siglongjmp/sigsetjmp) > 39 getpagesize = 0 [OK] > 40 ioctl_tiocinq = 0 [OK] > 41 ioctl_tiocinq = 0 [OK] > ... > > It did work as expected, but for nolibc, we still need to add sigaction/siglongjump/sigsetjmp support. > > Will send a patch based on Willy's latest branch, perhaps this may help us to > verify the future sigaction/siglongjump/sigsetjmp for nolibc. > > ref: https://www.ibm.com/docs/en/i/7.1?topic=ssw_ibm_i_71/apis/sigsetj.html > https://www.ibm.com/docs/en/zos/2.1.0?topic=functions-siglongjmp-restore-stack-environment-signal-mask This seems very complicated for fairly limited gain to be honest. If we really want to keep the current testcase we could also ensure that the pointer does not fall into the first page, as the first page is not mapped under Linux: 0 <= addr < PAGE_SIZE Or instead of PAGE_SIZE just hardcode 4096, as that should be the minimum size and and does not require a lookup. Thomas
Hi Thomas, On Mon, May 29, 2023 at 10:45:40AM +0200, Thomas Weißschuh wrote: > <lots of implementation> > > > usage: > > > > $ gcc -o nolibc-test tools/testing/selftests/nolibc/nolibc-test.c > > $ ./nolibc-test > > ... > > 35 gettimeofday_tz = 0 [OK] > > 36 gettimeofday_tv_tz = 0 [OK] > > 37 gettimeofday_bad1 = -1 [FAIL] (continued by sigaction/siglongjmp/sigsetjmp) > > 38 gettimeofday_bad2 = -1 [FAIL] (continued by sigaction/siglongjmp/sigsetjmp) > > 39 getpagesize = 0 [OK] > > 40 ioctl_tiocinq = 0 [OK] > > 41 ioctl_tiocinq = 0 [OK] > > ... > > > > It did work as expected, but for nolibc, we still need to add sigaction/siglongjump/sigsetjmp support. > > > > Will send a patch based on Willy's latest branch, perhaps this may help us to > > verify the future sigaction/siglongjump/sigsetjmp for nolibc. > > > > ref: https://www.ibm.com/docs/en/i/7.1?topic=ssw_ibm_i_71/apis/sigsetj.html > > https://www.ibm.com/docs/en/zos/2.1.0?topic=functions-siglongjmp-restore-stack-environment-signal-mask > > This seems very complicated for fairly limited gain to be honest. I agree as well. I'm not denying the fact that one day we may want to support signal, longjmp and friends but I'm not convinced we want to go through that just to make a few uncertain tests succeed. > If we really want to keep the current testcase we could also ensure that > the pointer does not fall into the first page, as the first page is not > mapped under Linux: > > 0 <= addr < PAGE_SIZE > > Or instead of PAGE_SIZE just hardcode 4096, as that should be the > minimum size and and does not require a lookup. I would not even do that. It brings nothing to the application layer and inflates the code. I'd rather just get rid of the EFAULT test cases that rely on an unreliable syscall (i.e. one that may either be a real syscall or an emulated one). The value brought by these tests is extremely low and they were implemented only because they were easy to do. If they're causing pain, let's just drop them. Willy