I pulled down the fix, built locally, and can confirm that this resolves the issue. Thank you for the quick patch!
-- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1844597 Title: fc1120a7f5f2d4b601003205c598077d3eb11ad2 causes a kernel panic in vfp_init on a clang built kernel Status in QEMU: In Progress Bug description: Commit 4cdabee7d6d2 ("ARM: configs: aspeed_g5: Enable AST2600") [1] in the Linux kernel enabled CONFIG_VFP. When building this config with Clang, the resulting kernel does not boot after commit fc1120a7f5 ("target/arm: Implement NSACR gating of floating point") [2] (present since the 4.1.0 release). The QEMU command: qemu-system-arm -m 512m \ -machine romulus-bmc \ -no-reboot \ -dtb out/arch/arm/boot/dts/aspeed-bmc-opp-romulus.dtb \ -initrd rootfs.cpio \ -display none \ -serial mon:stdio \ -kernel ${KBF}/arch/arm/boot/zImage If it is needed, the rootfs we are using is provided at a link below [3]. Debugging with QEMU reveals that the kernel panics in vfp_init, specifically at the line: vfpsid = fmrx(FPSID); in arch/arm/vfp/vfpmodule.c because of an illegal instruction: [ 0.058685] VFP support v0.3: [ 0.059159] Internal error: Oops - undefined instruction: 0 [#1] SMP ARM [ 0.059525] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.3.0-next-20190918-dirty #1 [ 0.059547] Hardware name: Generic DT based system [ 0.059702] PC is at vfp_init+0x50/0x1f4 [ 0.059721] LR is at vfp_init+0x4c/0x1f4 [ 0.059738] pc : [<80b0383c>] lr : [<80b03838>] psr: 60000153 [ 0.059756] sp : 9e497ec0 ip : 00000020 fp : 9e497ed8 [ 0.059773] r10: 00000000 r9 : ffffe000 r8 : 80c06048 [ 0.059792] r7 : 00000000 r6 : 80c0caac r5 : 80c6c418 r4 : 80b037ec [ 0.059811] r3 : 00000000 r2 : 339aa372 r1 : 00000000 r0 : 00000012 [ 0.059859] Flags: nZCv IRQs on FIQs off Mode SVC_32 ISA ARM Segment none [ 0.059883] Control: 00c5387d Table: 80004008 DAC: 00000051 [ 0.059997] Process swapper/0 (pid: 1, stack limit = 0x(ptrval)) [ 0.060048] Stack: (0x9e497ec0 to 0x9e498000) [ 0.060205] 7ec0: 80b037ec 80b6bf0c 80b037ec ffffffff 00000000 00000000 9e497f48 80b01100 [ 0.060310] 7ee0: 00000000 9eeff9e0 80a85734 809eb9be 00000000 8014b7f4 9eeff9e0 80a85734 [ 0.060408] 7f00: 9e497f48 8014b7f4 000000a4 00000001 00000001 00000000 80b0133c 9e497f38 [ 0.060509] 7f20: 00000000 9eeff9d5 339aa372 80b6be80 80b6bf0c 00000000 00000000 00000000 [ 0.060606] 7f40: 00000000 00000000 9e497f70 80b01864 00000001 00000001 00000000 80b0133c [ 0.060703] 7f60: 00000001 8085d268 00000000 00000000 9e497f80 80b01758 00000000 00000000 [ 0.060800] 7f80: 9e497f90 80b015e4 00000000 8085d268 9e497fa8 8085d27c 00000000 8085d268 [ 0.060897] 7fa0: 00000000 00000000 00000000 801010e8 00000000 00000000 00000000 00000000 [ 0.060993] 7fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 0.061090] 7fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000 [ 0.061625] [<80b0383c>] (vfp_init) from [<80b01100>] (do_one_initcall+0xa8/0x1e0) [ 0.061722] [<80b01100>] (do_one_initcall) from [<80b01864>] (do_initcall_level+0xfc/0x12c) [ 0.061742] [<80b01864>] (do_initcall_level) from [<80b01758>] (do_basic_setup+0x2c/0x3c) [ 0.061759] [<80b01758>] (do_basic_setup) from [<80b015e4>] (kernel_init_freeable+0x68/0x104) [ 0.061777] [<80b015e4>] (kernel_init_freeable) from [<8085d27c>] (kernel_init+0x14/0x26c) [ 0.061798] [<8085d27c>] (kernel_init) from [<801010e8>] (ret_from_fork+0x14/0x2c) [ 0.061835] Exception stack(0x9e497fb0 to 0x9e497ff8) [ 0.061896] 7fa0: 00000000 00000000 00000000 00000000 [ 0.061998] 7fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 0.062080] 7fe0: 00000000 00000000 00000000 00000000 00000013 00000000 [ 0.062263] Code: e5860000 e59f0174 ebd9d8fc e59f5170 (eef04a10) [ 0.062679] ---[ end trace 2d338c91e4e74562 ]--- Before fc1120a7f5: [ 0.069418] VFP support v0.3: implementor 41 architecture 1 part 20 variant b rev 5 Should you need to reproduce this locally: * clang 9.0.0 or later is needed to build this config. If you do not have easy access to such a build, we have a clang build script available [4] that can help with this: % ./build-llvm.py --branch llvmorg-9.0.0-rc6 \ --build-stage1-only \ --projects clang \ --targets ARM * Because of an unrelated build issue, linux-next needs to be used (or the singular patch that resolves it needs to be cherry-picked on top of 4cdabee7d6d2 [5]). The kernel make command used: % make -j$(nproc) -s \ ARCH=arm \ CC=clang \ CROSS_COMPILE=arm-linux-gnueabi- \ O=out \ distclean aspeed_g5_defconfig all [1]: https://git.kernel.org/linus/4cdabee7d6d2e439fea726a101e448c4ca6837f4 [2]: https://git.qemu.org/?p=qemu.git;a=commit;h=fc1120a7f5f2d4b601003205c598077d3eb11ad2 [3]: https://github.com/ClangBuiltLinux/continuous-integration/blob/800d84bf8c55ee04c50ed4c78144a96d889a91c5/images/arm/rootfs.cpio [4]: https://github.com/ClangBuiltLinux/tc-build [5]: http://git.armlinux.org.uk/cgit/linux-arm.git/commit/?id=7b3948597372e5a6b314208ac320362c204b7f0f To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1844597/+subscriptions
