* arm64: kernel v4.6-rc1 hangs on QEMU @ 2016-03-29 22:05 Yury Norov 2016-03-29 22:12 ` Arnd Bergmann 0 siblings, 1 reply; 6+ messages in thread From: Yury Norov @ 2016-03-29 22:05 UTC (permalink / raw) To: linux-arm-kernel; +Cc: linux-kernel Hi, Checked for both v4.6-rc1 and current master (1993b17). Config: arm64 defconfig QEMU: QEMU emulator version 2.3.0 (Debian 1:2.3+dfsg-5ubuntu9.2) Stacktrace: #0 arch_counter_get_cntvct () at ./arch/arm64/include/asm/arch_timer.h:121 #1 __delay (cycles=1024) at arch/arm64/lib/delay.c:31 #2 0xffffff8008340970 in __const_udelay (xloops=<optimized out>) at arch/arm64/lib/delay.c:41 #3 0xffffff800815420c in panic (fmt=<optimized out>) at kernel/panic.c:257 #4 0xffffff80080be588 in do_exit (code=11) at kernel/exit.c:666 #5 0xffffff8008089d08 in die (str=<optimized out>, regs=0xffffff8008aebe20 <init_thread_union+15904>, err=143867376) at arch/arm64/kernel/traps.c:298 #6 0xffffff8008089dec in arm64_notify_die (str=<optimized out>, regs=<optimized out>, info=<optimized out>, err=<optimized out>) at arch/arm64/kernel/traps.c:309 #7 0xffffff800808212c in do_undefinstr (regs=0xffffff8008aebe20 <init_thread_union+15904>) at arch/arm64/kernel/traps.c:399 #8 0xffffff8008a1fe08 in cpuinfo_store_boot_cpu () at arch/arm64/kernel/cpuinfo.c:252 #9 0xffffff8008a1fe08 in cpuinfo_store_boot_cpu () at arch/arm64/kernel/cpuinfo.c:252 #10 0xffffff8008a20388 in smp_prepare_boot_cpu () at arch/arm64/kernel/smp.c:403 #11 0xffffff8008a1d6ec in start_kernel () at init/main.c:511 #12 0xffffff80080811d8 in __mmap_switched () at arch/arm64/kernel/head.S:437 Backtrace stopped: previous frame identical to this frame (corrupt stack?) Corefile can be found at: https://drive.google.com/file/d/0B93nHerV55yNdFp5em54TEVnU2c/view?usp=sharing Yury. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: arm64: kernel v4.6-rc1 hangs on QEMU 2016-03-29 22:05 arm64: kernel v4.6-rc1 hangs on QEMU Yury Norov @ 2016-03-29 22:12 ` Arnd Bergmann 2016-03-29 22:22 ` Yury Norov 0 siblings, 1 reply; 6+ messages in thread From: Arnd Bergmann @ 2016-03-29 22:12 UTC (permalink / raw) To: linux-arm-kernel; +Cc: Yury Norov, linux-kernel On Wednesday 30 March 2016 01:05:02 Yury Norov wrote: > Checked for both v4.6-rc1 and current master (1993b17). > Config: arm64 defconfig > QEMU: QEMU emulator version 2.3.0 (Debian 1:2.3+dfsg-5ubuntu9.2) > > Stacktrace: > #0 arch_counter_get_cntvct () at > ./arch/arm64/include/asm/arch_timer.h:121 > #1 __delay (cycles=1024) at arch/arm64/lib/delay.c:31 > #2 0xffffff8008340970 in __const_udelay (xloops=<optimized out>) at > arch/arm64/lib/delay.c:41 > #3 0xffffff800815420c in panic (fmt=<optimized out>) at > kernel/panic.c:257 > #4 0xffffff80080be588 in do_exit (code=11) at kernel/exit.c:666 > #5 0xffffff8008089d08 in die (str=<optimized out>, regs=0xffffff8008aebe20 <init_thread_union+15904>, err=143867376) at arch/arm64/kernel/traps.c:298 > #6 0xffffff8008089dec in arm64_notify_die (str=<optimized out>, regs=<optimized out>, info=<optimized out>, err=<optimized out>) at arch/arm64/kernel/traps.c:309 > #7 0xffffff800808212c in do_undefinstr (regs=0xffffff8008aebe20 <init_thread_union+15904>) at arch/arm64/kernel/traps.c:399 > #8 0xffffff8008a1fe08 in cpuinfo_store_boot_cpu () at arch/arm64/kernel/cpuinfo.c:252 > #9 0xffffff8008a1fe08 in cpuinfo_store_boot_cpu () at arch/arm64/kernel/cpuinfo.c:252 > #10 0xffffff8008a20388 in smp_prepare_boot_cpu () at arch/arm64/kernel/smp.c:403 > #11 0xffffff8008a1d6ec in start_kernel () at init/main.c:511 > #12 0xffffff80080811d8 in __mmap_switched () at arch/arm64/kernel/head.S:437 > Backtrace stopped: previous frame identical to this frame (corrupt stack?) > Undefined instruction in cpuinfo_store_boot_cpu() could be related to the SYS_ID_AA64MMFR2_EL1 access that was recently added. What does the architecture say about reading unknown cpuid registers? Arnd ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: arm64: kernel v4.6-rc1 hangs on QEMU 2016-03-29 22:12 ` Arnd Bergmann @ 2016-03-29 22:22 ` Yury Norov 2016-03-29 22:32 ` Arnd Bergmann 0 siblings, 1 reply; 6+ messages in thread From: Yury Norov @ 2016-03-29 22:22 UTC (permalink / raw) To: Arnd Bergmann; +Cc: linux-arm-kernel, linux-kernel, alexey.klimov On Wed, Mar 30, 2016 at 12:12:30AM +0200, Arnd Bergmann wrote: > On Wednesday 30 March 2016 01:05:02 Yury Norov wrote: > > Checked for both v4.6-rc1 and current master (1993b17). > > Config: arm64 defconfig > > QEMU: QEMU emulator version 2.3.0 (Debian 1:2.3+dfsg-5ubuntu9.2) > > > > Stacktrace: > > #0 arch_counter_get_cntvct () at > > ./arch/arm64/include/asm/arch_timer.h:121 > > #1 __delay (cycles=1024) at arch/arm64/lib/delay.c:31 > > #2 0xffffff8008340970 in __const_udelay (xloops=<optimized out>) at > > arch/arm64/lib/delay.c:41 > > #3 0xffffff800815420c in panic (fmt=<optimized out>) at > > kernel/panic.c:257 > > #4 0xffffff80080be588 in do_exit (code=11) at kernel/exit.c:666 > > #5 0xffffff8008089d08 in die (str=<optimized out>, regs=0xffffff8008aebe20 <init_thread_union+15904>, err=143867376) at arch/arm64/kernel/traps.c:298 > > #6 0xffffff8008089dec in arm64_notify_die (str=<optimized out>, regs=<optimized out>, info=<optimized out>, err=<optimized out>) at arch/arm64/kernel/traps.c:309 > > #7 0xffffff800808212c in do_undefinstr (regs=0xffffff8008aebe20 <init_thread_union+15904>) at arch/arm64/kernel/traps.c:399 > > #8 0xffffff8008a1fe08 in cpuinfo_store_boot_cpu () at arch/arm64/kernel/cpuinfo.c:252 > > #9 0xffffff8008a1fe08 in cpuinfo_store_boot_cpu () at arch/arm64/kernel/cpuinfo.c:252 > > #10 0xffffff8008a20388 in smp_prepare_boot_cpu () at arch/arm64/kernel/smp.c:403 > > #11 0xffffff8008a1d6ec in start_kernel () at init/main.c:511 > > #12 0xffffff80080811d8 in __mmap_switched () at arch/arm64/kernel/head.S:437 > > Backtrace stopped: previous frame identical to this frame (corrupt stack?) > > > > Undefined instruction in cpuinfo_store_boot_cpu() could be related > to the SYS_ID_AA64MMFR2_EL1 access that was recently added. > > What does the architecture say about reading unknown cpuid registers? > > Arnd ThunderX has some unimplemented system registers. AFAIR, attempt to access it causes data abort. Yury. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: arm64: kernel v4.6-rc1 hangs on QEMU 2016-03-29 22:22 ` Yury Norov @ 2016-03-29 22:32 ` Arnd Bergmann 2016-03-29 22:52 ` Yury Norov 0 siblings, 1 reply; 6+ messages in thread From: Arnd Bergmann @ 2016-03-29 22:32 UTC (permalink / raw) To: Yury Norov; +Cc: linux-arm-kernel, linux-kernel, alexey.klimov On Wednesday 30 March 2016 01:22:17 Yury Norov wrote: > > > > Undefined instruction in cpuinfo_store_boot_cpu() could be related > > to the SYS_ID_AA64MMFR2_EL1 access that was recently added. > > > > What does the architecture say about reading unknown cpuid registers? > > > > Arnd > > ThunderX has some unimplemented system registers. AFAIR, attempt to access it > causes data abort. Ok, if that is the case, maybe the read_cpuid() macro can be changed so it contains a fixup for the trap? That should handle both data abort and undefinstr. Arnd ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: arm64: kernel v4.6-rc1 hangs on QEMU 2016-03-29 22:32 ` Arnd Bergmann @ 2016-03-29 22:52 ` Yury Norov 2016-03-30 6:44 ` Kefeng Wang 0 siblings, 1 reply; 6+ messages in thread From: Yury Norov @ 2016-03-29 22:52 UTC (permalink / raw) To: Arnd Bergmann; +Cc: linux-arm-kernel, linux-kernel, alexey.klimov On Wed, Mar 30, 2016 at 12:32:42AM +0200, Arnd Bergmann wrote: > On Wednesday 30 March 2016 01:22:17 Yury Norov wrote: > > > > > > Undefined instruction in cpuinfo_store_boot_cpu() could be related > > > to the SYS_ID_AA64MMFR2_EL1 access that was recently added. > > > > > > What does the architecture say about reading unknown cpuid registers? > > > > > > Arnd > > > > ThunderX has some unimplemented system registers. AFAIR, attempt to access it > > causes data abort. > > Ok, if that is the case, maybe the read_cpuid() macro can be changed > so it contains a fixup for the trap? That should handle both data abort > and undefinstr. > > Arnd Sounds alluring, but not clear what we'd return that way. I mean, how we'd distinguish between correct value and error code (0, -1 or whatever). But I think, we can do like this: val = read_cpuid_safe(reg, impossible_val); if (val == impossible_val) goto err; I think it will work for many cases. Yury. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: arm64: kernel v4.6-rc1 hangs on QEMU 2016-03-29 22:52 ` Yury Norov @ 2016-03-30 6:44 ` Kefeng Wang 0 siblings, 0 replies; 6+ messages in thread From: Kefeng Wang @ 2016-03-30 6:44 UTC (permalink / raw) To: Yury Norov, Arnd Bergmann; +Cc: linux-arm-kernel, linux-kernel, alexey.klimov On 2016/3/30 6:52, Yury Norov wrote: > On Wed, Mar 30, 2016 at 12:32:42AM +0200, Arnd Bergmann wrote: >> On Wednesday 30 March 2016 01:22:17 Yury Norov wrote: >>>> >>>> Undefined instruction in cpuinfo_store_boot_cpu() could be related >>>> to the SYS_ID_AA64MMFR2_EL1 access that was recently added. >>>> please use new qemu with commit e20d84c1407d43d5a2e2ac95dbb46db3b0af8f9f Author: Peter Maydell <peter.maydell@linaro.org> Date: Fri Feb 19 14:07:43 2016 +0000 target-arm: Make reserved ranges in ID_AA64* spaces RAZ, not UNDEF The v8 ARM ARM defines that unused spaces in the ID_AA64* system register ranges are Reserved and must RAZ, rather than being UNDEF. Implement this. In particular, ARM v8.2 adds a new feature register ID_AA64MMFR2, and newer versions of the Linux kernel will attempt to read this, which causes them not to boot up on versions of QEMU missing this fix. Since the encoding .opc0 = 3, .opc1 = 0, .crn = 0, .crm = 2, .opc2 = 6 is actually defined in ARMv8 (as ID_MMFR4), we give it an entry in the ARMCPU struct so CPUs can override it, though since none do this too will just RAZ. see https://lists.gnu.org/archive/html/qemu-devel/2016-02/msg04574.html >>>> What does the architecture say about reading unknown cpuid registers? >>>> >>>> Arnd >>> >>> ThunderX has some unimplemented system registers. AFAIR, attempt to access it >>> causes data abort. >> >> Ok, if that is the case, maybe the read_cpuid() macro can be changed >> so it contains a fixup for the trap? That should handle both data abort >> and undefinstr. >> >> Arnd > > Sounds alluring, but not clear what we'd return that way. I mean, how > we'd distinguish between correct value and error code (0, -1 or whatever). > But I think, we can do like this: > > val = read_cpuid_safe(reg, impossible_val); > if (val == impossible_val) > goto err; > > I think it will work for many cases. > > Yury. > > ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-03-30 6:44 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2016-03-29 22:05 arm64: kernel v4.6-rc1 hangs on QEMU Yury Norov 2016-03-29 22:12 ` Arnd Bergmann 2016-03-29 22:22 ` Yury Norov 2016-03-29 22:32 ` Arnd Bergmann 2016-03-29 22:52 ` Yury Norov 2016-03-30 6:44 ` Kefeng Wang
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