| Summary: | bug in implementation of new multi io apic code | ||||||
|---|---|---|---|---|---|---|---|
| Product: | [Retired] Red Hat Linux | Reporter: | Mike Wescott <wescott> | ||||
| Component: | kernel | Assignee: | Ingo Molnar <mingo> | ||||
| Status: | CLOSED NOTABUG | QA Contact: | |||||
| Severity: | medium | Docs Contact: | |||||
| Priority: | medium | ||||||
| Version: | 6.1 | ||||||
| Target Milestone: | --- | ||||||
| Target Release: | --- | ||||||
| Hardware: | i386 | ||||||
| OS: | Linux | ||||||
| Whiteboard: | |||||||
| Fixed In Version: | Doc Type: | Bug Fix | |||||
| Doc Text: | Story Points: | --- | |||||
| Clone Of: | Environment: | ||||||
| Last Closed: | 2000-08-22 17:19:33 UTC | Type: | --- | ||||
| Regression: | --- | Mount Type: | --- | ||||
| Documentation: | --- | CRM: | |||||
| Verified Versions: | Category: | --- | |||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||
| Cloudforms Team: | --- | ||||||
| Attachments: |
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Created attachment 5 [details]
patch for NCR 3416 and rh 6.1
Assigned to dledford Just as an Ingo FYI whether such old systems (which usually do not conform to the Intel Multiprocessor Specification) work with current kernels or not is a question of luck. Logical delivery mode is pretty much a must for things like targetted IPI delivery in the 2.4 kernel. Any patch that fixes such old systems should go through "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>, he is the author of most of the external 82489DX APIC code. |
See arch/i386/kernel/smp.c around line 546 there is the code if (mpf->mpf_physptr) smp_read_mpc((void *)mpf->mpf_physptr); If mpf->mpf_physptr is not set or if smp_read_mpc() finds no io_apic then the default mapping for io_apic is not made (unlike previous versions of the kernel). This panics on my (very old) SMP machine. A simple fix is to follow the above code with /* * We have an IO_APIC so use default if BIOS doesn't * know about any */ if (mp_apic_entries == 0) { mp_apic_entries++; mp_apics[0].mpc_apicaddr = mp_ioapic_addr; } Some additional fixes are also required for this machine (NCR 3416) which contains a local external 82489DX apic. This doesn't seem to want to work in logical mode, so I've also incorporated the fixes proposed by James.Bottomley@columbiasc.ncr.com. It was by trying to integrate his fix that I found this bug.