Messages in this thread Patch in this message |  | | Subject | Re: [PATCH v7 12/13] ACPI / init: Invoke early ACPI initialization earlier | From | Dou Liyang <> | Date | Tue, 18 Jul 2017 14:08:05 +0800 |
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Hi, Zheng
At 07/18/2017 01:18 PM, Zheng, Lv wrote: > Hi, > > Can the problem be fixed by invoking acpi_put_table() for mapped DMAR table?
Invoking acpi_put_table() is my first choice. But it made the kernel *panic* when we try to get the table again in intel_iommu_init() in late stage.
I am also confused that:
There are two places where we used DMAR table in Linux:
1) In detect_intel_iommu() in ACPI early stage:
... status = acpi_get_table(ACPI_SIG_DMAR, 0, &dmar_tbl); .... if (dmar_tbl) { acpi_put_table(dmar_tbl); dmar_tbl = NULL; }
2) In dmar_table_init() in ACPI late stage:
... status = acpi_get_table(ACPI_SIG_DMAR, 0, &dmar_tbl); ...
As we know, dmar_table_init() is called by intel_iommu_init() and intel_prepare_irq_remapping().
When I invoked acpi_put_table() in the intel_prepare_irq_remapping() in early stage like 1) shows, kernel will panic.
Thanks,
dou. > > Thanks > Lv > >> From: Dou Liyang [mailto:douly.fnst@cn.fujitsu.com] >> Sent: Friday, July 14, 2017 1:53 PM >> To: x86@kernel.org; linux-kernel@vger.kernel.org >> Cc: tglx@linutronix.de; mingo@kernel.org; hpa@zytor.com; ebiederm@xmission.com; bhe@redhat.com; >> peterz@infradead.org; izumi.taku@jp.fujitsu.com; tokunaga.keiich@jp.fujitsu.com; Dou Liyang >> <douly.fnst@cn.fujitsu.com>; linux-acpi@vger.kernel.org; Rafael J. Wysocki <rjw@rjwysocki.net>; Zheng, >> Lv <lv.zheng@intel.com>; Julian Wollrath <jwollrath@web.de> >> Subject: [PATCH v7 12/13] ACPI / init: Invoke early ACPI initialization earlier >> >> Linux uses acpi_early_init() to put the ACPI table management into >> the late stage from the early stage where the mapped ACPI tables is >> temporary and should be unmapped. >> >> But, now initializing interrupt delivery mode should map and parse the >> DMAR table earlier in the early stage. This causes an ACPI error when >> Linux reallocates the ACPI root tables. Because Linux doesn't unmapped >> the DMAR table after using in the early stage. >> >> Invoke acpi_early_init() earlier before late_time_init(), Keep the DMAR >> be mapped and parsed in late stage like before. >> >> Reported-by: Xiaolong Ye <xiaolong.ye@intel.com> >> Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com> >> Cc: linux-acpi@vger.kernel.org >> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> >> Cc: Zheng, Lv <lv.zheng@intel.com> >> Cc: Julian Wollrath <jwollrath@web.de> >> --- >> Test in my own PC(Lenovo M4340). >> Ask help for doing regression testing for the bug said in commit c4e1acbb35e4 >> ("ACPI / init: Invoke early ACPI initialization later"). >> >> init/main.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/init/main.c b/init/main.c >> index df58a41..7a09467 100644 >> --- a/init/main.c >> +++ b/init/main.c >> @@ -654,12 +654,12 @@ asmlinkage __visible void __init start_kernel(void) >> kmemleak_init(); >> setup_per_cpu_pageset(); >> numa_policy_init(); >> + acpi_early_init(); >> if (late_time_init) >> late_time_init(); >> calibrate_delay(); >> pidmap_init(); >> anon_vma_init(); >> - acpi_early_init(); >> #ifdef CONFIG_X86 >> if (efi_enabled(EFI_RUNTIME_SERVICES)) >> efi_enter_virtual_mode(); >> -- >> 2.5.5 >> >> > > > >
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