Re: [PATCH v7 12/13] ACPI / init: Invoke early ACPI initialization earlier

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Hi Baoquan,

At 07/27/2017 02:08 PM, bhe@xxxxxxxxxx wrote:
On 07/26/17 at 08:19pm, Dou Liyang wrote:
Hi Baoquan,
[...]

I am looking for Thinkpad x121e (AMD E-450 APU) to test. I have tested
it in Thinkpad s430, It's OK.

BTY, I am confused how does the ACPI subsystem affect PIT which
will be used to fast calibrate CPU frequency[2].

In combination with what Joey said[1] and the code, I guess,

The acpi_enable() called in acpi_enable_system() transfers the system
into ACPI mode and write data to an I/O port. PIT works using the I/O
port. In Thinkpad x121e with ACPI mode, the counter in PIT couldn't
count right and might got an error value.

[1] https://lkml.org/lkml/2014/3/12/3

Thanks,
	dou.

I checked code, and have no any idea. Add Joey Lee to list, see if he
can help answer this.


Do you have any idea?

[1] https://lkml.org/lkml/2014/3/10/123
[2] https://lkml.org/lkml/2014/3/12/3


 drivers/iommu/dmar.c                | 27 +++++++++++----------------
 drivers/iommu/intel-iommu.c         |  2 ++
 drivers/iommu/intel_irq_remapping.c | 17 ++++++++++++++++-
 include/linux/dmar.h                |  2 ++
 init/main.c                         |  2 +-
 5 files changed, 32 insertions(+), 18 deletions(-)

diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index c8b0329..e6261b7 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -68,6 +68,8 @@ DECLARE_RWSEM(dmar_global_lock);
 LIST_HEAD(dmar_drhd_units);

 struct acpi_table_header * __initdata dmar_tbl;
+struct acpi_table_header * __initdata dmar_tbl_original;
+
 static int dmar_dev_scope_status = 1;
 static unsigned long dmar_seq_ids[BITS_TO_LONGS(DMAR_UNITS_SUPPORTED)];

@@ -627,6 +629,7 @@ parse_dmar_table(void)
 	 * fixed map.
 	 */
 	dmar_table_detect();
+	dmar_tbl_original = dmar_tbl;

 	/*
 	 * ACPI tables may not be DMA protected by tboot, so use DMAR copy
@@ -811,26 +814,18 @@ int __init dmar_dev_scope_init(void)

 int __init dmar_table_init(void)
 {
-	static int dmar_table_initialized;
 	int ret;

-	if (dmar_table_initialized == 0) {
-		ret = parse_dmar_table();
-		if (ret < 0) {
-			if (ret != -ENODEV)
-				pr_info("Parse DMAR table failure.\n");
-		} else  if (list_empty(&dmar_drhd_units)) {
-			pr_info("No DMAR devices found\n");
-			ret = -ENODEV;
-		}
-
-		if (ret < 0)
-			dmar_table_initialized = ret;
-		else
-			dmar_table_initialized = 1;
+	ret = parse_dmar_table();
+	if (ret < 0) {
+		if (ret != -ENODEV)
+			pr_info("Parse DMAR table failure.\n");
+	} else  if (list_empty(&dmar_drhd_units)) {
+		pr_info("No DMAR devices found\n");
+		ret = -ENODEV;
 	}

-	return dmar_table_initialized < 0 ? dmar_table_initialized : 0;
+	return ret;
 }

 static void warn_invalid_dmar(u64 addr, const char *message)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 687f18f..90f74f4 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4832,6 +4832,8 @@ int __init intel_iommu_init(void)
 	}

 	down_write(&dmar_global_lock);
+
+	intel_iommu_free_dmars();
 	if (dmar_table_init()) {
 		if (force_on)
 			panic("tboot: Failed to initialize DMAR table\n");
diff --git a/drivers/iommu/intel_irq_remapping.c
b/drivers/iommu/intel_irq_remapping.c
index a5b89f6..ccaacda 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -675,7 +675,7 @@ static void __init intel_cleanup_irq_remapping(void)
 		pr_warn("Failed to enable irq remapping. You are vulnerable to
irq-injection attacks.\n");
 }

-static int __init intel_prepare_irq_remapping(void)
+static int __init __intel_prepare_irq_remapping(void)
 {
 	struct dmar_drhd_unit *drhd;
 	struct intel_iommu *iommu;
@@ -743,6 +743,21 @@ static int __init intel_prepare_irq_remapping(void)
 	return -ENODEV;
 }

+static int __init intel_prepare_irq_remapping(void)
+{
+	int ret;
+
+	ret = __intel_prepare_irq_remapping();
+
+	if (dmar_tbl_original) {
+		acpi_put_table(dmar_tbl_original);
+		dmar_tbl_original = NULL;
+		dmar_tbl = NULL;
+	}
+
+	return ret;
+}
+
 /*
  * Set Posted-Interrupts capability.
  */
diff --git a/include/linux/dmar.h b/include/linux/dmar.h
index e8ffba1..987b076 100644
--- a/include/linux/dmar.h
+++ b/include/linux/dmar.h
@@ -50,6 +50,8 @@ struct dmar_dev_scope {

 #ifdef CONFIG_DMAR_TABLE
 extern struct acpi_table_header *dmar_tbl;
+extern struct acpi_table_header *dmar_tbl_original;
+
 struct dmar_drhd_unit {
 	struct list_head list;		/* list of drhd units	*/
 	struct  acpi_dmar_header *hdr;	/* ACPI header		*/
diff --git a/init/main.c b/init/main.c
index 52dee20..052481f 100644
--- a/init/main.c
+++ b/init/main.c
@@ -655,12 +655,12 @@ 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();

Thanks,
	dou.



Thanks,

	dou.

Thanks
Lv

From: Dou Liyang [mailto:douly.fnst@xxxxxxxxxxxxxx]
Sent: Friday, July 14, 2017 1:53 PM
To: x86@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
Cc: tglx@xxxxxxxxxxxxx; mingo@xxxxxxxxxx; hpa@xxxxxxxxx; ebiederm@xxxxxxxxxxxx; bhe@xxxxxxxxxx;
peterz@xxxxxxxxxxxxx; izumi.taku@xxxxxxxxxxxxxx; tokunaga.keiich@xxxxxxxxxxxxxx; Dou Liyang
<douly.fnst@xxxxxxxxxxxxxx>; linux-acpi@xxxxxxxxxxxxxxx; Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>; Zheng,
Lv <lv.zheng@xxxxxxxxx>; Julian Wollrath <jwollrath@xxxxxx>
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@xxxxxxxxx>
Signed-off-by: Dou Liyang <douly.fnst@xxxxxxxxxxxxxx>
Cc: linux-acpi@xxxxxxxxxxxxxxx
Cc: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>
Cc: Zheng, Lv <lv.zheng@xxxxxxxxx>
Cc: Julian Wollrath <jwollrath@xxxxxx>
---
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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