On 1/31/2018 5:44 PM, Laszlo Ersek wrote:
On 01/31/18 08:00, Song, BinX wrote:
Current CPU feature dependency check will hang on when meet below or
similar case:
if (IsCpuFeatureSupported (CPU_FEATURE_AESNI)) {
Status = RegisterCpuFeature (
"AESNI",
AesniGetConfigData,
AesniSupport,
AesniInitialize,
CPU_FEATURE_AESNI,
CPU_FEATURE_MWAIT | CPU_FEATURE_BEFORE,
CPU_FEATURE_END
);
ASSERT_EFI_ERROR (Status);
}
if (IsCpuFeatureSupported (CPU_FEATURE_MWAIT)) {
Status = RegisterCpuFeature (
"MWAIT",
NULL,
MonitorMwaitSupport,
MonitorMwaitInitialize,
CPU_FEATURE_MWAIT,
CPU_FEATURE_AESNI | CPU_FEATURE_BEFORE,
CPU_FEATURE_END
);
ASSERT_EFI_ERROR (Status);
}
Solution is to separate current CPU feature dependency check into
sort and check two parts.
Sort function:
According to CPU feature's dependency, sort all CPU features.
Later dependency will override previous dependency if they are conflicted.
Check function:
Check sorted CPU features' relationship, ASSERT invalid relationship.
Cc: Eric Dong <[email protected]>
Cc: Laszlo Ersek <[email protected]>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Bell Song <[email protected]>
---
.../RegisterCpuFeaturesLib/CpuFeaturesInitialize.c | 271 ++++++++++++++++++++-
.../RegisterCpuFeaturesLib/RegisterCpuFeatures.h | 7 +
.../RegisterCpuFeaturesLib.c | 130 +---------
3 files changed, 278 insertions(+), 130 deletions(-)
diff --git a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
index 4d75c07..2fd0d5f 100644
--- a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
+++ b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
@@ -423,6 +423,271 @@ DumpRegisterTableOnProcessor (
}
/**
+ From FeatureBitMask, find the right feature entry in CPU feature list.
+
+ @param[in] FeatureList The pointer to CPU feature list.
+ @param[in] CurrentFeature The pointer to current CPU feature.
+ @param[in] BeforeFlag TRUE: BeforeFeatureBitMask; FALSE:
AfterFeatureBitMask.
+
+ @return The pointer to right CPU feature entry.
+**/
+LIST_ENTRY *
+FindFeatureInList(
+ IN LIST_ENTRY *CpuFeatureList,
+ IN CPU_FEATURES_ENTRY *CurrentCpuFeature,
+ IN BOOLEAN BeforeFlag
+ )
+{
+ LIST_ENTRY *TempEntry;
+ CPU_FEATURES_ENTRY *TempFeature;
+ UINT8 *FeatureBitMask;
+
+ FeatureBitMask = BeforeFlag ? CurrentCpuFeature->BeforeFeatureBitMask :
CurrentCpuFeature->AfterFeatureBitMask;
+ TempEntry = GetFirstNode (CpuFeatureList);
+ while (!IsNull (CpuFeatureList, TempEntry)) {
+ TempFeature = CPU_FEATURE_ENTRY_FROM_LINK (TempEntry);
+ if (IsBitMaskMatchCheck (FeatureBitMask, TempFeature->FeatureMask)){
+ return TempEntry;
+ }
+ TempEntry = TempEntry->ForwardLink;
+ }
+
+ DEBUG ((DEBUG_ERROR, "Error: Feature %a ", CurrentCpuFeature->FeatureName, BeforeFlag ? "before
":"after ", "condition is invalid!\n"));
Hi, I skimmed this patch quickly -- I can tell that I can't really tell
what's going on. I don't know how the feature dependencies are defined
in the first place, and what the bug is.
However, I do see that the above DEBUG macro invocation is incorrect.
The format string has one (1) %a conversion specification, but we pass
three (3) arguments.
I think the last argument ("condition is invalid!\n") should actually be
part of the format string. And then, the "before"/"after" string has to
be printed somehow as well.
Another superficial observation below:
+/**
+ Check sorted CPU features' relationship, ASSERT invalid one.
+
+ @param[in] FeatureList The pointer to CPU feature list.
+**/
+VOID
+CheckCpuFeaturesRelationShip (
I don't think we should capitalize "Ship" in this identifier.
Third comment: there are several ways to define "sorting", so I'm not
sure my question applies, but: can we replace the manual sorting with
SortLib?
Laszlo,
I haven't checked the patch in details.
But regarding to the SortLib suggestion, the feature entry is chained in
linked list, while SortLib can only perform sorting in array.
Bin,
Can we have a simpler fix to this issue?
If my understanding is correct, the patch tries to fix the infinite loop
in code.
If that's true, can we just firstly calculate how many loops are
expected before looping, then exit when the maximum loop is met?
Upon that, when the sort hasn't been finished, a wrong dependency
exists.
Thanks
Laszlo
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--
Thanks,
Ray
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