Hi, We ran into a bug in EDK2 relating to PCI-Express in PciBusDxe. Here's the flow of the bug:
1. PciBusDxe/PciEnumeratorSupport.c: Function BarExisted probes a BAR. It raises TPL to TPL_HIGH_LEVEL to avoid timer interrupts while probing the BAR and calls PciIo->Pci.Write. 2. BasePciExpressLib/PciExpressLib.c: The write reaches PciExpressWrite32, which calls GetPciExpressBaseAddress. 3. GetPciExpressBaseAddress retrieves the address from PcdPciExpressBaseAddress. 4. Reading the PCD calls DxePcdGet64 -> GetWorker -> EfiAcquireLock(&mPcdDatabaseLock), which is at TPL_NOTIFY level. This crashes the firmware because step 1 raised the TPL to TPL_HIGH_LEVEL. This doesn't happen when PcdPciExpressBaseAddress is fixed at build (because then the read is optimized to a static global variable), but when the PCD is dynamic PCI-Express is broken. Does anybody have a suggestion for fixing it? Options we thought about: - Change mPcdDatabaseLock.Tpl to TPL_HIGH_LEVEL - Don't use a PCD for the base address, put it in a static global variable and create functions to set and retrieve it. Thanks, Nikita _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
