From 86ba4f7b9f949e4c4bcb425f2a1ce490fea30df0 Mon Sep 17 00:00:00 2001 From: Shanker Donthineni Date: Sat, 18 Mar 2023 21:43:14 -0500 Subject: irqchip/gicv3: Workaround for NVIDIA erratum T241-FABRIC-4 [ Upstream commit 35727af2b15d98a2dd2811d631d3a3886111312e ] The T241 platform suffers from the T241-FABRIC-4 erratum which causes unexpected behavior in the GIC when multiple transactions are received simultaneously from different sources. This hardware issue impacts NVIDIA server platforms that use more than two T241 chips interconnected. Each chip has support for 320 {E}SPIs. This issue occurs when multiple packets from different GICs are incorrectly interleaved at the target chip. The erratum text below specifies exactly what can cause multiple transfer packets susceptible to interleaving and GIC state corruption. GIC state corruption can lead to a range of problems, including kernel panics, and unexpected behavior. >From the erratum text: "In some cases, inter-socket AXI4 Stream packets with multiple transfers, may be interleaved by the fabric when presented to ARM Generic Interrupt Controller. GIC expects all transfers of a packet to be delivered without any interleaving. The following GICv3 commands may result in multiple transfer packets over inter-socket AXI4 Stream interface: - Register reads from GICD_I* and GICD_N* - Register writes to 64-bit GICD registers other than GICD_IROUTERn* - ITS command MOVALL Multiple commands in GICv4+ utilize multiple transfer packets, including VMOVP, VMOVI, VMAPP, and 64-bit register accesses." This issue impacts system configurations with more than 2 sockets, that require multi-transfer packets to be sent over inter-socket AXI4 Stream interface between GIC instances on different sockets. GICv4 cannot be supported. GICv3 SW model can only be supported with the workaround. Single and Dual socket configurations are not impacted by this issue and support GICv3 and GICv4." Link: https://developer.nvidia.com/docs/t241-fabric-4/nvidia-t241-fabric-4-errata.pdf Writing to the chip alias region of the GICD_In{E} registers except GICD_ICENABLERn has an equivalent effect as writing to the global distributor. The SPI interrupt deactivate path is not impacted by the erratum. To fix this problem, implement a workaround that ensures read accesses to the GICD_In{E} registers are directed to the chip that owns the SPI, and disable GICv4.x features. To simplify code changes, the gic_configure_irq() function uses the same alias region for both read and write operations to GICD_ICFGR. Co-developed-by: Vikram Sethi Signed-off-by: Vikram Sethi Signed-off-by: Shanker Donthineni Acked-by: Sudeep Holla (for SMCCC/SOC ID bits) Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20230319024314.3540573-2-sdonthineni@nvidia.com Signed-off-by: Sasha Levin --- Documentation/arm64/silicon-errata.rst | 2 ++ 1 file changed, 2 insertions(+) (limited to 'Documentation') diff --git a/Documentation/arm64/silicon-errata.rst b/Documentation/arm64/silicon-errata.rst index 808ade4cc008..55492fea4427 100644 --- a/Documentation/arm64/silicon-errata.rst +++ b/Documentation/arm64/silicon-errata.rst @@ -170,6 +170,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | NVIDIA | Carmel Core | N/A | NVIDIA_CARMEL_CNP_ERRATUM | +----------------+-----------------+-----------------+-----------------------------+ +| NVIDIA | T241 GICv3/4.x | T241-FABRIC-4 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ +----------------+-----------------+-----------------+-----------------------------+ | Freescale/NXP | LS2080A/LS1043A | A-008585 | FSL_ERRATUM_A008585 | +----------------+-----------------+-----------------+-----------------------------+ -- cgit v1.2.3