From: Chengwen Feng Date: Wed, 1 Apr 2026 08:16:40 +0000 (+0800) Subject: PCI/TPH: Pass ACPI Processor UID to Cache Locality _DSM X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=abdd2a86535b59c76d14da2547160bc83e059c03;p=thirdparty%2Fkernel%2Flinux.git PCI/TPH: Pass ACPI Processor UID to Cache Locality _DSM pcie_tph_get_cpu_st() uses the Query Cache Locality Features _DSM [1] to retrieve the TPH Steering Tag for memory associated with the CPU identified by its "cpu_uid" parameter, a Linux logical CPU ID. The _DSM requires an ACPI Processor UID, which pcie_tph_get_cpu_st() previously assumed was the same as the Linux logical CPU ID. This is true on x86 but not on arm64, so pcie_tph_get_cpu_st() returned the wrong Steering Tag, resulting in incorrect TPH functionality on arm64. Convert the Linux logical CPU ID to the ACPI Processor UID with acpi_get_cpu_uid() before passing it to the _DSM. Additionally, rename the pcie_tph_get_cpu_st() parameter from "cpu_uid" to "cpu" to reflect that it represents a logical CPU ID (not an ACPI Processor UID). [1] According to ECN_TPH-ST_Revision_20200924 (https://members.pcisig.com/wg/PCI-SIG/document/15470), the input is defined as: "If the target is a processor, then this field represents the ACPI Processor UID of the processor as specified in the MADT. If the target is a processor container, then this field represents the ACPI Processor UID of the processor container as specified in the PPTT." Fixes: d2e8a34876ce ("PCI/TPH: Add Steering Tag support") Signed-off-by: Chengwen Feng Reviewed-by: Jonathan Cameron Reviewed-by: Bjorn Helgaas Link: https://patch.msgid.link/20260401081640.26875-9-fengchengwen@huawei.com Signed-off-by: Rafael J. Wysocki --- diff --git a/Documentation/PCI/tph.rst b/Documentation/PCI/tph.rst index e8993be64fd64..b6cf22b9bd90a 100644 --- a/Documentation/PCI/tph.rst +++ b/Documentation/PCI/tph.rst @@ -79,10 +79,10 @@ To retrieve a Steering Tag for a target memory associated with a specific CPU, use the following function:: int pcie_tph_get_cpu_st(struct pci_dev *pdev, enum tph_mem_type type, - unsigned int cpu_uid, u16 *tag); + unsigned int cpu, u16 *tag); The `type` argument is used to specify the memory type, either volatile -or persistent, of the target memory. The `cpu_uid` argument specifies the +or persistent, of the target memory. The `cpu` argument specifies the CPU where the memory is associated to. After the ST value is retrieved, the device driver can use the following diff --git a/drivers/pci/tph.c b/drivers/pci/tph.c index ca4f97be75389..b67c9ad14bdaa 100644 --- a/drivers/pci/tph.c +++ b/drivers/pci/tph.c @@ -236,21 +236,27 @@ static int write_tag_to_st_table(struct pci_dev *pdev, int index, u16 tag) * with a specific CPU * @pdev: PCI device * @mem_type: target memory type (volatile or persistent RAM) - * @cpu_uid: associated CPU id + * @cpu: associated CPU id * @tag: Steering Tag to be returned * * Return the Steering Tag for a target memory that is associated with a - * specific CPU as indicated by cpu_uid. + * specific CPU as indicated by cpu. * * Return: 0 if success, otherwise negative value (-errno) */ int pcie_tph_get_cpu_st(struct pci_dev *pdev, enum tph_mem_type mem_type, - unsigned int cpu_uid, u16 *tag) + unsigned int cpu, u16 *tag) { #ifdef CONFIG_ACPI struct pci_dev *rp; acpi_handle rp_acpi_handle; union st_info info; + u32 cpu_uid; + int ret; + + ret = acpi_get_cpu_uid(cpu, &cpu_uid); + if (ret != 0) + return ret; rp = pcie_find_root_port(pdev); if (!rp || !rp->bus || !rp->bus->bridge) @@ -265,9 +271,9 @@ int pcie_tph_get_cpu_st(struct pci_dev *pdev, enum tph_mem_type mem_type, *tag = tph_extract_tag(mem_type, pdev->tph_req_type, &info); - pci_dbg(pdev, "get steering tag: mem_type=%s, cpu_uid=%d, tag=%#04x\n", + pci_dbg(pdev, "get steering tag: mem_type=%s, cpu=%d, tag=%#04x\n", (mem_type == TPH_MEM_TYPE_VM) ? "volatile" : "persistent", - cpu_uid, *tag); + cpu, *tag); return 0; #else diff --git a/include/linux/pci-tph.h b/include/linux/pci-tph.h index ba28140ce6707..be68cd17f2f83 100644 --- a/include/linux/pci-tph.h +++ b/include/linux/pci-tph.h @@ -25,7 +25,7 @@ int pcie_tph_set_st_entry(struct pci_dev *pdev, unsigned int index, u16 tag); int pcie_tph_get_cpu_st(struct pci_dev *dev, enum tph_mem_type mem_type, - unsigned int cpu_uid, u16 *tag); + unsigned int cpu, u16 *tag); void pcie_disable_tph(struct pci_dev *pdev); int pcie_enable_tph(struct pci_dev *pdev, int mode); u16 pcie_tph_get_st_table_size(struct pci_dev *pdev); @@ -36,7 +36,7 @@ static inline int pcie_tph_set_st_entry(struct pci_dev *pdev, { return -EINVAL; } static inline int pcie_tph_get_cpu_st(struct pci_dev *dev, enum tph_mem_type mem_type, - unsigned int cpu_uid, u16 *tag) + unsigned int cpu, u16 *tag) { return -EINVAL; } static inline void pcie_disable_tph(struct pci_dev *pdev) { } static inline int pcie_enable_tph(struct pci_dev *pdev, int mode)