On 2016/6/22 22:51, Marc Zyngier wrote: > On 22/06/16 14:52, Tomasz Nowicki wrote: >> On 22.06.2016 15:25, Marc Zyngier wrote: >>> On 22/06/16 13:35, Tomasz Nowicki wrote: >>>> IORT shows representation of IO topology for ARM based systems. >>>> It describes how various components are connected together on >>>> parent-child basis e.g. PCI RC -> SMMU -> ITS. Also see IORT spec. >>>> http://infocenter.arm.com/help/topic/com.arm.doc.den0049b/DEN0049B_IO_Remapping_Table.pdf >>>> >>>> Initial support allows to detect IORT table presence and save its >>>> root pointer obtained through acpi_get_table(). The pointer validity >>>> depends on acpi_gbl_permanent_mmap because if acpi_gbl_permanent_mmap >>>> is not set while using IORT nodes we would dereference unmapped pointers. >>>> >>>> For the aforementioned reason call iort_table_detect() from acpi_init() >>>> which guarantees acpi_gbl_permanent_mmap to be set at that point. >>>> >>>> Add generic helpers which are helpful for scanning and retrieving >>>> information from IORT table content. List of the most important helpers: >>>> - iort_find_dev_node() finds IORT node for a given device >>>> - iort_node_map_rid() maps device RID and returns IORT node which provides >>>> final translation >>>> >>>> Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx> >>>> --- >>>> drivers/acpi/Kconfig | 3 + >>>> drivers/acpi/Makefile | 1 + >>>> drivers/acpi/bus.c | 2 + >>>> drivers/acpi/iort.c | 217 ++++++++++++++++++++++++++++++++++++++++++++++++++ >>>> include/linux/iort.h | 30 +++++++ >>>> 5 files changed, 253 insertions(+) >>>> create mode 100644 drivers/acpi/iort.c >>>> create mode 100644 include/linux/iort.h >>>> >>>> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig >>>> index b7e2e77..848471f 100644 >>>> --- a/drivers/acpi/Kconfig >>>> +++ b/drivers/acpi/Kconfig >>>> @@ -57,6 +57,9 @@ config ACPI_SYSTEM_POWER_STATES_SUPPORT >>>> config ACPI_CCA_REQUIRED >>>> bool >>>> >>>> +config IORT_TABLE >>>> + bool >>>> + >>>> config ACPI_DEBUGGER >>>> bool "AML debugger interface" >>>> select ACPI_DEBUG >>>> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile >>>> index 251ce85..c7c9b29 100644 >>>> --- a/drivers/acpi/Makefile >>>> +++ b/drivers/acpi/Makefile >>>> @@ -82,6 +82,7 @@ obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o >>>> obj-$(CONFIG_ACPI_BGRT) += bgrt.o >>>> obj-$(CONFIG_ACPI_CPPC_LIB) += cppc_acpi.o >>>> obj-$(CONFIG_ACPI_DEBUGGER_USER) += acpi_dbg.o >>>> +obj-$(CONFIG_IORT_TABLE) += iort.o >>>> >>>> # processor has its own "processor." module_param namespace >>>> processor-y := processor_driver.o >>>> diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c >>>> index 31e8da6..176c17d 100644 >>>> --- a/drivers/acpi/bus.c >>>> +++ b/drivers/acpi/bus.c >>>> @@ -33,6 +33,7 @@ >>>> #ifdef CONFIG_X86 >>>> #include <asm/mpspec.h> >>>> #endif >>>> +#include <linux/iort.h> >>>> #include <linux/pci.h> >>>> #include <acpi/apei.h> >>>> #include <linux/dmi.h> >>>> @@ -1118,6 +1119,7 @@ static int __init acpi_init(void) >>>> } >>>> >>>> pci_mmcfg_late_init(); >>>> + iort_table_detect(); >>>> acpi_scan_init(); >>>> acpi_ec_init(); >>>> acpi_debugfs_init(); >>>> diff --git a/drivers/acpi/iort.c b/drivers/acpi/iort.c >>>> new file mode 100644 >>>> index 0000000..fcfa008f >>>> --- /dev/null >>>> +++ b/drivers/acpi/iort.c >>>> @@ -0,0 +1,217 @@ >>>> +/* >>>> + * Copyright (C) 2016, Semihalf >>>> + * Author: Tomasz Nowicki <tn@xxxxxxxxxxxx> >>>> + * >>>> + * This program is free software; you can redistribute it and/or modify it >>>> + * under the terms and conditions of the GNU General Public License, >>>> + * version 2, as published by the Free Software Foundation. >>>> + * >>>> + * This program is distributed in the hope it will be useful, but WITHOUT >>>> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or >>>> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for >>>> + * more details. >>>> + * >>>> + * This file implements early detection/parsing of I/O mapping >>>> + * reported to OS through firmware via I/O Remapping Table (IORT) >>>> + * IORT document number: ARM DEN 0049A >>>> + */ >>>> + >>>> +#define pr_fmt(fmt) "ACPI: IORT: " fmt >>>> + >>>> +#include <linux/iort.h> >>>> +#include <linux/kernel.h> >>>> +#include <linux/pci.h> >>>> + >>>> +typedef acpi_status (*iort_find_node_callback) >>>> + (struct acpi_iort_node *node, void *context); >>>> + >>>> +/* Root pointer to the mapped IORT table */ >>>> +static struct acpi_table_header *iort_table; >>>> + >>>> +static struct acpi_iort_node * >>>> +iort_scan_node(enum acpi_iort_node_type type, >>>> + iort_find_node_callback callback, void *context) >>>> +{ >>>> + struct acpi_iort_node *iort_node, *iort_end; >>>> + struct acpi_table_iort *iort; >>>> + int i; >>>> + >>>> + /* Get the first IORT node */ >>>> + iort = (struct acpi_table_iort *)iort_table; >>>> + iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort, >>>> + iort->node_offset); >>>> + iort_end = ACPI_ADD_PTR(struct acpi_iort_node, iort_table, >>>> + iort_table->length); >>>> + >>>> + for (i = 0; i < iort->node_count; i++) { >>>> + if (WARN_TAINT(iort_node >= iort_end, TAINT_FIRMWARE_WORKAROUND, >>>> + "IORT node pointer overflows, bad table!\n")) >>>> + return NULL; >>>> + >>>> + if (iort_node->type == type) { >>>> + if (ACPI_SUCCESS(callback(iort_node, context))) >>>> + return iort_node; >>>> + } >>>> + >>>> + iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort_node, >>>> + iort_node->length); >>>> + } >>>> + >>>> + return NULL; >>>> +} >>>> + >>>> +static acpi_status >>>> +iort_match_node_callback(struct acpi_iort_node *node, void *context) >>>> +{ >>>> + struct device *dev = context; >>>> + >>>> + switch (node->type) { >>>> + case ACPI_IORT_NODE_NAMED_COMPONENT: { >>>> + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; >>>> + struct acpi_device *adev = to_acpi_device_node(dev->fwnode); >>>> + struct acpi_iort_named_component *ncomp; >>>> + >>>> + if (!adev) >>>> + break; >>>> + >>>> + ncomp = (struct acpi_iort_named_component *)node->node_data; >>>> + >>>> + if (ACPI_FAILURE(acpi_get_name(adev->handle, >>>> + ACPI_FULL_PATHNAME, &buffer))) { >>>> + dev_warn(dev, "Can't get device full path name\n"); >>>> + } else { >>>> + int match; >>>> + >>>> + match = !strcmp(ncomp->device_name, buffer.pointer); >>>> + kfree(buffer.pointer); >>> Why did you change this to a naked kfree? The ACPI code clearly states: >>> >>> /* >>> * Allocate a new buffer. We directectly call acpi_os_allocate here to >>> * purposefully bypass the (optionally enabled) internal allocation >>> * tracking mechanism since we only want to track internal >>> * allocations. Note: The caller should use acpi_os_free to free this >>> * buffer created via ACPI_ALLOCATE_BUFFER. >>> */ >> Yes we should use symmetric free function to acpi_os_allocate here, >> which means acpi_os_free should be used here. >> >> My main motivation was to free buffer.pointer instead of &buffer It needs to be free buffer.pointer. >> >> Would you mind to fix that (s/kfree/acpi_os_free) before merging ? > Sure. I tracked Marc's tree on git.kernel.org, it's acpi_os_free(buffer.pointer) there so my worry is gone :) Thanks Hanjun -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
