Re: [Linaro-acpi] [PATCH V8 1/8] ACPI: I/O Remapping Table (IORT) initial support

On Thu, Aug 18, 2016 at 06:55:50PM +0800, Dennis Chen wrote:

[...]

...

+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;

Here, the same as I comments on Lorenzo's patch. If IORT is missed in the firmware, then iort_table will be NULL, result in kernel panic in the codes followed.

The pointer is checked in the functions that are visible to other compilation units before calling this function:

iort_msi_map_rid() iort_get_device_domain()

I missed to check it when I added iort_node_match() and iort_iommu_configure() though, which makes me think that it is probably better to move the iort_table pointer check to iort_scan_node() so that it is done in one single place instead of adding it to all given external interfaces.

Lorenzo

Thanks, Dennis

...

• 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);
  

• 	acpi_os_free(buffer.pointer);
  

• 	if (match)
  

• 		return AE_OK;
  

• }
  

• break;
  

• }
• case ACPI_IORT_NODE_PCI_ROOT_COMPLEX: {

• struct acpi_iort_root_complex *pci_rc;
  

• struct pci_bus *bus;
  

• bus = to_pci_bus(dev);
  

• pci_rc = (struct acpi_iort_root_complex *)node->node_data;
  

• /*
  

•  * It is assumed that PCI segment numbers maps one-to-one
  

•  * with root complexes. Each segment number can represent only
  

•  * one root complex.
  

•  */
  

• if (pci_rc->pci_segment_number == pci_domain_nr(bus))
  

• 	return AE_OK;
  

• break;
  

• }
• }
• return AE_NOT_FOUND;

+}

+static int +iort_id_map(struct acpi_iort_id_mapping *map, u8 type, u32 rid_in, u32 *rid_out) +{

• /* Single mapping does not care for input id */
• if (map->flags & ACPI_IORT_ID_SINGLE_MAPPING) {

• if (type == ACPI_IORT_NODE_NAMED_COMPONENT ||
  

•     type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX) {
  

• 	*rid_out = map->output_base;
  

• 	return 0;
  

• }
  

• pr_warn(FW_BUG "[map %p] SINGLE MAPPING flag not allowed for node type %d, skipping ID map\n",
  

• 	map, type);
  

• return -ENXIO;
  

• }
• if (rid_in < map->input_base ||

•    (rid_in >= map->input_base + map->id_count))
  

• return -ENXIO;
  

• *rid_out = map->output_base + (rid_in - map->input_base);
• return 0;

+}

+static struct acpi_iort_node * +iort_node_map_rid(struct acpi_iort_node *node, u32 rid_in,

•   u32 *rid_out, u8 type)
  

+{

• u32 rid = rid_in;
• /* Parse the ID mapping tree to find specified node type */
• while (node) {

• struct acpi_iort_id_mapping *map;
  

• int i;
  

• if (node->type == type) {
  

• 	if (rid_out)
  

• 		*rid_out = rid;
  

• 	return node;
  

• }
  

• if (!node->mapping_offset || !node->mapping_count)
  

• 	goto fail_map;
  

• map = ACPI_ADD_PTR(struct acpi_iort_id_mapping, node,
  

• 		   node->mapping_offset);
  

• /* Firmware bug! */
  

• if (!map->output_reference) {
  

• 	pr_err(FW_BUG "[node %p type %d] ID map has NULL parent reference\n",
  

• 	       node, node->type);
  

• 	goto fail_map;
  

• }
  

• /* Do the RID translation */
  

• for (i = 0; i < node->mapping_count; i++, map++) {
  

• 	if (!iort_id_map(map, node->type, rid, &rid))
  

• 		break;
  

• }
  

• if (i == node->mapping_count)
  

• 	goto fail_map;
  

• node = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
  

• 		    map->output_reference);
  

• }

+fail_map:

• /* Map input RID to output RID unchanged on mapping failure*/
• if (rid_out)

• *rid_out = rid_in;
  

• return NULL;

+}

+static struct acpi_iort_node * +iort_find_dev_node(struct device *dev) +{

• struct pci_bus *pbus;
• if (!dev_is_pci(dev))

• return iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT,
  

• 		      iort_match_node_callback, dev);
  

• /* Find a PCI root bus */
• pbus = to_pci_dev(dev)->bus;
• while (!pci_is_root_bus(pbus))

• pbus = pbus->parent;
  

• return iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,

• 	      iort_match_node_callback, &pbus->dev);
  

+}

+void __init iort_table_detect(void) +{

• acpi_status status;
• status = acpi_get_table(ACPI_SIG_IORT, 0, &iort_table);
• if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {

• const char *msg = acpi_format_exception(status);
  

• pr_err("Failed to get table, %s\n", msg);
  

• }

+} diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c index 85b7d07..55a84da 100644 --- a/drivers/acpi/bus.c +++ b/drivers/acpi/bus.c @@ -36,6 +36,7 @@ #ifdef CONFIG_X86 #include <asm/mpspec.h> #endif +#include <linux/iort.h> #include <linux/pci.h> #include <acpi/apei.h> #include <linux/dmi.h> @@ -1186,6 +1187,7 @@ 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/include/linux/iort.h b/include/linux/iort.h new file mode 100644 index 0000000..cde6809 --- /dev/null +++ b/include/linux/iort.h @@ -0,0 +1,30 @@ +/*

• • Copyright (C) 2016, Semihalf
• • Author: Tomasz Nowicki tn@semihalf.com
• • 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.
• • You should have received a copy of the GNU General Public License along with
• • this program; if not, write to the Free Software Foundation, Inc., 59 Temple
• • Place - Suite 330, Boston, MA 02111-1307 USA.
• */

+#ifndef __IORT_H__ +#define __IORT_H__

+#include <linux/acpi.h>

+#ifdef CONFIG_IORT_TABLE +void iort_table_detect(void); +#else +static inline void iort_table_detect(void) { } +#endif

+#endif /* __IORT_H__ */

1.9.1

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