Re: [Linaro-acpi] [PATCH] ACPI: sysfs expose root tables RSDP/RSDT/XSDT

On 05/11/2015 08:30 AM, Graeme Gregory wrote:

On some architectures /dev/mem is being removed. For debug/analysis tools like FWTS/acpidump we therefore need to expose the ACPI root tables in sysfs like the other tables.

Signed-off-by: Graeme Gregory graeme.gregory@linaro.org

Nicely done.

---

drivers/acpi/sysfs.c | 119 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 119 insertions(+)

diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c index 0876d77..3f336f9 100644 --- a/drivers/acpi/sysfs.c +++ b/drivers/acpi/sysfs.c @@ -348,6 +348,123 @@ acpi_sysfs_table_handler(u32 event, void *table, void *context) return AE_OK; } +/*

• • On some architectures /dev/mem interface is not available so for debug
• • tools like FWTS, acpidump etc we will also need to export the three
• • root tables RSDP, RSDT, XSDT where they exist.
• */

+struct acpi_root_table_attr {

• struct bin_attribute attr;
• acpi_physical_address table_addr;

+};

+static ssize_t acpi_table_show_root(struct file *filp, struct kobject *kobj,

• 		    struct bin_attribute *bin_attr, char *buf,
  

• 		    loff_t offset, size_t count)
  

+{

• struct acpi_root_table_attr *table_attr =

• 	container_of(bin_attr,
  

• 		     struct acpi_root_table_attr, attr);
  

• void *table;
• int ret;
• table = acpi_os_map_memory(table_attr->table_addr, bin_attr->size);
• if (!table)

• return -EIO;
  

• ret = memory_read_from_buffer(buf, count, &offset, table,

• 		      bin_attr->size);
  

• acpi_os_unmap_memory(table, bin_attr->size);
• return ret;

+}

+static int acpi_root_tables_sysfs_init(struct kobject *tables_kobj) +{

• struct acpi_root_table_attr *root_tables_attr;
• struct acpi_table_rsdp *rsdp;
• struct acpi_table_header *table_header = NULL;
• acpi_physical_address rsdp_ptr, rsdt_ptr, xsdt_ptr;
• int ret;
• rsdp_ptr = acpi_os_get_root_pointer();
• if (!rsdp_ptr)

• return -EIO;
  

• rsdp = acpi_os_map_memory(rsdp_ptr, sizeof(*rsdp));
• if (!rsdp) {

• ret = -EIO;
  

• goto err;
  

• }
• root_tables_attr = kzalloc(sizeof(*root_tables_attr) * 3, GFP_KERNEL);
• root_tables_attr[0].table_addr = rsdp_ptr;
• root_tables_attr[0].attr.size = sizeof(*rsdp);
• root_tables_attr[0].attr.read = acpi_table_show_root;
• root_tables_attr[0].attr.attr.name = "RSDP";

Minor quibble: technically, this should be "RSD PTR". From a usability standpoint, it's unclear to me which would be better -- "RSD PTR" is the correct signature, but "RSDP" is probably what people expect.

• root_tables_attr[0].attr.attr.mode = 0400;
• ret = sysfs_create_bin_file(tables_kobj, &root_tables_attr[0].attr);
• if (ret)

• goto err;
  

• rsdt_ptr = rsdp->rsdt_physical_address;
• if (rsdt_ptr) {

• table_header = acpi_os_map_memory(rsdt_ptr,
  

• 				  sizeof(*table_header));
  

• if (!table_header) {
  

• 	ret = -EIO;
  

• 	goto err;
  

• }
  

• root_tables_attr[1].table_addr = rsdt_ptr;
  

• root_tables_attr[1].attr.size = table_header->length;
  

• root_tables_attr[1].attr.read = acpi_table_show_root;
  

• root_tables_attr[1].attr.attr.name = "RSDT";
  

• root_tables_attr[1].attr.attr.mode = 0400;
  

• ret = sysfs_create_bin_file(tables_kobj,
  

• 			    &root_tables_attr[1].attr);
  

• if (ret)
  

• 	goto err;
  

• acpi_os_unmap_memory(table_header, sizeof(*table_header));
  

• }
• xsdt_ptr = rsdp->xsdt_physical_address;
• if (xsdt_ptr) {

• table_header = acpi_os_map_memory(xsdt_ptr,
  

• 				  sizeof(*table_header));
  

• if (!table_header) {
  

• 	ret = -EIO;
  

• 	goto err;
  

• }
  

• root_tables_attr[2].table_addr = xsdt_ptr;
  

• root_tables_attr[2].attr.size = table_header->length;
  

• root_tables_attr[2].attr.read = acpi_table_show_root;
  

• root_tables_attr[2].attr.attr.name = "XSDT";
  

• root_tables_attr[2].attr.attr.mode = 0400;
  

• ret = sysfs_create_bin_file(tables_kobj,
  

• 			    &root_tables_attr[2].attr);
  

• if (ret)
  

• 	goto err;
  

• acpi_os_unmap_memory(table_header, sizeof(*table_header));
  

• }
• return ret;

+err:

• if (rsdp)

• acpi_os_map_memory(rsdp_ptr, sizeof(*rsdp));
  

• if (table_header)

• acpi_os_unmap_memory(table_header, sizeof(*table_header));
  

• return ret;

+}

static int acpi_tables_sysfs_init(void) { struct acpi_table_attr *table_attr; @@ -387,6 +504,8 @@ static int acpi_tables_sysfs_init(void) list_add_tail(&table_attr->node, &acpi_table_attr_list); }

• acpi_root_tables_sysfs_init(tables_kobj);
• kobject_uevent(tables_kobj, KOBJ_ADD); kobject_uevent(dynamic_tables_kobj, KOBJ_ADD); status = acpi_install_table_handler(acpi_sysfs_table_handler, NULL);

Other than the above,

Reviewd-by: Al Stone al.stone@linaro.org