From 19d54020883c210a0cc78e5c735900ee9e9f64b3 Mon Sep 17 00:00:00 2001 From: Jack Rosenthal Date: Fri, 4 Nov 2022 10:15:28 -0600 Subject: firmware: google: Implement cbmem in sysfs driver The CBMEM area is a downward-growing memory region used by coreboot to dynamically allocate tagged data structures ("CBMEM entries") that remain resident during boot. This implements a driver which exports access to the CBMEM entries via sysfs under /sys/bus/coreboot/devices/cbmem-. This implementation is quite versatile. Examples of how it could be used are given below: * Tools like util/cbmem from the coreboot tree could use this driver instead of finding CBMEM in /dev/mem directly. Alternatively, firmware developers debugging an issue may find the sysfs interface more ergonomic than the cbmem tool and choose to use it directly. * The crossystem tool, which exposes verified boot variables, can use this driver to read the vboot work buffer. * Tools which read the BIOS SPI flash (e.g., flashrom) can find the flash layout in CBMEM directly, which is significantly faster than searching the flash directly. Write access is provided to all CBMEM regions via /sys/bus/coreboot/devices/cbmem-/mem, as the existing cbmem tooling updates this memory region, and envisioned use cases with crossystem can benefit from updating memory regions. Link: https://issuetracker.google.com/239604743 Cc: Stephen Boyd Cc: Tzung-Bi Shih Reviewed-by: Guenter Roeck Reviewed-by: Julius Werner Tested-by: Jack Rosenthal Signed-off-by: Jack Rosenthal Link: https://lore.kernel.org/r/20221104161528.531248-1-jrosenth@chromium.org Signed-off-by: Greg Kroah-Hartman --- drivers/firmware/google/Kconfig | 15 ++++ drivers/firmware/google/Makefile | 3 + drivers/firmware/google/cbmem.c | 129 +++++++++++++++++++++++++++++++ drivers/firmware/google/coreboot_table.c | 11 ++- drivers/firmware/google/coreboot_table.h | 18 +++++ 5 files changed, 175 insertions(+), 1 deletion(-) create mode 100644 drivers/firmware/google/cbmem.c (limited to 'drivers/firmware') diff --git a/drivers/firmware/google/Kconfig b/drivers/firmware/google/Kconfig index 983e07dc022e..9f190eab43ed 100644 --- a/drivers/firmware/google/Kconfig +++ b/drivers/firmware/google/Kconfig @@ -19,6 +19,21 @@ config GOOGLE_SMI driver provides an interface for reading and writing NVRAM variables. +config GOOGLE_CBMEM + tristate "CBMEM entries in sysfs" + depends on GOOGLE_COREBOOT_TABLE + help + CBMEM is a downwards-growing memory region created by the + Coreboot BIOS containing tagged data structures from the + BIOS. These data structures expose things like the verified + boot firmware variables, flash layout, firmware event log, + and more. + + This option enables the cbmem module, which causes the + kernel to search for Coreboot CBMEM entries, and expose the + memory for each entry in sysfs under + /sys/bus/coreboot/devices/cbmem-. + config GOOGLE_COREBOOT_TABLE tristate "Coreboot Table Access" depends on HAS_IOMEM && (ACPI || OF) diff --git a/drivers/firmware/google/Makefile b/drivers/firmware/google/Makefile index d17caded5d88..8151e323cc43 100644 --- a/drivers/firmware/google/Makefile +++ b/drivers/firmware/google/Makefile @@ -7,5 +7,8 @@ obj-$(CONFIG_GOOGLE_MEMCONSOLE) += memconsole.o obj-$(CONFIG_GOOGLE_MEMCONSOLE_COREBOOT) += memconsole-coreboot.o obj-$(CONFIG_GOOGLE_MEMCONSOLE_X86_LEGACY) += memconsole-x86-legacy.o +# Must come after coreboot_table.o, as this driver depends on that bus type. +obj-$(CONFIG_GOOGLE_CBMEM) += cbmem.o + vpd-sysfs-y := vpd.o vpd_decode.o obj-$(CONFIG_GOOGLE_VPD) += vpd-sysfs.o diff --git a/drivers/firmware/google/cbmem.c b/drivers/firmware/google/cbmem.c new file mode 100644 index 000000000000..685f3070ce9d --- /dev/null +++ b/drivers/firmware/google/cbmem.c @@ -0,0 +1,129 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * cbmem.c + * + * Driver for exporting cbmem entries in sysfs. + * + * Copyright 2022 Google LLC + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "coreboot_table.h" + +struct cbmem_entry { + char *mem_file_buf; + u32 size; +}; + +static struct cbmem_entry *to_cbmem_entry(struct kobject *kobj) +{ + return dev_get_drvdata(kobj_to_dev(kobj)); +} + +static ssize_t mem_read(struct file *filp, struct kobject *kobj, + struct bin_attribute *bin_attr, char *buf, loff_t pos, + size_t count) +{ + struct cbmem_entry *entry = to_cbmem_entry(kobj); + + return memory_read_from_buffer(buf, count, &pos, entry->mem_file_buf, + entry->size); +} + +static ssize_t mem_write(struct file *filp, struct kobject *kobj, + struct bin_attribute *bin_attr, char *buf, loff_t pos, + size_t count) +{ + struct cbmem_entry *entry = to_cbmem_entry(kobj); + + if (pos < 0 || pos >= entry->size) + return -EINVAL; + if (count > entry->size - pos) + count = entry->size - pos; + + memcpy(entry->mem_file_buf + pos, buf, count); + return count; +} +static BIN_ATTR_ADMIN_RW(mem, 0); + +static ssize_t address_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct coreboot_device *cbdev = dev_to_coreboot_device(dev); + + return sysfs_emit(buf, "0x%llx\n", cbdev->cbmem_entry.address); +} +static DEVICE_ATTR_RO(address); + +static ssize_t size_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct coreboot_device *cbdev = dev_to_coreboot_device(dev); + + return sysfs_emit(buf, "0x%x\n", cbdev->cbmem_entry.entry_size); +} +static DEVICE_ATTR_RO(size); + +static struct attribute *attrs[] = { + &dev_attr_address.attr, + &dev_attr_size.attr, + NULL, +}; + +static struct bin_attribute *bin_attrs[] = { + &bin_attr_mem, + NULL, +}; + +static const struct attribute_group cbmem_entry_group = { + .attrs = attrs, + .bin_attrs = bin_attrs, +}; + +static const struct attribute_group *dev_groups[] = { + &cbmem_entry_group, + NULL, +}; + +static int cbmem_entry_probe(struct coreboot_device *dev) +{ + struct cbmem_entry *entry; + + entry = devm_kzalloc(&dev->dev, sizeof(*entry), GFP_KERNEL); + if (!entry) + return -ENOMEM; + + dev_set_drvdata(&dev->dev, entry); + entry->mem_file_buf = devm_memremap(&dev->dev, dev->cbmem_entry.address, + dev->cbmem_entry.entry_size, + MEMREMAP_WB); + if (!entry->mem_file_buf) + return -ENOMEM; + + entry->size = dev->cbmem_entry.entry_size; + + return 0; +} + +static struct coreboot_driver cbmem_entry_driver = { + .probe = cbmem_entry_probe, + .drv = { + .name = "cbmem", + .owner = THIS_MODULE, + .dev_groups = dev_groups, + }, + .tag = LB_TAG_CBMEM_ENTRY, +}; +module_coreboot_driver(cbmem_entry_driver); + +MODULE_AUTHOR("Jack Rosenthal "); +MODULE_LICENSE("GPL"); diff --git a/drivers/firmware/google/coreboot_table.c b/drivers/firmware/google/coreboot_table.c index c52bcaa9def6..7748067eb9e6 100644 --- a/drivers/firmware/google/coreboot_table.c +++ b/drivers/firmware/google/coreboot_table.c @@ -97,12 +97,21 @@ static int coreboot_table_populate(struct device *dev, void *ptr) if (!device) return -ENOMEM; - dev_set_name(&device->dev, "coreboot%d", i); device->dev.parent = dev; device->dev.bus = &coreboot_bus_type; device->dev.release = coreboot_device_release; memcpy(&device->entry, ptr_entry, entry->size); + switch (device->entry.tag) { + case LB_TAG_CBMEM_ENTRY: + dev_set_name(&device->dev, "cbmem-%08x", + device->cbmem_entry.id); + break; + default: + dev_set_name(&device->dev, "coreboot%d", i); + break; + } + ret = device_register(&device->dev); if (ret) { put_device(&device->dev); diff --git a/drivers/firmware/google/coreboot_table.h b/drivers/firmware/google/coreboot_table.h index beb778674acd..37f4d335a606 100644 --- a/drivers/firmware/google/coreboot_table.h +++ b/drivers/firmware/google/coreboot_table.h @@ -39,6 +39,18 @@ struct lb_cbmem_ref { u64 cbmem_addr; }; +#define LB_TAG_CBMEM_ENTRY 0x31 + +/* Corresponds to LB_TAG_CBMEM_ENTRY */ +struct lb_cbmem_entry { + u32 tag; + u32 size; + + u64 address; + u32 entry_size; + u32 id; +}; + /* Describes framebuffer setup by coreboot */ struct lb_framebuffer { u32 tag; @@ -65,10 +77,16 @@ struct coreboot_device { union { struct coreboot_table_entry entry; struct lb_cbmem_ref cbmem_ref; + struct lb_cbmem_entry cbmem_entry; struct lb_framebuffer framebuffer; }; }; +static inline struct coreboot_device *dev_to_coreboot_device(struct device *dev) +{ + return container_of(dev, struct coreboot_device, dev); +} + /* A driver for handling devices described in coreboot tables. */ struct coreboot_driver { int (*probe)(struct coreboot_device *); -- cgit From 7b51161696e803fd5f9ad55b20a64c2df313f95c Mon Sep 17 00:00:00 2001 From: Yang Yingliang Date: Thu, 17 Nov 2022 15:06:36 +0800 Subject: firmware: raspberrypi: fix possible memory leak in rpi_firmware_probe() In rpi_firmware_probe(), if mbox_request_channel() fails, the 'fw' will not be freed through rpi_firmware_delete(), fix this leak by calling kfree() in the error path. Fixes: 1e7c57355a3b ("firmware: raspberrypi: Keep count of all consumers") Signed-off-by: Yang Yingliang Link: https://lore.kernel.org/r/20221117070636.3849773-1-yangyingliang@huawei.com Acked-by: Joel Savitz Signed-off-by: Greg Kroah-Hartman --- drivers/firmware/raspberrypi.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/firmware') diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c index 4b8978b254f9..dba315f675bc 100644 --- a/drivers/firmware/raspberrypi.c +++ b/drivers/firmware/raspberrypi.c @@ -272,6 +272,7 @@ static int rpi_firmware_probe(struct platform_device *pdev) int ret = PTR_ERR(fw->chan); if (ret != -EPROBE_DEFER) dev_err(dev, "Failed to get mbox channel: %d\n", ret); + kfree(fw); return ret; } -- cgit From fa1ba41c17cd786925720bc1a9554d6c6624923d Mon Sep 17 00:00:00 2001 From: Peng Wu Date: Tue, 15 Nov 2022 09:11:38 +0000 Subject: firmware: google: fix a NULL vs IS_ERR() check in cbmem_entry_probe() The devm_memremap() function returns error pointers on error, it doesn't return NULL. Fixes: 19d54020883c ("firmware: google: Implement cbmem in sysfs driver") Signed-off-by: Peng Wu Reviewed-by: Guenter Roeck Reviewed-by: Jack Rosenthal Link: https://lore.kernel.org/r/20221115091138.51614-1-wupeng58@huawei.com Signed-off-by: Greg Kroah-Hartman --- drivers/firmware/google/cbmem.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/firmware') diff --git a/drivers/firmware/google/cbmem.c b/drivers/firmware/google/cbmem.c index 685f3070ce9d..88e587ba1e0d 100644 --- a/drivers/firmware/google/cbmem.c +++ b/drivers/firmware/google/cbmem.c @@ -106,8 +106,8 @@ static int cbmem_entry_probe(struct coreboot_device *dev) entry->mem_file_buf = devm_memremap(&dev->dev, dev->cbmem_entry.address, dev->cbmem_entry.entry_size, MEMREMAP_WB); - if (!entry->mem_file_buf) - return -ENOMEM; + if (IS_ERR(entry->mem_file_buf)) + return PTR_ERR(entry->mem_file_buf); entry->size = dev->cbmem_entry.entry_size; -- cgit