Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted

Pull I3C updates from Alexandre Belloni:
 "A new driver this cycle, for the AMD AXI I3C controller.

  There are also new features such as IBI wakeup support, SETAASA device
  discovery and ACPI support for the the DAA methods, meaning we can now
  communicate with the SPD devices on DDR5 modules.

  New driver:
   - AMD AXI I3C master controller

  Subsystem:
   - I3C Common Command Code (CCC) handling improvements, especially
     around GET CCCs
   - SETAASA device discovery support
   - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
     well as I2C devices on I3C bus
   - IBI-based wakeup support

  Drivers:
   - dw: SETAASA support
   - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
     controller support, PIO queue management support for HCI v1.2
   - renesas: improve suspend to RAM support, add runtime PM support"

* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
  i3c: dw: reduce do_daa time if there's no client
  i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
  i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
  i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
  i3c: dw: rename "pclk" to "apb" to match dt-binding
  i3c: dw: make struct dw_i3c_cmd smaller
  i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
  i3c: renesas: Don't register devices when ENTDAA times out
  i3c: master: dw-i3c-master: fix OD timing for first broadcast
  i3c: mipi-i3c-hci: Advertise IBI wakeup capability
  i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
  i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
  i3c: master: Reject IBI requests from non-IBI-capable devices
  i3c: master: Add helper to query bus wakeup requirements
  i3c: master: Report wakeup events for IBIs
  i3c: master: Support IBI-based wakeup capability
  i3c: master: Fix potential UAF in i3c_device_match()
  i3c: master: Fix potential UAF in i3c_device_uevent()
  i3c: Make dev->desc locking assumptions explicit
  i3c: master: Fix use-after-free of master->this
  ...

1 files changed, 180 insertions, 0 deletions

diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c
new file mode 100644
index 000000000..9c2ba9240
--- /dev/null
+++ b/fs/kernel_read_file.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/fs.h>
+#include <linux/fs_struct.h>
+#include <linux/kernel_read_file.h>
+#include <linux/security.h>
+#include <linux/vmalloc.h>
+
+/**
+ * kernel_read_file() - read file contents into a kernel buffer
+ *
+ * @file:	file to read from
+ * @offset:	where to start reading from (see below).
+ * @buf:	pointer to a "void *" buffer for reading into (if
+ *		*@buf is NULL, a buffer will be allocated, and
+ *		@buf_size will be ignored)
+ * @buf_size:	size of buf, if already allocated. If @buf not
+ *		allocated, this is the largest size to allocate.
+ * @file_size:	if non-NULL, the full size of @file will be
+ *		written here.
+ * @id:		the kernel_read_file_id identifying the type of
+ *		file contents being read (for LSMs to examine)
+ *
+ * @offset must be 0 unless both @buf and @file_size are non-NULL
+ * (i.e. the caller must be expecting to read partial file contents
+ * via an already-allocated @buf, in at most @buf_size chunks, and
+ * will be able to determine when the entire file was read by
+ * checking @file_size). This isn't a recommended way to read a
+ * file, though, since it is possible that the contents might
+ * change between calls to kernel_read_file().
+ *
+ * Returns number of bytes read (no single read will be bigger
+ * than SSIZE_MAX), or negative on error.
+ *
+ */
+ssize_t kernel_read_file(struct file *file, loff_t offset, void **buf,
+			 size_t buf_size, size_t *file_size,
+			 enum kernel_read_file_id id)
+{
+	loff_t i_size, pos;
+	ssize_t copied;
+	void *allocated = NULL;
+	bool whole_file;
+	int ret;
+
+	if (offset != 0 && (!*buf || !file_size))
+		return -EINVAL;
+
+	if (!S_ISREG(file_inode(file)->i_mode))
+		return -EINVAL;
+
+	ret = deny_write_access(file);
+	if (ret)
+		return ret;
+
+	i_size = i_size_read(file_inode(file));
+	if (i_size <= 0) {
+		ret = -EINVAL;
+		goto out;
+	}
+	/* The file is too big for sane activities. */
+	if (i_size > SSIZE_MAX) {
+		ret = -EFBIG;
+		goto out;
+	}
+	/* The entire file cannot be read in one buffer. */
+	if (!file_size && offset == 0 && i_size > buf_size) {
+		ret = -EFBIG;
+		goto out;
+	}
+
+	whole_file = (offset == 0 && i_size <= buf_size);
+	ret = security_kernel_read_file(file, id, whole_file);
+	if (ret)
+		goto out;
+
+	if (file_size)
+		*file_size = i_size;
+
+	if (!*buf)
+		*buf = allocated = vmalloc(i_size);
+	if (!*buf) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	pos = offset;
+	copied = 0;
+	while (copied < buf_size) {
+		ssize_t bytes;
+		size_t wanted = min_t(size_t, buf_size - copied,
+					      i_size - pos);
+
+		bytes = kernel_read(file, *buf + copied, wanted, &pos);
+		if (bytes < 0) {
+			ret = bytes;
+			goto out_free;
+		}
+
+		if (bytes == 0)
+			break;
+		copied += bytes;
+	}
+
+	if (whole_file) {
+		if (pos != i_size) {
+			ret = -EIO;
+			goto out_free;
+		}
+
+		ret = security_kernel_post_read_file(file, *buf, i_size, id);
+	}
+
+out_free:
+	if (ret < 0) {
+		if (allocated) {
+			vfree(*buf);
+			*buf = NULL;
+		}
+	}
+
+out:
+	allow_write_access(file);
+	return ret == 0 ? copied : ret;
+}
+EXPORT_SYMBOL_GPL(kernel_read_file);
+
+ssize_t kernel_read_file_from_path(const char *path, loff_t offset, void **buf,
+				   size_t buf_size, size_t *file_size,
+				   enum kernel_read_file_id id)
+{
+	struct file *file;
+	ssize_t ret;
+
+	if (!path || !*path)
+		return -EINVAL;
+
+	file = filp_open(path, O_RDONLY, 0);
+	if (IS_ERR(file))
+		return PTR_ERR(file);
+
+	ret = kernel_read_file(file, offset, buf, buf_size, file_size, id);
+	fput(file);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kernel_read_file_from_path);
+
+ssize_t kernel_read_file_from_path_initns(const char *path, loff_t offset,
+					  void **buf, size_t buf_size,
+					  size_t *file_size,
+					  enum kernel_read_file_id id)
+{
+	struct file *file;
+	ssize_t ret;
+
+	if (!path || !*path)
+		return -EINVAL;
+
+	scoped_with_init_fs()
+		file = filp_open(path, O_RDONLY, 0);
+	if (IS_ERR(file))
+		return PTR_ERR(file);
+
+	ret = kernel_read_file(file, offset, buf, buf_size, file_size, id);
+	fput(file);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns);
+
+ssize_t kernel_read_file_from_fd(int fd, loff_t offset, void **buf,
+				 size_t buf_size, size_t *file_size,
+				 enum kernel_read_file_id id)
+{
+	CLASS(fd, f)(fd);
+
+	if (fd_empty(f) || !(fd_file(f)->f_mode & FMODE_READ))
+		return -EBADF;
+
+	return kernel_read_file(fd_file(f), offset, buf, buf_size, file_size, id);
+}
+EXPORT_SYMBOL_GPL(kernel_read_file_from_fd);