linux-toradex.git/drivers/firmware/efi, branch v6.14-rc4

efi: Avoid cold plugged memory for placing the kernel

2025-02-04T13:08:22+00:00

UEFI 2.11 introduced EFI_MEMORY_HOT_PLUGGABLE to annotate system memory
regions that are 'cold plugged' at boot, i.e., hot pluggable memory that
is available from early boot, and described as system RAM by the
firmware.

Existing loaders and EFI applications running in the boot context will
happily use this memory for allocating data structures that cannot be
freed or moved at runtime, and this prevents the memory from being
unplugged. Going forward, the new EFI_MEMORY_HOT_PLUGGABLE attribute
should be tested, and memory annotated as such should be avoided for
such allocations.

In the EFI stub, there are a couple of occurrences where, instead of the
high-level AllocatePages() UEFI boot service, a low-level code sequence
is used that traverses the EFI memory map and carves out the requested
number of pages from a free region. This is needed, e.g., for allocating
as low as possible, or for allocating pages at random.

While AllocatePages() should presumably avoid special purpose memory and
cold plugged regions, this manual approach needs to incorporate this
logic itself, in order to prevent the kernel itself from ending up in a
hot unpluggable region, preventing it from being unplugged.

So add the EFI_MEMORY_HOTPLUGGABLE macro definition, and check for it
where appropriate.

Cc: stable@vger.kernel.org
Signed-off-by: Ard Biesheuvel

Merge tag 'driver-core-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2025-01-28T20:25:12+00:00

Pull driver core and debugfs updates from Greg KH:
 "Here is the big set of driver core and debugfs updates for 6.14-rc1.

  Included in here is a bunch of driver core, PCI, OF, and platform rust
  bindings (all acked by the different subsystem maintainers), hence the
  merge conflict with the rust tree, and some driver core api updates to
  mark things as const, which will also require some fixups due to new
  stuff coming in through other trees in this merge window.

  There are also a bunch of debugfs updates from Al, and there is at
  least one user that does have a regression with these, but Al is
  working on tracking down the fix for it. In my use (and everyone
  else's linux-next use), it does not seem like a big issue at the
  moment.

  Here's a short list of the things in here:

   - driver core rust bindings for PCI, platform, OF, and some i/o
     functions.

     We are almost at the "write a real driver in rust" stage now,
     depending on what you want to do.

   - misc device rust bindings and a sample driver to show how to use
     them

   - debugfs cleanups in the fs as well as the users of the fs api for
     places where drivers got it wrong or were unnecessarily doing
     things in complex ways.

   - driver core const work, making more of the api take const * for
     different parameters to make the rust bindings easier overall.

   - other small fixes and updates

  All of these have been in linux-next with all of the aforementioned
  merge conflicts, and the one debugfs issue, which looks to be resolved
  "soon""

* tag 'driver-core-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (95 commits)
  rust: device: Use as_char_ptr() to avoid explicit cast
  rust: device: Replace CString with CStr in property_present()
  devcoredump: Constify 'struct bin_attribute'
  devcoredump: Define 'struct bin_attribute' through macro
  rust: device: Add property_present()
  saner replacement for debugfs_rename()
  orangefs-debugfs: don't mess with ->d_name
  octeontx2: don't mess with ->d_parent or ->d_parent->d_name
  arm_scmi: don't mess with ->d_parent->d_name
  slub: don't mess with ->d_name
  sof-client-ipc-flood-test: don't mess with ->d_name
  qat: don't mess with ->d_name
  xhci: don't mess with ->d_iname
  mtu3: don't mess wiht ->d_iname
  greybus/camera - stop messing with ->d_iname
  mediatek: stop messing with ->d_iname
  netdevsim: don't embed file_operations into your structs
  b43legacy: make use of debugfs_get_aux()
  b43: stop embedding struct file_operations into their objects
  carl9170: stop embedding file_operations into their objects
  ...

efi: libstub: Use '-std=gnu11' to fix build with GCC 15

2025-01-22T11:57:45+00:00

GCC 15 changed the default C standard version to C23, which should not
have impacted the kernel because it requests the gnu11 standard via
'-std=' in the main Makefile. However, the EFI libstub Makefile uses its
own set of KBUILD_CFLAGS for x86 without a '-std=' value (i.e., using
the default), resulting in errors from the kernel's definitions of bool,
true, and false in stddef.h, which are reserved keywords under C23.

  ./include/linux/stddef.h:11:9: error: expected identifier before ‘false’
     11 |         false   = 0,
  ./include/linux/types.h:35:33: error: two or more data types in declaration specifiers
     35 | typedef _Bool                   bool;

Set '-std=gnu11' in the x86 cflags to resolve the error and consistently
use the same C standard version for the entire kernel. All other
architectures reuse KBUILD_CFLAGS from the rest of the kernel, so this
issue is not visible for them.

Cc: stable@vger.kernel.org
Reported-by: Kostadin Shishmanov 
Closes: https://lore.kernel.org/4OAhbllK7x4QJGpZjkYjtBYNLd_2whHx9oFiuZcGwtVR4hIzvduultkgfAIRZI3vQpZylu7Gl929HaYFRGeMEalWCpeMzCIIhLxxRhq4U-Y=@protonmail.com/
Reported-by: Jakub Jelinek 
Closes: https://lore.kernel.org/Z4467umXR2PZ0M1H@tucnak/
Signed-off-by: Nathan Chancellor 
Signed-off-by: Ard Biesheuvel

efi: sysfb_efi: fix W=1 warnings when EFI is not set

2025-01-14T07:35:28+00:00

A build with W=1 fails because there are code and data that are not
needed or used when CONFIG_EFI is not set. Move the "#ifdef CONFIG_EFI"
block to earlier in the source file so that the unused code/data are
not built.

drivers/firmware/efi/sysfb_efi.c:345:39: warning: ‘efifb_fwnode_ops’ defined but not used [-Wunused-const-variable=]
  345 | static const struct fwnode_operations efifb_fwnode_ops = {
      |                                       ^~~~~~~~~~~~~~~~
drivers/firmware/efi/sysfb_efi.c:238:35: warning: ‘efifb_dmi_swap_width_height’ defined but not used [-Wunused-const-variable=]
  238 | static const struct dmi_system_id efifb_dmi_swap_width_height[] __initconst = {
      |                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/firmware/efi/sysfb_efi.c:188:35: warning: ‘efifb_dmi_system_table’ defined but not used [-Wunused-const-variable=]
  188 | static const struct dmi_system_id efifb_dmi_system_table[] __initconst = {
      |                                   ^~~~~~~~~~~~~~~~~~~~~~

Fixes: 15d27b15de96 ("efi: sysfb_efi: fix build when EFI is not set")
Signed-off-by: Randy Dunlap 
Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-kbuild-all/202501071933.20nlmJJt-lkp@intel.com/
Cc: David Rheinsberg 
Cc: Hans de Goede 
Cc: Javier Martinez Canillas 
Cc: Peter Jones 
Cc: Simona Vetter 
Cc: linux-fbdev@vger.kernel.org
Cc: Ard Biesheuvel 
Cc: linux-efi@vger.kernel.org
Reviewed-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Signed-off-by: Ard Biesheuvel

efi/libstub: Use __free() helper for pool deallocations

2025-01-14T07:35:27+00:00

Annotate some local buffer allocations as __free(efi_pool) and simplify
the associated error handling accordingly. This removes a couple of
gotos and simplifies the code.

Signed-off-by: Ard Biesheuvel

efi/libstub: Use cleanup helpers for freeing copies of the memory map

2025-01-14T07:35:27+00:00

The EFI stub may obtain the memory map from the firmware numerous times,
and this involves doing a EFI pool allocation first, which needs to be
freed after use.

Streamline this using a cleanup helper, which makes the code easier to
follow.

Signed-off-by: Ard Biesheuvel

efi/libstub: Simplify PCI I/O handle buffer traversal

2025-01-14T07:35:27+00:00

Use LocateHandleBuffer() and a __free() cleanup helper to simplify the
PCI I/O handle buffer traversal code.

Signed-off-by: Ard Biesheuvel

efi/libstub: Refactor and clean up GOP resolution picker code

2025-01-14T07:35:27+00:00

The EFI stub implements various ways of setting the resolution of the
EFI framebuffer at boot, and this duplicates a lot of boilerplate for
iterating over the supported modes and extracting the resolution and
color depth.

Refactor this into a single helper that takes a callback, and use it for
the 'auto', 'list' and 'res' selection methods.

Signed-off-by: Ard Biesheuvel

efi/libstub: Simplify GOP handling code

2025-01-14T07:35:08+00:00

Use the LocateHandleBuffer() API and a __free() function to simplify the
logic that allocates a handle buffer to iterate over all GOP protocols
in the EFI database.

Signed-off-by: Ard Biesheuvel

efi/libstub: Use C99-style for loop to traverse handle buffer

2025-01-14T07:34:25+00:00

Tweak the for_each_efi_handle() macro in order to avoid the need on the
part of the caller to provide a loop counter variable.

Also move efi_get_handle_num() to the callers, so that each occurrence
can be replaced with the actual number returned by the simplified
LocateHandleBuffer API.

Signed-off-by: Ard Biesheuvel