kernel/drivers/firmware/efi/libstub/alignedmem.c, branch linux-6.18.y

efi/libstub: Add one kernel-doc comment

2024-01-30T20:44:21Z

Add the description of @memory_type to silence the warning: drivers/firmware/efi/libstub/alignedmem.c:27: warning: Function parameter or struct member 'memory_type' not described in 'efi_allocate_pages_aligned' Signed-off-by: Yang Li [ardb: tweak comment] Signed-off-by: Ard Biesheuvel

arm64: efi: Limit allocations to 48-bit addressable physical region

2022-12-07T18:50:44Z

The UEFI spec does not mention or reason about the configured size of the virtual address space at all, but it does mention that all memory should be identity mapped using a page size of 4 KiB. This means that a LPA2 capable system that has any system memory outside of the 48-bit addressable physical range and follows the spec to the letter may serve page allocation requests from regions of memory that the kernel cannot access unless it was built with LPA2 support and enables it at runtime. So let's ensure that all page allocations are limited to the 48-bit range. Signed-off-by: Ard Biesheuvel

efi: libstub: use EFI_LOADER_CODE region when moving the kernel in memory

2022-11-18T08:14:08Z

The EFI spec is not very clear about which permissions are being given when allocating pages of a certain type. However, it is quite obvious that EFI_LOADER_CODE is more likely to permit execution than EFI_LOADER_DATA, which becomes relevant once we permit booting the kernel proper with the firmware's 1:1 mapping still active. Ostensibly, recent systems such as the Surface Pro X grant executable permissions to EFI_LOADER_CODE regions but not EFI_LOADER_DATA regions. Signed-off-by: Ard Biesheuvel

efi/libstub: Fix gcc error around __umoddi3 for 32 bit builds

2020-07-09T06:45:09Z

32bit gcc doesn't support modulo operation on 64 bit data. It results in a __umoddi3 error while building EFI for 32 bit. Use bitwise operations instead of modulo operations to fix the issue. Signed-off-by: Atish Patra Link: https://lore.kernel.org/r/20200625234516.31406-2-atish.patra@wdc.com Signed-off-by: Ard Biesheuvel

efi/libstub: Add API function to allocate aligned memory

2020-04-24T12:52:16Z

Break out the code to create an aligned page allocation from mem.c and move it into a function efi_allocate_pages_aligned() in alignedmem.c. Update efi_allocate_pages() to invoke it unless the minimum alignment equals the EFI page size (4 KB), in which case the ordinary page allocator is sufficient. This way, efi_allocate_pages_aligned() will only be pulled into the build if it is actually being used (which will be on arm64 only in the immediate future) Signed-off-by: Ard Biesheuvel