On Mon, Apr 13, 2020 at 8:55 AM Ard Biesheuvel <ardb@xxxxxxxxxx> wrote:
>
> 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 <ardb@xxxxxxxxxx>
> ---
> drivers/firmware/efi/libstub/Makefile | 3 +-
> drivers/firmware/efi/libstub/alignedmem.c | 57 ++++++++++++++++++++
> drivers/firmware/efi/libstub/efistub.h | 3 ++
> drivers/firmware/efi/libstub/mem.c | 25 ++++-----
> 4 files changed, 71 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
> index 094eabdecfe6..1a09b9445394 100644
> --- a/drivers/firmware/efi/libstub/Makefile
> +++ b/drivers/firmware/efi/libstub/Makefile
> @@ -42,7 +42,8 @@ KCOV_INSTRUMENT := n
>
> lib-y := efi-stub-helper.o gop.o secureboot.o tpm.o \
> file.o mem.o random.o randomalloc.o pci.o \
> - skip_spaces.o lib-cmdline.o lib-ctype.o
> + skip_spaces.o lib-cmdline.o lib-ctype.o \
> + alignedmem.o
>
> # include the stub's generic dependencies from lib/ when building for ARM/arm64
> arm-deps-y := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c
> diff --git a/drivers/firmware/efi/libstub/alignedmem.c b/drivers/firmware/efi/libstub/alignedmem.c
> new file mode 100644
> index 000000000000..cc89c4d6196f
> --- /dev/null
> +++ b/drivers/firmware/efi/libstub/alignedmem.c
> @@ -0,0 +1,57 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/efi.h>
> +#include <asm/efi.h>
> +
> +#include "efistub.h"
> +
> +/**
> + * efi_allocate_pages_aligned() - Allocate memory pages
> + * @size: minimum number of bytes to allocate
> + * @addr: On return the address of the first allocated page. The first
> + * allocated page has alignment EFI_ALLOC_ALIGN which is an
> + * architecture dependent multiple of the page size.
> + * @max: the address that the last allocated memory page shall not
> + * exceed
> + * @align: minimum alignment of the base of the allocation
> + *
> + * Allocate pages as EFI_LOADER_DATA. The allocated pages are aligned according
> + * to @align, which should be >= EFI_ALLOC_ALIGN. The last allocated page will
> + * not exceed the address given by @max.
> + *
> + * Return: status code
> + */
> +efi_status_t efi_allocate_pages_aligned(unsigned long size, unsigned long *addr,
> + unsigned long max, unsigned long align)
> +{
> + efi_physical_addr_t alloc_addr;
> + efi_status_t status;
> + int slack;
> +
> + if (align < EFI_ALLOC_ALIGN)
> + align = EFI_ALLOC_ALIGN;
> +
> + alloc_addr = ALIGN_DOWN(max + 1, align) - 1;
> + size = round_up(size, EFI_ALLOC_ALIGN);
> + slack = align / EFI_PAGE_SIZE - 1;
> +
> + status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
> + EFI_LOADER_DATA, size / EFI_PAGE_SIZE + slack,
> + &alloc_addr);
> + if (status != EFI_SUCCESS)
> + return status;
> +
> + *addr = ALIGN((unsigned long)alloc_addr, align);
> +
> + if (slack > 0) {
> + int l = (alloc_addr % align) / EFI_PAGE_SIZE;
> +
> + if (l) {
> + efi_bs_call(free_pages, alloc_addr, slack - l + 1);
> + slack = l - 1;
> + }
> + if (slack)
> + efi_bs_call(free_pages, *addr + size, slack);
> + }
> + return EFI_SUCCESS;
> +}
> diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
> index 4844c3bd40df..5dcfadcf2bc1 100644
> --- a/drivers/firmware/efi/libstub/efistub.h
> +++ b/drivers/firmware/efi/libstub/efistub.h
> @@ -641,6 +641,9 @@ efi_status_t efi_low_alloc(unsigned long size, unsigned long align,
> efi_status_t efi_allocate_pages(unsigned long size, unsigned long *addr,
> unsigned long max);
>
> +efi_status_t efi_allocate_pages_aligned(unsigned long size, unsigned long *addr,
> + unsigned long max, unsigned long align);
> +
> efi_status_t efi_relocate_kernel(unsigned long *image_addr,
> unsigned long image_size,
> unsigned long alloc_size,
> diff --git a/drivers/firmware/efi/libstub/mem.c b/drivers/firmware/efi/libstub/mem.c
> index 869a79c8946f..0020b0fa9587 100644
> --- a/drivers/firmware/efi/libstub/mem.c
> +++ b/drivers/firmware/efi/libstub/mem.c
> @@ -93,31 +93,24 @@ efi_status_t efi_get_memory_map(struct efi_boot_memmap *map)
> efi_status_t efi_allocate_pages(unsigned long size, unsigned long *addr,
> unsigned long max)
> {
> - efi_physical_addr_t alloc_addr = ALIGN_DOWN(max + 1, EFI_ALLOC_ALIGN) - 1;
> - int slack = EFI_ALLOC_ALIGN / EFI_PAGE_SIZE - 1;
> + efi_physical_addr_t alloc_addr;
> efi_status_t status;
>
> - size = round_up(size, EFI_ALLOC_ALIGN);
> + if (EFI_ALLOC_ALIGN > EFI_PAGE_SIZE)
> + return efi_allocate_pages_aligned(size, addr, max,
> + EFI_ALLOC_ALIGN);
> +
> + alloc_addr = ALIGN_DOWN(max + 1, EFI_ALLOC_ALIGN) - 1;
> status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
> - EFI_LOADER_DATA, size / EFI_PAGE_SIZE + slack,
> + EFI_LOADER_DATA, DIV_ROUND_UP(size, EFI_PAGE_SIZE),
> &alloc_addr);
> if (status != EFI_SUCCESS)
> return status;
>
> - *addr = ALIGN((unsigned long)alloc_addr, EFI_ALLOC_ALIGN);
> -
> - if (slack > 0) {
> - int l = (alloc_addr % EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
> -
> - if (l) {
> - efi_bs_call(free_pages, alloc_addr, slack - l + 1);
> - slack = l - 1;
> - }
> - if (slack)
> - efi_bs_call(free_pages, *addr + size, slack);
> - }
> + *addr = alloc_addr;
> return EFI_SUCCESS;
> }
> +
> /**
> * efi_low_alloc_above() - allocate pages at or above given address
> * @size: size of the memory area to allocate
> --
> 2.17.1
>
Reviewed-by: Atish Patra <atish.patra@xxxxxxx>
--
Regards,
Atish
