[PATCH 03/16] efi: memory: use the lmb API's for allocating and freeing memory

[Heinrich Schuchardt]

On 9/5/24 10:27, Sughosh Ganu wrote:
> Use the LMB API's for allocating and freeing up memory. With this, the
> LMB module becomes the common backend for managing non U-Boot image
> memory that might be requested by other modules.
>
> Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
> ---
>   lib/efi_loader/Kconfig      |  1 +
>   lib/efi_loader/efi_memory.c | 74 ++++++++++---------------------------
>   2 files changed, 21 insertions(+), 54 deletions(-)
>
> diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
> index 6ffefa9103..911d4c6bbe 100644
> --- a/lib/efi_loader/Kconfig
> +++ b/lib/efi_loader/Kconfig
> @@ -18,6 +18,7 @@ config EFI_LOADER
>   	select DM_EVENT
>   	select EVENT_DYNAMIC
>   	select LIB_UUID
> +	select LMB
>   	imply PARTITION_UUIDS
>   	select REGEX
>   	imply FAT
> diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c
> index c6f1dd0945..90e07ed6a2 100644
> --- a/lib/efi_loader/efi_memory.c
> +++ b/lib/efi_loader/efi_memory.c
> @@ -9,6 +9,7 @@
>
>   #include <efi_loader.h>
>   #include <init.h>
> +#include <lmb.h>
>   #include <log.h>
>   #include <malloc.h>
>   #include <mapmem.h>
> @@ -432,53 +433,6 @@ static efi_status_t efi_check_allocated(u64 addr, bool must_be_allocated)
>   	return EFI_NOT_FOUND;
>   }
>
> -/**
> - * efi_find_free_memory() - find free memory pages
> - *
> - * @len:	size of memory area needed
> - * @max_addr:	highest address to allocate
> - * Return:	pointer to free memory area or 0
> - */
> -static uint64_t efi_find_free_memory(uint64_t len, uint64_t max_addr)
> -{
> -	struct efi_mem_list *lmem;
> -
> -	/*
> -	 * Prealign input max address, so we simplify our matching
> -	 * logic below and can just reuse it as return pointer.
> -	 */
> -	max_addr &= ~EFI_PAGE_MASK;
> -
> -	list_for_each_entry(lmem, &efi_mem, link) {
> -		struct efi_mem_desc *desc = &lmem->desc;
> -		uint64_t desc_len = desc->num_pages << EFI_PAGE_SHIFT;
> -		uint64_t desc_end = desc->physical_start + desc_len;
> -		uint64_t curmax = min(max_addr, desc_end);
> -		uint64_t ret = curmax - len;
> -
> -		/* We only take memory from free RAM */
> -		if (desc->type != EFI_CONVENTIONAL_MEMORY)
> -			continue;
> -
> -		/* Out of bounds for max_addr */
> -		if ((ret + len) > max_addr)
> -			continue;
> -
> -		/* Out of bounds for upper map limit */
> -		if ((ret + len) > desc_end)
> -			continue;
> -
> -		/* Out of bounds for lower map limit */
> -		if (ret < desc->physical_start)
> -			continue;
> -
> -		/* Return the highest address in this map within bounds */
> -		return ret;
> -	}
> -
> -	return 0;
> -}
> -
>   /**
>    * efi_allocate_pages - allocate memory pages
>    *
> @@ -493,6 +447,7 @@ efi_status_t efi_allocate_pages(enum efi_allocate_type type,
>   				efi_uintn_t pages, uint64_t *memory)
>   {
>   	u64 len;
> +	uint flags;
>   	efi_status_t ret;
>   	uint64_t addr;
>
> @@ -508,33 +463,35 @@ efi_status_t efi_allocate_pages(enum efi_allocate_type type,
>   	    (len >> EFI_PAGE_SHIFT) != (u64)pages)
>   		return EFI_OUT_OF_RESOURCES;
>
> +	flags = LMB_NOOVERWRITE | LMB_NONOTIFY;

In the EFI context we should use LMB notification to notify the
EFI_EVENT_GROUP_MEMORY_MAP_CHANGE event and update the memory map.

See chapter 7.1.2 EFI_BOOT_SERVICES.CreateEventEx() in the UEFI
specification.

>   	switch (type) {
>   	case EFI_ALLOCATE_ANY_PAGES:
>   		/* Any page */
> -		addr = efi_find_free_memory(len, -1ULL);
> +		addr = (u64)lmb_alloc_flags(len, EFI_PAGE_SIZE, flags);

On ARM64 we must ensure that "all 4KiB pages in the 64KiB page ... use
identical ARM Memory Page Attributes". I cannot see how LMB implements this.

See chapter 2.3.6 AArch64 Platforms in the UEFI specification.

If you pass the EFI memory type to LMB and store it there, we can avoid
duplication of the memory map and we can implement the 64 KiB pages
logic in LMB.

Best regards

Heinrich

>   		if (!addr)
>   			return EFI_OUT_OF_RESOURCES;
>   		break;
>   	case EFI_ALLOCATE_MAX_ADDRESS:
>   		/* Max address */
> -		addr = efi_find_free_memory(len, *memory);
> +		addr = (u64)lmb_alloc_base_flags(len, EFI_PAGE_SIZE, *memory,
> +						 flags);
>   		if (!addr)
>   			return EFI_OUT_OF_RESOURCES;
>   		break;
>   	case EFI_ALLOCATE_ADDRESS:
>   		if (*memory & EFI_PAGE_MASK)
>   			return EFI_NOT_FOUND;
> -		/* Exact address, reserve it. The addr is already in *memory. */
> -		ret = efi_check_allocated(*memory, false);
> -		if (ret != EFI_SUCCESS)
> -			return EFI_NOT_FOUND;
> -		addr = *memory;
> +
> +		addr = (u64)lmb_alloc_addr_flags(*memory, len, flags);
> +		if (!addr)
> +			return EFI_OUT_OF_RESOURCES;
>   		break;
>   	default:
>   		/* UEFI doesn't specify other allocation types */
>   		return EFI_INVALID_PARAMETER;
>   	}
>
> +	addr = (u64)(uintptr_t)map_sysmem(addr, 0);
>   	/* Reserve that map in our memory maps */
>   	ret = efi_add_memory_map_pg(addr, pages, memory_type, true);
>   	if (ret != EFI_SUCCESS)
> @@ -555,6 +512,9 @@ efi_status_t efi_allocate_pages(enum efi_allocate_type type,
>    */
>   efi_status_t efi_free_pages(uint64_t memory, efi_uintn_t pages)
>   {
> +	u64 len;
> +	uint flags;
> +	long status;
>   	efi_status_t ret;
>
>   	ret = efi_check_allocated(memory, true);
> @@ -568,6 +528,12 @@ efi_status_t efi_free_pages(uint64_t memory, efi_uintn_t pages)
>   		return EFI_INVALID_PARAMETER;
>   	}
>
> +	flags = LMB_NOOVERWRITE | LMB_NONOTIFY;
> +	len = (u64)pages << EFI_PAGE_SHIFT;
> +	status = lmb_free_flags(memory, len, flags);
> +	if (status)
> +		return EFI_NOT_FOUND;
> +
>   	ret = efi_add_memory_map_pg(memory, pages, EFI_CONVENTIONAL_MEMORY,
>   				    false);
>   	if (ret != EFI_SUCCESS)