Commit c0c8f778 authored by Luca Burelli's avatar Luca Burelli Committed by Benjamin Cabé
Browse files

llext: refactor llext_copy_region() 



This commit adjusts the logic of the LLEXT memory allocation routine by:

 * defining 'align' and 'alloc' variables once and updating them in the
   following code;

 * swapping the condition, converting it to an 'if(IS_ENABLED(...))' and
   using a direct calculation for the size to make the code easier to
   read;

 * updating and extending a few comments.

No functional change is intended.

Signed-off-by: default avatarLuca Burelli <l.burelli@arduino.cc>
parent 219cde66

subsys/llext/llext_mem.c

+26 −17
Original line number Diff line number Diff line
@@ -63,19 +63,27 @@ static int llext_copy_region(struct llext_loader *ldr, struct llext *ext, 
{

	int ret;

	elf_shdr_t *region = ldr->sects + mem_idx;

	uintptr_t region_alloc = region->sh_size;

	uintptr_t region_align = LLEXT_PAGE_SIZE;



	if (!region->sh_size) {

	if (!region_alloc) {

		return 0;

	}

	ext->mem_size[mem_idx] = region->sh_size;

	ext->mem_size[mem_idx] = region_alloc;



	if (IS_ENABLED(CONFIG_LLEXT_STORAGE_WRITABLE)) {

		/*

		 * Try to reuse data areas from the ELF buffer, if possible.

		 * If any of the following tests fail, a normal allocation

		 * will be attempted.

		 */

		if (region->sh_type != SHT_NOBITS) {

			/* Directly use data from the ELF buffer if peek() is supported */

			/* Region has data in the file, check if peek() is supported */

			ext->mem[mem_idx] = llext_peek(ldr, region->sh_offset);

			if (ext->mem[mem_idx]) {

				/* Map this region directly to the ELF buffer */

				llext_init_mem_part(ext, mem_idx, (uintptr_t)ext->mem[mem_idx],

						    region->sh_size);

						    region_alloc);

				ext->mem_on_heap[mem_idx] = false;

				return 0;

			}
@@ -94,21 +102,22 @@ static int llext_copy_region(struct llext_loader *ldr, struct llext *ext, 
		return -EFAULT;

	}



	/* On ARM with an MPU a pow(2, N)*32 sized and aligned region is needed,

	 * otherwise its typically an mmu page (sized and aligned memory region)

	 * we are after that we can assign memory permission bits on.

	/*

	 * Calculate the desired region size and alignment for a new allocation.

	 */

#ifndef CONFIG_ARM_MPU

	const uintptr_t region_alloc = ROUND_UP(region->sh_size, LLEXT_PAGE_SIZE);

	const uintptr_t region_align = LLEXT_PAGE_SIZE;

#else

	uintptr_t region_alloc = LLEXT_PAGE_SIZE;

	if (IS_ENABLED(CONFIG_ARM_MPU)) {

		/* On ARM with an MPU, regions must be sized and aligned to the same

		 * power of two (larger than 32).

		 */

		uintptr_t block_size = MAX(region_alloc, LLEXT_PAGE_SIZE);



	while (region_alloc < region->sh_size) {

		region_alloc *= 2;

		block_size = 1 << LOG2CEIL(block_size); /* align to next power of two */

		region_alloc = block_size;

		region_align = block_size;

	} else {

		/* Otherwise, round the region to multiples of LLEXT_PAGE_SIZE. */

		region_alloc = ROUND_UP(region_alloc, LLEXT_PAGE_SIZE);

	}

	uintptr_t region_align = region_alloc;

#endif



	ext->mem[mem_idx] = llext_aligned_alloc(region_align, region_alloc);

	if (!ext->mem[mem_idx]) {

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