llext_manager: persist llext_buf_loader

For inspection API to work, it is imperative to keep the LLEXT loader
object available. This patch adds a pointer to the full loader object
in the lib_manager_module structure. The loader object is allocated
once and never freed.

Signed-off-by: Luca Burelli <l.burelli@arduino.cc>

Author: pillo79

src/include/sof/lib_manager.h

@@ -97,12 +97,14 @@ struct lib_manager_segment_desc {
 };
 
 struct llext;
+struct llext_buf_loader;
 
 struct lib_manager_module {
 	unsigned int start_idx;	/* Index of the first driver from this module in
 				 * the library-global driver list */
 	const struct sof_man_module_manifest *mod_manifest;
 	struct llext *llext; /* Zephyr loadable extension context */
+	struct llext_buf_loader *ebl; /* Zephyr loadable extension buffer loader */
 	bool mapped;
 	struct lib_manager_segment_desc segment[LIB_MANAGER_N_SEGMENTS];
 };

src/library_manager/llext_manager.c

@@ -238,11 +238,12 @@ static bool llext_manager_section_detached(const elf_shdr_t *shdr)
 	return shdr->sh_addr < SOF_MODULE_DRAM_LINK_END;
 }
 
-static int llext_manager_link(struct llext_loader *ldr, const char *name,
+static int llext_manager_link(const char *name,
 			      struct lib_manager_module *mctx, const void **buildinfo,
 			      const struct sof_man_module_manifest **mod_manifest)
 {
 	struct llext **llext = &mctx->llext;
+	struct llext_loader *ldr = &mctx->ebl->loader;
 	int ret;
 
 	if (*llext && !mctx->mapped) {
@@ -352,6 +353,7 @@ static int llext_manager_mod_init(struct lib_manager_mod_ctx *ctx,
 			offs = mod_array[i].segment[LIB_MANAGER_TEXT].file_offset;
 			ctx->mod[n_mod].mapped = false;
 			ctx->mod[n_mod].llext = NULL;
+			ctx->mod[n_mod].ebl = NULL;
 			ctx->mod[n_mod++].start_idx = i;
 		}
 
@@ -429,16 +431,28 @@ static int llext_manager_link_single(uint32_t module_id, const struct sof_man_fw
 		mod_size = ALIGN_UP(mod_array[i].segment[LIB_MANAGER_TEXT].file_offset - mod_offset,
 				    PAGE_SZ);
 
-	uint8_t *dram_base = (uint8_t *)desc - SOF_MAN_ELF_TEXT_OFFSET;
-	struct llext_buf_loader ebl = LLEXT_BUF_LOADER(dram_base + mod_offset, mod_size);
+	if (!mctx->ebl) {
+		/* allocate once, never freed */
+		mctx->ebl = rmalloc(SOF_MEM_ZONE_RUNTIME_SHARED, 0, SOF_MEM_CAPS_RAM,
+				    sizeof(struct llext_buf_loader));
+		if (!mctx->ebl) {
+			tr_err(&lib_manager_tr, "loader alloc failed");
+			return 0;
+		}
+
+		uint8_t *dram_base = (uint8_t *)desc - SOF_MAN_ELF_TEXT_OFFSET;
+
+		*mctx->ebl = (struct llext_buf_loader)LLEXT_BUF_LOADER(dram_base + mod_offset,
+								       mod_size);
+	}
 
 	/*
 	 * LLEXT linking is only needed once for all the "drivers" in the
 	 * module. This calls llext_load(), which also takes references to any
 	 * dependencies, sets up sections and retrieves buildinfo and
 	 * mod_manifest
 	 */
-	ret = llext_manager_link(&ebl.loader, mod_array[entry_index - inst_idx].name, mctx,
+	ret = llext_manager_link(mod_array[entry_index - inst_idx].name, mctx,
 				 buildinfo, mod_manifest);
 	if (ret < 0) {
 		tr_err(&lib_manager_tr, "linking failed: %d", ret);