From patchwork series 427590

https://patchwork.ozlabs.org//project/linuxppc-dev/list/?series=427590

Author: Fox Snowpatch

arch/powerpc/include/asm/fadump.h

@@ -34,4 +34,11 @@ extern int early_init_dt_scan_fw_dump(unsigned long node, const char *uname,
 				      int depth, void *data);
 extern int fadump_reserve_mem(void);
 #endif
+
+#if defined(CONFIG_FA_DUMP) && defined(CONFIG_CMA)
+void fadump_cma_init(void);
+#else
+static inline void fadump_cma_init(void) { }
+#endif
+
 #endif /* _ASM_POWERPC_FADUMP_H */

arch/powerpc/kernel/fadump.c

@@ -78,26 +78,38 @@ static struct cma *fadump_cma;
  * But for some reason even if it fails we still have the memory reservation
  * with us and we can still continue doing fadump.
  */
-static int __init fadump_cma_init(void)
+void __init fadump_cma_init(void)
 {
-	unsigned long long base, size;
+	unsigned long long base, size, end;
 	int rc;
 
-	if (!fw_dump.fadump_enabled)
-		return 0;
-
+	if (!fw_dump.fadump_supported || !fw_dump.fadump_enabled ||
+			fw_dump.dump_active)
+		return;
 	/*
 	 * Do not use CMA if user has provided fadump=nocma kernel parameter.
-	 * Return 1 to continue with fadump old behaviour.
 	 */
-	if (fw_dump.nocma)
-		return 1;
+	if (fw_dump.nocma || !fw_dump.boot_memory_size)
+		return;
 
+	/*
+	 * [base, end) should be reserved during early init in
+	 * fadump_reserve_mem(). No need to check this here as
+	 * cma_init_reserved_mem() already checks for overlap.
+	 * Here we give the aligned chunk of this reserved memory to CMA.
+	 */
 	base = fw_dump.reserve_dump_area_start;
 	size = fw_dump.boot_memory_size;
+	end = base + size;
 
-	if (!size)
-		return 0;
+	base = ALIGN(base, CMA_MIN_ALIGNMENT_BYTES);
+	end = ALIGN_DOWN(end, CMA_MIN_ALIGNMENT_BYTES);
+	size = end - base;
+
+	if (end <= base) {
+		pr_warn("%s: Too less memory to give to CMA\n", __func__);
+		return;
+	}
 
 	rc = cma_init_reserved_mem(base, size, 0, "fadump_cma", &fadump_cma);
 	if (rc) {
@@ -108,7 +120,7 @@ static int __init fadump_cma_init(void)
 		 * blocked from production system usage.  Hence return 1,
 		 * so that we can continue with fadump.
 		 */
-		return 1;
+		return;
 	}
 
 	/*
@@ -120,15 +132,13 @@ static int __init fadump_cma_init(void)
 	/*
 	 * So we now have successfully initialized cma area for fadump.
 	 */
-	pr_info("Initialized 0x%lx bytes cma area at %ldMB from 0x%lx "
+	pr_info("Initialized [0x%llx, %luMB] cma area from [0x%lx, %luMB] "
 		"bytes of memory reserved for firmware-assisted dump\n",
-		cma_get_size(fadump_cma),
-		(unsigned long)cma_get_base(fadump_cma) >> 20,
-		fw_dump.reserve_dump_area_size);
-	return 1;
+		cma_get_base(fadump_cma), cma_get_size(fadump_cma) >> 20,
+		fw_dump.reserve_dump_area_start,
+		fw_dump.boot_memory_size >> 20);
+	return;
 }
-#else
-static int __init fadump_cma_init(void) { return 1; }
 #endif /* CONFIG_CMA */
 
 /*
@@ -558,13 +568,6 @@ int __init fadump_reserve_mem(void)
 	if (!fw_dump.dump_active) {
 		fw_dump.boot_memory_size =
 			PAGE_ALIGN(fadump_calculate_reserve_size());
-#ifdef CONFIG_CMA
-		if (!fw_dump.nocma) {
-			fw_dump.boot_memory_size =
-				ALIGN(fw_dump.boot_memory_size,
-				      CMA_MIN_ALIGNMENT_BYTES);
-		}
-#endif
 
 		bootmem_min = fw_dump.ops->fadump_get_bootmem_min();
 		if (fw_dump.boot_memory_size < bootmem_min) {
@@ -637,8 +640,6 @@ int __init fadump_reserve_mem(void)
 
 		pr_info("Reserved %lldMB of memory at %#016llx (System RAM: %lldMB)\n",
 			(size >> 20), base, (memblock_phys_mem_size() >> 20));
-
-		ret = fadump_cma_init();
 	}
 
 	return ret;

arch/powerpc/kernel/setup-common.c

@@ -997,9 +997,11 @@ void __init setup_arch(char **cmdline_p)
 	initmem_init();
 
 	/*
-	 * Reserve large chunks of memory for use by CMA for KVM and hugetlb. These must
-	 * be called after initmem_init(), so that pageblock_order is initialised.
+	 * Reserve large chunks of memory for use by CMA for fadump, KVM and
+	 * hugetlb. These must be called after initmem_init(), so that
+	 * pageblock_order is initialised.
 	 */
+	fadump_cma_init();
 	kvm_cma_reserve();
 	gigantic_hugetlb_cma_reserve();
 

mm/cma.c

@@ -182,6 +182,15 @@ int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
 	if (!size || !memblock_is_region_reserved(base, size))
 		return -EINVAL;
 
+	/*
+	 * CMA uses CMA_MIN_ALIGNMENT_BYTES as alignment requirement which
+	 * needs pageblock_order to be initialized. Let's enforce it.
+	 */
+	if (!pageblock_order) {
+		pr_err("pageblock_order not yet initialized. Called during early boot?\n");
+		return -EINVAL;
+	}
+
 	/* ensure minimal alignment required by mm core */
 	if (!IS_ALIGNED(base | size, CMA_MIN_ALIGNMENT_BYTES))
 		return -EINVAL;