initramfs: Provide a common initrd reserve function

The arm and riscv have same logic to check and reserve
the memory of initrd, let's provide a common function
to reduce duplicated code.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>

arch/arm/mm/init.c

@@ -153,47 +153,6 @@ phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
 	return phys;
 }
 
-static void __init arm_initrd_init(void)
-{
-#ifdef CONFIG_BLK_DEV_INITRD
-	phys_addr_t start;
-	unsigned long size;
-
-	initrd_start = initrd_end = 0;
-
-	if (!phys_initrd_size)
-		return;
-
-	/*
-	 * Round the memory region to page boundaries as per free_initrd_mem()
-	 * This allows us to detect whether the pages overlapping the initrd
-	 * are in use, but more importantly, reserves the entire set of pages
-	 * as we don't want these pages allocated for other purposes.
-	 */
-	start = round_down(phys_initrd_start, PAGE_SIZE);
-	size = phys_initrd_size + (phys_initrd_start - start);
-	size = round_up(size, PAGE_SIZE);
-
-	if (!memblock_is_region_memory(start, size)) {
-		pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
-		       (u64)start, size);
-		return;
-	}
-
-	if (memblock_is_region_reserved(start, size)) {
-		pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
-		       (u64)start, size);
-		return;
-	}
-
-	memblock_reserve(start, size);
-
-	/* Now convert initrd to virtual addresses */
-	initrd_start = __phys_to_virt(phys_initrd_start);
-	initrd_end = initrd_start + phys_initrd_size;
-#endif
-}
-
 #ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND
 void check_cpu_icache_size(int cpuid)
 {
@@ -215,7 +174,7 @@ void __init arm_memblock_init(const struct machine_desc *mdesc)
 	/* Register the kernel text, kernel data and initrd with memblock. */
 	memblock_reserve(__pa(KERNEL_START), KERNEL_END - KERNEL_START);
 
-	arm_initrd_init();
+	reserve_initrd_mem();
 
 	arm_mm_memblock_reserve();
 

arch/riscv/mm/init.c

@@ -105,55 +105,6 @@ void __init mem_init(void)
 	print_vm_layout();
 }
 
-#ifdef CONFIG_BLK_DEV_INITRD
-static void __init setup_initrd(void)
-{
-	phys_addr_t start;
-	unsigned long size;
-
-	/* Ignore the virtul address computed during device tree parsing */
-	initrd_start = initrd_end = 0;
-
-	if (!phys_initrd_size)
-		return;
-	/*
-	 * Round the memory region to page boundaries as per free_initrd_mem()
-	 * This allows us to detect whether the pages overlapping the initrd
-	 * are in use, but more importantly, reserves the entire set of pages
-	 * as we don't want these pages allocated for other purposes.
-	 */
-	start = round_down(phys_initrd_start, PAGE_SIZE);
-	size = phys_initrd_size + (phys_initrd_start - start);
-	size = round_up(size, PAGE_SIZE);
-
-	if (!memblock_is_region_memory(start, size)) {
-		pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region",
-		       (u64)start, size);
-		goto disable;
-	}
-
-	if (memblock_is_region_reserved(start, size)) {
-		pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region\n",
-		       (u64)start, size);
-		goto disable;
-	}
-
-	memblock_reserve(start, size);
-	/* Now convert initrd to virtual addresses */
-	initrd_start = (unsigned long)__va(phys_initrd_start);
-	initrd_end = initrd_start + phys_initrd_size;
-	initrd_below_start_ok = 1;
-
-	pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",
-		(void *)(initrd_start), size);
-	return;
-disable:
-	pr_cont(" - disabling initrd\n");
-	initrd_start = 0;
-	initrd_end = 0;
-}
-#endif /* CONFIG_BLK_DEV_INITRD */
-
 void __init setup_bootmem(void)
 {
 	phys_addr_t mem_start = 0;
@@ -186,9 +137,7 @@ void __init setup_bootmem(void)
 	dma32_phys_limit = min(4UL * SZ_1G, (unsigned long)PFN_PHYS(max_low_pfn));
 	set_max_mapnr(max_low_pfn);
 
-#ifdef CONFIG_BLK_DEV_INITRD
-	setup_initrd();
-#endif /* CONFIG_BLK_DEV_INITRD */
+	reserve_initrd_mem();
 
 	/*
 	 * Avoid using early_init_fdt_reserve_self() since __pa() does

include/linux/initrd.h

@@ -15,6 +15,12 @@ extern int initrd_below_start_ok;
 extern unsigned long initrd_start, initrd_end;
 extern void free_initrd_mem(unsigned long, unsigned long);
 
+#ifdef CONFIG_BLK_DEV_INITRD
+extern void __init reserve_initrd_mem(void);
+#else
+static inline void __init reserve_initrd_mem(void) {}
+#endif
+
 extern phys_addr_t phys_initrd_start;
 extern unsigned long phys_initrd_size;
 

init/initramfs.c

@@ -535,6 +535,51 @@ extern unsigned long __initramfs_size;
 #include <linux/initrd.h>
 #include <linux/kexec.h>
 
+void __init reserve_initrd_mem(void)
+{
+	phys_addr_t start;
+	unsigned long size;
+
+	/* Ignore the virtul address computed during device tree parsing */
+	initrd_start = initrd_end = 0;
+
+	if (!phys_initrd_size)
+		return;
+	/*
+	 * Round the memory region to page boundaries as per free_initrd_mem()
+	 * This allows us to detect whether the pages overlapping the initrd
+	 * are in use, but more importantly, reserves the entire set of pages
+	 * as we don't want these pages allocated for other purposes.
+	 */
+	start = round_down(phys_initrd_start, PAGE_SIZE);
+	size = phys_initrd_size + (phys_initrd_start - start);
+	size = round_up(size, PAGE_SIZE);
+
+	if (!memblock_is_region_memory(start, size)) {
+		pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region",
+		       (u64)start, size);
+		goto disable;
+	}
+
+	if (memblock_is_region_reserved(start, size)) {
+		pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region\n",
+		       (u64)start, size);
+		goto disable;
+	}
+
+	memblock_reserve(start, size);
+	/* Now convert initrd to virtual addresses */
+	initrd_start = (unsigned long)__va(phys_initrd_start);
+	initrd_end = initrd_start + phys_initrd_size;
+	initrd_below_start_ok = 1;
+
+	return;
+disable:
+	pr_cont(" - disabling initrd\n");
+	initrd_start = 0;
+	initrd_end = 0;
+}
+
 void __weak __init free_initrd_mem(unsigned long start, unsigned long end)
 {
 #ifdef CONFIG_ARCH_KEEP_MEMBLOCK