[RFC v2] arm:extend the reserved mrmory for initrd to be page aligned

[Wang, Yalin]

this patch extend the start and end address of initrd to be page aligned,
so that we can free all memory including the un-page aligned head or tail
page of initrd, if the start or end address of initrd are not page
aligned, the page can't be freed by free_initrd_mem() function.

Signed-off-by: Yalin Wang <yalin.wang@xxxxxxxxxxxxxx>
---
 arch/arm/mm/init.c   | 19 +++++++++++++++++--
 arch/arm64/mm/init.c | 37 +++++++++++++++++++++++++++++++++----
 2 files changed, 50 insertions(+), 6 deletions(-)

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 659c75d..8490b70 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -277,6 +277,8 @@ phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
 void __init arm_memblock_init(const struct machine_desc *mdesc)
 {
 	/* Register the kernel text, kernel data and initrd with memblock. */
+	phys_addr_t phys_initrd_start_orig __maybe_unused;
+	phys_addr_t phys_initrd_size_orig __maybe_unused;
 #ifdef CONFIG_XIP_KERNEL
 	memblock_reserve(__pa(_sdata), _end - _sdata);
 #else
@@ -289,6 +291,13 @@ void __init arm_memblock_init(const struct machine_desc *mdesc)
 		phys_initrd_size = initrd_end - initrd_start;
 	}
 	initrd_start = initrd_end = 0;
+	phys_initrd_start_orig = phys_initrd_start;
+	phys_initrd_size_orig = phys_initrd_size;
+	/* make sure the start and end address are page aligned */
+	phys_initrd_size = round_up(phys_initrd_start + phys_initrd_size, PAGE_SIZE);
+	phys_initrd_start = round_down(phys_initrd_start, PAGE_SIZE);
+	phys_initrd_size -= phys_initrd_start;
+
 	if (phys_initrd_size &&
 	    !memblock_is_region_memory(phys_initrd_start, phys_initrd_size)) {
 		pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
@@ -305,9 +314,10 @@ void __init arm_memblock_init(const struct machine_desc *mdesc)
 		memblock_reserve(phys_initrd_start, phys_initrd_size);
 
 		/* Now convert initrd to virtual addresses */
-		initrd_start = __phys_to_virt(phys_initrd_start);
-		initrd_end = initrd_start + phys_initrd_size;
+		initrd_start = __phys_to_virt(phys_initrd_start_orig);
+		initrd_end = initrd_start + phys_initrd_size_orig;
 	}
+
 #endif
 
 	arm_mm_memblock_reserve();
@@ -636,6 +646,11 @@ static int keep_initrd;
 void free_initrd_mem(unsigned long start, unsigned long end)
 {
 	if (!keep_initrd) {
+		if (start == initrd_start)
+			start = round_down(start, PAGE_SIZE);
+		if (end == initrd_end)
+			end = round_up(end, PAGE_SIZE);
+
 		poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
 		free_reserved_area((void *)start, (void *)end, -1, "initrd");
 	}
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 5472c24..9dfd9a6 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -138,15 +138,38 @@ static void arm64_memory_present(void)
 void __init arm64_memblock_init(void)
 {
 	phys_addr_t dma_phys_limit = 0;
-
+	phys_addr_t phys_initrd_start;
+	phys_addr_t phys_initrd_size;
 	/*
 	 * Register the kernel text, kernel data, initrd, and initial
 	 * pagetables with memblock.
 	 */
 	memblock_reserve(__pa(_text), _end - _text);
 #ifdef CONFIG_BLK_DEV_INITRD
-	if (initrd_start)
-		memblock_reserve(__virt_to_phys(initrd_start), initrd_end - initrd_start);
+	if (initrd_start) {
+		phys_initrd_start = __virt_to_phys(initrd_start);
+		phys_initrd_size = initrd_end - initrd_start;
+		/* make sure the start and end address are page aligned */
+		phys_initrd_size = round_up(phys_initrd_start + phys_initrd_size, PAGE_SIZE);
+		phys_initrd_start = round_down(phys_initrd_start, PAGE_SIZE);
+		phys_initrd_size -= phys_initrd_start;
+		if (phys_initrd_size &&
+				!memblock_is_region_memory(phys_initrd_start, phys_initrd_size)) {
+			pr_err("INITRD: %pa+%pa is not a memory region - disabling initrd\n",
+					&phys_initrd_start, &phys_initrd_size);
+			phys_initrd_start = phys_initrd_size = 0;
+		}
+		if (phys_initrd_size &&
+				memblock_is_region_reserved(phys_initrd_start, phys_initrd_size)) {
+			pr_err("INITRD: %pa+%pa overlaps in-use memory region - disabling initrd\n",
+					&phys_initrd_start, &phys_initrd_size);
+			phys_initrd_start = phys_initrd_size = 0;
+		}
+		if (phys_initrd_size)
+			memblock_reserve(phys_initrd_start, phys_initrd_size);
+		else
+			initrd_start = initrd_end = 0;
+	}
 #endif
 
 	if (!efi_enabled(EFI_MEMMAP))
@@ -334,8 +357,14 @@ static int keep_initrd;
 
 void free_initrd_mem(unsigned long start, unsigned long end)
 {
-	if (!keep_initrd)
+	if (!keep_initrd) {
+		if (start == initrd_start)
+			start = round_down(start, PAGE_SIZE);
+		if (end == initrd_end)
+			end = round_up(end, PAGE_SIZE);
+
 		free_reserved_area((void *)start, (void *)end, 0, "initrd");
+	}
 }
 
 static int __init keepinitrd_setup(char *__unused)
-- 
2.1.0
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