[PATCH 0/3] ARM initrd updates

[PATCH 0/3] ARM initrd updates

[Russell King - ARM Linux]

Three patches to cleanup and update the ARM initrd handling, after problems
identified by William Helsby.

The first patch merely moves the early initrd code into a separate
function, rather than being bundled up inside arm_memblock_init().

The second patch restructures the initrd code to be cleaner, but with
no functional changes.  We get rid of the repetitive phys_initrd_size
checks, as we can now just "return" from the function.

The third patch changes how we check for overlaps and the region that
we reserve.  Since the kernel deals with pages and not bytes for
allocation, the minimum granule for marking addresses reserved and
later freeing them is one page.  We already adjust the initrd addresses
in free_initrd_mem(), but we fail to mark the partially used pages
entirely reserved.  Add this.

 arch/arm/mm/init.c | 57 +++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 39 insertions(+), 18 deletions(-)

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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[PATCH 1/3] ARM: mm: move initrd init code out of arm_memblock_init()

[Russell King]

Move the ARM initrd initialisation code out of arm_memblock_init() into
its own function, so it can be cleaned up.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 arch/arm/mm/init.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 50e5402a8ef3..43d8825e59bb 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -228,11 +228,8 @@ phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
 	return phys;
 }
 
-void __init arm_memblock_init(const struct machine_desc *mdesc)
+static void __init arm_initrd_init(void)
 {
-	/* Register the kernel text, kernel data and initrd with memblock. */
-	memblock_reserve(__pa(KERNEL_START), KERNEL_END - KERNEL_START);
-
 #ifdef CONFIG_BLK_DEV_INITRD
 	/* FDT scan will populate initrd_start */
 	if (initrd_start && !phys_initrd_size) {
@@ -260,6 +257,14 @@ void __init arm_memblock_init(const struct machine_desc *mdesc)
 		initrd_end = initrd_start + phys_initrd_size;
 	}
 #endif
+}
+
+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();
 
 	arm_mm_memblock_reserve();
 
-- 
2.7.4

[PATCH 2/3] ARM: mm: clean up initrd initialisation

[Russell King]

Rather than repeatedly testing phys_initrd_size to see if the initrd
is still enabled, return from the new function to avoid executing the
remaining initialisation.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 arch/arm/mm/init.c | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 43d8825e59bb..15739a95552a 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -236,26 +236,29 @@ static void __init arm_initrd_init(void)
 		phys_initrd_start = __virt_to_phys(initrd_start);
 		phys_initrd_size = initrd_end - initrd_start;
 	}
+
 	initrd_start = initrd_end = 0;
-	if (phys_initrd_size &&
-	    !memblock_is_region_memory(phys_initrd_start, phys_initrd_size)) {
+
+	if (!phys_initrd_size)
+		return;
+
+	if (!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",
 		       (u64)phys_initrd_start, phys_initrd_size);
-		phys_initrd_start = phys_initrd_size = 0;
+		return;
 	}
-	if (phys_initrd_size &&
-	    memblock_is_region_reserved(phys_initrd_start, phys_initrd_size)) {
+
+	if (memblock_is_region_reserved(phys_initrd_start, phys_initrd_size)) {
 		pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
 		       (u64)phys_initrd_start, phys_initrd_size);
-		phys_initrd_start = phys_initrd_size = 0;
+		return;
 	}
-	if (phys_initrd_size) {
-		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;
-	}
+	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;
 #endif
 }
 
-- 
2.7.4

[PATCH 3/3] ARM: mm: round the initrd reservation to page boundaries

[Russell King]

Round the initrd memblock reservation to page boundaries to prevent
other data sharing the initrd pages.  This prevents an allocation
possibly overlapping with the initrd, which would later get trampled
on in free_initrd_mem().

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 arch/arm/mm/init.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 15739a95552a..d1e26610977d 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -231,6 +231,9 @@ phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
 static void __init arm_initrd_init(void)
 {
 #ifdef CONFIG_BLK_DEV_INITRD
+	phys_addr_t start;
+	unsigned long size;
+
 	/* FDT scan will populate initrd_start */
 	if (initrd_start && !phys_initrd_size) {
 		phys_initrd_start = __virt_to_phys(initrd_start);
@@ -242,19 +245,29 @@ static void __init arm_initrd_init(void)
 	if (!phys_initrd_size)
 		return;
 
-	if (!memblock_is_region_memory(phys_initrd_start, phys_initrd_size)) {
+	/*
+	 * 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)phys_initrd_start, phys_initrd_size);
+		       (u64)start, size);
 		return;
 	}
 
-	if (memblock_is_region_reserved(phys_initrd_start, phys_initrd_size)) {
+	if (memblock_is_region_reserved(start, size)) {
 		pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
-		       (u64)phys_initrd_start, phys_initrd_size);
+		       (u64)start, size);
 		return;
 	}
 
-	memblock_reserve(phys_initrd_start, phys_initrd_size);
+	memblock_reserve(start, size);
 
 	/* Now convert initrd to virtual addresses */
 	initrd_start = __phys_to_virt(phys_initrd_start);
-- 
2.7.4