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bootm: flush cache on aligned region

PATCH New your name 2 participants 2 messages Dec 20, 2017 – Dec 21, 2017

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#0 lore raw

PATCH 1/1 bootm: flush cache on aligned region

From: Andrey Yurovsky <[email protected]>

bootm_load_os() uses flush_cache() on the region where the OS image is loaded however the OS image may be part of a FIT image and thereby may not be aligned with respect to the machine's cache lines. Give flush_cache() an aligned start of the region to avoid misalignment.

Signed-off-by Andrey Yurovsky <[email protected]>
---
 common/bootm.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
common/bootm.c +4 -1
index adb12137c7..948807af25 100644
@@ -447,7 +447,10 @@ static int bootm_load_os(bootm_headers_t *images, unsigned long *load_end,
 		bootstage_error(BOOTSTAGE_ID_DECOMP_IMAGE);
 		return err;
 	}
-	flush_cache(load, ALIGN(*load_end - load, ARCH_DMA_MINALIGN));
+
+	ulong load_a = ALIGN(load, ARCH_DMA_MINALIGN);
+
+	flush_cache(load_a, ALIGN(*load_end - load_a, ARCH_DMA_MINALIGN));
 
 	debug("   kernel loaded at 0x%08lx, end = 0x%08lx\n", load, *load_end);
 	bootstage_mark(BOOTSTAGE_ID_KERNEL_LOADED);
Signature · 1 line
2.14.3
#1 lore raw

PATCH 1/1 bootm: flush cache on aligned region

Hi your name,

Quoted 17 lines · On Wed, 20 Dec 2017 09:12:28 -0800 your name wrote:

From: Andrey Yurovsky <[email protected]>

bootm_load_os() uses flush_cache() on the region where the OS image is loaded however the OS image may be part of a FIT image and thereby may not be aligned with respect to the machine's cache lines. Give flush_cache() an aligned start of the region to avoid misalignment.

Signed-off-by Andrey Yurovsky <[email protected]>
---
 common/bootm.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
common/bootm.c +0 -0
index adb12137c7..948807af25 100644

common/bootm.c static int bootm_load_os(bootm_headers_t *images, unsigned long *load_end, · line 452

Quoted 7 lines
common/bootm.c +3 -1
@@ -447,7 +447,10 @@ static int bootm_load_os(bootm_headers_t *images, unsigned long *load_end,
 		bootstage_error(BOOTSTAGE_ID_DECOMP_IMAGE);
 		return err;
 	}
-	flush_cache(load, ALIGN(*load_end - load, ARCH_DMA_MINALIGN));
+
+	ulong load_a = ALIGN(load, ARCH_DMA_MINALIGN);
+

This is WRONG. ALIGN() only ever _increases_ the value passed to it, so the first ARCH_DMA_MINALIGN - 1 bytes of the image may not be flushed in the worst case.

common/bootm.c static int bootm_load_os(bootm_headers_t *images, unsigned long *load_end, · line 456

Quoted 4 lines
common/bootm.c +1 -0
+	flush_cache(load_a, ALIGN(*load_end - load_a, ARCH_DMA_MINALIGN));
 
 	debug("   kernel loaded at 0x%08lx, end = 0x%08lx\n", load, *load_end);
 	bootstage_mark(BOOTSTAGE_ID_KERNEL_LOADED);

Lothar Waßmann