[PATCH] powerpc/mm: fix a hardcode on memory boundary checking

The offset of hugepage block will not be 16G, if the expected
page is more than one. Calculate the totol size instead of the
hardcode value.

Signed-off-by: Rui Teng <redacted>
---
 arch/powerpc/mm/hash_utils_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 8033493..b829f8e 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c

@@ -506,7 +506,7 @@ static int __init htab_dt_scan_hugepage_blocks(unsigned long node,
 	printk(KERN_INFO "Huge page(16GB) memory: "
 			"addr = 0x%lX size = 0x%lX pages = %d\n",
 			phys_addr, block_size, expected_pages);
-	if (phys_addr + (16 * GB) <= memblock_end_of_DRAM()) {
+	if (phys_addr + block_size * expected_pages <= memblock_end_of_DRAM()) {
 		memblock_reserve(phys_addr, block_size * expected_pages);
 		add_gpage(phys_addr, block_size, expected_pages);
 	}

-- 
2.9.0

Rui Teng [off-list ref] writes:

The offset of hugepage block will not be 16G, if the expected
page is more than one. Calculate the totol size instead of the
hardcode value.

I assume you found this by code inspection and not by triggering an
actual bug?

cheers

On 31/01/2017 5:11 PM, Michael Ellerman wrote:

Rui Teng [off-list ref] writes:

quoted

The offset of hugepage block will not be 16G, if the expected
page is more than one. Calculate the totol size instead of the
hardcode value.

I assume you found this by code inspection and not by triggering an
actual bug?

Yes, I found this problem only by code inspection. We were finding the
ways to enable 16G huge page besides changing the device tree. For example, provide a new interface to set these size and pages parameters.
So that I think it may cause problem here.

cheers

quoted

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 8033493..b829f8e 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c

@@ -506,7 +506,7 @@ static int __init htab_dt_scan_hugepage_blocks(unsigned long node,
 	printk(KERN_INFO "Huge page(16GB) memory: "
 			"addr = 0x%lX size = 0x%lX pages = %d\n",
 			phys_addr, block_size, expected_pages);
-	if (phys_addr + (16 * GB) <= memblock_end_of_DRAM()) {
+	if (phys_addr + block_size * expected_pages <= memblock_end_of_DRAM()) {
 		memblock_reserve(phys_addr, block_size * expected_pages);
 		add_gpage(phys_addr, block_size, expected_pages);
 	}
--

2.9.0

On 01/12/2017 02:39 PM, Rui Teng wrote:

The offset of hugepage block will not be 16G, if the expected
page is more than one. Calculate the totol size instead of the
hardcode value.

Signed-off-by: Rui Teng <redacted>

I have a redundant patch, this one is the original.

Tested-by: Anshuman Khandual <redacted>

On Thu, 2017-01-12 at 09:09:06 UTC, Rui Teng wrote:

The offset of hugepage block will not be 16G, if the expected
page is more than one. Calculate the totol size instead of the
hardcode value.

Signed-off-by: Rui Teng <redacted>
Tested-by: Anshuman Khandual <redacted>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/23493c121912a39f0262e0dbeb236e

cheers