Re: [PATCH] [powerpc] Export memory limit via device tree

On 07/11/2012 11:06 AM, Benjamin Herrenschmidt wrote:

quoted

diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
index c957b12..0c9695d 100644
--- a/arch/powerpc/kernel/machine_kexec.c
+++ b/arch/powerpc/kernel/machine_kexec.c

@@ -207,6 +207,12 @@ static struct property crashk_size_prop = {
  	.value = &crashk_size,
  };

+static struct property memory_limit_prop = {
+	.name = "linux,memory-limit",
+	.length = sizeof(phys_addr_t),
+	.value = &memory_limit,
+};
+

AFAIK. phys_addr_t can change size, so instead make it point to a known
fixes size quantity (a u64).

Ben,

Sorry for the delay in the response.

Some of the other properties are also of phys_addr_t, (e.g 
linux,crashkernel-base, linux,kernel-end ). Should we fix them as well ?

Or

Should we leave this also a phys_addr_t and let the userspace handle it ?

quoted

+
+	/* memory-limit is needed for constructing the crash regions */
+	prop = of_find_property(node, memory_limit_prop.name, NULL);
+	if (prop)
+		prom_remove_property(node, prop);
+
+	if (memory_limit)
+		prom_add_property(node, &memory_limit_prop);
+

There's a patch floating around making prom_update_property properly
handle both pre-existing and non-pre-existing props, you should probably
base yourself on top of it. I'm about to stick that patch in powerpc
-next

OK. I am testing the new patch based on the above commit. I will wait
for the clarification on the issue of the type, before I post it here.

Thanks
Suzuki