Certain devices can possess non-standard memory capacities, not constrained
to multiples of 1GB. Provide a kernel parameter so that we can map the
device memory completely on memory hotplug.
Restrict memory_block_size value to a power of 2 value similar to LMB size.
The memory block size should also be more than the section size.
Reviewed-by: Reza Arbab <ar...@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
---
.../admin-guide/kernel-parameters.txt | 3 +++
arch/powerpc/kernel/setup_64.c | 23 +++++++++++++++++++
arch/powerpc/mm/init_64.c | 17 ++++++++++----
3 files changed, 38 insertions(+), 5 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt
b/Documentation/admin-guide/kernel-parameters.txt
index a1457995fd41..4e49696e0976 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3201,6 +3201,9 @@
Note that even when enabled, there are a few cases where
the feature is not effective.
+ memory_block_size=size [PPC]
+ Use this parameter to configure the memory block size
value.
+
memtest= [KNL,X86,ARM,M68K,PPC,RISCV] Enable memtest
Format: <integer>
default : 0 <disable>
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 246201d0d879..cbdb924462c7 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -892,6 +892,29 @@ unsigned long memory_block_size_bytes(void)
return MIN_MEMORY_BLOCK_SIZE;
}
+
+/*
+ * Restrict to a power of 2 value for memblock which is larger than
+ * section size
+ */
+static int __init parse_mem_block_size(char *ptr)
+{
+ unsigned int order;
+ unsigned long size = memparse(ptr, NULL);
+
+ order = fls64(size);
+ if (!order)
+ return 0;
+
+ order--;
+ if (order < SECTION_SIZE_BITS)
+ return 0;
+
+ memory_block_size = 1UL << order;
+
+ return 0;
+}
+early_param("memory_block_size", parse_mem_block_size);
#endif
#if defined(CONFIG_PPC_INDIRECT_PIO) || defined(CONFIG_PPC_INDIRECT_MMIO)
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 29178b3aafe6..dbed37d6cffb 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -569,13 +569,20 @@ static int __init probe_memory_block_size(unsigned long
node, const char *uname,
return 0;
}
-/*
- * start with 1G memory block size. Early init will
- * fix this with correct value.
- */
-unsigned long memory_block_size __ro_after_init = 1UL << 30;
+unsigned long memory_block_size __ro_after_init;
static void __init early_init_memory_block_size(void)
{
+ /*
+ * if it is set via early param just return.
+ */
+ if (memory_block_size)
+ return;
+
+ /*
+ * start with 1G memory block size. update_memory_block_size()
+ * will derive the right value based on device tree details.
+ */
+ memory_block_size = SZ_1G;
/*
* We need to do memory_block_size probe early so that
* radix__early_init_mmu() can use this as limit for
--
2.41.0
