[PATCH v4 2/3] ACPI / NUMA: Add warning message if the padding size for KASLR is not enough

From: Masayoshi Mizuma
Date: Thu Sep 27 2018 - 16:34:10 EST


From: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx>

Add warning message if the padding size for KASLR,
rand_mem_physical_padding, is not enough. The message also
says the suitable padding size.

Signed-off-by: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx>
---
arch/x86/include/asm/setup.h | 2 ++
drivers/acpi/numa.c | 14 ++++++++++++++
2 files changed, 16 insertions(+)

diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index ae13bc9..65a5bf8 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -80,6 +80,8 @@ static inline unsigned long kaslr_offset(void)
return (unsigned long)&_text - __START_KERNEL;
}

+extern int rand_mem_physical_padding;
+
/*
* Do NOT EVER look at the BIOS memory size location.
* It does not work on many machines.
diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
index 8516760..9c3cc3c 100644
--- a/drivers/acpi/numa.c
+++ b/drivers/acpi/numa.c
@@ -32,6 +32,7 @@
#include <linux/numa.h>
#include <linux/nodemask.h>
#include <linux/topology.h>
+#include <asm/setup.h>

static nodemask_t nodes_found_map = NODE_MASK_NONE;

@@ -435,6 +436,8 @@ acpi_table_parse_srat(enum acpi_srat_type id,
int __init acpi_numa_init(void)
{
int cnt = 0;
+ u32 max_phys_addr_tb;
+ u64 max_phys_addr;

if (acpi_disabled)
return -EINVAL;
@@ -463,6 +466,17 @@ int __init acpi_numa_init(void)

cnt = acpi_table_parse_srat(ACPI_SRAT_TYPE_MEMORY_AFFINITY,
acpi_parse_memory_affinity, 0);
+
+ if (parsed_numa_memblks && kaslr_enabled()) {
+ max_phys_addr = PFN_PHYS(max_possible_pfn);
+ max_phys_addr_tb = (roundup(max_phys_addr, 1ULL << 40)) >> 40;
+
+ if (max_phys_addr_tb > rand_mem_physical_padding)
+ pr_warn("Set 'rand_mem_physical_padding=%d' "
+ "as the kernel parameter. "
+ "Otherwise, memory hotadd may be failed.\n",
+ max_phys_addr_tb);
+ }
}

/* SLIT: System Locality Information Table */
--
2.18.0