[tip:x86/boot] ACPI/NUMA: Add warning message if the padding size for KASLR is not enough

From: tip-bot for Masayoshi Mizuma
Date: Tue Oct 02 2018 - 06:19:21 EST


Commit-ID: 3b054ca88c4f4dd5f516a12d4b6d6bd0ae826f41
Gitweb: https://git.kernel.org/tip/3b054ca88c4f4dd5f516a12d4b6d6bd0ae826f41
Author: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx>
AuthorDate: Mon, 1 Oct 2018 10:08:42 -0400
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 2 Oct 2018 11:47:21 +0200

ACPI/NUMA: Add warning message if the padding size for KASLR is not enough

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>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Masayoshi Mizuma <msys.mizuma@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20181001140843.26137-3-msys.mizuma@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
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 ae13bc974416..65a5bf8f6aba 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 85167603b9c9..3d69834c692f 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 +436,7 @@ acpi_table_parse_srat(enum acpi_srat_type id,
int __init acpi_numa_init(void)
{
int cnt = 0;
+ u64 max_possible_phys, max_actual_phys, threshold;

if (acpi_disabled)
return -EINVAL;
@@ -463,6 +465,18 @@ int __init acpi_numa_init(void)

cnt = acpi_table_parse_srat(ACPI_SRAT_TYPE_MEMORY_AFFINITY,
acpi_parse_memory_affinity, 0);
+
+ /* check the padding size for KASLR is enough. */
+ if (parsed_numa_memblks && kaslr_enabled()) {
+ max_actual_phys = roundup(PFN_PHYS(max_pfn), 1ULL << 40);
+ max_possible_phys = roundup(PFN_PHYS(max_possible_pfn), 1ULL << 40);
+ threshold = max_actual_phys + ((u64)rand_mem_physical_padding << 40);
+
+ if (max_possible_phys > threshold) {
+ pr_warn("Set 'rand_mem_physical_padding=%llu' to avoid memory hotadd failure.\n",
+ (max_possible_phys - max_actual_phys) >> 40);
+ }
+ }
}

/* SLIT: System Locality Information Table */