linux-kernel - [tip:x86/boot] x86/kaslr, ACPI/NUMA: Fix KASLR build error

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Message-ID: <tip-9d94e8b1d4f94a3c4cee5ad11a1be460cd070839@git.kernel.org>
Date:   Tue, 9 Oct 2018 03:39:51 -0700
From:   "tip-bot for Peter Zijlstra (Intel)" <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     naresh.kamboju@...aro.org, hpa@...or.com, tglx@...utronix.de,
        mingo@...nel.org, broonie@...nel.org, linux-kernel@...r.kernel.org,
        torvalds@...ux-foundation.org, m.mizuma@...fujitsu.com,
        bhe@...hat.com, bp@...e.de, peterz@...radead.org
Subject: [tip:x86/boot] x86/kaslr, ACPI/NUMA: Fix KASLR build error

Commit-ID:  9d94e8b1d4f94a3c4cee5ad11a1be460cd070839
Gitweb:     https://git.kernel.org/tip/9d94e8b1d4f94a3c4cee5ad11a1be460cd070839
Author:     Peter Zijlstra (Intel) <peterz@...radead.org>
AuthorDate: Wed, 3 Oct 2018 14:41:27 +0200
Committer:  Borislav Petkov <bp@...e.de>
CommitDate: Tue, 9 Oct 2018 12:30:25 +0200

x86/kaslr, ACPI/NUMA: Fix KASLR build error

There is no point in trying to compile KASLR-specific code when there is
no KASLR.

 [ bp: Move the whole crap into kaslr.c and make
   rand_mem_physical_padding static. Make kaslr_check_padding()
   weak to avoid build breakage on other architectures. ]

Reported-by: Naresh Kamboju <naresh.kamboju@...aro.org>
Reported-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: <m.mizuma@...fujitsu.com>
Cc: <bhe@...hat.com>
Cc: <torvalds@...ux-foundation.org>
Cc: <tglx@...utronix.de>
Cc: <mingo@...nel.org>
Cc: <hpa@...or.com>
Link: http://lkml.kernel.org/r/20181003123402.GA15494@hirez.programming.kicks-ass.net
---
 arch/x86/include/asm/setup.h |  2 --
 arch/x86/mm/kaslr.c          | 19 ++++++++++++++++++-
 drivers/acpi/numa.c          | 17 +++++------------
 3 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index 65a5bf8f6aba..ae13bc974416 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -80,8 +80,6 @@ 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/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index 00cf4cae38f5..b3471388288d 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -23,6 +23,7 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/random.h>
+#include <linux/bootmem.h>
 
 #include <asm/pgalloc.h>
 #include <asm/pgtable.h>
@@ -40,7 +41,7 @@
  */
 static const unsigned long vaddr_end = CPU_ENTRY_AREA_BASE;
 
-int __initdata rand_mem_physical_padding = CONFIG_RANDOMIZE_MEMORY_PHYSICAL_PADDING;
+static int __initdata rand_mem_physical_padding = CONFIG_RANDOMIZE_MEMORY_PHYSICAL_PADDING;
 /*
  * Memory regions randomized by KASLR (except modules that use a separate logic
  * earlier during boot). The list is ordered based on virtual addresses. This
@@ -70,6 +71,22 @@ static inline bool kaslr_memory_enabled(void)
 	return kaslr_enabled() && !IS_ENABLED(CONFIG_KASAN);
 }
 
+/*
+ * Check the padding size for KASLR is enough.
+ */
+void __init kaslr_check_padding(void)
+{
+	u64 max_possible_phys, max_actual_phys, threshold;
+
+	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);
+}
+
 static int __init rand_mem_physical_padding_setup(char *str)
 {
 	int max_padding = (1 << (MAX_PHYSMEM_BITS - TB_SHIFT)) - 1;
diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
index 3d69834c692f..ba62004f4d86 100644
--- a/drivers/acpi/numa.c
+++ b/drivers/acpi/numa.c
@@ -32,7 +32,6 @@
 #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;
 
@@ -433,10 +432,12 @@ acpi_table_parse_srat(enum acpi_srat_type id,
 					    handler, max_entries);
 }
 
+/* To be overridden by architectures */
+void __init __weak kaslr_check_padding(void) { }
+
 int __init acpi_numa_init(void)
 {
 	int cnt = 0;
-	u64 max_possible_phys, max_actual_phys, threshold;
 
 	if (acpi_disabled)
 		return -EINVAL;
@@ -466,17 +467,9 @@ 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 (parsed_numa_memblks)
+			kaslr_check_padding();
 
-			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 */