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

[Masayoshi Mizuma]

From: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx>
Subject: [PATCH] Fix for build error if CONFIG_RANDOMIZE_BASE is not defined.

Fix the following build error.

  ld: drivers/acpi/numa.o: in function `acpi_numa_init':
  drivers/acpi/numa.c:473: undefined reference to `rand_mem_physical_padding'
  make: *** [Makefile:1030: vmlinux] Error 1

- Add get_rand_mem_physical_padding() which returns
  rand_mem_physical_padding or 0 if
  CONFIG_RANDOMIZE_MEMORY is not defined.
- Make rand_mem_physical_padding static

Signed-off-by: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx>
---
 arch/x86/include/asm/setup.h | 9 ++++++++-
 arch/x86/mm/kaslr.c          | 9 +++++++--
 drivers/acpi/numa.c          | 3 ++-
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index 65a5bf8..1765a15 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -80,7 +80,14 @@ static inline unsigned long kaslr_offset(void)
 	return (unsigned long)&_text - __START_KERNEL;
 }

-extern int rand_mem_physical_padding;
+#ifdef CONFIG_RANDOMIZE_MEMORY
+extern inline int __init get_rand_mem_physical_padding(void);
+#else
+static inline int __init get_rand_mem_physical_padding(void)
+{
+	return 0;
+}
+#endif

 /*
  * Do NOT EVER look at the BIOS memory size location.
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index 00cf4ca..eb47f05 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -40,7 +40,7 @@
  */
 static const unsigned long vaddr_end = CPU_ENTRY_AREA_BASE;

-int __initdata rand_mem_physical_padding = CONFIG_RANDOMIZE_MEMORY_PHYSICAL_PADDING;
+static int rand_mem_physical_padding __initdata = 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 +70,11 @@ static inline bool kaslr_memory_enabled(void)
 	return kaslr_enabled() && !IS_ENABLED(CONFIG_KASAN);
 }

+inline int __init get_rand_mem_physical_padding(void)
+{
+	return rand_mem_physical_padding;
+}
+
 static int __init rand_mem_physical_padding_setup(char *str)
 {
 	int max_padding = (1 << (MAX_PHYSMEM_BITS - TB_SHIFT)) - 1;
@@ -117,7 +122,7 @@ void __init kernel_randomize_memory(void)
 	 */
 	BUG_ON(kaslr_regions[0].base != &page_offset_base);
 	memory_tb = DIV_ROUND_UP(max_pfn << PAGE_SHIFT, 1UL << TB_SHIFT) +
-		rand_mem_physical_padding;
+		get_rand_mem_physical_padding();

 	/* Adapt phyiscal memory region size based on available memory */
 	if (memory_tb < kaslr_regions[0].size_tb)
diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
index 3d69834..303b024 100644
--- a/drivers/acpi/numa.c
+++ b/drivers/acpi/numa.c
@@ -470,7 +470,8 @@ int __init acpi_numa_init(void)
 		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);
+			threshold = max_actual_phys +
+				((u64)get_rand_mem_physical_padding() << 40);

 			if (max_possible_phys > threshold) {
 				pr_warn("Set 'rand_mem_physical_padding=%llu' to avoid memory hotadd failure.\n",
--
2.18.0


On Tue, Oct 02, 2018 at 03:18:41AM -0700, tip-bot for Masayoshi Mizuma wrote:
> 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 */