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Message-ID: <20181003124814.GA4227@zn.tnic>
Date: Wed, 3 Oct 2018 14:48:14 +0200
From: Borislav Petkov <bp@...en8.de>
To: Peter Zijlstra <peterz@...radead.org>
Cc: m.mizuma@...fujitsu.com, bhe@...hat.com,
torvalds@...ux-foundation.org, msys.mizuma@...il.com,
tglx@...utronix.de, linux-kernel@...r.kernel.org, mingo@...nel.org,
hpa@...or.com, linux-tip-commits@...r.kernel.org
Subject: Re: [tip:x86/boot] ACPI/NUMA: Add warning message if the padding
size for KASLR is not enough
On Wed, Oct 03, 2018 at 02:34:02PM +0200, Peter Zijlstra wrote:
>
> Subject: ACPI/NUMA: Fix KASLR build error
>
> There is no point in trying to compile KASLR specific code when there is
> no KASLR.
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> ---
Yeah, Peter and I were just talking on IRC and he gave me a much better
idea how to fix this, see below. I'll run this through the *config builder and
commit it if no complaints.
---
From: "Peter Zijlstra (Intel)" <peterz@...radead.org>
Date: Wed, 3 Oct 2018 14:41:27 +0200
Subject: [PATCH] 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. ]
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/kaslr.h | 2 ++
arch/x86/include/asm/setup.h | 2 --
arch/x86/mm/kaslr.c | 18 +++++++++++++++++-
drivers/acpi/numa.c | 15 +++------------
4 files changed, 22 insertions(+), 15 deletions(-)
diff --git a/arch/x86/include/asm/kaslr.h b/arch/x86/include/asm/kaslr.h
index db7ba2feb947..95ef3fc01d12 100644
--- a/arch/x86/include/asm/kaslr.h
+++ b/arch/x86/include/asm/kaslr.h
@@ -6,8 +6,10 @@ unsigned long kaslr_get_random_long(const char *purpose);
#ifdef CONFIG_RANDOMIZE_MEMORY
void kernel_randomize_memory(void);
+void kaslr_check_padding(void);
#else
static inline void kernel_randomize_memory(void) { }
+static inline void kaslr_check_padding(void) { }
#endif /* CONFIG_RANDOMIZE_MEMORY */
#endif
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..d58b7da0d55c 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 __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 +70,22 @@ static inline bool kaslr_memory_enabled(void)
return kaslr_enabled() && !IS_ENABLED(CONFIG_KASAN);
}
+/*
+ * Check the padding size for KASLR is enough.
+ */
+void 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..4408e37600ef 100644
--- a/drivers/acpi/numa.c
+++ b/drivers/acpi/numa.c
@@ -32,7 +32,7 @@
#include <linux/numa.h>
#include <linux/nodemask.h>
#include <linux/topology.h>
-#include <asm/setup.h>
+#include <asm/kaslr.h>
static nodemask_t nodes_found_map = NODE_MASK_NONE;
@@ -436,7 +436,6 @@ 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;
@@ -466,17 +465,9 @@ 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 */
--
2.19.0.271.gfe8321ec057f
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
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