[PATCH 2/2] x86/mm/KASLR: Adjust the vmemmap size according to paging mode

From: Baoquan He <bhe@redhat.com>
To: tglx@linutronix.de, mingo@kernel.org, hpa@zytor.com,
	thgarnie@google.com, kirill.shutemov@linux.intel.com
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
	Baoquan He <bhe@redhat.com>
Subject: [PATCH 2/2] x86/mm/KASLR: Adjust the vmemmap size according to paging mode
Date: Wed, 29 Aug 2018 10:17:54 +0800	[thread overview]
Message-ID: <20180829021754.21850-2-bhe@redhat.com> (raw)
In-Reply-To: <20180829021754.21850-1-bhe@redhat.com>

Vmemmap area has different base and size depending on paging mode.
Now we just hardcode its size as 1TB in memory KASLR, it's not
right for 5-level paging mode.

Adjust it according to paging mode and use it during memory KASLR.

Signed-off-by: Baoquan He <bhe@redhat.com>
---
 arch/x86/include/asm/pgtable_64_types.h | 5 +++++
 arch/x86/mm/kaslr.c                     | 3 ++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index 04edd2d58211..fa759d2d3186 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -126,14 +126,19 @@ extern unsigned int ptrs_per_p4d;
 #define __VMEMMAP_BASE_L4	0xffffea0000000000UL
 #define __VMEMMAP_BASE_L5	0xffd4000000000000UL
 
+#define VMEMMAP_SIZE_TB_L4	1UL
+#define VMEMMAP_SIZE_TB_L5	512UL
+
 #ifdef CONFIG_DYNAMIC_MEMORY_LAYOUT
 # define VMALLOC_START		vmalloc_base
 # define VMALLOC_SIZE_TB	(pgtable_l5_enabled() ? VMALLOC_SIZE_TB_L5 : VMALLOC_SIZE_TB_L4)
 # define VMEMMAP_START		vmemmap_base
+# define VMEMMAP_SIZE_TB	(pgtable_l5_enabled() ? VMEMMAP_SIZE_TB_L5 : VMEMMAP_SIZE_TB_L4)
 #else
 # define VMALLOC_START		__VMALLOC_BASE_L4
 # define VMALLOC_SIZE_TB	VMALLOC_SIZE_TB_L4
 # define VMEMMAP_START		__VMEMMAP_BASE_L4
+# define VMEMMAP_SIZE_TB	VMEMMAP_SIZE_TB_L4
 #endif /* CONFIG_DYNAMIC_MEMORY_LAYOUT */
 
 #define VMALLOC_END		(VMALLOC_START + (VMALLOC_SIZE_TB << 40) - 1)
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index 0988971069c9..69228af4c7d7 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -51,7 +51,7 @@ static __initdata struct kaslr_memory_region {
 } kaslr_regions[] = {
 	{ &page_offset_base, 0 },
 	{ &vmalloc_base, 0 },
-	{ &vmemmap_base, 1 },
+	{ &vmemmap_base, 0 },
 };
 
 /* Get size in bytes used by the memory region */
@@ -95,6 +95,7 @@ void __init kernel_randomize_memory(void)
 
 	kaslr_regions[0].size_tb = 1 << (MAX_PHYSMEM_BITS - TB_SHIFT);
 	kaslr_regions[1].size_tb = VMALLOC_SIZE_TB;
+	kaslr_regions[2].size_tb = VMEMMAP_SIZE_TB;
 
 	/*
 	 * Update Physical memory mapping to available and
-- 
2.13.6

