From: Baoquan He <bhe@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org,
peterz@infradead.org, x86@kernel.org, travis@sgi.com,
thgarnie@google.com, keescook@chromium.org,
akpm@linux-foundation.org, yamada.masahiro@socionext.com,
kirill@shutemov.name, Baoquan He <bhe@redhat.com>
Subject: [PATCH v3 5/6] x86/mm/KASLR: Calculate the actual size of vmemmap region
Date: Sat, 16 Feb 2019 22:00:07 +0800 [thread overview]
Message-ID: <20190216140008.28671-6-bhe@redhat.com> (raw)
In-Reply-To: <20190216140008.28671-1-bhe@redhat.com>
Vmemmap region has different maximum size depending on paging mode.
Now its size is hardcoded as 1TB in memory KASLR, this is not
right for 5-level paging mode. It will cause overflow if vmemmap
region is randomized to be adjacent to cpu_entry_area region and
its actual size is bigger than 1TB.
So here calculate how many TB by the actual size of vmemmap region
and align up to 1TB boundary.
Signed-off-by: Baoquan He <bhe@redhat.com>
---
arch/x86/mm/kaslr.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index 97768df923e3..ca12ed4e5239 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -101,7 +101,7 @@ static __initdata struct kaslr_memory_region {
} kaslr_regions[] = {
{ &page_offset_base, 0 },
{ &vmalloc_base, 0 },
- { &vmemmap_base, 1 },
+ { &vmemmap_base, 0 },
};
/*
@@ -121,6 +121,7 @@ void __init kernel_randomize_memory(void)
unsigned long rand, memory_tb;
struct rnd_state rand_state;
unsigned long remain_entropy;
+ unsigned long vmemmap_size;
vaddr_start = pgtable_l5_enabled() ? __PAGE_OFFSET_BASE_L5 : __PAGE_OFFSET_BASE_L4;
vaddr = vaddr_start;
@@ -152,6 +153,14 @@ void __init kernel_randomize_memory(void)
if (memory_tb < kaslr_regions[0].size_tb)
kaslr_regions[0].size_tb = memory_tb;
+ /*
+ * Calculate how many TB vmemmap region needs, and align to
+ * 1TB boundary.
+ */
+ vmemmap_size = (kaslr_regions[0].size_tb << (TB_SHIFT - PAGE_SHIFT)) *
+ sizeof(struct page);
+ kaslr_regions[2].size_tb = DIV_ROUND_UP(vmemmap_size, 1UL << TB_SHIFT);
+
/* Calculate entropy available between regions */
remain_entropy = vaddr_end - vaddr_start;
for (i = 0; i < ARRAY_SIZE(kaslr_regions); i++)
--
2.17.2
next prev parent reply other threads:[~2019-02-16 14:04 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-16 14:00 [PATCH v3 0/6] Several patches to fix code bugs, improve documents and clean up Baoquan He
2019-02-16 14:00 ` [PATCH v3 1/6] x86/mm/KASLR: Improve code comments about struct kaslr_memory_region Baoquan He
2019-02-17 17:07 ` Kees Cook
2019-02-18 3:17 ` Baoquan He
2019-03-12 3:45 ` Baoquan He
2019-03-12 0:55 ` Baoquan He
2019-02-16 14:00 ` [PATCH v3 2/6] x86/mm/KASLR: Open code unnecessary function get_padding Baoquan He
2019-02-17 17:14 ` Kees Cook
2019-02-16 14:00 ` [PATCH v3 3/6] mm: Add build time sanity check for struct page size Baoquan He
2019-02-17 16:50 ` Kees Cook
2019-02-18 8:07 ` Baoquan He
2019-02-16 14:00 ` [PATCH v3 4/6] x86/mm/KASLR: Fix the wrong calculation of memory region initial size Baoquan He
2019-02-17 16:53 ` Kees Cook
2019-02-18 8:30 ` Baoquan He
2019-02-16 14:00 ` Baoquan He [this message]
2019-02-17 17:25 ` [PATCH v3 5/6] x86/mm/KASLR: Calculate the actual size of vmemmap region Kees Cook
2019-02-18 9:50 ` Baoquan He
2019-02-18 10:09 ` Baoquan He
2019-02-18 10:11 ` Baoquan He
2019-02-16 14:00 ` [PATCH v3 6/6] x86/mm/KASLR: Do not adapt the size of the direct mapping section for SGI UV system Baoquan He
2019-02-17 2:09 ` Baoquan He
2019-02-18 19:24 ` Mike Travis
2019-02-19 0:04 ` Baoquan He
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