From: Baoquan He <bhe@redhat.com>
To: linux-kernel@vger.kernel.org, mingo@kernel.org,
lcapitulino@redhat.com, keescook@chromium.org,
tglx@linutronix.de
Cc: x86@kernel.org, hpa@zytor.com, fanc.fnst@cn.fujitsu.com,
yasu.isimatu@gmail.com, indou.takao@jp.fujitsu.com,
douly.fnst@cn.fujitsu.com, Baoquan He <bhe@redhat.com>
Subject: [PATCH v2 1/2] x86/boot/KASLR: Add two functions for 1GB huge pages handling
Date: Mon, 25 Jun 2018 11:16:55 +0800 [thread overview]
Message-ID: <20180625031656.12443-2-bhe@redhat.com> (raw)
In-Reply-To: <20180625031656.12443-1-bhe@redhat.com>
Functions parse_gb_huge_pages() and process_gb_huge_pages() are
introduced to handle a conflict between KASLR and huge pages of
GB, will be used in the next patch.
Function parse_gb_huge_pages() is used to parse kernel
command-line to get how many 1GB huge pages have been specified.
A static global variable 'max_gb_huge_pages' is added to store
the number.
And process_gb_huge_pages() is used to skip as many 1GB huge pages
as possible from the passed in memory region according to the
specified number.
Signed-off-by: Baoquan He <bhe@redhat.com>
---
arch/x86/boot/compressed/kaslr.c | 83 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 83 insertions(+)
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index b87a7582853d..0fea96f9cc28 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -215,6 +215,35 @@ static void mem_avoid_memmap(char *str)
memmap_too_large = true;
}
+/* Store the number of 1GB huge pages which users specified.*/
+static unsigned long max_gb_huge_pages;
+
+static void parse_gb_huge_pages(char *param, char *val)
+{
+ static bool gbpage_sz;
+ char *p;
+
+ if (!strcmp(param, "hugepagesz")) {
+ p = val;
+ if (memparse(p, &p) != PUD_SIZE) {
+ gbpage_sz = false;
+ return;
+ }
+
+ if (gbpage_sz)
+ warn("Repeatedly set hugeTLB page size of 1G!\n");
+ gbpage_sz = true;
+ return;
+ }
+
+ if (!strcmp(param, "hugepages") && gbpage_sz) {
+ p = val;
+ max_gb_huge_pages = simple_strtoull(p, &p, 0);
+ return;
+ }
+}
+
+
static int handle_mem_memmap(void)
{
char *args = (char *)get_cmd_line_ptr();
@@ -466,6 +495,60 @@ static void store_slot_info(struct mem_vector *region, unsigned long image_size)
}
}
+/*
+ * Skip as many 1GB huge pages as possible in the passed region
+ * according to the number which users specified.
+ */
+static void
+process_gb_huge_pages(struct mem_vector *region, unsigned long image_size)
+{
+ unsigned long addr, size = 0;
+ struct mem_vector tmp;
+ int i = 0;
+
+ if (!max_gb_huge_pages) {
+ store_slot_info(region, image_size);
+ return;
+ }
+
+ addr = ALIGN(region->start, PUD_SIZE);
+ /* Did we raise the address above the passed in memory entry? */
+ if (addr < region->start + region->size)
+ size = region->size - (addr - region->start);
+
+ /* Check how many 1GB huge pages can be filtered out*/
+ while (size > PUD_SIZE && max_gb_huge_pages) {
+ size -= PUD_SIZE;
+ max_gb_huge_pages--;
+ i++;
+ }
+
+ /* No good 1GB huge pages found. */
+ if (!i) {
+ store_slot_info(region, image_size);
+ return;
+ }
+
+ /*
+ * Skip those 'i'*1GB good huge pages. And continue checking and
+ * processing the remaining head or tail part of the passed region
+ * if available.
+ */
+
+ if (addr >= region->start + image_size) {
+ tmp.start = region->start;
+ tmp.size = addr - region->start;
+ store_slot_info(&tmp, image_size);
+ }
+
+ size = region->size - (addr - region->start) - i * PUD_SIZE;
+ if (size >= image_size) {
+ tmp.start = addr + i * PUD_SIZE;
+ tmp.size = size;
+ store_slot_info(&tmp, image_size);
+ }
+}
+
static unsigned long slots_fetch_random(void)
{
unsigned long slot;
--
2.13.6
next prev parent reply other threads:[~2018-06-25 3:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-25 3:16 [PATCH v2 0/2] x86/boot/KASLR: Skip specified number of 1GB huge pages when do physical randomization Baoquan He
2018-06-25 3:16 ` Baoquan He [this message]
2018-07-03 15:58 ` [tip:x86/boot] x86/boot/KASLR: Add two new functions for 1GB huge pages handling tip-bot for Baoquan He
2018-06-25 3:16 ` [PATCH v2 2/2] x86/boot/KASLR: Skip specified number of 1GB huge pages when do physical randomization Baoquan He
2018-07-03 15:58 ` [tip:x86/boot] x86/boot/KASLR: Skip specified number of 1GB huge pages when doing physical randomization (KASLR) tip-bot for Baoquan He
2018-06-26 15:06 ` [PATCH v2 0/2] x86/boot/KASLR: Skip specified number of 1GB huge pages when do physical randomization Luiz Capitulino
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