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Date: Tue, 2 Apr 2019 12:10:46 +0800
From: Pingfan Liu <kernelfans@...il.com>
To: x86@...nel.org
Cc: Pingfan Liu <kernelfans@...il.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
"H. Peter Anvin" <hpa@...or.com>, Baoquan He <bhe@...hat.com>,
Will Deacon <will.deacon@....com>,
Nicolas Pitre <nico@...aro.org>,
Chao Fan <fanc.fnst@...fujitsu.com>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
Ard Biesheuvel <ard.biesheuvel@...aro.org>,
linux-kernel@...r.kernel.org
Subject: [PATCHv3] x86/boot/KASLR: skip the specified crashkernel region
crashkernel=x@y or or =range1:size1[,range2:size2,...]@offset option may
fail to reserve the required memory region if KASLR puts kernel into the
region. To avoid this uncertainty, asking KASLR to skip the required
region.
Signed-off-by: Pingfan Liu <kernelfans@...il.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Baoquan He <bhe@...hat.com>
Cc: Will Deacon <will.deacon@....com>
Cc: Nicolas Pitre <nico@...aro.org>
Cc: Pingfan Liu <kernelfans@...il.com>
Cc: Chao Fan <fanc.fnst@...fujitsu.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc: linux-kernel@...r.kernel.org
---
v2 -> v3: adding parsing of crashkernel=range1:size1[,range2:size2,...]@offset
arch/x86/boot/compressed/kaslr.c | 116 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 114 insertions(+), 2 deletions(-)
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 2e53c05..7f698f4 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -107,6 +107,7 @@ enum mem_avoid_index {
MEM_AVOID_BOOTPARAMS,
MEM_AVOID_MEMMAP_BEGIN,
MEM_AVOID_MEMMAP_END = MEM_AVOID_MEMMAP_BEGIN + MAX_MEMMAP_REGIONS - 1,
+ MEM_AVOID_CRASHKERNEL,
MEM_AVOID_MAX,
};
@@ -238,6 +239,115 @@ static void parse_gb_huge_pages(char *param, char *val)
}
}
+/* code heavily copied from parse_crashkernel_mem() */
+static void handle_crashkernel_mem(char *cmdline,
+ unsigned long long system_ram,
+ unsigned long long *crash_size,
+ unsigned long long *crash_base)
+{
+ char *tmp, *cur = cmdline;
+
+ /* for each entry of the comma-separated list */
+ do {
+ unsigned long long start, end = ULLONG_MAX, size;
+
+ /* get the start of the range */
+ start = memparse(cur, &tmp);
+ /* no value given */
+ if (cur == tmp)
+ return;
+ cur = tmp;
+ if (*cur != '-')
+ return;
+ cur++;
+
+ /* if no ':' is here, than we read the end */
+ if (*cur != ':') {
+ end = memparse(cur, &tmp);
+ /* no value given */
+ if (cur == tmp)
+ return;
+ cur = tmp;
+ /* invalid if crashkernel end <= start */
+ if (end <= start)
+ return;
+ }
+ /* expect ":" after range */
+ if (*cur != ':')
+ return;
+ cur++;
+
+ size = memparse(cur, &tmp);
+ /* no size value given */
+ if (cur == tmp)
+ return;
+ cur = tmp;
+ if (size >= system_ram)
+ return;
+
+ /* match ? */
+ if (system_ram >= start && system_ram < end) {
+ *crash_size = size;
+ break;
+ }
+ } while (*cur++ == ',');
+
+ if (*crash_size > 0) {
+ while (*cur && *cur != ' ' && *cur != '@')
+ cur++;
+ if (*cur == '@') {
+ cur++;
+ *crash_base = memparse(cur, &tmp);
+ }
+ }
+}
+
+/* handle crashkernel=x@y or =range1:size1[,range2:size2,...]@offset options */
+static void mem_avoid_specified_crashkernel_region(char *option)
+{
+ unsigned long long crash_size, crash_base = 0;
+ char *first_colon, *first_space, *cur = option;
+
+ first_colon = strchr(option, ':');
+ first_space = strchr(option, ' ');
+ /* if contain ":" */
+ if (first_colon && (!first_space || first_colon < first_space)) {
+ int i;
+ u64 total_sz = 0;
+ struct boot_e820_entry *entry;
+
+ for (i = 0; i < boot_params->e820_entries; i++) {
+ entry = &boot_params->e820_table[i];
+ /* Skip non-RAM entries. */
+ if (entry->type != E820_TYPE_RAM)
+ continue;
+ total_sz += entry->size;
+ }
+ handle_crashkernel_mem(option, total_sz, &crash_size,
+ &crash_base);
+ } else {
+ crash_size = memparse(option, &cur);
+ if (option == cur)
+ return;
+ while (*cur && *cur != ' ' && *cur != '@')
+ cur++;
+ if (*cur == '@') {
+ option = cur + 1;
+ crash_base = memparse(option, &cur);
+ }
+ }
+ if (crash_base) {
+ mem_avoid[MEM_AVOID_CRASHKERNEL].start = crash_base;
+ mem_avoid[MEM_AVOID_CRASHKERNEL].size = crash_size;
+ } else {
+ /*
+ * Clearing mem_avoid if no offset is given. This is consistent
+ * with kernel, which uses the last crashkernel= option.
+ */
+ mem_avoid[MEM_AVOID_CRASHKERNEL].start = 0;
+ mem_avoid[MEM_AVOID_CRASHKERNEL].size = 0;
+ }
+}
static void handle_mem_options(void)
{
@@ -248,7 +358,7 @@ static void handle_mem_options(void)
u64 mem_size;
if (!strstr(args, "memmap=") && !strstr(args, "mem=") &&
- !strstr(args, "hugepages"))
+ !strstr(args, "hugepages") && !strstr(args, "crashkernel="))
return;
tmp_cmdline = malloc(len + 1);
@@ -284,6 +394,8 @@ static void handle_mem_options(void)
goto out;
mem_limit = mem_size;
+ } else if (strstr(param, "crashkernel")) {
+ mem_avoid_specified_crashkernel_region(val);
}
}
@@ -412,7 +524,7 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size,
/* We don't need to set a mapping for setup_data. */
- /* Mark the memmap regions we need to avoid */
+ /* Mark the regions we need to avoid */
handle_mem_options();
/* Enumerate the immovable memory regions */
--
2.7.4
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