[PATCHv5 0/2] x86/boot/KASLR: skip the specified crashkernel region

[PATCHv5 0/2] x86/boot/KASLR: skip the specified crashkernel region

[Pingfan Liu]

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.
And the parsing routine can be re-used at this early boot stage.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Chao Fan <fanc.fnst@cn.fujitsu.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
CC: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org
---
v3 -> v4:
  reuse the parse_crashkernel_xx routines
v4 -> v5:
  drop unnecessary initialization of crash_base in [2/2]

Pingfan Liu (2):
  kernel/crash_core: separate the parsing routines to
    lib/parse_crashkernel.c
  x86/boot/KASLR: skip the specified crashkernel region

 arch/x86/boot/compressed/kaslr.c |  40 ++++++
 kernel/crash_core.c              | 273 ------------------------------------
 lib/Makefile                     |   2 +
 lib/parse_crashkernel.c          | 289 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 331 insertions(+), 273 deletions(-)
 create mode 100644 lib/parse_crashkernel.c

-- 
2.7.4

[PATCHv5 1/2] crash: Carve out crashkernel= cmdline parsing

[Pingfan Liu]

Make the "crashkernel=" parsing functionality available to the early
KASLR code. Will be used by a later patch to parse crashkernel regions
which KASLR should aviod.

Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Chao Fan <fanc.fnst@cn.fujitsu.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
CC: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org
---
 kernel/crash_core.c     | 273 ----------------------------------------------
 lib/Makefile            |   2 +
 lib/parse_crashkernel.c | 280 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 282 insertions(+), 273 deletions(-)
 create mode 100644 lib/parse_crashkernel.c

diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 093c9f9..37c4d6f 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -21,279 +21,6 @@ u32 *vmcoreinfo_note;
 /* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
 static unsigned char *vmcoreinfo_data_safecopy;
 
-/*
- * parsing the "crashkernel" commandline
- *
- * this code is intended to be called from architecture specific code
- */
-
-
-/*
- * This function parses command lines in the format
- *
- *   crashkernel=ramsize-range:size[,...][@offset]
- *
- * The function returns 0 on success and -EINVAL on failure.
- */
-static int __init parse_crashkernel_mem(char *cmdline,
-					unsigned long long system_ram,
-					unsigned long long *crash_size,
-					unsigned long long *crash_base)
-{
-	char *cur = cmdline, *tmp;
-
-	/* 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);
-		if (cur == tmp) {
-			pr_warn("crashkernel: Memory value expected\n");
-			return -EINVAL;
-		}
-		cur = tmp;
-		if (*cur != '-') {
-			pr_warn("crashkernel: '-' expected\n");
-			return -EINVAL;
-		}
-		cur++;
-
-		/* if no ':' is here, than we read the end */
-		if (*cur != ':') {
-			end = memparse(cur, &tmp);
-			if (cur == tmp) {
-				pr_warn("crashkernel: Memory value expected\n");
-				return -EINVAL;
-			}
-			cur = tmp;
-			if (end <= start) {
-				pr_warn("crashkernel: end <= start\n");
-				return -EINVAL;
-			}
-		}
-
-		if (*cur != ':') {
-			pr_warn("crashkernel: ':' expected\n");
-			return -EINVAL;
-		}
-		cur++;
-
-		size = memparse(cur, &tmp);
-		if (cur == tmp) {
-			pr_warn("Memory value expected\n");
-			return -EINVAL;
-		}
-		cur = tmp;
-		if (size >= system_ram) {
-			pr_warn("crashkernel: invalid size\n");
-			return -EINVAL;
-		}
-
-		/* 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);
-			if (cur == tmp) {
-				pr_warn("Memory value expected after '@'\n");
-				return -EINVAL;
-			}
-		}
-	} else
-		pr_info("crashkernel size resulted in zero bytes\n");
-
-	return 0;
-}
-
-/*
- * That function parses "simple" (old) crashkernel command lines like
- *
- *	crashkernel=size[@offset]
- *
- * It returns 0 on success and -EINVAL on failure.
- */
-static int __init parse_crashkernel_simple(char *cmdline,
-					   unsigned long long *crash_size,
-					   unsigned long long *crash_base)
-{
-	char *cur = cmdline;
-
-	*crash_size = memparse(cmdline, &cur);
-	if (cmdline == cur) {
-		pr_warn("crashkernel: memory value expected\n");
-		return -EINVAL;
-	}
-
-	if (*cur == '@')
-		*crash_base = memparse(cur+1, &cur);
-	else if (*cur != ' ' && *cur != '\0') {
-		pr_warn("crashkernel: unrecognized char: %c\n", *cur);
-		return -EINVAL;
-	}
-
-	return 0;
-}
-
-#define SUFFIX_HIGH 0
-#define SUFFIX_LOW  1
-#define SUFFIX_NULL 2
-static __initdata char *suffix_tbl[] = {
-	[SUFFIX_HIGH] = ",high",
-	[SUFFIX_LOW]  = ",low",
-	[SUFFIX_NULL] = NULL,
-};
-
-/*
- * That function parses "suffix"  crashkernel command lines like
- *
- *	crashkernel=size,[high|low]
- *
- * It returns 0 on success and -EINVAL on failure.
- */
-static int __init parse_crashkernel_suffix(char *cmdline,
-					   unsigned long long	*crash_size,
-					   const char *suffix)
-{
-	char *cur = cmdline;
-
-	*crash_size = memparse(cmdline, &cur);
-	if (cmdline == cur) {
-		pr_warn("crashkernel: memory value expected\n");
-		return -EINVAL;
-	}
-
-	/* check with suffix */
-	if (strncmp(cur, suffix, strlen(suffix))) {
-		pr_warn("crashkernel: unrecognized char: %c\n", *cur);
-		return -EINVAL;
-	}
-	cur += strlen(suffix);
-	if (*cur != ' ' && *cur != '\0') {
-		pr_warn("crashkernel: unrecognized char: %c\n", *cur);
-		return -EINVAL;
-	}
-
-	return 0;
-}
-
-static __init char *get_last_crashkernel(char *cmdline,
-			     const char *name,
-			     const char *suffix)
-{
-	char *p = cmdline, *ck_cmdline = NULL;
-
-	/* find crashkernel and use the last one if there are more */
-	p = strstr(p, name);
-	while (p) {
-		char *end_p = strchr(p, ' ');
-		char *q;
-
-		if (!end_p)
-			end_p = p + strlen(p);
-
-		if (!suffix) {
-			int i;
-
-			/* skip the one with any known suffix */
-			for (i = 0; suffix_tbl[i]; i++) {
-				q = end_p - strlen(suffix_tbl[i]);
-				if (!strncmp(q, suffix_tbl[i],
-					     strlen(suffix_tbl[i])))
-					goto next;
-			}
-			ck_cmdline = p;
-		} else {
-			q = end_p - strlen(suffix);
-			if (!strncmp(q, suffix, strlen(suffix)))
-				ck_cmdline = p;
-		}
-next:
-		p = strstr(p+1, name);
-	}
-
-	if (!ck_cmdline)
-		return NULL;
-
-	return ck_cmdline;
-}
-
-static int __init __parse_crashkernel(char *cmdline,
-			     unsigned long long system_ram,
-			     unsigned long long *crash_size,
-			     unsigned long long *crash_base,
-			     const char *name,
-			     const char *suffix)
-{
-	char	*first_colon, *first_space;
-	char	*ck_cmdline;
-
-	BUG_ON(!crash_size || !crash_base);
-	*crash_size = 0;
-	*crash_base = 0;
-
-	ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
-
-	if (!ck_cmdline)
-		return -EINVAL;
-
-	ck_cmdline += strlen(name);
-
-	if (suffix)
-		return parse_crashkernel_suffix(ck_cmdline, crash_size,
-				suffix);
-	/*
-	 * if the commandline contains a ':', then that's the extended
-	 * syntax -- if not, it must be the classic syntax
-	 */
-	first_colon = strchr(ck_cmdline, ':');
-	first_space = strchr(ck_cmdline, ' ');
-	if (first_colon && (!first_space || first_colon < first_space))
-		return parse_crashkernel_mem(ck_cmdline, system_ram,
-				crash_size, crash_base);
-
-	return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base);
-}
-
-/*
- * That function is the entry point for command line parsing and should be
- * called from the arch-specific code.
- */
-int __init parse_crashkernel(char *cmdline,
-			     unsigned long long system_ram,
-			     unsigned long long *crash_size,
-			     unsigned long long *crash_base)
-{
-	return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
-					"crashkernel=", NULL);
-}
-
-int __init parse_crashkernel_high(char *cmdline,
-			     unsigned long long system_ram,
-			     unsigned long long *crash_size,
-			     unsigned long long *crash_base)
-{
-	return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
-				"crashkernel=", suffix_tbl[SUFFIX_HIGH]);
-}
-
-int __init parse_crashkernel_low(char *cmdline,
-			     unsigned long long system_ram,
-			     unsigned long long *crash_size,
-			     unsigned long long *crash_base)
-{
-	return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
-				"crashkernel=", suffix_tbl[SUFFIX_LOW]);
-}
-
 Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
 			  void *data, size_t data_len)
 {
diff --git a/lib/Makefile b/lib/Makefile
index 18c2be5..75c46f0 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -175,6 +175,8 @@ obj-$(CONFIG_OF_RECONFIG_NOTIFIER_ERROR_INJECT) += \
 	of-reconfig-notifier-error-inject.o
 obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
 
+obj-$(CONFIG_CRASH_CORE) += parse_crashkernel.o
+
 lib-$(CONFIG_GENERIC_BUG) += bug.o
 
 obj-$(CONFIG_HAVE_ARCH_TRACEHOOK) += syscall.o
diff --git a/lib/parse_crashkernel.c b/lib/parse_crashkernel.c
new file mode 100644
index 0000000..b9a8dc6
--- /dev/null
+++ b/lib/parse_crashkernel.c
@@ -0,0 +1,280 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * parsing the "crashkernel" commandline
+ *
+ * this code is intended to be called from architecture specific code
+ */
+#include <linux/crash_core.h>
+
+/*
+ * parsing the "crashkernel" commandline
+ *
+ * this code is intended to be called from architecture specific code
+ */
+
+
+/*
+ * This function parses command lines in the format
+ *
+ *   crashkernel=ramsize-range:size[,...][@offset]
+ *
+ * The function returns 0 on success and -EINVAL on failure.
+ */
+static int __init parse_crashkernel_mem(char *cmdline,
+					unsigned long long system_ram,
+					unsigned long long *crash_size,
+					unsigned long long *crash_base)
+{
+	char *cur = cmdline, *tmp;
+
+	/* 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);
+		if (cur == tmp) {
+			pr_warn("crashkernel: Memory value expected\n");
+			return -EINVAL;
+		}
+		cur = tmp;
+		if (*cur != '-') {
+			pr_warn("crashkernel: '-' expected\n");
+			return -EINVAL;
+		}
+		cur++;
+
+		/* if no ':' is here, than we read the end */
+		if (*cur != ':') {
+			end = memparse(cur, &tmp);
+			if (cur == tmp) {
+				pr_warn("crashkernel: Memory value expected\n");
+				return -EINVAL;
+			}
+			cur = tmp;
+			if (end <= start) {
+				pr_warn("crashkernel: end <= start\n");
+				return -EINVAL;
+			}
+		}
+
+		if (*cur != ':') {
+			pr_warn("crashkernel: ':' expected\n");
+			return -EINVAL;
+		}
+		cur++;
+
+		size = memparse(cur, &tmp);
+		if (cur == tmp) {
+			pr_warn("Memory value expected\n");
+			return -EINVAL;
+		}
+		cur = tmp;
+		if (size >= system_ram) {
+			pr_warn("crashkernel: invalid size\n");
+			return -EINVAL;
+		}
+
+		/* 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);
+			if (cur == tmp) {
+				pr_warn("Memory value expected after '@'\n");
+				return -EINVAL;
+			}
+		}
+	} else
+		pr_info("crashkernel size resulted in zero bytes\n");
+
+	return 0;
+}
+
+/*
+ * That function parses "simple" (old) crashkernel command lines like
+ *
+ *	crashkernel=size[@offset]
+ *
+ * It returns 0 on success and -EINVAL on failure.
+ */
+static int __init parse_crashkernel_simple(char *cmdline,
+					   unsigned long long *crash_size,
+					   unsigned long long *crash_base)
+{
+	char *cur = cmdline;
+
+	*crash_size = memparse(cmdline, &cur);
+	if (cmdline == cur) {
+		pr_warn("crashkernel: memory value expected\n");
+		return -EINVAL;
+	}
+
+	if (*cur == '@')
+		*crash_base = memparse(cur+1, &cur);
+	else if (*cur != ' ' && *cur != '\0') {
+		pr_warn("crashkernel: unrecognized char: %c\n", *cur);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+#define SUFFIX_HIGH 0
+#define SUFFIX_LOW  1
+#define SUFFIX_NULL 2
+static __initdata char *suffix_tbl[] = {
+	[SUFFIX_HIGH] = ",high",
+	[SUFFIX_LOW]  = ",low",
+	[SUFFIX_NULL] = NULL,
+};
+
+/*
+ * That function parses "suffix"  crashkernel command lines like
+ *
+ *	crashkernel=size,[high|low]
+ *
+ * It returns 0 on success and -EINVAL on failure.
+ */
+static int __init parse_crashkernel_suffix(char *cmdline,
+					   unsigned long long	*crash_size,
+					   const char *suffix)
+{
+	char *cur = cmdline;
+
+	*crash_size = memparse(cmdline, &cur);
+	if (cmdline == cur) {
+		pr_warn("crashkernel: memory value expected\n");
+		return -EINVAL;
+	}
+
+	/* check with suffix */
+	if (strncmp(cur, suffix, strlen(suffix))) {
+		pr_warn("crashkernel: unrecognized char: %c\n", *cur);
+		return -EINVAL;
+	}
+	cur += strlen(suffix);
+	if (*cur != ' ' && *cur != '\0') {
+		pr_warn("crashkernel: unrecognized char: %c\n", *cur);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static __init char *get_last_crashkernel(char *cmdline,
+			     const char *name,
+			     const char *suffix)
+{
+	char *p = cmdline, *ck_cmdline = NULL;
+
+	/* find crashkernel and use the last one if there are more */
+	p = strstr(p, name);
+	while (p) {
+		char *end_p = strchr(p, ' ');
+		char *q;
+
+		if (!end_p)
+			end_p = p + strlen(p);
+
+		if (!suffix) {
+			int i;
+
+			/* skip the one with any known suffix */
+			for (i = 0; suffix_tbl[i]; i++) {
+				q = end_p - strlen(suffix_tbl[i]);
+				if (!strncmp(q, suffix_tbl[i],
+					     strlen(suffix_tbl[i])))
+					goto next;
+			}
+			ck_cmdline = p;
+		} else {
+			q = end_p - strlen(suffix);
+			if (!strncmp(q, suffix, strlen(suffix)))
+				ck_cmdline = p;
+		}
+next:
+		p = strstr(p+1, name);
+	}
+
+	if (!ck_cmdline)
+		return NULL;
+
+	return ck_cmdline;
+}
+
+static int __init __parse_crashkernel(char *cmdline,
+			     unsigned long long system_ram,
+			     unsigned long long *crash_size,
+			     unsigned long long *crash_base,
+			     const char *name,
+			     const char *suffix)
+{
+	char	*first_colon, *first_space;
+	char	*ck_cmdline;
+
+	BUG_ON(!crash_size || !crash_base);
+	*crash_size = 0;
+	*crash_base = 0;
+
+	ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
+
+	if (!ck_cmdline)
+		return -EINVAL;
+
+	ck_cmdline += strlen(name);
+
+	if (suffix)
+		return parse_crashkernel_suffix(ck_cmdline, crash_size,
+				suffix);
+	/*
+	 * if the commandline contains a ':', then that's the extended
+	 * syntax -- if not, it must be the classic syntax
+	 */
+	first_colon = strchr(ck_cmdline, ':');
+	first_space = strchr(ck_cmdline, ' ');
+	if (first_colon && (!first_space || first_colon < first_space))
+		return parse_crashkernel_mem(ck_cmdline, system_ram,
+				crash_size, crash_base);
+
+	return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base);
+}
+
+/*
+ * That function is the entry point for command line parsing and should be
+ * called from the arch-specific code.
+ */
+int __init parse_crashkernel(char *cmdline,
+			     unsigned long long system_ram,
+			     unsigned long long *crash_size,
+			     unsigned long long *crash_base)
+{
+	return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
+					"crashkernel=", NULL);
+}
+
+int __init parse_crashkernel_high(char *cmdline,
+			     unsigned long long system_ram,
+			     unsigned long long *crash_size,
+			     unsigned long long *crash_base)
+{
+	return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
+				"crashkernel=", suffix_tbl[SUFFIX_HIGH]);
+}
+
+int __init parse_crashkernel_low(char *cmdline,
+			     unsigned long long system_ram,
+			     unsigned long long *crash_size,
+			     unsigned long long *crash_base)
+{
+	return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
+				"crashkernel=", suffix_tbl[SUFFIX_LOW]);
+}
-- 
2.7.4

[PATCHv5 2/2] x86/boot/KASLR: skip the specified crashkernel region

[Pingfan Liu]

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@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Chao Fan <fanc.fnst@cn.fujitsu.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
CC: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org
---
 arch/x86/boot/compressed/kaslr.c | 40 ++++++++++++++++++++++++++++++++++++++++
 lib/parse_crashkernel.c          | 10 ++++++++++
 2 files changed, 50 insertions(+)

diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 2e53c05..12f72a3 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,
 };
 
@@ -131,6 +132,11 @@ char *skip_spaces(const char *str)
 }
 #include "../../../../lib/ctype.c"
 #include "../../../../lib/cmdline.c"
+#ifdef CONFIG_CRASH_CORE
+#define printk
+#define _BOOT_KASLR
+#include "../../../../lib/parse_crashkernel.c"
+#endif
 
 static int
 parse_memmap(char *p, unsigned long long *start, unsigned long long *size)
@@ -292,6 +298,39 @@ static void handle_mem_options(void)
 	return;
 }
 
+static u64 mem_ram_size(void)
+{
+	struct boot_e820_entry *entry;
+	u64 total_sz = 0;
+	int i;
+
+	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;
+	}
+	return total_sz;
+}
+
+/*
+ * For crashkernel=size@offset or =range1:size1[,range2:size2,...]@offset
+ * options, recording mem_avoid for them.
+ */
+static void handle_crashkernel_options(void)
+{
+	unsigned long long crash_size, crash_base;
+	char *cmdline = (char *)get_cmd_line_ptr();
+	u64 total_sz = mem_ram_size();
+
+	parse_crashkernel(cmdline, total_sz, &crash_size, &crash_base);
+	if (crash_base) {
+		mem_avoid[MEM_AVOID_CRASHKERNEL].start = crash_base;
+		mem_avoid[MEM_AVOID_CRASHKERNEL].size = crash_size;
+	}
+}
+
 /*
  * In theory, KASLR can put the kernel anywhere in the range of [16M, 64T).
  * The mem_avoid array is used to store the ranges that need to be avoided
@@ -414,6 +453,7 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size,
 
 	/* Mark the memmap regions we need to avoid */
 	handle_mem_options();
+	handle_crashkernel_options();
 
 	/* Enumerate the immovable memory regions */
 	num_immovable_mem = count_immovable_mem_regions();
diff --git a/lib/parse_crashkernel.c b/lib/parse_crashkernel.c
index b9a8dc6..4644379 100644
--- a/lib/parse_crashkernel.c
+++ b/lib/parse_crashkernel.c
@@ -137,6 +137,7 @@ static __initdata char *suffix_tbl[] = {
 	[SUFFIX_NULL] = NULL,
 };
 
+#ifndef _BOOT_KASLR
 /*
  * That function parses "suffix"  crashkernel command lines like
  *
@@ -169,6 +170,7 @@ static int __init parse_crashkernel_suffix(char *cmdline,
 
 	return 0;
 }
+#endif
 
 static __init char *get_last_crashkernel(char *cmdline,
 			     const char *name,
@@ -232,9 +234,11 @@ static int __init __parse_crashkernel(char *cmdline,
 
 	ck_cmdline += strlen(name);
 
+#ifndef _BOOT_KASLR
 	if (suffix)
 		return parse_crashkernel_suffix(ck_cmdline, crash_size,
 				suffix);
+#endif
 	/*
 	 * if the commandline contains a ':', then that's the extended
 	 * syntax -- if not, it must be the classic syntax
@@ -261,6 +265,11 @@ int __init parse_crashkernel(char *cmdline,
 					"crashkernel=", NULL);
 }
 
+/*
+ * At boot stage, KASLR does not care about crashkernel=size,[high|low], which
+ * never specifies the offset of region.
+ */
+#ifndef _BOOT_KASLR
 int __init parse_crashkernel_high(char *cmdline,
 			     unsigned long long system_ram,
 			     unsigned long long *crash_size,
@@ -278,3 +287,4 @@ int __init parse_crashkernel_low(char *cmdline,
 	return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
 				"crashkernel=", suffix_tbl[SUFFIX_LOW]);
 }
+#endif
-- 
2.7.4

Re: [PATCHv5 0/2] x86/boot/KASLR: skip the specified crashkernel region

[Pingfan Liu]

Maintainers, ping?
Hi Borislav, during the review of V4, you suggested to re-design the
return value of parse_crashkernel(), the latest try is on
https://lore.kernel.org/patchwork/patch/1065514/. It seems hard to
move on in that thread. On the other hand, my series "[PATCHv5 0/2]
x86/boot/KASLR: skip the specified crashkernel region" has no depend
on the "re-design the return value of parse_crashkernel()".

Thanks,
  Pingfan
On Tue, May 7, 2019 at 12:32 PM Pingfan Liu <kernelfans@gmail.com> wrote:
>
> 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.
> And the parsing routine can be re-used at this early boot stage.
>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Baoquan He <bhe@redhat.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Nicolas Pitre <nico@linaro.org>
> Cc: Vivek Goyal <vgoyal@redhat.com>
> Cc: Chao Fan <fanc.fnst@cn.fujitsu.com>
> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> CC: Hari Bathini <hbathini@linux.vnet.ibm.com>
> Cc: linux-kernel@vger.kernel.org
> ---
> v3 -> v4:
>   reuse the parse_crashkernel_xx routines
> v4 -> v5:
>   drop unnecessary initialization of crash_base in [2/2]
>
> Pingfan Liu (2):
>   kernel/crash_core: separate the parsing routines to
>     lib/parse_crashkernel.c
>   x86/boot/KASLR: skip the specified crashkernel region
>
>  arch/x86/boot/compressed/kaslr.c |  40 ++++++
>  kernel/crash_core.c              | 273 ------------------------------------
>  lib/Makefile                     |   2 +
>  lib/parse_crashkernel.c          | 289 +++++++++++++++++++++++++++++++++++++++
>  4 files changed, 331 insertions(+), 273 deletions(-)
>  create mode 100644 lib/parse_crashkernel.c
>
> --
> 2.7.4
>