6 files changed, 180 insertions, 28 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index d1cc3a9fa14f..8ccbf27aead4 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -596,9 +596,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         is selected automatically. Check
                         Documentation/kdump/kdump.txt for further details.
 
-        crashkernel_low=size[KMG]
-                        [KNL, x86] parts under 4G.
-
         crashkernel=range1:size1[,range2:size2,...][@offset]
                         [KNL] Same as above, but depends on the memory
                         in the running system. The syntax of range is
@@ -606,6 +603,26 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         a memory unit (amount[KMG]). See also
                         Documentation/kdump/kdump.txt for an example.
 
+        crashkernel=size[KMG],high
+                        [KNL, x86_64] range could be above 4G. Allow kernel
+                        to allocate physical memory region from top, so could
+                        be above 4G if system have more than 4G ram installed.
+                        Otherwise memory region will be allocated below 4G, if
+                        available.
+                        It will be ignored if crashkernel=X is specified.
+        crashkernel=size[KMG],low
+                        [KNL, x86_64] range under 4G. When crashkernel=X,high
+                        is passed, kernel could allocate physical memory region
+                        above 4G, that cause second kernel crash on system
+                        that require some amount of low memory, e.g. swiotlb
+                        requires at least 64M+32K low memory.  Kernel would
+                        try to allocate 72M below 4G automatically.
+                        This one let user to specify own low range under 4G
+                        for second kernel instead.
+                        0: to disable low allocation.
+                        It will be ignored when crashkernel=X,high is not used
+                        or memory reserved is below 4G.
+
         cs89x0_dma=     [HW,NET]
                         Format: <dma>
 
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 90d8cc930f5e..fae9134a2de9 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -507,11 +507,14 @@ static void __init memblock_x86_reserve_range_setup_data(void)
 /*
  * Keep the crash kernel below this limit.  On 32 bits earlier kernels
  * would limit the kernel to the low 512 MiB due to mapping restrictions.
+ * On 64bit, old kexec-tools need to under 896MiB.
  */
 #ifdef CONFIG_X86_32
-# define CRASH_KERNEL_ADDR_MAX  (512 << 20)
+# define CRASH_KERNEL_ADDR_LOW_MAX      (512 << 20)
+# define CRASH_KERNEL_ADDR_HIGH_MAX     (512 << 20)
 #else
-# define CRASH_KERNEL_ADDR_MAX  MAXMEM
+# define CRASH_KERNEL_ADDR_LOW_MAX      (896UL<<20)
+# define CRASH_KERNEL_ADDR_HIGH_MAX     MAXMEM
 #endif
 
 static void __init reserve_crashkernel_low(void)
@@ -521,19 +524,35 @@ static void __init reserve_crashkernel_low(void)
         unsigned long long low_base = 0, low_size = 0;
         unsigned long total_low_mem;
         unsigned long long base;
+        bool auto_set = false;
         int ret;
 
         total_low_mem = memblock_mem_size(1UL<<(32-PAGE_SHIFT));
+        /* crashkernel=Y,low */
         ret = parse_crashkernel_low(boot_command_line, total_low_mem,
                                                 &low_size, &base);
-        if (ret != 0 || low_size <= 0)
-                return;
+        if (ret != 0) {
+                /*
+                 * two parts from lib/swiotlb.c:
+                 *      swiotlb size: user specified with swiotlb= or default.
+                 *      swiotlb overflow buffer: now is hardcoded to 32k.
+                 *              We round it to 8M for other buffers that
+                 *              may need to stay low too.
+                 */
+                low_size = swiotlb_size_or_default() + (8UL<<20);
+                auto_set = true;
+        } else {
+                /* passed with crashkernel=0,low ? */
+                if (!low_size)
+                        return;
+        }
 
         low_base = memblock_find_in_range(low_size, (1ULL<<32),
                                         low_size, alignment);
 
         if (!low_base) {
-                pr_info("crashkernel low reservation failed - No suitable area found.\n");
+                if (!auto_set)
+                        pr_info("crashkernel low reservation failed - No suitable area found.\n");
 
                 return;
         }
@@ -554,14 +573,22 @@ static void __init reserve_crashkernel(void)
         const unsigned long long alignment = 16<<20;    /* 16M */
         unsigned long long total_mem;
         unsigned long long crash_size, crash_base;
+        bool high = false;
         int ret;
 
         total_mem = memblock_phys_mem_size();
 
+        /* crashkernel=XM */
         ret = parse_crashkernel(boot_command_line, total_mem,
                         &crash_size, &crash_base);
-        if (ret != 0 || crash_size <= 0)
-                return;
+        if (ret != 0 || crash_size <= 0) {
+                /* crashkernel=X,high */
+                ret = parse_crashkernel_high(boot_command_line, total_mem,
+                                &crash_size, &crash_base);
+                if (ret != 0 || crash_size <= 0)
+                        return;
+                high = true;
+        }
 
         /* 0 means: find the address automatically */
         if (crash_base <= 0) {
@@ -569,7 +596,9 @@ static void __init reserve_crashkernel(void)
                  *  kexec want bzImage is below CRASH_KERNEL_ADDR_MAX
                  */
                 crash_base = memblock_find_in_range(alignment,
-                               CRASH_KERNEL_ADDR_MAX, crash_size, alignment);
+                                        high ? CRASH_KERNEL_ADDR_HIGH_MAX :
+                                               CRASH_KERNEL_ADDR_LOW_MAX,
+                                        crash_size, alignment);
 
                 if (!crash_base) {
                         pr_info("crashkernel reservation failed - No suitable area found.\n");
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index d2e6927bbaae..d78d28a733b1 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -200,6 +200,8 @@ extern size_t vmcoreinfo_max_size;
 
 int __init parse_crashkernel(char *cmdline, unsigned long long system_ram,
                 unsigned long long *crash_size, unsigned long long *crash_base);
+int parse_crashkernel_high(char *cmdline, unsigned long long system_ram,
+                unsigned long long *crash_size, unsigned long long *crash_base);
 int parse_crashkernel_low(char *cmdline, unsigned long long system_ram,
                 unsigned long long *crash_size, unsigned long long *crash_base);
 int crash_shrink_memory(unsigned long new_size);
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 2de42f9401d2..a5ffd32642fd 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -25,6 +25,7 @@ extern int swiotlb_force;
 extern void swiotlb_init(int verbose);
 int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
 extern unsigned long swiotlb_nr_tbl(void);
+unsigned long swiotlb_size_or_default(void);
 extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);
 
 /*
diff --git a/kernel/kexec.c b/kernel/kexec.c
index bddd3d7a74b6..ffd4e111fd67 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -55,7 +55,7 @@ struct resource crashk_res = {
         .flags = IORESOURCE_BUSY | IORESOURCE_MEM
 };
 struct resource crashk_low_res = {
-        .name  = "Crash kernel low",
+        .name  = "Crash kernel",
         .start = 0,
         .end   = 0,
         .flags = IORESOURCE_BUSY | IORESOURCE_MEM
@@ -1368,35 +1368,114 @@ static int __init parse_crashkernel_simple(char 		*cmdline,
         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 is the entry point for command line parsing and should be
- * called from the arch-specific code.
+ * 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,
+                                           unsigned long long   *crash_base,
+                                           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\n");
+                return -EINVAL;
+        }
+        cur += strlen(suffix);
+        if (*cur != ' ' && *cur != '\0') {
+                pr_warn("crashkernel: unrecognized char\n");
+                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 *name,
+                             const char *suffix)
 {
-        char    *p = cmdline, *ck_cmdline = NULL;
         char    *first_colon, *first_space;
+        char    *ck_cmdline;
 
         BUG_ON(!crash_size || !crash_base);
         *crash_size = 0;
         *crash_base = 0;
 
-        /* find crashkernel and use the last one if there are more */
-        p = strstr(p, name);
-        while (p) {
-                ck_cmdline = p;
-                p = strstr(p+1, name);
-        }
+        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,
+                                crash_base, suffix);
         /*
          * if the commandline contains a ':', then that's the extended
          * syntax -- if not, it must be the classic syntax
@@ -1413,13 +1492,26 @@ static int __init __parse_crashkernel(char *cmdline,
         return 0;
 }
 
+/*
+ * 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=");
+                                        "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,
@@ -1428,7 +1520,7 @@ int __init parse_crashkernel_low(char *cmdline,
                              unsigned long long *crash_base)
 {
         return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
-                                        "crashkernel_low=");
+                                "crashkernel=", suffix_tbl[SUFFIX_LOW]);
 }
 
 static void update_vmcoreinfo_note(void)
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index bfe02b8fc55b..d23762e6652c 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -105,9 +105,9 @@ setup_io_tlb_npages(char *str)
         if (!strcmp(str, "force"))
                 swiotlb_force = 1;
 
-        return 1;
+        return 0;
 }
-__setup("swiotlb=", setup_io_tlb_npages);
+early_param("swiotlb", setup_io_tlb_npages);
 /* make io_tlb_overflow tunable too? */
 
 unsigned long swiotlb_nr_tbl(void)
@@ -115,6 +115,18 @@ unsigned long swiotlb_nr_tbl(void)
         return io_tlb_nslabs;
 }
 EXPORT_SYMBOL_GPL(swiotlb_nr_tbl);
+
+/* default to 64MB */
+#define IO_TLB_DEFAULT_SIZE (64UL<<20)
+unsigned long swiotlb_size_or_default(void)
+{
+        unsigned long size;
+
+        size = io_tlb_nslabs << IO_TLB_SHIFT;
+
+        return size ? size : (IO_TLB_DEFAULT_SIZE);
+}
+
 /* Note that this doesn't work with highmem page */
 static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,
                                       volatile void *address)
@@ -188,8 +200,7 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
 void  __init
 swiotlb_init(int verbose)
 {
-        /* default to 64MB */
-        size_t default_size = 64UL<<20;
+        size_t default_size = IO_TLB_DEFAULT_SIZE;
         unsigned char *vstart;
         unsigned long bytes;