kexeckernel= is used to reserve memory for normal kexec kernel for
faster reboot.

Rename reserve_crashkernel() to reserve_crash_or_kexec_kernel(), and
generalize it by adding an argument that specifies what is reserved:
"crashkernel=" for crash kernel region
"kexeckernel=" for normal kexec region

Signed-off-by: Pavel Tatashin <pasha.tatas...@soleen.com>
---
 .../admin-guide/kernel-parameters.txt         | 10 +--
 arch/arm64/kernel/setup.c                     |  5 ++
 arch/arm64/mm/init.c                          | 83 ++++++++++++-------
 3 files changed, 63 insertions(+), 35 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt 
b/Documentation/admin-guide/kernel-parameters.txt
index 0f5ce665c7f5..a18222c1fbee 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -740,11 +740,11 @@
                        or memory reserved is below 4G.
 
        kexeckernel=size[KMG][@offset[KMG]]
-                       [KNL] Using kexec, Linux can reboot to a new kernel.
-                       This parameter reserves the physical memory region
-                       [offset, offset + size] for that kernel. If '@offset' is
-                       omitted, then a suitable offset is selected
-                       automatically.
+                       [KNL, ARM64] Using kexec, Linux can reboot to a new
+                       kernel. This parameter reserves the physical memory
+                       region [offset, offset + size] for that kernel. If
+                       '@offset' is omitted, then a suitable offset is
+                       selected automatically.
 
        cryptomgr.notests
                        [KNL] Disable crypto self-tests
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 7e541f947b4c..9f308fa103c5 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -235,6 +235,11 @@ static void __init request_standard_resources(void)
                if (crashk_res.end && crashk_res.start >= res->start &&
                    crashk_res.end <= res->end)
                        request_resource(res, &crashk_res);
+
+               /* Userspace will find "Kexec kernel" region in /proc/iomem. */
+               if (kexeck_res.end && kexeck_res.start >= res->start &&
+                   kexeck_res.end <= res->end)
+                       request_resource(res, &kexeck_res);
 #endif
        }
 }
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index f3c795278def..dfef39f72faf 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -54,61 +54,83 @@ phys_addr_t arm64_dma_phys_limit __ro_after_init;
 
 #ifdef CONFIG_KEXEC_CORE
 /*
- * reserve_crashkernel() - reserves memory for crash kernel
+ * reserve_crash_or_kexec_kernel() - reserves memory for crash kernel or
+ * for normal kexec kernel.
  *
- * This function reserves memory area given in "crashkernel=" kernel command
- * line parameter. The memory reserved is used by dump capture kernel when
- * primary kernel is crashing.
+ * This function reserves memory area given in "crashkernel=" or "kexeckenel="
+ * kernel command line parameter. The memory reserved is used by dump capture
+ * kernel when primary kernel is crashing, or to load new kexec kernel for
+ * faster reboot without relocation.
  */
-static void __init reserve_crashkernel(void)
+static void __init reserve_crash_or_kexec_kernel(char *cmd)
 {
-       unsigned long long crash_base, crash_size;
+       unsigned long long base, size;
+       struct resource *res;
+       char s[16];
        int ret;
 
-       ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
-                               &crash_size, &crash_base);
-       /* no crashkernel= or invalid value specified */
-       if (ret || !crash_size)
+       /* cmd must be either: "crashkernel=" or "kexeckernel=" */
+       if (!strcmp(cmd, "crashkernel=")) {
+               res = &crashk_res;
+       } else if (!strcmp(cmd, "kexeckernel=")) {
+               res = &kexeck_res;
+       } else {
+               pr_err("%s: invalid cmd %s\n", __func__, cmd);
+               return;
+       }
+
+       /* remove trailing '=' for a nicer printfs */
+       strcpy(s, cmd);
+       s[strlen(s) - 1] = '\0';
+
+       ret = parse_crash_or_kexec_kernel(boot_command_line,
+                                         memblock_phys_mem_size(),
+                                         &size, &base, cmd, NULL);
+       /* no specified command or invalid value specified */
+       if (ret || !size)
                return;
 
-       crash_size = PAGE_ALIGN(crash_size);
+       size = PAGE_ALIGN(size);
 
-       if (crash_base == 0) {
+       if (base == 0) {
                /* Current arm64 boot protocol requires 2MB alignment */
-               crash_base = memblock_find_in_range(0, ARCH_LOW_ADDRESS_LIMIT,
-                               crash_size, SZ_2M);
-               if (crash_base == 0) {
-                       pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
-                               crash_size);
+               base = memblock_find_in_range(0, ARCH_LOW_ADDRESS_LIMIT,
+                                             size, SZ_2M);
+               if (base == 0) {
+                       pr_warn("cannot allocate %s (size:0x%llx)\n",
+                               s, size);
                        return;
                }
        } else {
                /* User specifies base address explicitly. */
-               if (!memblock_is_region_memory(crash_base, crash_size)) {
-                       pr_warn("cannot reserve crashkernel: region is not 
memory\n");
+               if (!memblock_is_region_memory(base, size)) {
+                       pr_warn("cannot reserve %s: region is not memory\n",
+                               s);
                        return;
                }
 
-               if (memblock_is_region_reserved(crash_base, crash_size)) {
-                       pr_warn("cannot reserve crashkernel: region overlaps 
reserved memory\n");
+               if (memblock_is_region_reserved(base, size)) {
+                       pr_warn("cannot reserve %s: region overlaps reserved 
memory\n",
+                               s);
                        return;
                }
 
-               if (!IS_ALIGNED(crash_base, SZ_2M)) {
-                       pr_warn("cannot reserve crashkernel: base address is 
not 2MB aligned\n");
+               if (!IS_ALIGNED(base, SZ_2M)) {
+                       pr_warn("cannot reserve %s: base address is not 2MB 
aligned\n",
+                               s);
                        return;
                }
        }
-       memblock_reserve(crash_base, crash_size);
+       memblock_reserve(base, size);
 
-       pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
-               crash_base, crash_base + crash_size, crash_size >> 20);
+       pr_info("%s reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
+               s, base, base + size, size >> 20);
 
-       crashk_res.start = crash_base;
-       crashk_res.end = crash_base + crash_size - 1;
+       res->start = base;
+       res->end = base + size - 1;
 }
 #else
-static void __init reserve_crashkernel(void)
+static void __init reserve_crash_or_kexec_kernel(char *cmd)
 {
 }
 #endif /* CONFIG_KEXEC_CORE */
@@ -411,7 +433,8 @@ void __init arm64_memblock_init(void)
        else
                arm64_dma_phys_limit = PHYS_MASK + 1;
 
-       reserve_crashkernel();
+       reserve_crash_or_kexec_kernel("crashkernel=");
+       reserve_crash_or_kexec_kernel("kexeckernel=");
 
        reserve_elfcorehdr();
 
-- 
2.22.0

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