Make the functions reserve_crashkernel[_low]() as generic.
Arm64 will use these to reimplement crashkernel=X.

Signed-off-by: Chen Zhou <chenzho...@huawei.com>
Tested-by: John Donnelly <john.p.donne...@oracle.com>
---
 arch/x86/include/asm/kexec.h |  25 ++++++
 arch/x86/kernel/setup.c      | 143 +------------------------------
 include/linux/crash_core.h   |   3 +
 include/linux/kexec.h        |   2 -
 kernel/crash_core.c          | 159 +++++++++++++++++++++++++++++++++++
 kernel/kexec_core.c          |  17 ----
 6 files changed, 189 insertions(+), 160 deletions(-)

diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index be18dc7ae51f..2b18f918203e 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -21,6 +21,27 @@
 /* 16M alignment for crash kernel regions */
 #define CRASH_ALIGN            SZ_16M
 
+/*
+ * Keep the crash kernel below this limit.
+ *
+ * Earlier 32-bits kernels would limit the kernel to the low 512 MB range
+ * due to mapping restrictions.
+ *
+ * 64-bit kdump kernels need to be restricted to be under 64 TB, which is
+ * the upper limit of system RAM in 4-level paging mode. Since the kdump
+ * jump could be from 5-level paging to 4-level paging, the jump will fail if
+ * the kernel is put above 64 TB, and during the 1st kernel bootup there's
+ * no good way to detect the paging mode of the target kernel which will be
+ * loaded for dumping.
+ */
+#ifdef CONFIG_X86_32
+# define CRASH_ADDR_LOW_MAX    SZ_512M
+# define CRASH_ADDR_HIGH_MAX   SZ_512M
+#else
+# define CRASH_ADDR_LOW_MAX    SZ_4G
+# define CRASH_ADDR_HIGH_MAX   SZ_64T
+#endif
+
 #ifndef __ASSEMBLY__
 
 #include <linux/string.h>
@@ -200,6 +221,10 @@ typedef void crash_vmclear_fn(void);
 extern crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss;
 extern void kdump_nmi_shootdown_cpus(void);
 
+#ifdef CONFIG_KEXEC_CORE
+extern void __init reserve_crashkernel(void);
+#endif
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_X86_KEXEC_H */
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 5d676efc32f6..d136d6ad3fa8 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -38,6 +38,7 @@
 #include <asm/io_apic.h>
 #include <asm/kasan.h>
 #include <asm/kaslr.h>
+#include <asm/kexec.h>
 #include <asm/mce.h>
 #include <asm/mtrr.h>
 #include <asm/realmode.h>
@@ -384,147 +385,7 @@ static void __init 
memblock_x86_reserve_range_setup_data(void)
        }
 }
 
-/*
- * --------- Crashkernel reservation ------------------------------
- */
-
-#ifdef CONFIG_KEXEC_CORE
-
-/*
- * Keep the crash kernel below this limit.
- *
- * Earlier 32-bits kernels would limit the kernel to the low 512 MB range
- * due to mapping restrictions.
- *
- * 64-bit kdump kernels need to be restricted to be under 64 TB, which is
- * the upper limit of system RAM in 4-level paging mode. Since the kdump
- * jump could be from 5-level paging to 4-level paging, the jump will fail if
- * the kernel is put above 64 TB, and during the 1st kernel bootup there's
- * no good way to detect the paging mode of the target kernel which will be
- * loaded for dumping.
- */
-#ifdef CONFIG_X86_32
-# define CRASH_ADDR_LOW_MAX    SZ_512M
-# define CRASH_ADDR_HIGH_MAX   SZ_512M
-#else
-# define CRASH_ADDR_LOW_MAX    SZ_4G
-# define CRASH_ADDR_HIGH_MAX   SZ_64T
-#endif
-
-static int __init reserve_crashkernel_low(void)
-{
-#ifdef CONFIG_X86_64
-       unsigned long long base, low_base = 0, low_size = 0;
-       unsigned long low_mem_limit;
-       int ret;
-
-       low_mem_limit = min(memblock_phys_mem_size(), CRASH_ADDR_LOW_MAX);
-
-       /* crashkernel=Y,low */
-       ret = parse_crashkernel_low(boot_command_line, low_mem_limit, 
&low_size, &base);
-       if (ret) {
-               /*
-                * two parts from kernel/dma/swiotlb.c:
-                * -swiotlb size: user-specified with swiotlb= or default.
-                *
-                * -swiotlb overflow buffer: now hardcoded to 32k. We round it
-                * to 8M for other buffers that may need to stay low too. Also
-                * make sure we allocate enough extra low memory so that we
-                * don't run out of DMA buffers for 32-bit devices.
-                */
-               low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL 
<< 20);
-       } else {
-               /* passed with crashkernel=0,low ? */
-               if (!low_size)
-                       return 0;
-       }
-
-       low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
-                       CRASH_ADDR_LOW_MAX);
-       if (!low_base) {
-               pr_err("Cannot reserve %ldMB crashkernel low memory, please try 
smaller size.\n",
-                      (unsigned long)(low_size >> 20));
-               return -ENOMEM;
-       }
-
-       pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (low 
RAM limit: %ldMB)\n",
-               (unsigned long)(low_size >> 20),
-               (unsigned long)(low_base >> 20),
-               (unsigned long)(low_mem_limit >> 20));
-
-       crashk_low_res.start = low_base;
-       crashk_low_res.end   = low_base + low_size - 1;
-#endif
-       return 0;
-}
-
-static void __init reserve_crashkernel(void)
-{
-       unsigned long long crash_size, crash_base, total_mem;
-       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) {
-               /* 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) {
-               /*
-                * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
-                * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
-                * also allocates 256M extra low memory for DMA buffers
-                * and swiotlb.
-                * But the extra memory is not required for all machines.
-                * So try low memory first and fall back to high memory
-                * unless "crashkernel=size[KMG],high" is specified.
-                */
-               if (!high)
-                       crash_base = memblock_phys_alloc_range(crash_size,
-                                               CRASH_ALIGN, CRASH_ALIGN,
-                                               CRASH_ADDR_LOW_MAX);
-               if (!crash_base)
-                       crash_base = memblock_phys_alloc_range(crash_size,
-                                               CRASH_ALIGN, CRASH_ALIGN,
-                                               CRASH_ADDR_HIGH_MAX);
-               if (!crash_base) {
-                       pr_info("crashkernel reservation failed - No suitable 
area found.\n");
-                       return;
-               }
-       } else {
-               unsigned long long start;
-
-               start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, 
crash_base,
-                                                 crash_base + crash_size);
-               if (start != crash_base) {
-                       pr_info("crashkernel reservation failed - memory is in 
use.\n");
-                       return;
-               }
-       }
-
-       if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
-               memblock_free(crash_base, crash_size);
-               return;
-       }
-
-       pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System 
RAM: %ldMB)\n",
-               (unsigned long)(crash_size >> 20),
-               (unsigned long)(crash_base >> 20),
-               (unsigned long)(total_mem >> 20));
-
-       crashk_res.start = crash_base;
-       crashk_res.end   = crash_base + crash_size - 1;
-}
-#else
+#ifndef CONFIG_KEXEC_CORE
 static void __init reserve_crashkernel(void)
 {
 }
diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index 206bde8308b2..fc0ef33a76f7 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -69,6 +69,9 @@ extern unsigned char *vmcoreinfo_data;
 extern size_t vmcoreinfo_size;
 extern u32 *vmcoreinfo_note;
 
+extern struct resource crashk_res;
+extern struct resource crashk_low_res;
+
 /* raw contents of kernel .notes section */
 extern const void __start_notes __weak;
 extern const void __stop_notes __weak;
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 9e93bef52968..f301f2f5cfc4 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -337,8 +337,6 @@ extern int kexec_load_disabled;
 
 /* Location of a reserved region to hold the crash kernel.
  */
-extern struct resource crashk_res;
-extern struct resource crashk_low_res;
 extern note_buf_t __percpu *crash_notes;
 
 /* flag to track if kexec reboot is in progress */
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 825284baaf46..a0e790d6ea0f 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -7,6 +7,12 @@
 #include <linux/crash_core.h>
 #include <linux/utsname.h>
 #include <linux/vmalloc.h>
+#include <linux/memblock.h>
+#include <linux/swiotlb.h>
+
+#ifdef CONFIG_KEXEC_CORE
+#include <asm/kexec.h>
+#endif
 
 #include <asm/page.h>
 #include <asm/sections.h>
@@ -21,6 +27,22 @@ u32 *vmcoreinfo_note;
 /* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
 static unsigned char *vmcoreinfo_data_safecopy;
 
+/* Location of the reserved area for the crash kernel */
+struct resource crashk_res = {
+       .name  = "Crash kernel",
+       .start = 0,
+       .end   = 0,
+       .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
+       .desc  = IORES_DESC_CRASH_KERNEL
+};
+struct resource crashk_low_res = {
+       .name  = "Crash kernel",
+       .start = 0,
+       .end   = 0,
+       .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
+       .desc  = IORES_DESC_CRASH_KERNEL
+};
+
 /*
  * parsing the "crashkernel" commandline
  *
@@ -294,6 +316,143 @@ int __init parse_crashkernel_low(char *cmdline,
                                "crashkernel=", suffix_tbl[SUFFIX_LOW]);
 }
 
+/*
+ * --------- Crashkernel reservation ------------------------------
+ */
+
+#ifdef CONFIG_KEXEC_CORE
+
+#ifdef CONFIG_X86
+static int __init reserve_crashkernel_low(void)
+{
+#ifdef CONFIG_X86_64
+       unsigned long long base, low_base = 0, low_size = 0;
+       unsigned long low_mem_limit;
+       int ret;
+
+       low_mem_limit = min(memblock_phys_mem_size(), CRASH_ADDR_LOW_MAX);
+
+       /* crashkernel=Y,low */
+       ret = parse_crashkernel_low(boot_command_line, low_mem_limit, 
&low_size, &base);
+       if (ret) {
+               /*
+                * two parts from kernel/dma/swiotlb.c:
+                * -swiotlb size: user-specified with swiotlb= or default.
+                *
+                * -swiotlb overflow buffer: now hardcoded to 32k. We round it
+                * to 8M for other buffers that may need to stay low too. Also
+                * make sure we allocate enough extra low memory so that we
+                * don't run out of DMA buffers for 32-bit devices.
+                */
+               low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL 
<< 20);
+       } else {
+               /* passed with crashkernel=0,low ? */
+               if (!low_size)
+                       return 0;
+       }
+
+       low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
+                       CRASH_ADDR_LOW_MAX);
+       if (!low_base) {
+               pr_err("Cannot reserve %ldMB crashkernel low memory, please try 
smaller size.\n",
+                      (unsigned long)(low_size >> 20));
+               return -ENOMEM;
+       }
+
+       pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (low 
RAM limit: %ldMB)\n",
+               (unsigned long)(low_size >> 20),
+               (unsigned long)(low_base >> 20),
+               (unsigned long)(low_mem_limit >> 20));
+
+       crashk_low_res.start = low_base;
+       crashk_low_res.end   = low_base + low_size - 1;
+#endif
+       return 0;
+}
+
+/*
+ * reserve_crashkernel() - reserves memory for crash 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.
+ */
+void __init reserve_crashkernel(void)
+{
+       unsigned long long crash_size, crash_base, total_mem;
+       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) {
+               /* 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) {
+               /*
+                * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
+                * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
+                * also allocates 256M extra low memory for DMA buffers
+                * and swiotlb.
+                * But the extra memory is not required for all machines.
+                * So try low memory first and fall back to high memory
+                * unless "crashkernel=size[KMG],high" is specified.
+                */
+               if (!high)
+                       crash_base = memblock_phys_alloc_range(crash_size,
+                                               CRASH_ALIGN, CRASH_ALIGN,
+                                               CRASH_ADDR_LOW_MAX);
+               if (!crash_base)
+                       crash_base = memblock_phys_alloc_range(crash_size,
+                                               CRASH_ALIGN, CRASH_ALIGN,
+                                               CRASH_ADDR_HIGH_MAX);
+               if (!crash_base) {
+                       pr_info("crashkernel reservation failed - No suitable 
area found.\n");
+                       return;
+               }
+       } else {
+               /* User specifies base address explicitly. */
+               unsigned long long start;
+
+               if (!IS_ALIGNED(crash_base, CRASH_ALIGN)) {
+                       pr_warn("cannot reserve crashkernel: base address is 
not %ldMB aligned\n",
+                               (unsigned long)CRASH_ALIGN >> 20);
+                       return;
+               }
+
+               start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, 
crash_base,
+                                                 crash_base + crash_size);
+               if (start != crash_base) {
+                       pr_info("crashkernel reservation failed - memory is in 
use.\n");
+                       return;
+               }
+       }
+
+       if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
+               memblock_free(crash_base, crash_size);
+               return;
+       }
+
+       pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System 
RAM: %ldMB)\n",
+               (unsigned long)(crash_size >> 20),
+               (unsigned long)(crash_base >> 20),
+               (unsigned long)(total_mem >> 20));
+
+       crashk_res.start = crash_base;
+       crashk_res.end   = crash_base + crash_size - 1;
+}
+#endif /* CONFIG_X86 */
+#endif /* CONFIG_KEXEC_CORE */
+
 Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
                          void *data, size_t data_len)
 {
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 4f8efc278aa7..265799e93caf 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -52,23 +52,6 @@ note_buf_t __percpu *crash_notes;
 /* Flag to indicate we are going to kexec a new kernel */
 bool kexec_in_progress = false;
 
-
-/* Location of the reserved area for the crash kernel */
-struct resource crashk_res = {
-       .name  = "Crash kernel",
-       .start = 0,
-       .end   = 0,
-       .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
-       .desc  = IORES_DESC_CRASH_KERNEL
-};
-struct resource crashk_low_res = {
-       .name  = "Crash kernel",
-       .start = 0,
-       .end   = 0,
-       .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
-       .desc  = IORES_DESC_CRASH_KERNEL
-};
-
 int kexec_should_crash(struct task_struct *p)
 {
        /*
-- 
2.20.1


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