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Subject[PATCH 1/4] x86: kdump: move reserve_crashkernel_low() into kexec_core.c
Date
In preparation for supporting reserving crashkernel above 4G
in arm64 as x86_64 does, move reserve_crashkernel_low() into
kexec/kexec_core.c.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
---
arch/x86/include/asm/kexec.h | 3 ++
arch/x86/kernel/setup.c | 66 +++++---------------------------------------
include/linux/kexec.h | 5 ++++
kernel/kexec_core.c | 56 +++++++++++++++++++++++++++++++++++++
4 files changed, 71 insertions(+), 59 deletions(-)

diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 003f2da..c51f293 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -18,6 +18,9 @@

# define KEXEC_CONTROL_CODE_MAX_SIZE 2048

+/* 16M alignment for crash kernel regions */
+#define CRASH_ALIGN SZ_16M
+
#ifndef __ASSEMBLY__

#include <linux/string.h>
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 905dae8..9ee33b6 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -448,9 +448,6 @@ static void __init memblock_x86_reserve_range_setup_data(void)

#ifdef CONFIG_KEXEC_CORE

-/* 16M alignment for crash kernel regions */
-#define CRASH_ALIGN SZ_16M
-
/*
* 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.
@@ -463,59 +460,6 @@ static void __init memblock_x86_reserve_range_setup_data(void)
# define CRASH_ADDR_HIGH_MAX MAXMEM
#endif

-static int __init reserve_crashkernel_low(void)
-{
-#ifdef CONFIG_X86_64
- unsigned long long base, low_base = 0, low_size = 0;
- unsigned long total_low_mem;
- 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) {
- /*
- * two parts from lib/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_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN);
- if (!low_base) {
- pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
- (unsigned long)(low_size >> 20));
- return -ENOMEM;
- }
-
- ret = memblock_reserve(low_base, low_size);
- if (ret) {
- pr_err("%s: Error reserving crashkernel low memblock.\n", __func__);
- return ret;
- }
-
- pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (System low RAM: %ldMB)\n",
- (unsigned long)(low_size >> 20),
- (unsigned long)(low_base >> 20),
- (unsigned long)(total_low_mem >> 20));
-
- crashk_low_res.start = low_base;
- crashk_low_res.end = low_base + low_size - 1;
- insert_resource(&iomem_resource, &crashk_low_res);
-#endif
- return 0;
-}
-
static void __init reserve_crashkernel(void)
{
unsigned long long crash_size, crash_base, total_mem;
@@ -579,9 +523,13 @@ static void __init reserve_crashkernel(void)
return;
}

- if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
- memblock_free(crash_base, crash_size);
- return;
+ if (crash_base >= (1ULL << 32)) {
+ if (reserve_crashkernel_low()) {
+ memblock_free(crash_base, crash_size);
+ return;
+ }
+
+ insert_resource(&iomem_resource, &crashk_low_res);
}

pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index b9b1bc5..096ad63 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -63,6 +63,10 @@

#define KEXEC_CORE_NOTE_NAME CRASH_CORE_NOTE_NAME

+#ifndef CRASH_ALIGN
+#define CRASH_ALIGN SZ_128M
+#endif
+
/*
* This structure is used to hold the arguments that are used when loading
* kernel binaries.
@@ -281,6 +285,7 @@ extern void __crash_kexec(struct pt_regs *);
extern void crash_kexec(struct pt_regs *);
int kexec_should_crash(struct task_struct *);
int kexec_crash_loaded(void);
+int __init reserve_crashkernel_low(void);
void crash_save_cpu(struct pt_regs *regs, int cpu);
extern int kimage_crash_copy_vmcoreinfo(struct kimage *image);

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index d714044..3492abd 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -39,6 +39,8 @@
#include <linux/compiler.h>
#include <linux/hugetlb.h>
#include <linux/frame.h>
+#include <linux/memblock.h>
+#include <linux/swiotlb.h>

#include <asm/page.h>
#include <asm/sections.h>
@@ -96,6 +98,60 @@ int kexec_crash_loaded(void)
}
EXPORT_SYMBOL_GPL(kexec_crash_loaded);

+int __init reserve_crashkernel_low(void)
+{
+ unsigned long long base, low_base = 0, low_size = 0;
+ unsigned long total_low_mem;
+ 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) {
+ /*
+ * two parts from lib/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_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN);
+ if (!low_base) {
+ pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
+ (unsigned long)(low_size >> 20));
+ return -ENOMEM;
+ }
+
+ ret = memblock_reserve(low_base, low_size);
+ if (ret) {
+ pr_err("%s: Error reserving crashkernel low memblock.\n",
+ __func__);
+ return ret;
+ }
+
+ pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (System low RAM: %ldMB)\n",
+ (unsigned long)(low_size >> 20),
+ (unsigned long)(low_base >> 20),
+ (unsigned long)(total_low_mem >> 20));
+
+ crashk_low_res.start = low_base;
+ crashk_low_res.end = low_base + low_size - 1;
+
+ return 0;
+}
+
/*
* When kexec transitions to the new kernel there is a one-to-one
* mapping between physical and virtual addresses. On processors
--
2.7.4
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