[PATCH v12 4/9] x86: kdump: move reserve_crashkernel[_low]() into crash_core.c

Chen Zhou
2020-09-07T17:20:53Z

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

There is no functional change.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
---
arch/x86/include/asm/kexec.h | 25 +++++
arch/x86/kernel/setup.c | 163 +------------------------------
include/linux/crash_core.h | 4 +
include/linux/kexec.h | 2 -
kernel/crash_core.c | 179 +++++++++++++++++++++++++++++++++++
kernel/kexec_core.c | 17 ----
6 files changed, 210 insertions(+), 180 deletions(-)

diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 83f200dd54a1..adf5e9a016bd 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -21,6 +21,27 @@
/* 2M alignment for crash kernel regions */
#define CRASH_ALIGN SZ_2M

+/*
+ * 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 71a6a6e7ca5b..927ba83e8da4 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -22,8 +22,6 @@

#include <uapi/linux/mount.h>

-#include <xen/xen.h>
-
#include <asm/apic.h>
#include <asm/numa.h>
#include <asm/bios_ebda.h>
@@ -35,6 +33,7 @@
#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>
@@ -396,165 +395,7 @@ 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 total_low_mem;
- int ret;
-
- total_low_mem = memblock_mem_size(CRASH_ADDR_LOW_MAX >> PAGE_SHIFT);
-
- /* crashkernel=Y,low */
- ret = parse_crashkernel_low(boot_command_line, total_low_mem, &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_find_in_range(CRASH_ALIGN, CRASH_ADDR_LOW_MAX, 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;
- 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;
- }
-
- if (xen_pv_domain()) {
- pr_info("Ignoring crashkernel for a Xen PV domain\n");
- return;
- }
-
- /* 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_find_in_range(CRASH_ALIGN,
- CRASH_ADDR_LOW_MAX,
- crash_size, CRASH_ALIGN);
- if (!crash_base)
- crash_base = memblock_find_in_range(CRASH_ALIGN,
- CRASH_ADDR_HIGH_MAX,
- crash_size, CRASH_ALIGN);
- if (!crash_base) {
- pr_info("crashkernel reservation failed - No suitable area found.\n");
- return;
- }
- } else {
- unsigned long long start;
-
- start = memblock_find_in_range(crash_base,
- crash_base + crash_size,
- crash_size, CRASH_ALIGN);
- if (start != crash_base) {
- pr_info("crashkernel reservation failed - memory is in use.\n");
- return;
- }
- }
- ret = memblock_reserve(crash_base, crash_size);
- if (ret) {
- pr_err("%s: Error reserving crashkernel memblock.\n", __func__);
- 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;
- insert_resource(&iomem_resource, &crashk_res);
-}
-#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 6594dbc34a37..eabbb703d2a3 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -66,6 +66,9 @@ 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;
@@ -80,5 +83,6 @@ 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 __init reserve_crashkernel_low(void);

#endif /* LINUX_CRASH_CORE_H */
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 106e4500fd53..d968ef268fb4 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -7,7 +7,12 @@
#include <linux/crash_core.h>
#include <linux/utsname.h>
#include <linux/vmalloc.h>
+#include <linux/memblock.h>
+#include <linux/swiotlb.h>

+#include <xen/xen.h>
+
+#include <asm/kexec.h>
#include <asm/page.h>
#include <asm/sections.h>

@@ -21,6 +26,22 @@ 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 +315,164 @@ int __init parse_crashkernel_low(char *cmdline,
"crashkernel=", suffix_tbl[SUFFIX_LOW]);
}

+/*
+ * --------- Crashkernel reservation ------------------------------
+ */
+
+int __init reserve_crashkernel_low(void)
+{
+#if defined(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(CRASH_ADDR_LOW_MAX >> 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(CRASH_ALIGN, CRASH_ADDR_LOW_MAX, 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;
+}
+
+#if defined(CONFIG_X86)
+#ifdef CONFIG_KEXEC_CORE
+/*
+ * 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);
+ /* no crashkernel= or invalid value specified */
+ if (ret || !crash_size) {
+ /* crashkernel=X,high */
+ ret = parse_crashkernel_high(boot_command_line, total_mem,
+ &crash_size, &crash_base);
+ if (ret || !crash_size)
+ return;
+ high = true;
+ }
+
+ if (xen_pv_domain()) {
+ pr_info("Ignoring crashkernel for a Xen PV domain\n");
+ return;
+ }
+
+ /* 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_find_in_range(CRASH_ALIGN,
+ CRASH_ADDR_LOW_MAX,
+ crash_size, CRASH_ALIGN);
+ if (!crash_base)
+ crash_base = memblock_find_in_range(CRASH_ALIGN,
+ CRASH_ADDR_HIGH_MAX,
+ crash_size, CRASH_ALIGN);
+ 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_find_in_range(crash_base,
+ crash_base + crash_size,
+ crash_size, CRASH_ALIGN);
+ if (start != crash_base) {
+ pr_info("crashkernel reservation failed - memory is in use.\n");
+ return;
+ }
+ }
+ ret = memblock_reserve(crash_base, crash_size);
+ if (ret) {
+ pr_err("%s: Error reserving crashkernel memblock.\n", __func__);
+ 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;
+ insert_resource(&iomem_resource, &crashk_res);
+}
+#endif /* CONFIG_KEXEC_CORE */
+#endif
+
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 c19c0dad1ebe..db66bbabfff3 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -53,23 +53,6 @@ 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