[PATCH v17 05/10] x86: kdump: move reserve_crashkernel[_low]() into crash_core.c

Zhen Lei
2021-12-10T06:55:28Z

From: Chen Zhou <chenzhou10@huawei.com>

Make the functions reserve_crashkernel[_low]() as generic. Since
reserve_crashkernel[_low]() implementations are quite similar on other
architectures as well, we can have more users of this later.

So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
select this by X86.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
Tested-by: Dave Kleikamp <dave.kleikamp@oracle.com>
---
arch/Kconfig | 3 +
arch/x86/Kconfig | 2 +
arch/x86/include/asm/elf.h | 3 +
arch/x86/include/asm/kexec.h | 28 ++++++-
arch/x86/kernel/setup.c | 143 +-------------------------------
include/linux/crash_core.h | 3 +
include/linux/kexec.h | 2 -
kernel/crash_core.c | 156 +++++++++++++++++++++++++++++++++++
kernel/kexec_core.c | 17 ----
9 files changed, 194 insertions(+), 163 deletions(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index d3c4ab249e9c275..7bdb32c41985dc5 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -24,6 +24,9 @@ config KEXEC_ELF
config HAVE_IMA_KEXEC
bool

+config ARCH_WANT_RESERVE_CRASH_KERNEL
+ bool
+
config SET_FS
bool

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5c2ccb85f2efb86..bd78ed8193079b9 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -12,6 +12,7 @@ config X86_32
depends on !64BIT
# Options that are inherently 32-bit kernel only:
select ARCH_WANT_IPC_PARSE_VERSION
+ select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
select CLKSRC_I8253
select CLONE_BACKWARDS
select GENERIC_VDSO_32
@@ -28,6 +29,7 @@ config X86_64
select ARCH_HAS_GIGANTIC_PAGE
select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
select ARCH_USE_CMPXCHG_LOCKREF
+ select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
select HAVE_ARCH_SOFT_DIRTY
select MODULES_USE_ELF_RELA
select NEED_DMA_MAP_STATE
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 29fea180a6658e8..7a6c36cff8331f5 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -94,6 +94,9 @@ extern unsigned int vdso32_enabled;

#define elf_check_arch(x) elf_check_arch_ia32(x)

+/* We can also handle crash dumps from 64 bit kernel. */
+# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
+
/* SVR4/i386 ABI (pages 3-31, 3-32) says that when the program starts %edx
contains a pointer to a function which might be registered using `atexit'.
This provides a mean for the dynamic linker to call DT_FINI functions for
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 3a22e65262aa70b..3ff38a1353a2b86 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>
@@ -51,9 +72,6 @@ struct kimage;

/* The native architecture */
# define KEXEC_ARCH KEXEC_ARCH_386
-
-/* We can also handle crash dumps from 64 bit kernel. */
-# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
#else
/* Maximum physical address we can use pages from */
# define KEXEC_SOURCE_MEMORY_LIMIT (MAXMEM-1)
@@ -195,6 +213,10 @@ 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 7ae00716a208f82..5519baa7f4b964e 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -39,6 +39,7 @@
#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>
@@ -386,147 +387,7 @@ 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, SZ_1M, 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_phys_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 de62a722431e7db..f6b99da4ed08ecf 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -73,6 +73,9 @@ 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;
+
Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
void *data, size_t data_len);
void final_note(Elf_Word *buf);
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 0c994ae37729e1e..cd744d962f6f417 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -352,8 +352,6 @@ 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 eb53f5ec62c900f..b23cfc0ca8905fd 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -8,6 +8,12 @@
#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>
@@ -22,6 +28,22 @@ 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
*
@@ -295,6 +317,140 @@ int __init parse_crashkernel_low(char *cmdline,
"crashkernel=", suffix_tbl[SUFFIX_LOW]);
}

+/*
+ * --------- Crashkernel reservation ------------------------------
+ */
+
+#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
+static int __init reserve_crashkernel_low(void)
+{
+#ifdef CONFIG_64BIT
+ 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, SZ_1M, 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_phys_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_ARCH_WANT_RESERVE_CRASH_KERNEL */
+
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 5a5d192a89ac307..1e0d4909bbb6b77 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -54,23 +54,6 @@ 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)
{
/*
--
2.25.1