Messages in this thread | | | Date | Mon, 13 Dec 2021 08:30:06 -0600 | Subject | Re: [PATCH v17 05/10] x86: kdump: move reserve_crashkernel[_low]() into crash_core.c | From | john.p.donnelly@oracle ... |
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On 12/10/21 12:55 AM, Zhen Lei wrote: > 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>
Acked-by: John Donnelly <john.p.donnelly@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) > { > /*
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