On 2020/11/12 16:11, Mike Rapoport wrote:
> On Sat, Oct 31, 2020 at 03:44:33PM +0800, Chen Zhou wrote:
>> Make the functions reserve_crashkernel[_low]() as generic.
>> Arm64 will use these to reimplement crashkernel=X.
>>
>> Signed-off-by: Chen Zhou <chenzhou10@xxxxxxxxxx>
>> Tested-by: John Donnelly <John.p.donnelly@xxxxxxxxxx>
>> ---
>> arch/x86/include/asm/kexec.h | 25 ++++++
>> arch/x86/kernel/setup.c | 151 +-------------------------------
>> include/linux/crash_core.h | 4 +
>> include/linux/kexec.h | 2 -
>> kernel/crash_core.c | 164 +++++++++++++++++++++++++++++++++++
>> kernel/kexec_core.c | 17 ----
>> 6 files changed, 195 insertions(+), 168 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
>> index 8cf9d3fd31c7..34afa7b645f9 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_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 1289f079ad5f..00b3840d30f9 100644
>> --- a/arch/x86/kernel/setup.c
>> +++ b/arch/x86/kernel/setup.c
>> @@ -25,8 +25,6 @@
>>
>> #include <uapi/linux/mount.h>
>>
>> -#include <xen/xen.h>
>> -
>> #include <asm/apic.h>
>> #include <asm/numa.h>
>> #include <asm/bios_ebda.h>
>> @@ -38,6 +36,7 @@
>> #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>
>> @@ -389,153 +388,7 @@ 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;
>> - 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;
>> - }
> This is relevant only to x86, maybe we could move this check to
> setup_arch before calling reserve_crashkernel() to keep it in x86?
Yes, we could move this check to setup_arch.
>
>> -
>> - /* 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;
>> - 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 206bde8308b2..5021d7c70aee 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;
>> @@ -83,5 +86,6 @@ 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..d39892bdb9ae 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 +315,149 @@ int __init parse_crashkernel_low(char *cmdline,
>> "crashkernel=", suffix_tbl[SUFFIX_LOW]);
>> }
>>
>> +/*
>> + * --------- Crashkernel reservation ------------------------------
>> + */
>> +
>> +int __init reserve_crashkernel_low(void)
> static?
Ok, i will update in next version.
>
>> +{
>> +#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;
>> + insert_resource(&iomem_resource, &crashk_low_res);
>> +#endif
>> + return 0;
>> +}
>> +
>> +#ifdef 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);
>> + 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_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;
>> + 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 8798a8183974..2ca887514145 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
>>
