| Message ID | 20190507035058.63992-2-chenzhou10@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | support reserving crashkernel above 4G on arm64 kdump | expand |
Hello, On 07/05/2019 04:50, Chen Zhou wrote: > In preparation for supporting reserving crashkernel above 4G > in arm64 as x86_64 does, move reserve_crashkernel_low() into > kexec/kexec_core.c. > 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 > @@ -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 The behaviour of this #ifdef has disappeared, won't 32bit x86 now try and reserve a chunk of unnecessary 'low' memory? [...] > @@ -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); Previously reserve_crashkernel_low() was #ifdefed to do nothing if !CONFIG_X86_64, I don't see how 32bit is skipping this reservation... > } > > 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 Why 128M? Wouldn't we rather each architecture tells us its minimum alignment? > 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), SZ_8M? > + 256UL << 20); SZ_256M? > + } 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; > +} Thanks, James
Hi, On 05/07/19 at 11:50am, Chen Zhou wrote: > In preparation for supporting reserving crashkernel above 4G > in arm64 as x86_64 does, move reserve_crashkernel_low() into > kexec/kexec_core.c. Other than the comments from James, can you move the function into kernel/crash_core.c, we already have some functions moved there for sharing. Thanks Dave
Hi James, Thanks for your review. On 2019/6/6 0:29, James Morse wrote: > Hello, > > On 07/05/2019 04:50, Chen Zhou wrote: >> In preparation for supporting reserving crashkernel above 4G >> in arm64 as x86_64 does, move reserve_crashkernel_low() into >> kexec/kexec_core.c. > > >> 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 >> @@ -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 > > The behaviour of this #ifdef has disappeared, won't 32bit x86 now try and reserve a chunk > of unnecessary 'low' memory? > > [...] At present, reserve_crashkernel_low() is called only when reserving crashkernel above 4G, so i deleted this #ifdef. If we called reserve_crashkernel_low() at the beginning of reserve_crashkernel(), i need to add it back. > > >> @@ -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); > > > Previously reserve_crashkernel_low() was #ifdefed to do nothing if !CONFIG_X86_64, I don't > see how 32bit is skipping this reservation... > > >> } >> >> 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 > > Why 128M? Wouldn't we rather each architecture tells us its minimum alignment? Yeah, each architecture should tells us its minimum alignment. I added this default size to fix compiling error on some architecture which didn't define it. I will add x86_64 and arm64 restriction on reserve_crashkernel_low() and delete this define. > > >> 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), > > SZ_8M? > >> + 256UL << 20); > > SZ_256M? > There is compiling warning "warning: comparison of distinct pointer types lacks a cast" if just use SZ_8M or SZ_256M. We need cast swiotlb_size_or_default() to type int,so i kept the old as in x86_64. > >> + } 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; >> +} > > > Thanks, > > James > > . > Thanks, Chen Zhou
Hi Dave, On 2019/6/12 16:45, Dave Young wrote: > Other than the comments from James, can you move the function into > kernel/crash_core.c, we already have some functions moved there for > sharing. Sure. Thanks, Chen Zhou
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
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(-)