| Message ID | 20211228132612.1860-12-thunder.leizhen@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | support reserving crashkernel above 4G on arm64 kdump | expand |
On 12/28/21 7:26AM, Zhen Lei wrote: > From: Chen Zhou <chenzhou10@huawei.com> > > There are following issues in arm64 kdump: > 1. We use crashkernel=X to reserve crashkernel below 4G, which > will fail when there is no enough low memory. > 2. If reserving crashkernel above 4G, in this case, crash dump > kernel will boot failure because there is no low memory available > for allocation. > > To solve these issues, change the behavior of crashkernel=X and > introduce crashkernel=X,[high,low]. crashkernel=X tries low allocation > in DMA zone, and fall back to high allocation if it fails. > We can also use "crashkernel=X,high" to select a region above DMA zone, > which also tries to allocate at least 256M in DMA zone automatically. > "crashkernel=Y,low" can be used to allocate specified size low memory. > > Another minor change, there may be two regions reserved for crash > dump kernel, in order to distinct from the high region and make no > effect to the use of existing kexec-tools, rename the low region as > "Crash kernel (low)". > > Signed-off-by: Chen Zhou <chenzhou10@huawei.com> > Co-developed-by: Zhen Lei <thunder.leizhen@huawei.com> > Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> > --- > arch/arm64/kernel/machine_kexec.c | 5 +++- > arch/arm64/kernel/machine_kexec_file.c | 12 ++++++-- > arch/arm64/kernel/setup.c | 13 +++++++- > arch/arm64/mm/init.c | 41 ++++++++++---------------- > 4 files changed, 42 insertions(+), 29 deletions(-) > > diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c > index 6fb31c117ebe08c..6665bf31f6b6a19 100644 > --- a/arch/arm64/kernel/machine_kexec.c > +++ b/arch/arm64/kernel/machine_kexec.c > @@ -327,7 +327,10 @@ bool crash_is_nosave(unsigned long pfn) > > /* in reserved memory? */ > addr = __pfn_to_phys(pfn); > - if ((addr < crashk_res.start) || (crashk_res.end < addr)) > + if (((addr < crashk_res.start) || (crashk_res.end < addr)) && !crashk_low_res.end) > + return false; > + > + if ((addr < crashk_low_res.start) || (crashk_low_res.end < addr)) > return false; > > if (!kexec_crash_image) > diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c > index 59c648d51848886..889951291cc0f9c 100644 > --- a/arch/arm64/kernel/machine_kexec_file.c > +++ b/arch/arm64/kernel/machine_kexec_file.c > @@ -65,10 +65,18 @@ static int prepare_elf_headers(void **addr, unsigned long *sz) > > /* Exclude crashkernel region */ > ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); > + if (ret) > + goto out; > + > + if (crashk_low_res.end) { > + ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end); > + if (ret) > + goto out; > + } > > - if (!ret) > - ret = crash_prepare_elf64_headers(cmem, true, addr, sz); > + ret = crash_prepare_elf64_headers(cmem, true, addr, sz); > > +out: > kfree(cmem); > return ret; > } > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c > index be5f85b0a24de69..4bb2e55366be64d 100644 > --- a/arch/arm64/kernel/setup.c > +++ b/arch/arm64/kernel/setup.c > @@ -248,7 +248,18 @@ static void __init request_standard_resources(void) > kernel_data.end <= res->end) > request_resource(res, &kernel_data); > #ifdef CONFIG_KEXEC_CORE > - /* Userspace will find "Crash kernel" region in /proc/iomem. */ > + /* > + * Userspace will find "Crash kernel" or "Crash kernel (low)" > + * region in /proc/iomem. > + * In order to distinct from the high region and make no effect > + * to the use of existing kexec-tools, rename the low region as > + * "Crash kernel (low)". > + */ > + if (crashk_low_res.end && crashk_low_res.start >= res->start && > + crashk_low_res.end <= res->end) { > + crashk_low_res.name = "Crash kernel (low)"; > + request_resource(res, &crashk_low_res); > + } > if (crashk_res.end && crashk_res.start >= res->start && > crashk_res.end <= res->end) > request_resource(res, &crashk_res); > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index be4595dc7459115..91b8038a1529068 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -74,41 +74,32 @@ phys_addr_t arm64_dma_phys_limit __ro_after_init; > */ > static void __init reserve_crashkernel(void) > { > - unsigned long long crash_base, crash_size; > - unsigned long long crash_max = CRASH_ADDR_LOW_MAX; > + unsigned long long crash_size, crash_base, total_mem, low_size; low_size needs to be initialized to -1. If parse_crashkernel() succeeds, then an uninitialized low_size will be passed to reserve_crashkernel_mem(). > + bool high = false; > int ret; > > - ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(), > - &crash_size, &crash_base); > - /* no crashkernel= or invalid value specified */ > - if (ret || !crash_size) > - return; > - > - crash_size = PAGE_ALIGN(crash_size); > - > - /* User specifies base address explicitly. */ > - if (crash_base) > - crash_max = crash_base + crash_size; > + total_mem = memblock_phys_mem_size(); > > - /* Current arm64 boot protocol requires 2MB alignment */ > - crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, > - crash_base, crash_max); > - if (!crash_base) { > - pr_warn("cannot allocate crashkernel (size:0x%llx)\n", > - crash_size); > - return; > + ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base); > + if (ret != 0 || crash_size <= 0) { > + /* crashkernel=X,high and possible crashkernel=Y,low */ > + ret = parse_crashkernel_high_low(boot_command_line, &crash_size, &low_size); > + if (ret) > + return; > + high = true; > } > > - pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n", > - crash_base, crash_base + crash_size, crash_size >> 20); > + ret = reserve_crashkernel_mem(total_mem, crash_size, crash_base, low_size, high); > + if (ret) > + return; > > /* > * The crashkernel memory will be removed from the kernel linear > * map. Inform kmemleak so that it won't try to access it. > */ > - kmemleak_ignore_phys(crash_base); > - crashk_res.start = crash_base; > - crashk_res.end = crash_base + crash_size - 1; > + kmemleak_ignore_phys(crashk_res.start); > + if (crashk_low_res.end) > + kmemleak_ignore_phys(crashk_low_res.start); > } > #else > static void __init reserve_crashkernel(void)
On 2022/1/12 22:45, Dave Kleikamp wrote: > On 12/28/21 7:26AM, Zhen Lei wrote: >> From: Chen Zhou <chenzhou10@huawei.com> >> >> There are following issues in arm64 kdump: >> 1. We use crashkernel=X to reserve crashkernel below 4G, which >> will fail when there is no enough low memory. >> 2. If reserving crashkernel above 4G, in this case, crash dump >> kernel will boot failure because there is no low memory available >> for allocation. >> >> To solve these issues, change the behavior of crashkernel=X and >> introduce crashkernel=X,[high,low]. crashkernel=X tries low allocation >> in DMA zone, and fall back to high allocation if it fails. >> We can also use "crashkernel=X,high" to select a region above DMA zone, >> which also tries to allocate at least 256M in DMA zone automatically. >> "crashkernel=Y,low" can be used to allocate specified size low memory. >> >> Another minor change, there may be two regions reserved for crash >> dump kernel, in order to distinct from the high region and make no >> effect to the use of existing kexec-tools, rename the low region as >> "Crash kernel (low)". >> >> Signed-off-by: Chen Zhou <chenzhou10@huawei.com> >> Co-developed-by: Zhen Lei <thunder.leizhen@huawei.com> >> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> >> --- >> arch/arm64/kernel/machine_kexec.c | 5 +++- >> arch/arm64/kernel/machine_kexec_file.c | 12 ++++++-- >> arch/arm64/kernel/setup.c | 13 +++++++- >> arch/arm64/mm/init.c | 41 ++++++++++---------------- >> 4 files changed, 42 insertions(+), 29 deletions(-) >> >> diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c >> index 6fb31c117ebe08c..6665bf31f6b6a19 100644 >> --- a/arch/arm64/kernel/machine_kexec.c >> +++ b/arch/arm64/kernel/machine_kexec.c >> @@ -327,7 +327,10 @@ bool crash_is_nosave(unsigned long pfn) >> /* in reserved memory? */ >> addr = __pfn_to_phys(pfn); >> - if ((addr < crashk_res.start) || (crashk_res.end < addr)) >> + if (((addr < crashk_res.start) || (crashk_res.end < addr)) && !crashk_low_res.end) >> + return false; >> + >> + if ((addr < crashk_low_res.start) || (crashk_low_res.end < addr)) >> return false; >> if (!kexec_crash_image) >> diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c >> index 59c648d51848886..889951291cc0f9c 100644 >> --- a/arch/arm64/kernel/machine_kexec_file.c >> +++ b/arch/arm64/kernel/machine_kexec_file.c >> @@ -65,10 +65,18 @@ static int prepare_elf_headers(void **addr, unsigned long *sz) >> /* Exclude crashkernel region */ >> ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); >> + if (ret) >> + goto out; >> + >> + if (crashk_low_res.end) { >> + ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end); >> + if (ret) >> + goto out; >> + } >> - if (!ret) >> - ret = crash_prepare_elf64_headers(cmem, true, addr, sz); >> + ret = crash_prepare_elf64_headers(cmem, true, addr, sz); >> +out: >> kfree(cmem); >> return ret; >> } >> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c >> index be5f85b0a24de69..4bb2e55366be64d 100644 >> --- a/arch/arm64/kernel/setup.c >> +++ b/arch/arm64/kernel/setup.c >> @@ -248,7 +248,18 @@ static void __init request_standard_resources(void) >> kernel_data.end <= res->end) >> request_resource(res, &kernel_data); >> #ifdef CONFIG_KEXEC_CORE >> - /* Userspace will find "Crash kernel" region in /proc/iomem. */ >> + /* >> + * Userspace will find "Crash kernel" or "Crash kernel (low)" >> + * region in /proc/iomem. >> + * In order to distinct from the high region and make no effect >> + * to the use of existing kexec-tools, rename the low region as >> + * "Crash kernel (low)". >> + */ >> + if (crashk_low_res.end && crashk_low_res.start >= res->start && >> + crashk_low_res.end <= res->end) { >> + crashk_low_res.name = "Crash kernel (low)"; >> + request_resource(res, &crashk_low_res); >> + } >> if (crashk_res.end && crashk_res.start >= res->start && >> crashk_res.end <= res->end) >> request_resource(res, &crashk_res); >> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c >> index be4595dc7459115..91b8038a1529068 100644 >> --- a/arch/arm64/mm/init.c >> +++ b/arch/arm64/mm/init.c >> @@ -74,41 +74,32 @@ phys_addr_t arm64_dma_phys_limit __ro_after_init; >> */ >> static void __init reserve_crashkernel(void) >> { >> - unsigned long long crash_base, crash_size; >> - unsigned long long crash_max = CRASH_ADDR_LOW_MAX; >> + unsigned long long crash_size, crash_base, total_mem, low_size; > > low_size needs to be initialized to -1. > > If parse_crashkernel() succeeds, then an uninitialized low_size will be passed to reserve_crashkernel_mem(). Right, thanks, I noticed that too. I'm waiting for v5.17-rc1 to release v20. In addition, I found that the current implementation on x86 was problematic in case "crashkernel=4G crashkernel=512M,low". According to the document, "crashkernel=512M,low" should not take effect at this case. But reserve_crashkernel_low() didn't do that well. > >> + bool high = false; >> int ret; >> - ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(), >> - &crash_size, &crash_base); >> - /* no crashkernel= or invalid value specified */ >> - if (ret || !crash_size) >> - return; >> - >> - crash_size = PAGE_ALIGN(crash_size); >> - >> - /* User specifies base address explicitly. */ >> - if (crash_base) >> - crash_max = crash_base + crash_size; >> + total_mem = memblock_phys_mem_size(); >> - /* Current arm64 boot protocol requires 2MB alignment */ >> - crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, >> - crash_base, crash_max); >> - if (!crash_base) { >> - pr_warn("cannot allocate crashkernel (size:0x%llx)\n", >> - crash_size); >> - return; >> + ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base); >> + if (ret != 0 || crash_size <= 0) { >> + /* crashkernel=X,high and possible crashkernel=Y,low */ >> + ret = parse_crashkernel_high_low(boot_command_line, &crash_size, &low_size); >> + if (ret) >> + return; >> + high = true; >> } >> - pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n", >> - crash_base, crash_base + crash_size, crash_size >> 20); >> + ret = reserve_crashkernel_mem(total_mem, crash_size, crash_base, low_size, high); >> + if (ret) >> + return; >> /* >> * The crashkernel memory will be removed from the kernel linear >> * map. Inform kmemleak so that it won't try to access it. >> */ >> - kmemleak_ignore_phys(crash_base); >> - crashk_res.start = crash_base; >> - crashk_res.end = crash_base + crash_size - 1; >> + kmemleak_ignore_phys(crashk_res.start); >> + if (crashk_low_res.end) >> + kmemleak_ignore_phys(crashk_low_res.start); >> } >> #else >> static void __init reserve_crashkernel(void) > > . >
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c index 6fb31c117ebe08c..6665bf31f6b6a19 100644 --- a/arch/arm64/kernel/machine_kexec.c +++ b/arch/arm64/kernel/machine_kexec.c @@ -327,7 +327,10 @@ bool crash_is_nosave(unsigned long pfn) /* in reserved memory? */ addr = __pfn_to_phys(pfn); - if ((addr < crashk_res.start) || (crashk_res.end < addr)) + if (((addr < crashk_res.start) || (crashk_res.end < addr)) && !crashk_low_res.end) + return false; + + if ((addr < crashk_low_res.start) || (crashk_low_res.end < addr)) return false; if (!kexec_crash_image) diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c index 59c648d51848886..889951291cc0f9c 100644 --- a/arch/arm64/kernel/machine_kexec_file.c +++ b/arch/arm64/kernel/machine_kexec_file.c @@ -65,10 +65,18 @@ static int prepare_elf_headers(void **addr, unsigned long *sz) /* Exclude crashkernel region */ ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); + if (ret) + goto out; + + if (crashk_low_res.end) { + ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end); + if (ret) + goto out; + } - if (!ret) - ret = crash_prepare_elf64_headers(cmem, true, addr, sz); + ret = crash_prepare_elf64_headers(cmem, true, addr, sz); +out: kfree(cmem); return ret; } diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index be5f85b0a24de69..4bb2e55366be64d 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -248,7 +248,18 @@ static void __init request_standard_resources(void) kernel_data.end <= res->end) request_resource(res, &kernel_data); #ifdef CONFIG_KEXEC_CORE - /* Userspace will find "Crash kernel" region in /proc/iomem. */ + /* + * Userspace will find "Crash kernel" or "Crash kernel (low)" + * region in /proc/iomem. + * In order to distinct from the high region and make no effect + * to the use of existing kexec-tools, rename the low region as + * "Crash kernel (low)". + */ + if (crashk_low_res.end && crashk_low_res.start >= res->start && + crashk_low_res.end <= res->end) { + crashk_low_res.name = "Crash kernel (low)"; + request_resource(res, &crashk_low_res); + } if (crashk_res.end && crashk_res.start >= res->start && crashk_res.end <= res->end) request_resource(res, &crashk_res); diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index be4595dc7459115..91b8038a1529068 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -74,41 +74,32 @@ phys_addr_t arm64_dma_phys_limit __ro_after_init; */ static void __init reserve_crashkernel(void) { - unsigned long long crash_base, crash_size; - unsigned long long crash_max = CRASH_ADDR_LOW_MAX; + unsigned long long crash_size, crash_base, total_mem, low_size; + bool high = false; int ret; - ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(), - &crash_size, &crash_base); - /* no crashkernel= or invalid value specified */ - if (ret || !crash_size) - return; - - crash_size = PAGE_ALIGN(crash_size); - - /* User specifies base address explicitly. */ - if (crash_base) - crash_max = crash_base + crash_size; + total_mem = memblock_phys_mem_size(); - /* Current arm64 boot protocol requires 2MB alignment */ - crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, - crash_base, crash_max); - if (!crash_base) { - pr_warn("cannot allocate crashkernel (size:0x%llx)\n", - crash_size); - return; + ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base); + if (ret != 0 || crash_size <= 0) { + /* crashkernel=X,high and possible crashkernel=Y,low */ + ret = parse_crashkernel_high_low(boot_command_line, &crash_size, &low_size); + if (ret) + return; + high = true; } - pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n", - crash_base, crash_base + crash_size, crash_size >> 20); + ret = reserve_crashkernel_mem(total_mem, crash_size, crash_base, low_size, high); + if (ret) + return; /* * The crashkernel memory will be removed from the kernel linear * map. Inform kmemleak so that it won't try to access it. */ - kmemleak_ignore_phys(crash_base); - crashk_res.start = crash_base; - crashk_res.end = crash_base + crash_size - 1; + kmemleak_ignore_phys(crashk_res.start); + if (crashk_low_res.end) + kmemleak_ignore_phys(crashk_low_res.start); } #else static void __init reserve_crashkernel(void)