| Message ID | 20180711074203.3019-12-takahiro.akashi@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Akashi, On 11/07/18 08:41, AKASHI Takahiro wrote: > Enabling crash dump (kdump) includes > * prepare contents of ELF header of a core dump file, /proc/vmcore, > using crash_prepare_elf64_headers(), and > * add two device tree properties, "linux,usable-memory-range" and > "linux,elfcorehdr", which represent respectively a memory range > to be used by crash dump kernel and the header's location > diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h > index 69333694e3e2..eeb5766928b0 100644 > --- a/arch/arm64/include/asm/kexec.h > +++ b/arch/arm64/include/asm/kexec.h > @@ -99,6 +99,10 @@ static inline void crash_post_resume(void) {} > struct kimage_arch { > phys_addr_t dtb_mem; > void *dtb_buf; > + /* Core ELF header buffer */ > + void *elf_headers; Shouldn't this be a phys_addr_t if it comes from kbuf.mem? (dtb_mem is, and they type tells us which way round the runtime/kexec-time pointers are) > + unsigned long elf_headers_sz; > + unsigned long elf_load_addr; > }; > > /** > diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c > index a0b44fe18b95..261564df7210 100644 > --- a/arch/arm64/kernel/machine_kexec_file.c > +++ b/arch/arm64/kernel/machine_kexec_file.c > @@ -132,6 +173,45 @@ static int setup_dtb(struct kimage *image, > return ret; > } > > +static int prepare_elf_headers(void **addr, unsigned long *sz) > +{ > + struct crash_mem *cmem; > + unsigned int nr_ranges; > + int ret; > + u64 i; > + phys_addr_t start, end; > + nr_ranges = 1; /* for exclusion of crashkernel region */ > + for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE, 0, > + &start, &end, NULL) Nit: flags = MEMBLOCK_NONE? Just to make it obvious this is how MEMBLOCK_NOMAP regions are weeded out. This is going to get interesting if we ever support hotpluggable memory... but it works for now and implicitly removes the nomap regions. > + nr_ranges++; > + > + cmem = kmalloc(sizeof(struct crash_mem) + > + sizeof(struct crash_mem_range) * nr_ranges, GFP_KERNEL); > + if (!cmem) > + return -ENOMEM; > + > + cmem->max_nr_ranges = nr_ranges; > + cmem->nr_ranges = 0; > + for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE, 0, > + &start, &end, NULL) { > + cmem->ranges[cmem->nr_ranges].start = start; > + cmem->ranges[cmem->nr_ranges].end = end - 1; > + cmem->nr_ranges++; > + } > + > + /* Exclude crashkernel region */ > + ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); > + if (ret) > + goto out; > + > + ret = crash_prepare_elf64_headers(cmem, true, addr, sz); > + > +out: Nit: You could save the goto if you wrote this as: | if (!ret) | ret = crash_prepare_elf64_headers(cmem, true, addr, sz); > + kfree(cmem); > + return ret; > +} > + > int load_other_segments(struct kimage *image, > unsigned long kernel_load_addr, > unsigned long kernel_size, > @@ -139,11 +219,43 @@ int load_other_segments(struct kimage *image, > char *cmdline, unsigned long cmdline_len) > { > struct kexec_buf kbuf; > + void *hdrs_addr; > + unsigned long hdrs_sz; > unsigned long initrd_load_addr = 0; > char *dtb = NULL; > unsigned long dtb_len = 0; > int ret = 0; > > + /* load elf core header */ > + if (image->type == KEXEC_TYPE_CRASH) { > + ret = prepare_elf_headers(&hdrs_addr, &hdrs_sz); > + if (ret) { > + pr_err("Preparing elf core header failed\n"); > + goto out_err; > + } > + > + kbuf.image = image; > + kbuf.buffer = hdrs_addr; > + kbuf.bufsz = hdrs_sz; > + kbuf.memsz = hdrs_sz; > + kbuf.buf_align = PAGE_SIZE; Whose PAGE_SIZE? Won't this break if the kdump kernel is 64K pages, but the first kernel uses 4K? Should we change this to the largest supported PAGE_SIZE: SZ_64K? > + kbuf.buf_min = crashk_res.start; > + kbuf.buf_max = crashk_res.end + 1; > + kbuf.top_down = true; > + > + ret = kexec_add_buffer(&kbuf); > + if (ret) { > + vfree(hdrs_addr); > + goto out_err; > + } > + image->arch.elf_headers = hdrs_addr; > + image->arch.elf_headers_sz = hdrs_sz; > + image->arch.elf_load_addr = kbuf.mem; > + > + pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n", > + image->arch.elf_load_addr, hdrs_sz, hdrs_sz); > + } > + > kbuf.image = image; > /* not allocate anything below the kernel */ > kbuf.buf_min = kernel_load_addr + kernel_size; I think the initramfs can escape the crash kernel range because you add to the buf_max region: | /* within 1GB-aligned window of up to 32GB in size */ | kbuf.buf_max = round_down(kernel_load_addr, SZ_1G) | + (unsigned long)SZ_1G * 32; I think we need a helper to clamp these min/max ranges to within the crash kernel range, as its needs doing in a few places. Thanks, James
Hi James, On Wed, Jul 18, 2018 at 05:50:22PM +0100, James Morse wrote: > Hi Akashi, > > On 11/07/18 08:41, AKASHI Takahiro wrote: > > Enabling crash dump (kdump) includes > > * prepare contents of ELF header of a core dump file, /proc/vmcore, > > using crash_prepare_elf64_headers(), and > > * add two device tree properties, "linux,usable-memory-range" and > > "linux,elfcorehdr", which represent respectively a memory range > > to be used by crash dump kernel and the header's location > > > diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h > > index 69333694e3e2..eeb5766928b0 100644 > > --- a/arch/arm64/include/asm/kexec.h > > +++ b/arch/arm64/include/asm/kexec.h > > @@ -99,6 +99,10 @@ static inline void crash_post_resume(void) {} > > struct kimage_arch { > > phys_addr_t dtb_mem; > > void *dtb_buf; > > + /* Core ELF header buffer */ > > > + void *elf_headers; > > Shouldn't this be a phys_addr_t if it comes from kbuf.mem? Do you mean elf_load_addr? You're right. But kexec_buf defined mem as unsigned long and so I'd rather change dtb_mem to unsigned long instead of elf_load_addr, which will also be renamed to elf_headers_mem for clarification. > (dtb_mem is, and they type tells us which way round the runtime/kexec-time > pointers are) > > > > + unsigned long elf_headers_sz; > > + unsigned long elf_load_addr; > > }; > > > > /** > > > > diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c > > index a0b44fe18b95..261564df7210 100644 > > --- a/arch/arm64/kernel/machine_kexec_file.c > > +++ b/arch/arm64/kernel/machine_kexec_file.c > > @@ -132,6 +173,45 @@ static int setup_dtb(struct kimage *image, > > return ret; > > } > > > > +static int prepare_elf_headers(void **addr, unsigned long *sz) > > +{ > > + struct crash_mem *cmem; > > + unsigned int nr_ranges; > > + int ret; > > + u64 i; > > + phys_addr_t start, end; > > > + nr_ranges = 1; /* for exclusion of crashkernel region */ > > + for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE, 0, > > + &start, &end, NULL) > > Nit: flags = MEMBLOCK_NONE? Just to make it obvious this is how MEMBLOCK_NOMAP > regions are weeded out. OK. > This is going to get interesting if we ever support hotpluggable memory... but > it works for now and implicitly removes the nomap regions. > > > > + nr_ranges++; > > > + > > + cmem = kmalloc(sizeof(struct crash_mem) + > > + sizeof(struct crash_mem_range) * nr_ranges, GFP_KERNEL); > > + if (!cmem) > > + return -ENOMEM; > > + > > + cmem->max_nr_ranges = nr_ranges; > > + cmem->nr_ranges = 0; > > + for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE, 0, > > + &start, &end, NULL) { > > + cmem->ranges[cmem->nr_ranges].start = start; > > + cmem->ranges[cmem->nr_ranges].end = end - 1; > > + cmem->nr_ranges++; > > + } > > + > > + /* Exclude crashkernel region */ > > + ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); > > > > + if (ret) > > + goto out; > > + > > + ret = crash_prepare_elf64_headers(cmem, true, addr, sz); > > + > > +out: > > Nit: You could save the goto if you wrote this as: > | if (!ret) > | ret = crash_prepare_elf64_headers(cmem, true, addr, sz); OK. > > + kfree(cmem); > > + return ret; > > +} > > + > > int load_other_segments(struct kimage *image, > > unsigned long kernel_load_addr, > > unsigned long kernel_size, > > @@ -139,11 +219,43 @@ int load_other_segments(struct kimage *image, > > char *cmdline, unsigned long cmdline_len) > > { > > struct kexec_buf kbuf; > > + void *hdrs_addr; > > + unsigned long hdrs_sz; > > unsigned long initrd_load_addr = 0; > > char *dtb = NULL; > > unsigned long dtb_len = 0; > > int ret = 0; > > > > + /* load elf core header */ > > + if (image->type == KEXEC_TYPE_CRASH) { > > + ret = prepare_elf_headers(&hdrs_addr, &hdrs_sz); > > + if (ret) { > > + pr_err("Preparing elf core header failed\n"); > > + goto out_err; > > + } > > + > > + kbuf.image = image; > > + kbuf.buffer = hdrs_addr; > > + kbuf.bufsz = hdrs_sz; > > + kbuf.memsz = hdrs_sz; > > > + kbuf.buf_align = PAGE_SIZE; > > Whose PAGE_SIZE? > > Won't this break if the kdump kernel is 64K pages, but the first kernel uses 4K? > Should we change this to the largest supported PAGE_SIZE: SZ_64K? Ah, yes. > > + kbuf.buf_min = crashk_res.start; > > + kbuf.buf_max = crashk_res.end + 1; > > + kbuf.top_down = true; > > + > > + ret = kexec_add_buffer(&kbuf); > > + if (ret) { > > + vfree(hdrs_addr); > > + goto out_err; > > + } > > + image->arch.elf_headers = hdrs_addr; > > + image->arch.elf_headers_sz = hdrs_sz; > > + image->arch.elf_load_addr = kbuf.mem; > > + > > + pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n", > > + image->arch.elf_load_addr, hdrs_sz, hdrs_sz); > > + } > > + > > kbuf.image = image; > > /* not allocate anything below the kernel */ > > kbuf.buf_min = kernel_load_addr + kernel_size; > > > I think the initramfs can escape the crash kernel range because you add to the > buf_max region: > | /* within 1GB-aligned window of up to 32GB in size */ > | kbuf.buf_max = round_down(kernel_load_addr, SZ_1G) > | + (unsigned long)SZ_1G * 32; No worries. kexec_add_buffer() will limit the search only within crashk_res anyway. On the other hand, the code: > > + if (image->type == KEXEC_TYPE_CRASH) { (snip) > > + kbuf.buf_min = crashk_res.start; > > + kbuf.buf_max = crashk_res.end + 1; can be misleading. I will fix it as follows: | kbuf.buf_min = kernel_load_addr + kernel_size; | kbuf.buf_max = ULONG_MAX; (and likewise, will fix image_load().) Thank you again for your valuable comments. Are you reviewing other patches in my v11? If not, I will post v12 tomorrow. -Takahiro AKASHI > > I think we need a helper to clamp these min/max ranges to within the crash > kernel range, as its needs doing in a few places. > > > Thanks, > > James
Hi Akashi, On 23/07/18 06:39, AKASHI Takahiro wrote: > On Wed, Jul 18, 2018 at 05:50:22PM +0100, James Morse wrote: >> On 11/07/18 08:41, AKASHI Takahiro wrote: >>> Enabling crash dump (kdump) includes >>> * prepare contents of ELF header of a core dump file, /proc/vmcore, >>> using crash_prepare_elf64_headers(), and >>> * add two device tree properties, "linux,usable-memory-range" and >>> "linux,elfcorehdr", which represent respectively a memory range >>> to be used by crash dump kernel and the header's location >> >>> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h >>> index 69333694e3e2..eeb5766928b0 100644 >>> --- a/arch/arm64/include/asm/kexec.h >>> +++ b/arch/arm64/include/asm/kexec.h >>> @@ -99,6 +99,10 @@ static inline void crash_post_resume(void) {} >>> struct kimage_arch { >>> phys_addr_t dtb_mem; >>> void *dtb_buf; >>> + /* Core ELF header buffer */ >> >>> + void *elf_headers; >> >> Shouldn't this be a phys_addr_t if it comes from kbuf.mem? > > Do you mean elf_load_addr? You're right. > But kexec_buf defined mem as unsigned long and so I'd rather change > dtb_mem to unsigned long instead of elf_load_addr, which will also be > renamed to elf_headers_mem for clarification. >> (dtb_mem is, and they type tells us which way round the runtime/kexec-time >> pointers are) My preference would be for physical addresses to always be phys_addr_t, but as long as we can easily spot the difference kexec-time versus runtime addresses, it will save bugs where we use the wrong one. >>> diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c >>> index a0b44fe18b95..261564df7210 100644 >>> --- a/arch/arm64/kernel/machine_kexec_file.c >>> +++ b/arch/arm64/kernel/machine_kexec_file.c >>> @@ -132,6 +173,45 @@ static int setup_dtb(struct kimage *image, >>> + kbuf.buf_min = crashk_res.start; >>> + kbuf.buf_max = crashk_res.end + 1; >>> + kbuf.top_down = true; >>> + >>> + ret = kexec_add_buffer(&kbuf); >>> + if (ret) { >>> + vfree(hdrs_addr); >>> + goto out_err; >>> + } >>> + image->arch.elf_headers = hdrs_addr; >>> + image->arch.elf_headers_sz = hdrs_sz; >>> + image->arch.elf_load_addr = kbuf.mem; >>> + >>> + pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n", >>> + image->arch.elf_load_addr, hdrs_sz, hdrs_sz); >>> + } >>> + >>> kbuf.image = image; >>> /* not allocate anything below the kernel */ >>> kbuf.buf_min = kernel_load_addr + kernel_size; >> I think the initramfs can escape the crash kernel range because you add to the >> buf_max region: >> | /* within 1GB-aligned window of up to 32GB in size */ >> | kbuf.buf_max = round_down(kernel_load_addr, SZ_1G) >> | + (unsigned long)SZ_1G * 32; > > No worries. > kexec_add_buffer() will limit the search only within crashk_res anyway. via arch_kexec_walk_mem()? Got it. But strangely the buf_min and buf_max still matter because locate_mem_hole_callback() uses them. > Are you reviewing other patches in my v11? > If not, I will post v12 tomorrow. No, (I try to batch replies to avoid that happening). I'm reading up on Secure-boot and trying to test the pe_verification stuff... Thanks, James
diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h index 69333694e3e2..eeb5766928b0 100644 --- a/arch/arm64/include/asm/kexec.h +++ b/arch/arm64/include/asm/kexec.h @@ -99,6 +99,10 @@ static inline void crash_post_resume(void) {} struct kimage_arch { phys_addr_t dtb_mem; void *dtb_buf; + /* Core ELF header buffer */ + void *elf_headers; + unsigned long elf_headers_sz; + unsigned long elf_load_addr; }; /** diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c index a47cf9bc699e..df1e341d3a28 100644 --- a/arch/arm64/kernel/kexec_image.c +++ b/arch/arm64/kernel/kexec_image.c @@ -67,8 +67,13 @@ static void *image_load(struct kimage *image, /* Load the kernel */ kbuf.image = image; - kbuf.buf_min = 0; - kbuf.buf_max = ULONG_MAX; + if (image->type == KEXEC_TYPE_CRASH) { + kbuf.buf_min = crashk_res.start; + kbuf.buf_max = crashk_res.end + 1; + } else { + kbuf.buf_min = 0; + kbuf.buf_max = ULONG_MAX; + } kbuf.top_down = false; kbuf.buffer = kernel; diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c index a0b44fe18b95..261564df7210 100644 --- a/arch/arm64/kernel/machine_kexec_file.c +++ b/arch/arm64/kernel/machine_kexec_file.c @@ -16,7 +16,9 @@ #include <linux/libfdt.h> #include <linux/memblock.h> #include <linux/of_fdt.h> +#include <linux/slab.h> #include <linux/types.h> +#include <linux/vmalloc.h> #include <asm/byteorder.h> const struct kexec_file_ops * const kexec_file_loaders[] = { @@ -29,6 +31,10 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image) vfree(image->arch.dtb_buf); image->arch.dtb_buf = NULL; + vfree(image->arch.elf_headers); + image->arch.elf_headers = NULL; + image->arch.elf_headers_sz = 0; + return kexec_image_post_load_cleanup_default(image); } @@ -38,13 +44,31 @@ static int setup_dtb(struct kimage *image, char **dtb_buf, size_t *dtb_buf_len) { char *buf = NULL; - size_t buf_size; + size_t buf_size, range_size; int nodeoffset; u64 value; int ret; + /* check ranges against root's #address-cells and #size-cells */ + if (image->type == KEXEC_TYPE_CRASH && + (!of_fdt_cells_size_fitted(image->arch.elf_load_addr, + image->arch.elf_headers_sz) || + !of_fdt_cells_size_fitted(crashk_res.start, + crashk_res.end - crashk_res.start + 1))) { + pr_err("Crash memory region doesn't fit into DT's root cell sizes.\n"); + ret = -EINVAL; + goto out_err; + } + /* duplicate dt blob */ buf_size = fdt_totalsize(initial_boot_params); + range_size = of_fdt_reg_cells_size(); + + if (image->type == KEXEC_TYPE_CRASH) { + buf_size += fdt_prop_len("linux,elfcorehdr", range_size); + buf_size += fdt_prop_len("linux,usable-memory-range", + range_size); + } if (initrd_load_addr) { /* can be redundant, but trimmed at the end */ @@ -74,6 +98,23 @@ static int setup_dtb(struct kimage *image, goto out_err; } + if (image->type == KEXEC_TYPE_CRASH) { + /* add linux,elfcorehdr */ + ret = fdt_setprop_reg(buf, nodeoffset, "linux,elfcorehdr", + image->arch.elf_load_addr, + image->arch.elf_headers_sz); + if (ret) + goto out_err; + + /* add linux,usable-memory-range */ + ret = fdt_setprop_reg(buf, nodeoffset, + "linux,usable-memory-range", + crashk_res.start, + crashk_res.end - crashk_res.start + 1); + if (ret) + goto out_err; + } + /* add bootargs */ if (cmdline) { ret = fdt_setprop_string(buf, nodeoffset, "bootargs", cmdline); @@ -132,6 +173,45 @@ static int setup_dtb(struct kimage *image, return ret; } +static int prepare_elf_headers(void **addr, unsigned long *sz) +{ + struct crash_mem *cmem; + unsigned int nr_ranges; + int ret; + u64 i; + phys_addr_t start, end; + + nr_ranges = 1; /* for exclusion of crashkernel region */ + for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE, 0, + &start, &end, NULL) + nr_ranges++; + + cmem = kmalloc(sizeof(struct crash_mem) + + sizeof(struct crash_mem_range) * nr_ranges, GFP_KERNEL); + if (!cmem) + return -ENOMEM; + + cmem->max_nr_ranges = nr_ranges; + cmem->nr_ranges = 0; + for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE, 0, + &start, &end, NULL) { + cmem->ranges[cmem->nr_ranges].start = start; + cmem->ranges[cmem->nr_ranges].end = end - 1; + cmem->nr_ranges++; + } + + /* Exclude crashkernel region */ + ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); + if (ret) + goto out; + + ret = crash_prepare_elf64_headers(cmem, true, addr, sz); + +out: + kfree(cmem); + return ret; +} + int load_other_segments(struct kimage *image, unsigned long kernel_load_addr, unsigned long kernel_size, @@ -139,11 +219,43 @@ int load_other_segments(struct kimage *image, char *cmdline, unsigned long cmdline_len) { struct kexec_buf kbuf; + void *hdrs_addr; + unsigned long hdrs_sz; unsigned long initrd_load_addr = 0; char *dtb = NULL; unsigned long dtb_len = 0; int ret = 0; + /* load elf core header */ + if (image->type == KEXEC_TYPE_CRASH) { + ret = prepare_elf_headers(&hdrs_addr, &hdrs_sz); + if (ret) { + pr_err("Preparing elf core header failed\n"); + goto out_err; + } + + kbuf.image = image; + kbuf.buffer = hdrs_addr; + kbuf.bufsz = hdrs_sz; + kbuf.memsz = hdrs_sz; + kbuf.buf_align = PAGE_SIZE; + kbuf.buf_min = crashk_res.start; + kbuf.buf_max = crashk_res.end + 1; + kbuf.top_down = true; + + ret = kexec_add_buffer(&kbuf); + if (ret) { + vfree(hdrs_addr); + goto out_err; + } + image->arch.elf_headers = hdrs_addr; + image->arch.elf_headers_sz = hdrs_sz; + image->arch.elf_load_addr = kbuf.mem; + + pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n", + image->arch.elf_load_addr, hdrs_sz, hdrs_sz); + } + kbuf.image = image; /* not allocate anything below the kernel */ kbuf.buf_min = kernel_load_addr + kernel_size;
Enabling crash dump (kdump) includes * prepare contents of ELF header of a core dump file, /proc/vmcore, using crash_prepare_elf64_headers(), and * add two device tree properties, "linux,usable-memory-range" and "linux,elfcorehdr", which represent respectively a memory range to be used by crash dump kernel and the header's location Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> --- arch/arm64/include/asm/kexec.h | 4 + arch/arm64/kernel/kexec_image.c | 9 +- arch/arm64/kernel/machine_kexec_file.c | 114 ++++++++++++++++++++++++- 3 files changed, 124 insertions(+), 3 deletions(-)