mips: elfinfo
Maxim Uvarov
muvarov at gmail.com
Thu Dec 16 10:33:25 EST 2010
2010/12/16 Simon Horman <horms at verge.net.au>:
> Hi Maxim,
>
> I noticed that your change "Patch adds kernel data section to final vmcore.
> This forces gdb read kernel" causes the build to break as it was applied
> after Eric's "crashdump: Move kern_vaddr_start from kexec_info into
> crash_elf_info" patch.
>
> I have it in mind to resolve this something along the lines of
> the patch below. However, I now see the following warning:
>
> kexec/arch/mips/crashdump-mips.c: In function `get_kernel_vaddr_and_size':
> kexec/arch/mips/crashdump-mips.c:81: warning: integer constant is too large for "unsigned long" type
>
> Which corresponds to this code:
>
> elf_info->kern_vaddr_start = elf_info->kern_paddr_start |
> 0xffffffff80000000UL;
>
> I am compiling for 32-bit, so at a glance that constant does
> seem to large.
>
Ah, yes this values does not fit to 32 bit UL.
> Also, if you have any tips on a cross-compiling environment for 64bit
> on a x86_32 or x86_64 host I would be most grateful.
>
I tested it with building on 32 bit host. readelf -a shows that vmcore
had memory segment according to kernel memory.
So that, gdb began to read real values instead of uninitialized.
Actually elf_info->kern_paddr_start | 0xffffffff80000000UL; is needed
only for 64 bit mips.
Because we read kernel memory ranges from /proc/vmcore and there are
values without 0xffffffff at the beginning.
But 0xfffff... are needed in case if we need access to this address from kernel.
32 bit mips kernel does not need adding 0xfffffff. But it think there
will be only warning and nothing wrong.
Maxim.
>
> diff --git a/kexec/arch/mips/crashdump-mips.c b/kexec/arch/mips/crashdump-mips.c
> index 5ea4f4f..b937ab5 100644
> --- a/kexec/arch/mips/crashdump-mips.c
> +++ b/kexec/arch/mips/crashdump-mips.c
> @@ -51,7 +51,7 @@ unsigned long long saved_max_mem;
>
> /* Read kernel physical load addr from the file returned by proc_iomem()
> * (Kernel Code) and store in kexec_info */
> -static int get_kernel_paddr(struct kexec_info *info)
> +static int get_kernel_paddr(struct crash_elf_info *elf_info)
> {
> uint64_t start;
>
> @@ -59,7 +59,7 @@ static int get_kernel_paddr(struct kexec_info *info)
> return 0;
>
> if (parse_iomem_single("Kernel code\n", &start, NULL) == 0) {
> - info->kern_paddr_start = start;
> + elf_info->kern_paddr_start = start;
> #ifdef DEBUG
> printf("kernel load physical addr start = 0x%lx\n", start);
> #endif
> @@ -70,21 +70,22 @@ static int get_kernel_paddr(struct kexec_info *info)
> return -1;
> }
>
> -static int get_kernel_vaddr_and_size(struct kexec_info *info)
> +static int get_kernel_vaddr_and_size(struct crash_elf_info *elf_info)
> {
> uint64_t end;
>
> - if (!info->kern_paddr_start)
> + if (!elf_info->kern_paddr_start)
> return -1;
>
> - info->kern_vaddr_start = info->kern_paddr_start | 0xffffffff80000000UL;
> + elf_info->kern_vaddr_start = elf_info->kern_paddr_start |
> + 0xffffffff80000000UL;
> if (parse_iomem_single("Kernel data\n", NULL, &end) == 0) {
> - info->kern_size = end - info->kern_paddr_start;
> + elf_info->kern_size = end - elf_info->kern_paddr_start;
> #ifdef DEBUG
> printf("kernel_vaddr= 0x%llx paddr %llx\n",
> - info->kern_vaddr_start,
> - info->kern_paddr_start);
> - printf("kernel size = 0x%llx\n", info->kern_size);
> + elf_info->kern_vaddr_start,
> + elf_info->kern_paddr_start);
> + printf("kernel size = 0x%llx\n", elf_info->kern_size);
> #endif
> return 0;
> }
> @@ -355,11 +356,20 @@ int load_crashdump_segments(struct kexec_info *info, char* mod_cmdline,
> unsigned long sz, elfcorehdr;
> int nr_ranges, align = 1024;
> struct memory_range *mem_range;
> + crash_create_elf_headers_func crash_create = crash_create_elf32_headers;
> + struct crash_elf_info *elf_info = &elf_info32;
>
> - if (get_kernel_paddr(info))
> +#ifdef __mips64
> + if (arch_options.core_header_type == CORE_TYPE_ELF64) {
> + elf_info = &elf_info64;
> + crash_create = crash_create_elf64;
> + }
> +#endif
> +
> + if (get_kernel_paddr(elf_info))
> return -1;
>
> - if (get_kernel_vaddr_and_size(info))
> + if (get_kernel_vaddr_and_size(elf_info))
> return -1;
>
> if (get_crash_memory_ranges(&mem_range, &nr_ranges) < 0)
> @@ -373,28 +383,9 @@ int load_crashdump_segments(struct kexec_info *info, char* mod_cmdline,
> crash_reserved_mem.start,
> crash_reserved_mem.end, -1);
>
> -#ifdef __mips64
> - /* Create elf header segment and store crash image data. */
> - if (arch_options.core_header_type == CORE_TYPE_ELF64) {
> - if (crash_create_elf64_headers(info, &elf_info64,
> - crash_memory_range, nr_ranges,
> - &tmp, &sz,
> - ELF_CORE_HEADER_ALIGN) < 0)
> - return -1;
> - } else {
> - if (crash_create_elf32_headers(info, &elf_info32,
> - crash_memory_range, nr_ranges,
> - &tmp, &sz,
> - ELF_CORE_HEADER_ALIGN) < 0)
> - return -1;
> - }
> -#else
> - if (crash_create_elf32_headers(info, &elf_info32,
> - crash_memory_range, nr_ranges,
> - &tmp, &sz,
> - ELF_CORE_HEADER_ALIGN) < 0)
> + if (crash_create(info, elf_info, crash_memory_range, nr_ranges,
> + &tmp, &sz, ELF_CORE_HEADER_ALIGN) < 0)
> return -1;
> -#endif
> elfcorehdr = add_buffer(info, tmp, sz, sz, align,
> crash_reserved_mem.start,
> crash_reserved_mem.end, -1);
> diff --git a/kexec/crashdump.h b/kexec/crashdump.h
> index eccdb9f..060bb88 100644
> --- a/kexec/crashdump.h
> +++ b/kexec/crashdump.h
> @@ -35,6 +35,13 @@ struct crash_elf_info {
> int (*get_note_info)(int cpu, uint64_t *addr, uint64_t *len);
> };
>
> +typedef int(*crash_create_elf_headers_func)(struct kexec_info *info,
> + struct crash_elf_info *elf_info,
> + struct memory_range *range,
> + int ranges,
> + void **buf, unsigned long *size,
> + unsigned long align);
> +
> int crash_create_elf32_headers(struct kexec_info *info,
> struct crash_elf_info *elf_info,
> struct memory_range *range, int ranges,
>
--
Best regards,
Maxim Uvarov
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