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Message-ID: <943d7b14-4278-0259-cc20-c9c72b7ab085@oracle.com>
Date: Wed, 31 Aug 2022 12:20:09 -0500
From: Eric DeVolder <eric.devolder@...cle.com>
To: Baoquan He <bhe@...hat.com>
Cc: linux-kernel@...r.kernel.org, x86@...nel.org,
kexec@...ts.infradead.org, ebiederm@...ssion.com,
dyoung@...hat.com, vgoyal@...hat.com, tglx@...utronix.de,
mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com,
hpa@...or.com, nramas@...ux.microsoft.com, thomas.lendacky@....com,
robh@...nel.org, efault@....de, rppt@...nel.org, david@...hat.com,
sourabhjain@...ux.ibm.com, konrad.wilk@...cle.com,
boris.ostrovsky@...cle.com
Subject: Re: [PATCH v11 1/7] crash: move crash_prepare_elf64_headers
On 8/30/22 21:50, Baoquan He wrote:
> On 08/26/22 at 01:36pm, Eric DeVolder wrote:
>> At the outcome of this patch set, the crash_prepare_elf64_headers()
>> is utilized on both the kexec_file_load and kexec_load paths. As
>> such, need to move this function out of kexec_file.c and into a
>> common location crash_core.c.
>>
>> No functionality change.
>>
>> Signed-off-by: Eric DeVolder <eric.devolder@...cle.com>
>
> LGTM,
>
> Baoquan He <bhe@...hat.com>
Thank you! I'll record that as Acked-by, unless you tell me otherwise.
eric
>
>> ---
>> kernel/crash_core.c | 100 ++++++++++++++++++++++++++++++++++++++++++++
>> kernel/kexec_file.c | 99 -------------------------------------------
>> 2 files changed, 100 insertions(+), 99 deletions(-)
>>
>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
>> index 07b26df453a9..8c8c82386e8d 100644
>> --- a/kernel/crash_core.c
>> +++ b/kernel/crash_core.c
>> @@ -10,6 +10,7 @@
>> #include <linux/utsname.h>
>> #include <linux/vmalloc.h>
>> #include <linux/sizes.h>
>> +#include <linux/kexec.h>
>>
>> #include <asm/page.h>
>> #include <asm/sections.h>
>> @@ -314,6 +315,105 @@ static int __init parse_crashkernel_dummy(char *arg)
>> }
>> early_param("crashkernel", parse_crashkernel_dummy);
>>
>> +int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
>> + void **addr, unsigned long *sz)
>> +{
>> + Elf64_Ehdr *ehdr;
>> + Elf64_Phdr *phdr;
>> + unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
>> + unsigned char *buf;
>> + unsigned int cpu, i;
>> + unsigned long long notes_addr;
>> + unsigned long mstart, mend;
>> +
>> + /* extra phdr for vmcoreinfo ELF note */
>> + nr_phdr = nr_cpus + 1;
>> + nr_phdr += mem->nr_ranges;
>> +
>> + /*
>> + * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
>> + * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
>> + * I think this is required by tools like gdb. So same physical
>> + * memory will be mapped in two ELF headers. One will contain kernel
>> + * text virtual addresses and other will have __va(physical) addresses.
>> + */
>> +
>> + nr_phdr++;
>> + elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
>> + elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
>> +
>> + buf = vzalloc(elf_sz);
>> + if (!buf)
>> + return -ENOMEM;
>> +
>> + ehdr = (Elf64_Ehdr *)buf;
>> + phdr = (Elf64_Phdr *)(ehdr + 1);
>> + memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
>> + ehdr->e_ident[EI_CLASS] = ELFCLASS64;
>> + ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
>> + ehdr->e_ident[EI_VERSION] = EV_CURRENT;
>> + ehdr->e_ident[EI_OSABI] = ELF_OSABI;
>> + memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
>> + ehdr->e_type = ET_CORE;
>> + ehdr->e_machine = ELF_ARCH;
>> + ehdr->e_version = EV_CURRENT;
>> + ehdr->e_phoff = sizeof(Elf64_Ehdr);
>> + ehdr->e_ehsize = sizeof(Elf64_Ehdr);
>> + ehdr->e_phentsize = sizeof(Elf64_Phdr);
>> +
>> + /* Prepare one phdr of type PT_NOTE for each present CPU */
>> + for_each_present_cpu(cpu) {
>> + phdr->p_type = PT_NOTE;
>> + notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
>> + phdr->p_offset = phdr->p_paddr = notes_addr;
>> + phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
>> + (ehdr->e_phnum)++;
>> + phdr++;
>> + }
>> +
>> + /* Prepare one PT_NOTE header for vmcoreinfo */
>> + phdr->p_type = PT_NOTE;
>> + phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
>> + phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
>> + (ehdr->e_phnum)++;
>> + phdr++;
>> +
>> + /* Prepare PT_LOAD type program header for kernel text region */
>> + if (need_kernel_map) {
>> + phdr->p_type = PT_LOAD;
>> + phdr->p_flags = PF_R|PF_W|PF_X;
>> + phdr->p_vaddr = (unsigned long) _text;
>> + phdr->p_filesz = phdr->p_memsz = _end - _text;
>> + phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
>> + ehdr->e_phnum++;
>> + phdr++;
>> + }
>> +
>> + /* Go through all the ranges in mem->ranges[] and prepare phdr */
>> + for (i = 0; i < mem->nr_ranges; i++) {
>> + mstart = mem->ranges[i].start;
>> + mend = mem->ranges[i].end;
>> +
>> + phdr->p_type = PT_LOAD;
>> + phdr->p_flags = PF_R|PF_W|PF_X;
>> + phdr->p_offset = mstart;
>> +
>> + phdr->p_paddr = mstart;
>> + phdr->p_vaddr = (unsigned long) __va(mstart);
>> + phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
>> + phdr->p_align = 0;
>> + ehdr->e_phnum++;
>> + pr_debug("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
>> + phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
>> + ehdr->e_phnum, phdr->p_offset);
>> + phdr++;
>> + }
>> +
>> + *addr = buf;
>> + *sz = elf_sz;
>> + return 0;
>> +}
>> +
>> Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
>> void *data, size_t data_len)
>> {
>> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
>> index 1d546dc97c50..8017eeb43036 100644
>> --- a/kernel/kexec_file.c
>> +++ b/kernel/kexec_file.c
>> @@ -1217,102 +1217,3 @@ int crash_exclude_mem_range(struct crash_mem *mem,
>> mem->nr_ranges++;
>> return 0;
>> }
>> -
>> -int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
>> - void **addr, unsigned long *sz)
>> -{
>> - Elf64_Ehdr *ehdr;
>> - Elf64_Phdr *phdr;
>> - unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
>> - unsigned char *buf;
>> - unsigned int cpu, i;
>> - unsigned long long notes_addr;
>> - unsigned long mstart, mend;
>> -
>> - /* extra phdr for vmcoreinfo ELF note */
>> - nr_phdr = nr_cpus + 1;
>> - nr_phdr += mem->nr_ranges;
>> -
>> - /*
>> - * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
>> - * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
>> - * I think this is required by tools like gdb. So same physical
>> - * memory will be mapped in two ELF headers. One will contain kernel
>> - * text virtual addresses and other will have __va(physical) addresses.
>> - */
>> -
>> - nr_phdr++;
>> - elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
>> - elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
>> -
>> - buf = vzalloc(elf_sz);
>> - if (!buf)
>> - return -ENOMEM;
>> -
>> - ehdr = (Elf64_Ehdr *)buf;
>> - phdr = (Elf64_Phdr *)(ehdr + 1);
>> - memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
>> - ehdr->e_ident[EI_CLASS] = ELFCLASS64;
>> - ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
>> - ehdr->e_ident[EI_VERSION] = EV_CURRENT;
>> - ehdr->e_ident[EI_OSABI] = ELF_OSABI;
>> - memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
>> - ehdr->e_type = ET_CORE;
>> - ehdr->e_machine = ELF_ARCH;
>> - ehdr->e_version = EV_CURRENT;
>> - ehdr->e_phoff = sizeof(Elf64_Ehdr);
>> - ehdr->e_ehsize = sizeof(Elf64_Ehdr);
>> - ehdr->e_phentsize = sizeof(Elf64_Phdr);
>> -
>> - /* Prepare one phdr of type PT_NOTE for each present CPU */
>> - for_each_present_cpu(cpu) {
>> - phdr->p_type = PT_NOTE;
>> - notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
>> - phdr->p_offset = phdr->p_paddr = notes_addr;
>> - phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
>> - (ehdr->e_phnum)++;
>> - phdr++;
>> - }
>> -
>> - /* Prepare one PT_NOTE header for vmcoreinfo */
>> - phdr->p_type = PT_NOTE;
>> - phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
>> - phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
>> - (ehdr->e_phnum)++;
>> - phdr++;
>> -
>> - /* Prepare PT_LOAD type program header for kernel text region */
>> - if (need_kernel_map) {
>> - phdr->p_type = PT_LOAD;
>> - phdr->p_flags = PF_R|PF_W|PF_X;
>> - phdr->p_vaddr = (unsigned long) _text;
>> - phdr->p_filesz = phdr->p_memsz = _end - _text;
>> - phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
>> - ehdr->e_phnum++;
>> - phdr++;
>> - }
>> -
>> - /* Go through all the ranges in mem->ranges[] and prepare phdr */
>> - for (i = 0; i < mem->nr_ranges; i++) {
>> - mstart = mem->ranges[i].start;
>> - mend = mem->ranges[i].end;
>> -
>> - phdr->p_type = PT_LOAD;
>> - phdr->p_flags = PF_R|PF_W|PF_X;
>> - phdr->p_offset = mstart;
>> -
>> - phdr->p_paddr = mstart;
>> - phdr->p_vaddr = (unsigned long) __va(mstart);
>> - phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
>> - phdr->p_align = 0;
>> - ehdr->e_phnum++;
>> - pr_debug("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
>> - phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
>> - ehdr->e_phnum, phdr->p_offset);
>> - phdr++;
>> - }
>> -
>> - *addr = buf;
>> - *sz = elf_sz;
>> - return 0;
>> -}
>> --
>> 2.31.1
>>
>
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