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Message-ID: <Yw7MhU957+cPQ50/@MiWiFi-R3L-srv>
Date: Wed, 31 Aug 2022 10:50:45 +0800
From: Baoquan He <bhe@...hat.com>
To: Eric DeVolder <eric.devolder@...cle.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 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>
> ---
> 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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