Messages in this thread | | | Date | Tue, 6 May 2014 13:15:58 +0100 | From | Will Deacon <> | Subject | Re: [RESEND PATCH] ARM: kdump: Add vmcore_elf64_check_arch |
| |
On Sat, May 03, 2014 at 02:44:46PM +0100, Liu Hua wrote: > Hi Will or Russell,
Hello,
> With CONFIG_LPAE=y, memory in 32-bit ARM systems can exceed > 4G. So if we use kdump in such systems. The capture kernel > should parse 64-bit elf header(parse_crash_elf64_headers). > > And this process can not pass because ARM linux only provides > zero vmcore_elf64_check_arch function by commit 4b3bf7aef. > > This patch adds check functions related to elf64 header.
[...]
> diff --git a/arch/arm/kernel/elf.c b/arch/arm/kernel/elf.c > index d0d1e83..452086a 100644 > --- a/arch/arm/kernel/elf.c > +++ b/arch/arm/kernel/elf.c > @@ -38,6 +38,39 @@ int elf_check_arch(const struct elf32_hdr *x) > } > EXPORT_SYMBOL(elf_check_arch); > > +int elf_check_arch_64(const struct elf64_hdr *x) > +{ > + unsigned int eflags; > + > + /* Make sure it's an ARM executable */ > + if (x->e_machine != EM_ARM) > + return 0; > + > + /* Make sure the entry address is reasonable */ > + if (x->e_entry & 1) { > + if (!(elf_hwcap & HWCAP_THUMB)) > + return 0; > + } else if (x->e_entry & 3) > + return 0; > + > + eflags = x->e_flags; > + if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN) { > + unsigned int flt_fmt; > + > + /* APCS26 is only allowed if the CPU supports it */ > + if ((eflags & EF_ARM_APCS_26) && !(elf_hwcap & HWCAP_26BIT)) > + return 0; > + > + flt_fmt = eflags & (EF_ARM_VFP_FLOAT | EF_ARM_SOFT_FLOAT); > + > + /* VFP requires the supporting code */ > + if (flt_fmt == EF_ARM_VFP_FLOAT && !(elf_hwcap & HWCAP_VFP)) > + return 0; > + } > + return 1; > +} > +EXPORT_SYMBOL(elf_check_arch_64);
This function looks identical to elf_check_arch. Why do we need to duplicate that code? You could use some pre-processor magic to make the core part of the functions agnostic to header type.
In fact, if elf_check_arch could handle both header types then the generic definition of vmcore_elf64_check_arch in include/linux/crash_dump.h would work out of the box.
Will
| |