On Mon, Jun 20, 2016 at 11:02:22AM +0530, Pratyush Anand wrote: > +Atsushi > > Hi Takahiro, > > On 16/06/2016:11:48:28 PM, Geoff Levand wrote: > > From: AKASHI Takahiro <takahiro.akashi at linaro.org> > > > > For the current crash utility, we need to know, at least, > > - kimage_voffset > > - PHYS_OFFSET > > to handle the contents of core dump file (/proc/vmcore) correctly due to > > the introduction of KASLR (CONFIG_RANDOMIZE_BASE) in v4.6. > > This patch puts them as VMCOREINFO's into the file. > > > > - VA_BITS > > is also added for makedumpfile command. > > Thanks for adding them. They are quite helpful for makedumpfile as well. > > > More VMCOREINFO's may be added later. > > Yes, we will need to pass VMCOREINFO_SYMBOL(_text) and VMCOREINFO_SYMBOL(_end) > in order to work with makedumpfile. I know that adding those symbols is the easiest way, but theoretically, if we know the physical address of "swapper_pg_dir", instead of its virtual address, we can access all the memory pointed to by any kernel virtual address. How do you rationalize that we need to know "_text" and "_end"? Thanks, -Takahiro AKASHI > I already have makedumpfile patches [1] which uses _text and _end, but not > sending them to makedumpfile upstream, until you will be agreeing to take [2] in > future. Please let me know your opinion about it. If it would be acceptable then > I may send aarch64 makedumpfile improvements to upstream. > > [1] https://github.com/pratyushanand/makedumpfile/commit/d9590fec049976b8fee0d6b4e66e6f3e99ff1113 > [2] https://github.com/pratyushanand/linux/commit/1d94df20c575c725910c9c29a129b9f14e7e900b > > ~Pratyush > > > > > Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org> > > --- > > arch/arm64/kernel/machine_kexec.c | 11 +++++++++++ > > 1 file changed, 11 insertions(+) > > > > diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c > > index f270967..57a30fb 100644 > > --- a/arch/arm64/kernel/machine_kexec.c > > +++ b/arch/arm64/kernel/machine_kexec.c > > @@ -18,6 +18,7 @@ > > > > #include <asm/cacheflush.h> > > #include <asm/cpu_ops.h> > > +#include <asm/memory.h> > > #include <asm/mmu_context.h> > > > > #include "cpu-reset.h" > > @@ -278,3 +279,13 @@ void machine_crash_shutdown(struct pt_regs *regs) > > > > pr_info("Starting crashdump kernel...\n"); > > } > > + > > +void arch_crash_save_vmcoreinfo(void) > > +{ > > + VMCOREINFO_NUMBER(VA_BITS); > > + /* Please note VMCOREINFO_NUMBER() uses "%d", not "%x" */ > > + vmcoreinfo_append_str("NUMBER(kimage_voffset)=0x%llx\n", > > + kimage_voffset); > > + vmcoreinfo_append_str("NUMBER(PHYS_OFFSET)=0x%llx\n", > > + PHYS_OFFSET); > > +} > > -- > > 2.5.0 > > > > > > > > _______________________________________________ > > linux-arm-kernel mailing list > > linux-arm-kernel at lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
