On Mon, 27 Nov 2023 at 09:53, RuiRui Yang <ruyang@xxxxxxxxxx> wrote:
>
> On Sat, 25 Nov 2023 at 14:54, WANG Rui <wangrui@xxxxxxxxxxx> wrote:
> >
> > Currently, kexec loads vmlinux.efi to address 0 instead of the link
> > address. This causes kexec to fail to boot the new vmlinux.efi on qemu.
> >
> > pei_loongarch_load: kernel_segment: 0000000000000000
> > pei_loongarch_load: kernel_entry: 00000000013f1000
> > pei_loongarch_load: image_size: 0000000001ca0000
> > pei_loongarch_load: text_offset: 0000000000200000
> > pei_loongarch_load: phys_offset: 0000000000000000
> > pei_loongarch_load: PE format: yes
> > loongarch_load_other_segments:333: command_line: kexec console=ttyS0,115200
> > kexec_load: entry = 0x13f1000 flags = 0x1020000
> > nr_segments = 2
> > segment[0].buf = 0x7fffeea38010
> > segment[0].bufsz = 0x1b55200
> > segment[0].mem = (nil)
> > segment[0].memsz = 0x1ca0000
> > segment[1].buf = 0x5555570940b0
> > segment[1].bufsz = 0x200
> > segment[1].mem = 0x1ca0000
> > segment[1].memsz = 0x4000
> >
> > This patch constrains the range of the kernel segment by `hole_min`
> > and `hole_max` to place vmlinux.efi exactly at the link address.
> >
> > pei_loongarch_load: kernel_segment: 0000000000200000
> > pei_loongarch_load: kernel_entry: 00000000013f1000
> > pei_loongarch_load: image_size: 0000000001ca0000
> > pei_loongarch_load: text_offset: 0000000000200000
> > pei_loongarch_load: phys_offset: 0000000000000000
> > pei_loongarch_load: PE format: yes
> > loongarch_load_other_segments:339: command_line: kexec console=ttyS0,115200
> > kexec_load: entry = 0x13f1000 flags = 0x1020000
> > nr_segments = 2
> > segment[0].buf = 0x7ffff2028010
> > segment[0].bufsz = 0x1b55200
> > segment[0].mem = 0x200000
> > segment[0].memsz = 0x1ca0000
> > segment[1].buf = 0x555557498098
> > segment[1].bufsz = 0x200
> > segment[1].mem = 0x1ea0000
> > segment[1].memsz = 0x4000
> >
> > Signed-off-by: WANG Rui <wangrui@xxxxxxxxxxx>
> > ---
> >
> > v1->v2:
> > * Fix the issue preventing it from working on the physical machine.
> >
> > kexec/arch/loongarch/kexec-loongarch.c | 10 +++++++---
> > 1 file changed, 7 insertions(+), 3 deletions(-)
> >
> > diff --git a/kexec/arch/loongarch/kexec-loongarch.c b/kexec/arch/loongarch/kexec-loongarch.c
> > index 62ff8fd..32a42d2 100644
> > --- a/kexec/arch/loongarch/kexec-loongarch.c
> > +++ b/kexec/arch/loongarch/kexec-loongarch.c
> > @@ -265,9 +265,13 @@ unsigned long loongarch_locate_kernel_segment(struct kexec_info *info)
> > hole = ULONG_MAX;
> > }
> > } else {
> > - hole = locate_hole(info,
> > - loongarch_mem.text_offset + loongarch_mem.image_size,
> > - MiB(1), 0, ULONG_MAX, 1);
> > + unsigned long hole_min;
> > + unsigned long hole_max;
> > +
> > + hole_min = loongarch_mem.text_offset;
> > + hole_max = hole_min + loongarch_mem.image_size;
> > + hole = locate_hole(info, loongarch_mem.image_size,
> > + MiB(1), hole_min, hole_max, 1);
> >
> > if (hole == ULONG_MAX)
> > dbgprintf("%s: locate_hole failed\n", __func__);
>
> Hi,
>
> Previously when I played with the zboot kernel on a kvm guest I
> noticed this issue, but I found that the 1st 2M memory is memblock
> reserved but it is not shown in /proc/iomem as reserved, I suspect the
> 1st 2M is not usable for some arch specific reason but I was not sure.
> Below patch can fix it but due to my rusty knowledge of loongarch I
Correct about my English wording a bit, I meant about rusty knowledge
of kexec details and newbish loongarch knowledge,
BTW, the webmail often randomly choose the sender email, I usually use
another email for community, that is Dave Young <dyoung@xxxxxxxxxx>,
same person ;)
Anyway, since this is loongarch specific, it would be better to leave
you guys the arch people to see how to fix it better.
> did not send it out. I suspect even if the locate_hole avoids the
> wrong memory, in the 2nd kernel it could still access it. Correct?
>
> Index: linux/arch/loongarch/kernel/mem.c
> ===================================================================
> --- linux.orig/arch/loongarch/kernel/mem.c 2023-06-02
> 10:24:09.633593320 +0800
> +++ linux/arch/loongarch/kernel/mem.c 2023-10-05 15:27:05.609455460 +0800
> @@ -52,8 +52,8 @@
> memblock_set_current_limit(PFN_PHYS(max_low_pfn));
> memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0);
>
> - /* Reserve the first 2MB */
> - memblock_reserve(PHYS_OFFSET, 0x200000);
> + /* Mark the first 2MB as nomap */
> + memblock_mark_nomap(PHYS_OFFSET, 0x200000);
>
> /* Reserve the kernel text/data/bss */
> memblock_reserve(__pa_symbol(&_text),
>
>
> > --
> > 2.42.0
> >
> >
> > _______________________________________________
> > kexec mailing list
> > kexec@xxxxxxxxxxxxxxxxxxx
> > http://lists.infradead.org/mailman/listinfo/kexec
> >
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