Re: [Crash-utility] ramdump support for va_bits_actual
Hi Dave,
On Sat, Apr 18, 2020 at 2:08 PM Dave Anderson <anderson(a)redhat.com> wrote:
----- Original Message -----
> Hi Dave,
>
> Noticed that raw ramdumps of 5.4 kernel aren't working with crash tip.
> With the patches attached, I could get it working. Please take a look.
>
> Thanks,
> Vinayak
>
Hi Vinayak,
A couple quick questions come to mind...
First, I haven't checked all possible READMEM plugins, but for example, if this
function is run on a live system, the -1 file descriptor would cause the READMEM()
call to fail:
I changed it like this and it works for ramdump. I don't actually have
a live setup to try this. Let me try
to set up one.
diff --git a/arm64.c b/arm64.c
index 04efc13..fce3f8e 100644
--- a/arm64.c
+++ b/arm64.c
@@ -981,7 +981,7 @@ arm64_calc_physvirt_offset(void)
if ((sp = kernel_symbol_search("physvirt_offset")) &&
machdep->machspec->kimage_voffset) {
- if (READMEM(-1, &physvirt_offset, sizeof(physvirt_offset),
+ if (READMEM(pc->mfd, &physvirt_offset, sizeof(physvirt_offset),
sp->value, sp->value -
machdep->machspec->kimage_voffset) > 0) {
ms->physvirt_offset = physvirt_offset;
static void
+arm64_calc_physvirt_offset(void)
+{
+ struct machine_specific *ms = machdep->machspec;
+ ulong physvirt_offset;
+ struct syment *sp;
+
+ ms->physvirt_offset = ms->phys_offset - ms->page_offset;
+
+ if ((sp = kernel_symbol_search("physvirt_offset")) &&
+ machdep->machspec->kimage_voffset) {
+ if (READMEM(-1, &physvirt_offset, sizeof(physvirt_offset),
+ sp->value, sp->value -
+ machdep->machspec->kimage_voffset) > 0) {
+ ms->physvirt_offset = physvirt_offset;
+ }
+ }
+
+ if (CRASHDEBUG(1))
+ fprintf(fp, "using %lx as physvirt_offset\n",
ms->physvirt_offset);
+}
And here -- are you missing some brackets? (run "make warn")
I did try "make warn" and it does not show any issues.Am I missing something ?
But regardless of that, why are you setting it back to 48 if it's
greater than 48?
I did that because machspec->CONFIG_ARM64_VA_BITS is used for calculation of
vmemmap size. In kernel vmemmap size is calculated using VA_BITS_MIN and it is
defined like this
#if VA_BITS > 48
#define VA_BITS_MIN (48)
#else
#define VA_BITS_MIN (VA_BITS)
#endif
But I realize now that its not the right thing to do, because
machspec->CONFIG_ARM64_VA_BITS
is later used in arm64_calc_VA_BITS to verify machspec->VA_BITS. So
what about this ?
diff --git a/arm64.c b/arm64.c
index 04efc13..a35a30e 100644
--- a/arm64.c
+++ b/arm64.c
@@ -4023,8 +4023,6 @@ arm64_calc_virtual_memory_ranges(void)
if ((ret = get_kernel_config("CONFIG_ARM64_VA_BITS",
&string)) == IKCONFIG_STR)
machdep->machspec->CONFIG_ARM64_VA_BITS = atol(string);
- if
(machdep->machspec->CONFIG_ARM64_VA_BITS > 48)
-
machdep->machspec->CONFIG_ARM64_VA_BITS = 48;
}
}
@@ -4049,7 +4047,12 @@ arm64_calc_virtual_memory_ranges(void)
#define STRUCT_PAGE_MAX_SHIFT 6
if (ms->VA_BITS_ACTUAL) {
- vmemmap_size = (1UL) << (ms->CONFIG_ARM64_VA_BITS -
machdep->pageshift - 1 + STRUCT_PAGE_MAX_SHIFT);
+ ulong va_bits_min = 48;
+
+ if (machdep->machspec->CONFIG_ARM64_VA_BITS < 48)
+ va_bits_min = ms->CONFIG_ARM64_VA_BITS;
+
+ vmemmap_size = (1UL) << (va_bits_min -
machdep->pageshift - 1 + STRUCT_PAGE_MAX_SHIFT);
vmalloc_end = (- PUD_SIZE - vmemmap_size - KILOBYTES(64));
vmemmap_start = (-vmemmap_size);
ms->vmalloc_end = vmalloc_end - 1;
Thanks,
Vinayak
Thanks,
Dave
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