[Crash-utility] [PATCH v4] arm64: Add vmemmap support
If the kernel exports the vmmemap then we can use that symbol in
crash to optimize access. vmmemap is just an array of page structs
after all.
This patch tries to:
1.) Get the "vmemmap" from the vmcore file.
If we can use the "vmemmap", we implement the arm64_vmemmap_is_page_ptr
and set it to machdep->is_page_ptr.
2.) We implement the fast page_to_pfn code in arm64_vmemmap_is_page_ptr.
3.) Dump it in "help -m"
Test result:
Without the this patch:
#files -p xxx > /dev/null (xxx is the inode of vmlinux which is 441M)
This costed about 185 seconds.
With the this patch:
#files -p xxx > /dev/null (xxx is the inode of vmlinux which is 441M)
This costed 3 seconds.
Signed-off-by: Huang Shijie <shijie(a)os.amperecomputing.com>
---
v3 --> v4:
Use "files -p" to measure the time.
Dump it in "help -m"
---
arm64.c | 26 ++++++++++++++++++++++++++
defs.h | 1 +
2 files changed, 27 insertions(+)
diff --git a/arm64.c b/arm64.c
index 57965c6..fc4ba64 100644
--- a/arm64.c
+++ b/arm64.c
@@ -117,6 +117,28 @@ static void arm64_calc_kernel_start(void)
ms->kimage_end = (sp ? sp->value : 0);
}
+static int
+arm64_vmemmap_is_page_ptr(ulong addr, physaddr_t *phys)
+{
+ ulong size = SIZE(page);
+ ulong pfn, nr;
+
+
+ if (IS_SPARSEMEM() && (machdep->flags & VMEMMAP) &&
+ (addr >= VMEMMAP_VADDR && addr <= VMEMMAP_END) &&
+ !((addr - VMEMMAP_VADDR) % size)) {
+
+ pfn = (addr - machdep->machspec->vmemmap) / size;
+ nr = pfn_to_section_nr(pfn);
+ if (valid_section_nr(nr)) {
+ if (phys)
+ *phys = PTOB(pfn);
+ return TRUE;
+ }
+ }
+ return FALSE;
+}
+
/*
* Do all necessary machine-specific setup here. This is called several times
* during initialization.
@@ -382,6 +404,9 @@ arm64_init(int when)
machdep->stacksize = ARM64_STACK_SIZE;
machdep->flags |= VMEMMAP;
+ /* If vmemmap exists, it means kernel enabled CONFIG_SPARSEMEM_VMEMMAP */
+ if (arm64_get_vmcoreinfo(&ms->vmemmap, "SYMBOL(vmemmap)", NUM_HEX))
+ machdep->is_page_ptr = arm64_vmemmap_is_page_ptr;
machdep->uvtop = arm64_uvtop;
machdep->is_uvaddr = arm64_is_uvaddr;
@@ -1096,6 +1121,7 @@ arm64_dump_machdep_table(ulong arg)
fprintf(fp, " vmemmap_vaddr: %016lx\n", ms->vmemmap_vaddr);
fprintf(fp, " vmemmap_end: %016lx\n", ms->vmemmap_end);
if (machdep->flags & NEW_VMEMMAP) {
+ fprintf(fp, " vmemmap: %016lx\n", ms->vmemmap);
fprintf(fp, " kimage_text: %016lx\n", ms->kimage_text);
fprintf(fp, " kimage_end: %016lx\n", ms->kimage_end);
fprintf(fp, " kimage_voffset: %016lx\n", ms->kimage_voffset);
diff --git a/defs.h b/defs.h
index 0558d13..3431a32 100644
--- a/defs.h
+++ b/defs.h
@@ -3486,6 +3486,7 @@ struct machine_specific {
ulong CONFIG_ARM64_KERNELPACMASK;
ulong physvirt_offset;
ulong struct_page_size;
+ ulong vmemmap;
};
struct arm64_stackframe {
--
2.40.1