After kernel commit e2a073dde921 ("arm64: omit [_text, _stext) from
permanent kernel mapping"), the range [_text, _stext] is reclaimed. But
the current crash code still assumes kernel starting from "_text".
This change only affects the vmalloced area on arm64 and may result a
false in arm64_IS_VMALLOC_ADDR().
Since vmcore has no extra information about this trival change, it can
only be deduced from kernel version, which means ms->kimage_text can not
be correctly initialized until kernel_init() finishes. Here on arm64, it
can be done at the point machdep_init(POST_GDB). This is fine
since there is no access to vmalloced area at this stage.
Signed-off-by: Pingfan Liu <piliu@xxxxxxxxxx>
---
arm64.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/arm64.c b/arm64.c
index de1038a..3ab8489 100644
--- a/arm64.c
+++ b/arm64.c
@@ -92,6 +92,20 @@ static void arm64_calc_VA_BITS(void);
static int arm64_is_uvaddr(ulong, struct task_context *);
static void arm64_calc_KERNELPACMASK(void);
+static void arm64_calc_kernel_start(void)
+{
+ struct machine_specific *ms = machdep->machspec;
+ struct syment *sp;
+
+ if (THIS_KERNEL_VERSION >= LINUX(5,11,0))
+ sp = kernel_symbol_search("_stext");
+ else
+ sp = kernel_symbol_search("_text");
+
+ ms->kimage_text = (sp ? sp->value : 0);
+ sp = kernel_symbol_search("_end");
+ ms->kimage_end = (sp ? sp->value : 0);
+}
/*
* Do all necessary machine-specific setup here. This is called several times
@@ -241,6 +255,7 @@ arm64_init(int when)
if (machdep->flags & NEW_VMEMMAP) {
struct syment *sp;
+ /* It is finally decided in arm64_calc_kernel_start() */
sp = kernel_symbol_search("_text");
ms->kimage_text = (sp ? sp->value : 0);
sp = kernel_symbol_search("_end");
@@ -387,6 +402,8 @@ arm64_init(int when)
break;
case POST_GDB:
+ /* Rely on kernel version to decide the kernel start address */
+ arm64_calc_kernel_start();
arm64_calc_virtual_memory_ranges();
arm64_get_section_size_bits();
--
2.31.1
--
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