kexec-tools commit 61b8c79b0fb7 ("arm64/crashdump-arm64: deduce the
paddr of _text") tries to deduce the paddr of _text, but turns out
partially.
That commit is based on "The Image must be placed text_offset bytes from
a 2MB aligned base address anywhere in usable system RAM and called
there" in linux/Documentation/arm64/booting.rst, plus text_offset field
is zero.
But in practice, some boot loaders does not obey the convention, and
still boots up the kernel successfully.
Revisiting kernel commit e2a073dde921 ("arm64: omit [_text, _stext) from
permanent kernel mapping"), the kernel code size changes from (unsigned
long)__init_begin - (unsigned long)_text to (unsigned long)__init_begin
- (unsigned long)_stext
And it should be a better factor to decide which label starts the
"Kernel code" in /proc/iomem.
Signed-off-by: Pingfan Liu <piliu@xxxxxxxxxx>
Cc: Simon Horman <horms@xxxxxxxxxxxx>
To: kexec@xxxxxxxxxxxxxxxxxxx
---
kexec/arch/arm64/crashdump-arm64.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/kexec/arch/arm64/crashdump-arm64.c b/kexec/arch/arm64/crashdump-arm64.c
index 03d6204..a02019a 100644
--- a/kexec/arch/arm64/crashdump-arm64.c
+++ b/kexec/arch/arm64/crashdump-arm64.c
@@ -91,14 +91,22 @@ static int iomem_range_callback(void *UNUSED(data), int UNUSED(nr),
return mem_regions_alloc_and_add(&system_memory_rgns,
base, length, RANGE_RAM);
else if (strncmp(str, KERNEL_CODE, strlen(KERNEL_CODE)) == 0) {
+
+ unsigned long long kva_text = get_kernel_sym("_text");
+ unsigned long long kva_stext = get_kernel_sym("_stext");
+ unsigned long long kva_text_end = get_kernel_sym("__init_begin");
+
/*
* old: kernel_code.start = __pa_symbol(_text);
* new: kernel_code.start = __pa_symbol(_stext);
*
- * By utilizing the fact that paddr(_text) should align on 2MB, plus
- * _stext - _text <= 64K.
+ * For compatibility, deduce by comparing the gap "__init_begin - _stext"
+ * and the res size of "Kernel code" in /proc/iomem
*/
- elf_info.kern_paddr_start = base & ((0xffffffffffffffffUL) << 21);
+ if (kva_text_end - kva_stext == length)
+ elf_info.kern_paddr_start = base - (kva_stext - kva_text);
+ else
+ elf_info.kern_paddr_start = base;
}
else if (strncmp(str, KERNEL_DATA, strlen(KERNEL_DATA)) == 0)
elf_info.kern_size = base + length - elf_info.kern_paddr_start;
--
2.31.1
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