Le 04/11/2021 à 22:44, Andrew Morton a écrit :
On Fri, 01 Oct 2021 17:14:41 +1000 Daniel Axtens [off-list ref] wrote:
quoted
quoted
#ifdef __KERNEL__
+/*
+ * Check if an address is part of freed initmem. After initmem is freed,
+ * memory can be allocated from it, and such allocations would then have
+ * addresses within the range [_stext, _end].
+ */
+#ifndef arch_is_kernel_initmem_freed
+static int arch_is_kernel_initmem_freed(unsigned long addr)
+{
+ if (system_state < SYSTEM_FREEING_INITMEM)
+ return 0;
+
+ return init_section_contains((void *)addr, 1);
Is init_section_contains sufficient here?
include/asm-generic/sections.h says:
* [__init_begin, __init_end]: contains .init.* sections, but .init.text.*
* may be out of this range on some architectures.
* [_sinittext, _einittext]: contains .init.text.* sections
init_section_contains only checks __init_*:
static inline bool init_section_contains(void *virt, size_t size)
{
return memory_contains(__init_begin, __init_end, virt, size);
}
Do we need to check against _sinittext and _einittext?
Your proposed generic code will work for powerpc and s390 because those
archs only test against __init_* anyway. I don't know if any platform
actually does place .init.text outside of __init_begin=>__init_end, but
the comment seems to suggest that they could.
Christophe?
Sorry for answering late.
I've been thorugh free_initmem() in each architecture. The only sections involved in the freeing actions are [__init_begin, __init_end], so I think checking against __init_being, __init_end is enough.
If some architecture has init text outside of this section, then it is not freed hence not necessary to check.
Christophe