[patch 116/262] mm: make generic arch_is_kernel_initmem_freed() do what it says

Andrew Morton
2021-11-05T20:40:46Z

From: Christophe Leroy <christophe.leroy@csgroup.eu>
Subject: mm: make generic arch_is_kernel_initmem_freed() do what it says

Commit 7a5da02de8d6 ("locking/lockdep: check for freed initmem in
static_obj()") added arch_is_kernel_initmem_freed() which is supposed to
report whether an object is part of already freed init memory.

For the time being, the generic version of arch_is_kernel_initmem_freed()
always reports 'false', allthough free_initmem() is generically called on
all architectures.

Therefore, change the generic version of arch_is_kernel_initmem_freed() to
check whether free_initmem() has been called. If so, then check if a
given address falls into init memory.

To ease the use of system_state, move it out of line into its only caller
which is lockdep.c

Link: https://lkml.kernel.org/r/1d40783e676e07858be97d881f449ee7ea8adfb1.1633001016.git.christophe.leroy@csgroup.eu
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

include/asm-generic/sections.h | 14 --------------
kernel/locking/lockdep.c | 15 +++++++++++++++
2 files changed, 15 insertions(+), 14 deletions(-)

--- a/include/asm-generic/sections.h~mm-make-generic-arch_is_kernel_initmem_freed-do-what-it-says
+++ a/include/asm-generic/sections.h
@@ -80,20 +80,6 @@ static inline int arch_is_kernel_data(un
}
#endif

-/*
- * Check if an address is part of freed initmem. This is needed on architectures
- * with virt == phys kernel mapping, for code that wants to check if an address
- * is part of a static object within [_stext, _end]. 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 inline int arch_is_kernel_initmem_freed(unsigned long addr)
-{
- return 0;
-}
-#endif
-
/**
* memory_contains - checks if an object is contained within a memory region
* @begin: virtual address of the beginning of the memory region
--- a/kernel/locking/lockdep.c~mm-make-generic-arch_is_kernel_initmem_freed-do-what-it-says
+++ a/kernel/locking/lockdep.c
@@ -788,6 +788,21 @@ static int very_verbose(struct lock_clas
* Is this the address of a static object:
*/
#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);
+}
+#endif
+
static int static_obj(const void *obj)
{
unsigned long start = (unsigned long) &_stext,
_