[PATCH 1/3] mm: Make generic arch_is_kernel_initmem_freed() do what it says

* [PATCH 1/3] mm: Make generic arch_is_kernel_initmem_freed() do what it says
@ 2021-09-24 13:48 Christophe Leroy
  2021-09-24 13:48 ` [PATCH 2/3] powerpc: Use generic version of arch_is_kernel_initmem_freed() Christophe Leroy
                   ` (2 more replies)
  0 siblings, 3 replies; 5+ messages in thread
From: Christophe Leroy @ 2021-09-24 13:48 UTC (permalink / raw)
  To: Andrew Morton, arnd
  Cc: Christophe Leroy, linux-kernel, linux-mm, linux-s390,
	linuxppc-dev, linux-arch, Gerald Schaefer

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.

In order to use function init_section_contains(), the fonction is
moved at the end of asm-generic/section.h

Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 include/asm-generic/sections.h | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index d16302d3eb59..d1e5bb2c6b72 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -80,20 +80,6 @@ static inline int arch_is_kernel_data(unsigned long addr)
 }
 #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
@@ -172,4 +158,21 @@ static inline bool is_kernel_rodata(unsigned long addr)
 	       addr < (unsigned long)__end_rodata;
 }
 
+/*
+ * 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)
+{
+	if (system_state < SYSTEM_RUNNING)
+		return 0;
+
+	return init_section_contains((void *)addr, 1);
+}
+#endif
+
 #endif /* _ASM_GENERIC_SECTIONS_H_ */
-- 
2.31.1



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