diff mbox series

[v2,2/4] mm: Make generic arch_is_kernel_initmem_freed() do what it says

Message ID ec69cc95a98548c862c22b742936244fdb0c7984.1632813331.git.christophe.leroy@csgroup.eu (mailing list archive)
State Superseded
Headers show
Series [v2,1/4] mm: Create a new system state and fix core_kernel_text() | expand
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Commit Message

Christophe Leroy Sept. 28, 2021, 7:15 a.m. UTC
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>
---
v2: Change to using the new SYSTEM_FREEING_INITMEM state
---
 include/asm-generic/sections.h | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

Comments

Andrew Morton Sept. 29, 2021, 3:30 a.m. UTC | #1
On Tue, 28 Sep 2021 09:15:35 +0200 Christophe Leroy <christophe.leroy@csgroup.eu> wrote:

> 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

i386 allmodconfig:

In file included from arch/x86/platform/intel-quark/imr.c:28:
./include/asm-generic/sections.h: In function 'arch_is_kernel_initmem_freed':
./include/asm-generic/sections.h:171:6: error: 'system_state' undeclared (first use in this function)
  171 |  if (system_state < SYSTEM_FREEING_INITMEM)
      |      ^~~~~~~~~~~~
./include/asm-generic/sections.h:171:6: note: each undeclared identifier is reported only once for each function it appears in
./include/asm-generic/sections.h:171:21: error: 'SYSTEM_FREEING_INITMEM' undeclared (first use in this function)
  171 |  if (system_state < SYSTEM_FREEING_INITMEM)
      |                     ^~~~~~~~~~~~~~~~~~~~~~


I don't think it would be a good idea to include kernel.h from
sections.h - it's unclear to me which is the "innermost" of those two. 
It would be better to uninline arch_is_kernel_initmem_freed().  Surely
there's no real reason for inlining it?

Anyway, I'll drop the series for now.
diff mbox series

Patch

diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index d16302d3eb59..13f301239007 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_FREEING_INITMEM)
+		return 0;
+
+	return init_section_contains((void *)addr, 1);
+}
+#endif
+
 #endif /* _ASM_GENERIC_SECTIONS_H_ */