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asm-generic: Define CONFIG_HAVE_FUNCTION_DESCRIPTORS

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Replace HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR by a config option
named CONFIG_HAVE_FUNCTION_DESCRIPTORS and use it instead of
'dereference_function_descriptor' macro to know whether an
arch has function descriptors.

To limit churn in one of the following patches, use
an #ifdef/#else construct with empty first part
instead of an #ifndef in asm-generic/sections.h

On powerpc, make sure the config option matches the ABI used
by the compiler with a BUILD_BUG_ON() and add missing _CALL_ELF=2
when calling 'sparse' so that sparse sees the same piece of
code as GCC.

And include a helper to check whether an arch has function
descriptors or not : have_function_descriptors()

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/4a0f11fb0ea74a3197bc44dd7ba25e53a24fd03d.1644928018.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy
2022-02-15 13:41:02 +01:00
committed by Michael Ellerman
parent 41a88b4547
commit a257cacc38
10 changed files with 20 additions and 8 deletions
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8
include/asm-generic/sections.h
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@@ -59,11 +59,17 @@ extern char __noinstr_text_start[], __noinstr_text_end[];
extern __visible const void __nosave_begin, __nosave_end;
/* Function descriptor handling (if any). Override in asm/sections.h */
#ifndef dereference_function_descriptor
#ifdef CONFIG_HAVE_FUNCTION_DESCRIPTORS
#else
#define dereference_function_descriptor(p) ((void *)(p))
#define dereference_kernel_function_descriptor(p) ((void *)(p))
#endif
static inline bool have_function_descriptors(void)
{
return IS_ENABLED(CONFIG_HAVE_FUNCTION_DESCRIPTORS);
}
/**
* memory_contains - checks if an object is contained within a memory region
* @begin: virtual address of the beginning of the memory region