diff mbox series

[v2,06/13] asm-generic: Use HAVE_FUNCTION_DESCRIPTORS to define associated stubs

Message ID 4fda65cda906e56aa87806b658e0828c64792403.1634190022.git.christophe.leroy@csgroup.eu (mailing list archive)
State Awaiting Upstream, archived
Headers show
Series Fix LKDTM for PPC64/IA64/PARISC | expand

Commit Message

Christophe Leroy Oct. 14, 2021, 5:49 a.m. UTC
Replace HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR by
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

Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/ia64/include/asm/sections.h    | 5 +++--
 arch/parisc/include/asm/sections.h  | 6 ++++--
 arch/powerpc/include/asm/sections.h | 6 ++++--
 include/asm-generic/sections.h      | 3 ++-
 include/linux/kallsyms.h            | 2 +-
 5 files changed, 14 insertions(+), 8 deletions(-)

Comments

Nicholas Piggin Oct. 15, 2021, 6:16 a.m. UTC | #1
Excerpts from Christophe Leroy's message of October 14, 2021 3:49 pm:
> Replace HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR by
> 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

Is it worth putting this into Kconfig if you're going to
change it? In any case

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>

> 
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---
>  arch/ia64/include/asm/sections.h    | 5 +++--
>  arch/parisc/include/asm/sections.h  | 6 ++++--
>  arch/powerpc/include/asm/sections.h | 6 ++++--
>  include/asm-generic/sections.h      | 3 ++-
>  include/linux/kallsyms.h            | 2 +-
>  5 files changed, 14 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/ia64/include/asm/sections.h b/arch/ia64/include/asm/sections.h
> index 35f24e52149a..6e55e545bf02 100644
> --- a/arch/ia64/include/asm/sections.h
> +++ b/arch/ia64/include/asm/sections.h
> @@ -9,6 +9,9 @@
>  
>  #include <linux/elf.h>
>  #include <linux/uaccess.h>
> +
> +#define HAVE_FUNCTION_DESCRIPTORS 1
> +
>  #include <asm-generic/sections.h>
>  
>  extern char __phys_per_cpu_start[];
> @@ -27,8 +30,6 @@ extern char __start_gate_brl_fsys_bubble_down_patchlist[], __end_gate_brl_fsys_b
>  extern char __start_unwind[], __end_unwind[];
>  extern char __start_ivt_text[], __end_ivt_text[];
>  
> -#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
> -
>  #undef dereference_function_descriptor
>  static inline void *dereference_function_descriptor(void *ptr)
>  {
> diff --git a/arch/parisc/include/asm/sections.h b/arch/parisc/include/asm/sections.h
> index bb52aea0cb21..85149a89ff3e 100644
> --- a/arch/parisc/include/asm/sections.h
> +++ b/arch/parisc/include/asm/sections.h
> @@ -2,6 +2,10 @@
>  #ifndef _PARISC_SECTIONS_H
>  #define _PARISC_SECTIONS_H
>  
> +#ifdef CONFIG_64BIT
> +#define HAVE_FUNCTION_DESCRIPTORS 1
> +#endif
> +
>  /* nothing to see, move along */
>  #include <asm-generic/sections.h>
>  
> @@ -9,8 +13,6 @@ extern char __alt_instructions[], __alt_instructions_end[];
>  
>  #ifdef CONFIG_64BIT
>  
> -#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
> -
>  #undef dereference_function_descriptor
>  void *dereference_function_descriptor(void *);
>  
> diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h
> index 32e7035863ac..bba97b8c38cf 100644
> --- a/arch/powerpc/include/asm/sections.h
> +++ b/arch/powerpc/include/asm/sections.h
> @@ -8,6 +8,10 @@
>  
>  #define arch_is_kernel_initmem_freed arch_is_kernel_initmem_freed
>  
> +#ifdef PPC64_ELF_ABI_v1
> +#define HAVE_FUNCTION_DESCRIPTORS 1
> +#endif
> +
>  #include <asm-generic/sections.h>
>  
>  extern bool init_mem_is_free;
> @@ -69,8 +73,6 @@ static inline int overlaps_kernel_text(unsigned long start, unsigned long end)
>  
>  #ifdef PPC64_ELF_ABI_v1
>  
> -#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
> -
>  #undef dereference_function_descriptor
>  static inline void *dereference_function_descriptor(void *ptr)
>  {
> diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
> index d16302d3eb59..b677e926e6b3 100644
> --- a/include/asm-generic/sections.h
> +++ b/include/asm-generic/sections.h
> @@ -59,7 +59,8 @@ 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 HAVE_FUNCTION_DESCRIPTORS
> +#else
>  #define dereference_function_descriptor(p) ((void *)(p))
>  #define dereference_kernel_function_descriptor(p) ((void *)(p))
>  #endif
> diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
> index a1d6fc82d7f0..9f277baeb559 100644
> --- a/include/linux/kallsyms.h
> +++ b/include/linux/kallsyms.h
> @@ -57,7 +57,7 @@ static inline int is_ksym_addr(unsigned long addr)
>  
>  static inline void *dereference_symbol_descriptor(void *ptr)
>  {
> -#ifdef HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR
> +#ifdef HAVE_FUNCTION_DESCRIPTORS
>  	struct module *mod;
>  
>  	ptr = dereference_kernel_function_descriptor(ptr);
> -- 
> 2.31.1
> 
> 
>
Christophe Leroy Oct. 15, 2021, 6:24 a.m. UTC | #2
Le 15/10/2021 à 08:16, Nicholas Piggin a écrit :
> Excerpts from Christophe Leroy's message of October 14, 2021 3:49 pm:
>> Replace HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR by
>> 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
> 
> Is it worth putting this into Kconfig if you're going to
> change it? In any case

That was what I wanted to do in the begining but how can I do that in 
Kconfig ?

#ifdef __powerpc64__
#if defined(_CALL_ELF) && _CALL_ELF == 2
#define PPC64_ELF_ABI_v2
#else
#define PPC64_ELF_ABI_v1
#endif
#endif /* __powerpc64__ */

#ifdef PPC64_ELF_ABI_v1
#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1

Christophe

> 
> Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
> 
>>
>> Reviewed-by: Kees Cook <keescook@chromium.org>
>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
>> ---
>>   arch/ia64/include/asm/sections.h    | 5 +++--
>>   arch/parisc/include/asm/sections.h  | 6 ++++--
>>   arch/powerpc/include/asm/sections.h | 6 ++++--
>>   include/asm-generic/sections.h      | 3 ++-
>>   include/linux/kallsyms.h            | 2 +-
>>   5 files changed, 14 insertions(+), 8 deletions(-)
>>
>> diff --git a/arch/ia64/include/asm/sections.h b/arch/ia64/include/asm/sections.h
>> index 35f24e52149a..6e55e545bf02 100644
>> --- a/arch/ia64/include/asm/sections.h
>> +++ b/arch/ia64/include/asm/sections.h
>> @@ -9,6 +9,9 @@
>>   
>>   #include <linux/elf.h>
>>   #include <linux/uaccess.h>
>> +
>> +#define HAVE_FUNCTION_DESCRIPTORS 1
>> +
>>   #include <asm-generic/sections.h>
>>   
>>   extern char __phys_per_cpu_start[];
>> @@ -27,8 +30,6 @@ extern char __start_gate_brl_fsys_bubble_down_patchlist[], __end_gate_brl_fsys_b
>>   extern char __start_unwind[], __end_unwind[];
>>   extern char __start_ivt_text[], __end_ivt_text[];
>>   
>> -#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
>> -
>>   #undef dereference_function_descriptor
>>   static inline void *dereference_function_descriptor(void *ptr)
>>   {
>> diff --git a/arch/parisc/include/asm/sections.h b/arch/parisc/include/asm/sections.h
>> index bb52aea0cb21..85149a89ff3e 100644
>> --- a/arch/parisc/include/asm/sections.h
>> +++ b/arch/parisc/include/asm/sections.h
>> @@ -2,6 +2,10 @@
>>   #ifndef _PARISC_SECTIONS_H
>>   #define _PARISC_SECTIONS_H
>>   
>> +#ifdef CONFIG_64BIT
>> +#define HAVE_FUNCTION_DESCRIPTORS 1
>> +#endif
>> +
>>   /* nothing to see, move along */
>>   #include <asm-generic/sections.h>
>>   
>> @@ -9,8 +13,6 @@ extern char __alt_instructions[], __alt_instructions_end[];
>>   
>>   #ifdef CONFIG_64BIT
>>   
>> -#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
>> -
>>   #undef dereference_function_descriptor
>>   void *dereference_function_descriptor(void *);
>>   
>> diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h
>> index 32e7035863ac..bba97b8c38cf 100644
>> --- a/arch/powerpc/include/asm/sections.h
>> +++ b/arch/powerpc/include/asm/sections.h
>> @@ -8,6 +8,10 @@
>>   
>>   #define arch_is_kernel_initmem_freed arch_is_kernel_initmem_freed
>>   
>> +#ifdef PPC64_ELF_ABI_v1
>> +#define HAVE_FUNCTION_DESCRIPTORS 1
>> +#endif
>> +
>>   #include <asm-generic/sections.h>
>>   
>>   extern bool init_mem_is_free;
>> @@ -69,8 +73,6 @@ static inline int overlaps_kernel_text(unsigned long start, unsigned long end)
>>   
>>   #ifdef PPC64_ELF_ABI_v1
>>   
>> -#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
>> -
>>   #undef dereference_function_descriptor
>>   static inline void *dereference_function_descriptor(void *ptr)
>>   {
>> diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
>> index d16302d3eb59..b677e926e6b3 100644
>> --- a/include/asm-generic/sections.h
>> +++ b/include/asm-generic/sections.h
>> @@ -59,7 +59,8 @@ 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 HAVE_FUNCTION_DESCRIPTORS
>> +#else
>>   #define dereference_function_descriptor(p) ((void *)(p))
>>   #define dereference_kernel_function_descriptor(p) ((void *)(p))
>>   #endif
>> diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
>> index a1d6fc82d7f0..9f277baeb559 100644
>> --- a/include/linux/kallsyms.h
>> +++ b/include/linux/kallsyms.h
>> @@ -57,7 +57,7 @@ static inline int is_ksym_addr(unsigned long addr)
>>   
>>   static inline void *dereference_symbol_descriptor(void *ptr)
>>   {
>> -#ifdef HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR
>> +#ifdef HAVE_FUNCTION_DESCRIPTORS
>>   	struct module *mod;
>>   
>>   	ptr = dereference_kernel_function_descriptor(ptr);
>> -- 
>> 2.31.1
>>
>>
>>
Nicholas Piggin Oct. 15, 2021, 8:02 a.m. UTC | #3
Excerpts from Christophe Leroy's message of October 15, 2021 4:24 pm:
> 
> 
> Le 15/10/2021 à 08:16, Nicholas Piggin a écrit :
>> Excerpts from Christophe Leroy's message of October 14, 2021 3:49 pm:
>>> Replace HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR by
>>> 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
>> 
>> Is it worth putting this into Kconfig if you're going to
>> change it? In any case
> 
> That was what I wanted to do in the begining but how can I do that in 
> Kconfig ?
> 
> #ifdef __powerpc64__
> #if defined(_CALL_ELF) && _CALL_ELF == 2
> #define PPC64_ELF_ABI_v2
> #else
> #define PPC64_ELF_ABI_v1
> #endif
> #endif /* __powerpc64__ */
> 
> #ifdef PPC64_ELF_ABI_v1
> #define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1

We have ELFv2 ABI / function descriptors iff big-endian so you could 
just select based on that.

I have a patch that makes the ABI version configurable which cleans
some of this up a bit, but that can be rebased on your series if we
ever merge it. Maybe just add BUILD_BUG_ONs in the above ifdef block
to ensure CONFIG_HAVE_FUNCTION_DESCRIPTORS was set the right way, so
I don't forget.

Thanks,
Nick
Nicholas Piggin Oct. 15, 2021, 11:52 a.m. UTC | #4
Excerpts from Nicholas Piggin's message of October 15, 2021 6:02 pm:
> Excerpts from Christophe Leroy's message of October 15, 2021 4:24 pm:
>> 
>> 
>> Le 15/10/2021 à 08:16, Nicholas Piggin a écrit :
>>> Excerpts from Christophe Leroy's message of October 14, 2021 3:49 pm:
>>>> Replace HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR by
>>>> 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
>>> 
>>> Is it worth putting this into Kconfig if you're going to
>>> change it? In any case
>> 
>> That was what I wanted to do in the begining but how can I do that in 
>> Kconfig ?
>> 
>> #ifdef __powerpc64__
>> #if defined(_CALL_ELF) && _CALL_ELF == 2
>> #define PPC64_ELF_ABI_v2
>> #else
>> #define PPC64_ELF_ABI_v1
>> #endif
>> #endif /* __powerpc64__ */
>> 
>> #ifdef PPC64_ELF_ABI_v1
>> #define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
> 
> We have ELFv2 ABI / function descriptors iff big-endian so you could 
> just select based on that.

Of course that should read ELFv1. To be clearer: BE is ELFv1 ABI and
LE is ELFv2 ABI.

Thanks,
Nick
diff mbox series

Patch

diff --git a/arch/ia64/include/asm/sections.h b/arch/ia64/include/asm/sections.h
index 35f24e52149a..6e55e545bf02 100644
--- a/arch/ia64/include/asm/sections.h
+++ b/arch/ia64/include/asm/sections.h
@@ -9,6 +9,9 @@ 
 
 #include <linux/elf.h>
 #include <linux/uaccess.h>
+
+#define HAVE_FUNCTION_DESCRIPTORS 1
+
 #include <asm-generic/sections.h>
 
 extern char __phys_per_cpu_start[];
@@ -27,8 +30,6 @@  extern char __start_gate_brl_fsys_bubble_down_patchlist[], __end_gate_brl_fsys_b
 extern char __start_unwind[], __end_unwind[];
 extern char __start_ivt_text[], __end_ivt_text[];
 
-#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
-
 #undef dereference_function_descriptor
 static inline void *dereference_function_descriptor(void *ptr)
 {
diff --git a/arch/parisc/include/asm/sections.h b/arch/parisc/include/asm/sections.h
index bb52aea0cb21..85149a89ff3e 100644
--- a/arch/parisc/include/asm/sections.h
+++ b/arch/parisc/include/asm/sections.h
@@ -2,6 +2,10 @@ 
 #ifndef _PARISC_SECTIONS_H
 #define _PARISC_SECTIONS_H
 
+#ifdef CONFIG_64BIT
+#define HAVE_FUNCTION_DESCRIPTORS 1
+#endif
+
 /* nothing to see, move along */
 #include <asm-generic/sections.h>
 
@@ -9,8 +13,6 @@  extern char __alt_instructions[], __alt_instructions_end[];
 
 #ifdef CONFIG_64BIT
 
-#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
-
 #undef dereference_function_descriptor
 void *dereference_function_descriptor(void *);
 
diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h
index 32e7035863ac..bba97b8c38cf 100644
--- a/arch/powerpc/include/asm/sections.h
+++ b/arch/powerpc/include/asm/sections.h
@@ -8,6 +8,10 @@ 
 
 #define arch_is_kernel_initmem_freed arch_is_kernel_initmem_freed
 
+#ifdef PPC64_ELF_ABI_v1
+#define HAVE_FUNCTION_DESCRIPTORS 1
+#endif
+
 #include <asm-generic/sections.h>
 
 extern bool init_mem_is_free;
@@ -69,8 +73,6 @@  static inline int overlaps_kernel_text(unsigned long start, unsigned long end)
 
 #ifdef PPC64_ELF_ABI_v1
 
-#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
-
 #undef dereference_function_descriptor
 static inline void *dereference_function_descriptor(void *ptr)
 {
diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index d16302d3eb59..b677e926e6b3 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -59,7 +59,8 @@  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 HAVE_FUNCTION_DESCRIPTORS
+#else
 #define dereference_function_descriptor(p) ((void *)(p))
 #define dereference_kernel_function_descriptor(p) ((void *)(p))
 #endif
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index a1d6fc82d7f0..9f277baeb559 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -57,7 +57,7 @@  static inline int is_ksym_addr(unsigned long addr)
 
 static inline void *dereference_symbol_descriptor(void *ptr)
 {
-#ifdef HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR
+#ifdef HAVE_FUNCTION_DESCRIPTORS
 	struct module *mod;
 
 	ptr = dereference_kernel_function_descriptor(ptr);