Re: [PATCH v2 02/13] powerpc: Rename 'funcaddr' to 'addr' in 'struct ppc64_opd_entry'

Christophe Leroy
2021-10-15T04:59:31Z

Le 14/10/2021 à 23:45, Daniel Axtens a écrit :
> Christophe Leroy <christophe.leroy@csgroup.eu> writes:
>
>> There are three architectures with function descriptors, try to
>> have common names for the address they contain in order to
>> refactor some functions into generic functions later.
>>
>> powerpc has 'funcaddr'
>> ia64 has 'ip'
>> parisc has 'addr'
>>
>> Vote for 'addr' and update 'struct ppc64_opd_entry' accordingly.
>
> I would have picked 'funcaddr', but at least 'addr' is better than 'ip'!
> And I agree that consistency, and then making things generic is worthwhile.

It's a function descriptor, there is only one address field, I don't
think there is any ambiguïty here, and I prefer modifying the least
impacted architectures.

Changing addr to funcaddr in PARISC would result in the following
changes, on an architecture I know nothing about. It's more changes than
we have on powerpc.

arch/parisc/include/asm/elf.h | 4 ++--
arch/parisc/kernel/kexec.c | 2 +-
arch/parisc/kernel/module.c | 12 ++++++------
arch/parisc/kernel/process.c | 2 +-
arch/parisc/kernel/signal.c | 4 ++--
5 files changed, 12 insertions(+), 12 deletions(-)

>
> I grepped the latest powerpc/next for uses of 'funcaddr'. There were 5,
> your patch changes all 5.
>
> The series passes build tests and this patch has no checkpatch or other
> style concerns.
>
> On that basis:
> Reviewed-by: Daniel Axtens <dja@axtens.net>
>
> Kind regards,
> Daniel
>
>> Reviewed-by: Kees Cook <keescook@chromium.org>
>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
>> ---
>> arch/powerpc/include/asm/elf.h | 2 +-
>> arch/powerpc/include/asm/sections.h | 2 +-
>> arch/powerpc/kernel/module_64.c | 6 +++---
>> 3 files changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/elf.h b/arch/powerpc/include/asm/elf.h
>> index a4406714c060..bb0f278f9ed4 100644
>> --- a/arch/powerpc/include/asm/elf.h
>> +++ b/arch/powerpc/include/asm/elf.h
>> @@ -178,7 +178,7 @@ void relocate(unsigned long final_address);
>>
>> /* There's actually a third entry here, but it's unused */
>> struct ppc64_opd_entry {
>> - unsigned long funcaddr;
>> + unsigned long addr;
>> unsigned long r2;
>> };
>>
>> diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h
>> index 6e4af4492a14..32e7035863ac 100644
>> --- a/arch/powerpc/include/asm/sections.h
>> +++ b/arch/powerpc/include/asm/sections.h
>> @@ -77,7 +77,7 @@ static inline void *dereference_function_descriptor(void *ptr)
>> struct ppc64_opd_entry *desc = ptr;
>> void *p;
>>
>> - if (!get_kernel_nofault(p, (void *)&desc->funcaddr))
>> + if (!get_kernel_nofault(p, (void *)&desc->addr))
>> ptr = p;
>> return ptr;
>> }
>> diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
>> index 6baa676e7cb6..82908c9be627 100644
>> --- a/arch/powerpc/kernel/module_64.c
>> +++ b/arch/powerpc/kernel/module_64.c
>> @@ -72,11 +72,11 @@ static func_desc_t func_desc(unsigned long addr)
>> }
>> static unsigned long func_addr(unsigned long addr)
>> {
>> - return func_desc(addr).funcaddr;
>> + return func_desc(addr).addr;
>> }
>> static unsigned long stub_func_addr(func_desc_t func)
>> {
>> - return func.funcaddr;
>> + return func.addr;
>> }
>> static unsigned int local_entry_offset(const Elf64_Sym *sym)
>> {
>> @@ -187,7 +187,7 @@ static int relacmp(const void *_x, const void *_y)
>> static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
>> const Elf64_Shdr *sechdrs)
>> {
>> - /* One extra reloc so it's always 0-funcaddr terminated */
>> + /* One extra reloc so it's always 0-addr terminated */
>> unsigned long relocs = 1;
>> unsigned i;
>>
>> --
>> 2.31.1