| Message ID | 1470988871-2799-4-git-send-email-jszhang@marvell.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Jisheng, On 12 August 2016 at 10:01, Jisheng Zhang <jszhang@marvell.com> wrote: > __initdata and __read_mostly should be placed after the variable name > for the variable to be placed in the intended section. > Why? > Signed-off-by: Jisheng Zhang <jszhang@marvell.com> > --- > arch/arm64/kernel/kaslr.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c > index b054691..8ebabc4 100644 > --- a/arch/arm64/kernel/kaslr.c > +++ b/arch/arm64/kernel/kaslr.c > @@ -20,8 +20,8 @@ > #include <asm/pgtable.h> > #include <asm/sections.h> > > -u64 __read_mostly module_alloc_base; > -u16 __initdata memstart_offset_seed; > +u64 module_alloc_base __read_mostly; > +u16 memstart_offset_seed __initdata; > > static __init u64 get_kaslr_seed(void *fdt) > { > -- > 2.8.1 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Hi Ard, On Fri, 12 Aug 2016 14:02:40 +0200 Ard Biesheuvel wrote: > Hi Jisheng, > > On 12 August 2016 at 10:01, Jisheng Zhang <jszhang@marvell.com> wrote: > > __initdata and __read_mostly should be placed after the variable name > > for the variable to be placed in the intended section. > > > > Why? include/linux/init.h says something as: * For initialized data: * You should insert __initdata or __initconst between the variable name * and equal sign followed by value, e.g.: * * static int init_variable __initdata = 0; * static const char linux_logo[] __initconst = { 0x32, 0x36, ... }; and examples in gcc manual also put __attribute__ (...) after variable name. https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#Common-Variable-Attributes Then I grep the source, found most lines (especially arch/arm64/*) put the __initdata and __read_mostly after the variable name. However, I built the code with three different gcc, the result looks identical no matter where these markers put. So the commit msg looks wrong, what about changes it as "put __initdata and __read_mostly after the variable name to keep the style consistent"? Thanks, Jisheng > > > Signed-off-by: Jisheng Zhang <jszhang@marvell.com> > > --- > > arch/arm64/kernel/kaslr.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c > > index b054691..8ebabc4 100644 > > --- a/arch/arm64/kernel/kaslr.c > > +++ b/arch/arm64/kernel/kaslr.c > > @@ -20,8 +20,8 @@ > > #include <asm/pgtable.h> > > #include <asm/sections.h> > > > > -u64 __read_mostly module_alloc_base; > > -u16 __initdata memstart_offset_seed; > > +u64 module_alloc_base __read_mostly; > > +u16 memstart_offset_seed __initdata; > > > > static __init u64 get_kaslr_seed(void *fdt) > > { > > -- > > 2.8.1 > > > > > > _______________________________________________ > > linux-arm-kernel mailing list > > linux-arm-kernel@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Hi Ard, On Mon, 15 Aug 2016 12:52:14 +0800 Jisheng Zhang wrote: > Hi Ard, > > On Fri, 12 Aug 2016 14:02:40 +0200 Ard Biesheuvel wrote: > > > Hi Jisheng, > > > > On 12 August 2016 at 10:01, Jisheng Zhang <jszhang@marvell.com> wrote: > > > __initdata and __read_mostly should be placed after the variable name > > > for the variable to be placed in the intended section. > > > > > > > Why? > > include/linux/init.h says something as: > > * For initialized data: > * You should insert __initdata or __initconst between the variable name > * and equal sign followed by value, e.g.: > * > * static int init_variable __initdata = 0; > * static const char linux_logo[] __initconst = { 0x32, 0x36, ... }; > > and examples in gcc manual also put __attribute__ (...) after variable name. > > https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#Common-Variable-Attributes > > Then I grep the source, found most lines (especially arch/arm64/*) put the > __initdata and __read_mostly after the variable name. > > However, I built the code with three different gcc, the result looks identical > no matter where these markers put. So the commit msg looks wrong, what about > changes it as > > "put __initdata and __read_mostly after the variable name > to keep the style consistent"? After some consideration, I want to drop this patch in newer version since it's not a bug, just "style" Thanks for your reviewing, Jisheng
On 15 August 2016 at 07:57, Jisheng Zhang <jszhang@marvell.com> wrote: > Hi Ard, > > On Mon, 15 Aug 2016 12:52:14 +0800 Jisheng Zhang wrote: > >> Hi Ard, >> >> On Fri, 12 Aug 2016 14:02:40 +0200 Ard Biesheuvel wrote: >> >> > Hi Jisheng, >> > >> > On 12 August 2016 at 10:01, Jisheng Zhang <jszhang@marvell.com> wrote: >> > > __initdata and __read_mostly should be placed after the variable name >> > > for the variable to be placed in the intended section. >> > > >> > >> > Why? >> >> include/linux/init.h says something as: >> >> * For initialized data: >> * You should insert __initdata or __initconst between the variable name >> * and equal sign followed by value, e.g.: >> * >> * static int init_variable __initdata = 0; >> * static const char linux_logo[] __initconst = { 0x32, 0x36, ... }; >> >> and examples in gcc manual also put __attribute__ (...) after variable name. >> >> https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#Common-Variable-Attributes >> >> Then I grep the source, found most lines (especially arch/arm64/*) put the >> __initdata and __read_mostly after the variable name. >> >> However, I built the code with three different gcc, the result looks identical >> no matter where these markers put. So the commit msg looks wrong, what about >> changes it as >> >> "put __initdata and __read_mostly after the variable name >> to keep the style consistent"? > > After some consideration, I want to drop this patch in newer version since > it's not a bug, just "style" > OK, thanks for clearing that up. I don't object to the patch, but I wanted to get confirmation that the current code is also correct. Thanks, Ard.
diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c index b054691..8ebabc4 100644 --- a/arch/arm64/kernel/kaslr.c +++ b/arch/arm64/kernel/kaslr.c @@ -20,8 +20,8 @@ #include <asm/pgtable.h> #include <asm/sections.h> -u64 __read_mostly module_alloc_base; -u16 __initdata memstart_offset_seed; +u64 module_alloc_base __read_mostly; +u16 memstart_offset_seed __initdata; static __init u64 get_kaslr_seed(void *fdt) {
__initdata and __read_mostly should be placed after the variable name for the variable to be placed in the intended section. Signed-off-by: Jisheng Zhang <jszhang@marvell.com> --- arch/arm64/kernel/kaslr.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)