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[2/3] ARM: orion: mark orion_ge00_mvmdio_bus_name as const

Message ID 20180220162519.1498223-2-arnd@arndb.de (mailing list archive)
State New, archived
Headers show

Commit Message

Arnd Bergmann Feb. 20, 2018, 4:24 p.m. UTC
A section type mismatch warning shows up when building with LTO,
since orion_ge00_mvmdio_bus_name was put in __initconst but not marked
const itself:

include/linux/of.h: In function 'spear_setup_of_timer':
arch/arm/mach-spear/time.c:207:34: error: 'timer_of_match' causes a section type conflict with 'orion_ge00_mvmdio_bus_name'
 static const struct of_device_id timer_of_match[] __initconst = {
                                  ^
arch/arm/plat-orion/common.c:475:32: note: 'orion_ge00_mvmdio_bus_name' was declared here
 static __initconst const char *orion_ge00_mvmdio_bus_name = "orion-mii";
                                ^

This marks it const as well.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/arm/plat-orion/common.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Andrew Lunn Feb. 21, 2018, 3:49 a.m. UTC | #1
On Tue, Feb 20, 2018 at 05:24:51PM +0100, Arnd Bergmann wrote:
> A section type mismatch warning shows up when building with LTO,
> since orion_ge00_mvmdio_bus_name was put in __initconst but not marked
> const itself:
> 
> include/linux/of.h: In function 'spear_setup_of_timer':
> arch/arm/mach-spear/time.c:207:34: error: 'timer_of_match' causes a section type conflict with 'orion_ge00_mvmdio_bus_name'
>  static const struct of_device_id timer_of_match[] __initconst = {
>                                   ^
> arch/arm/plat-orion/common.c:475:32: note: 'orion_ge00_mvmdio_bus_name' was declared here
>  static __initconst const char *orion_ge00_mvmdio_bus_name = "orion-mii";
>
> This marks it const as well.

Hi Arnd

I'm not sure this is the correct fix. orion_ge00_mvmdio_bus_name is
assigned to orion_ge00_switch_board_info->bus_id. This is then passed
to mdiobus_register_board_info() which makes a copy of
orion_ge00_switch_board_info and adds it to its linked list. The
original orion_ge00_switch_board_info will get freed since it is
__initdata, but the copy still has a pointer to
orion_ge00_mvmdio_bus_name, which also gets freed.

I think the correct fix is to remove the __initconst from
orion_ge00_mvmdio_bus_name. Marking it const is however valid.

	Andrew
Arnd Bergmann Feb. 21, 2018, 11:34 a.m. UTC | #2
On Wed, Feb 21, 2018 at 4:49 AM, Andrew Lunn <andrew@lunn.ch> wrote:
> On Tue, Feb 20, 2018 at 05:24:51PM +0100, Arnd Bergmann wrote:
>> A section type mismatch warning shows up when building with LTO,
>> since orion_ge00_mvmdio_bus_name was put in __initconst but not marked
>> const itself:
>>
>> include/linux/of.h: In function 'spear_setup_of_timer':
>> arch/arm/mach-spear/time.c:207:34: error: 'timer_of_match' causes a section type conflict with 'orion_ge00_mvmdio_bus_name'
>>  static const struct of_device_id timer_of_match[] __initconst = {
>>                                   ^
>> arch/arm/plat-orion/common.c:475:32: note: 'orion_ge00_mvmdio_bus_name' was declared here
>>  static __initconst const char *orion_ge00_mvmdio_bus_name = "orion-mii";
>>
>> This marks it const as well.
>
> Hi Arnd
>
> I'm not sure this is the correct fix. orion_ge00_mvmdio_bus_name is
> assigned to orion_ge00_switch_board_info->bus_id. This is then passed
> to mdiobus_register_board_info() which makes a copy of
> orion_ge00_switch_board_info and adds it to its linked list. The
> original orion_ge00_switch_board_info will get freed since it is
> __initdata, but the copy still has a pointer to
> orion_ge00_mvmdio_bus_name, which also gets freed.
>
> I think the correct fix is to remove the __initconst from
> orion_ge00_mvmdio_bus_name. Marking it const is however valid.

I looked at it some more and agree with your analysis, thanks for your
review!

I also checked the only other user of mdiobus_register_board_info(),
and made sure it does not have this problem.

I've prepared a new patch now, will send that after some more testing.

      Arnd
diff mbox

Patch

diff --git a/arch/arm/plat-orion/common.c b/arch/arm/plat-orion/common.c
index aff6994950ba..4e1d8270537c 100644
--- a/arch/arm/plat-orion/common.c
+++ b/arch/arm/plat-orion/common.c
@@ -472,7 +472,7 @@  void __init orion_ge11_init(struct mv643xx_eth_platform_data *eth_data,
 /*****************************************************************************
  * Ethernet switch
  ****************************************************************************/
-static __initconst const char *orion_ge00_mvmdio_bus_name = "orion-mii";
+static __initconst const char *const orion_ge00_mvmdio_bus_name = "orion-mii";
 static __initdata struct mdio_board_info
 		  orion_ge00_switch_board_info;