[PATCH] ARM: orion: fix orion_ge00_switch_board_info initialization

[PATCH] ARM: orion: fix orion_ge00_switch_board_info initialization

[Arnd Bergmann]

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";
                                ^

As pointed out by Andrew Lunn, it should in fact be 'const' but not
'__initconst' because the string is never copied but may be accessed
after the init sections are freed. To fix that, I get rid of the
extra symbol and rewrite the initialization in a simpler way that
assigns both the bus_id and modalias statically.

I spotted another theoretical bug in the same place, where d->netdev[i]
may be an out of bounds access, this can be fixed by moving the device
assignment into the loop.

Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v2: complete rewrite
---
 arch/arm/plat-orion/common.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/arch/arm/plat-orion/common.c b/arch/arm/plat-orion/common.c
index aff6994950ba..a2399fd66e97 100644
--- a/arch/arm/plat-orion/common.c
+++ b/arch/arm/plat-orion/common.c
@@ -472,28 +472,27 @@ 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 __initdata struct mdio_board_info
-		  orion_ge00_switch_board_info;
+static __initdata struct mdio_board_info orion_ge00_switch_board_info = {
+	.bus_id   = "orion-mii",
+	.modalias = "mv88e6085",
+};
 
 void __init orion_ge00_switch_init(struct dsa_chip_data *d)
 {
-	struct mdio_board_info *bd;
 	unsigned int i;
 
 	if (!IS_BUILTIN(CONFIG_PHYLIB))
 		return;
 
-	for (i = 0; i < ARRAY_SIZE(d->port_names); i++)
-		if (!strcmp(d->port_names[i], "cpu"))
+	for (i = 0; i < ARRAY_SIZE(d->port_names); i++) {
+		if (!strcmp(d->port_names[i], "cpu")) {
+			d->netdev[i] = &orion_ge00.dev;
 			break;
+		}
+	}
 
-	bd = &orion_ge00_switch_board_info;
-	bd->bus_id = orion_ge00_mvmdio_bus_name;
-	bd->mdio_addr = d->sw_addr;
-	d->netdev[i] = &orion_ge00.dev;
-	strcpy(bd->modalias, "mv88e6085");
-	bd->platform_data = d;
+	orion_ge00_switch_board_info.mdio_addr = d->sw_addr;
+	orion_ge00_switch_board_info.platform_data = d;
 
 	mdiobus_register_board_info(&orion_ge00_switch_board_info, 1);
 }
-- 
2.9.0

Re: [PATCH] ARM: orion: fix orion_ge00_switch_board_info initialization

[Andrew Lunn]

On Wed, Feb 21, 2018 at 01:18:49PM +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";
>                                 ^
> 
> As pointed out by Andrew Lunn, it should in fact be 'const' but not
> '__initconst' because the string is never copied but may be accessed
> after the init sections are freed. To fix that, I get rid of the
> extra symbol and rewrite the initialization in a simpler way that
> assigns both the bus_id and modalias statically.
> 
> I spotted another theoretical bug in the same place, where d->netdev[i]
> may be an out of bounds access, this can be fixed by moving the device
> assignment into the loop.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew

Re: [PATCH] ARM: orion: fix orion_ge00_switch_board_info initialization

[Arnd Bergmann]

On Thu, Feb 22, 2018 at 2:30 PM, Andrew Lunn <andrew@lunn.ch> wrote:
> On Wed, Feb 21, 2018 at 01:18:49PM +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";
>>                                 ^
>>
>> As pointed out by Andrew Lunn, it should in fact be 'const' but not
>> '__initconst' because the string is never copied but may be accessed
>> after the init sections are freed. To fix that, I get rid of the
>> extra symbol and rewrite the initialization in a simpler way that
>> assigns both the bus_id and modalias statically.
>>
>> I spotted another theoretical bug in the same place, where d->netdev[i]
>> may be an out of bounds access, this can be fixed by moving the device
>> assignment into the loop.
>>
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>

Thanks, applied into fixes branch with your Reviewed-by tag now.

        Arnd