Re: [PATCH] bcm: address clang inline asm incompatibility

From: Ard Biesheuvel
Date: Wed Jan 28 2015 - 20:06:38 EST


On 28 January 2015 at 05:18, Behan Webster <behanw@xxxxxxxxxxxxxxxxxx> wrote:
> From: Alex Elder <elder@xxxxxxxxxx>
>
> My GCC-based build environment likes to call register r12 by the
> name "ip" in inline asm. Behan Webster informed me that his Clang-
> based build environment likes "r12" instead.
>
> Try to make them both happy.
>
> Signed-off-by: Alex Elder <elder@xxxxxxxxxx>
> Signed-off-by: Behan Webster <behanw@xxxxxxxxxxxxxxxxxx>
> ---
> arch/arm/mach-bcm/bcm_kona_smc.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/mach-bcm/bcm_kona_smc.c b/arch/arm/mach-bcm/bcm_kona_smc.c
> index a55a7ec..3937bd5 100644
> --- a/arch/arm/mach-bcm/bcm_kona_smc.c
> +++ b/arch/arm/mach-bcm/bcm_kona_smc.c
> @@ -106,9 +106,14 @@ int __init bcm_kona_smc_init(void)
> * request result appropriately. This result value is found in r0
> * when the "smc" request completes.
> */
> +#ifdef __clang__
> +#define R12 "r12"
> +#else /* !__clang__ */
> +#define R12 "ip" /* gcc calls r12 "ip" */
> +#endif /* !__clang__ */

Why not just use r12 for both?

> static int bcm_kona_do_smc(u32 service_id, u32 buffer_phys)
> {
> - register u32 ip asm("ip"); /* Also called r12 */
> + register u32 ip asm(R12); /* Also called r12 */
> register u32 r0 asm("r0");
> register u32 r4 asm("r4");
> register u32 r5 asm("r5");
> @@ -120,7 +125,7 @@ static int bcm_kona_do_smc(u32 service_id, u32 buffer_phys)
>
> asm volatile (
> /* Make sure we got the registers we want */
> - __asmeq("%0", "ip")
> + __asmeq("%0", R12)
> __asmeq("%1", "r0")
> __asmeq("%2", "r4")
> __asmeq("%3", "r5")
> --
> 1.9.1
>
>
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