Re: [PATCH 1/2] arm64: kernel: Add SMC Session ID to results

Bjorn Andersson
2016-08-24T18:24:14Z

On Fri 19 Aug 22:51 PDT 2016, Andy Gross wrote:

> This patch adds the SMC Session ID to the results passed back from SMC
> calls. The Qualcomm SMC implementation provides for interrupted SMC
> functions. When this occurs, the SMC call will return a session ID that
> is required to be used when resuming the interrupted SMC call.
>
> Signed-off-by: Andy Gross <andy.gross@linaro.org>

This fixes the spurious remoteproc firmware authentication failures I've
seen lately.

Tested-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn

> ---
> arch/arm64/kernel/asm-offsets.c | 1 +
> arch/arm64/kernel/smccc-call.S | 1 +
> include/linux/arm-smccc.h | 4 +++-
> 3 files changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
> index 05070b7..ff38c58 100644
> --- a/arch/arm64/kernel/asm-offsets.c
> +++ b/arch/arm64/kernel/asm-offsets.c
> @@ -141,6 +141,7 @@ int main(void)
> #endif
> DEFINE(ARM_SMCCC_RES_X0_OFFS, offsetof(struct arm_smccc_res, a0));
> DEFINE(ARM_SMCCC_RES_X2_OFFS, offsetof(struct arm_smccc_res, a2));
> + DEFINE(ARM_SMCCC_RES_X6_OFFS, offsetof(struct arm_smccc_res, a6));
> BLANK();
> DEFINE(HIBERN_PBE_ORIG, offsetof(struct pbe, orig_address));
> DEFINE(HIBERN_PBE_ADDR, offsetof(struct pbe, address));
> diff --git a/arch/arm64/kernel/smccc-call.S b/arch/arm64/kernel/smccc-call.S
> index ae0496f..278dc9a 100644
> --- a/arch/arm64/kernel/smccc-call.S
> +++ b/arch/arm64/kernel/smccc-call.S
> @@ -20,6 +20,7 @@
> ldr x4, [sp]
> stp x0, x1, [x4, #ARM_SMCCC_RES_X0_OFFS]
> stp x2, x3, [x4, #ARM_SMCCC_RES_X2_OFFS]
> + str x6, [x4, #ARM_SMCCC_RES_X6_OFFS]
> ret
> .cfi_endproc
> .endm
> diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
> index b5abfda..82d919f 100644
> --- a/include/linux/arm-smccc.h
> +++ b/include/linux/arm-smccc.h
> @@ -63,18 +63,20 @@
> /**
> * struct arm_smccc_res - Result from SMC/HVC call
> * @a0-a3 result values from registers 0 to 3
> + * @a6 Session ID register (optional)
> */
> struct arm_smccc_res {
> unsigned long a0;
> unsigned long a1;
> unsigned long a2;
> unsigned long a3;
> + unsigned long a6;
> };
>
> /**
> * arm_smccc_smc() - make SMC calls
> * @a0-a7: arguments passed in registers 0 to 7
> - * @res: result values from registers 0 to 3
> + * @res: result values from registers 0 to 3 and optional register 6
> *
> * This function is used to make SMC calls following SMC Calling Convention.
> * The content of the supplied param are copied to registers 0 to 7 prior
> --
> 1.9.1
>