[PATCH 1/2] arm64: kernel: Add SMC Session ID to results
From: Will Deacon <hidden>
Date: 2016-08-22 13:43:50
Also in:
linux-arm-msm, lkml
On Sat, Aug 20, 2016 at 12:51:13AM -0500, 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 <redacted> --- 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(-)
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quoted hunk ↗ jump to hunk
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
AFAICT from reading the SMCCC spec, parameter register 6 is "Unpredictable, Scratch registers" in return state, so I don't think this is correct. What am I missing? Will