[PATCH v5 1/5] arm/arm64: add smccc ARCH32
From: Will Deacon <hidden>
Date: 2015-08-19 16:50:16
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linux-devicetree, lkml
On Wed, Aug 19, 2015 at 09:40:25AM +0100, Jens Wiklander wrote:
Adds helpers to do SMC based on ARM SMC Calling Convention. CONFIG_HAVE_SMCCC is enabled for architectures that may support the SMC instruction. It's the responsibility of the caller to know if the SMC instruction is supported by the platform.
[...]
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/kernel/smccc-call.S b/arch/arm64/kernel/smccc-call.S new file mode 100644 index 0000000..3ce7fe8 --- /dev/null +++ b/arch/arm64/kernel/smccc-call.S@@ -0,0 +1,34 @@ +/* + * Copyright (c) 2015, Linaro Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License Version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ +#include <linux/linkage.h> + +#define SMC_PARAM_W0_OFFS 0 +#define SMC_PARAM_W2_OFFS 8 +#define SMC_PARAM_W4_OFFS 16 +#define SMC_PARAM_W6_OFFS 24 + +/* void smccc_call32(struct smccc_param32 *param) */ +ENTRY(smccc_call32) + stp x28, x30, [sp, #-16]!
Why are you saving lr?
+ mov x28, x0 + ldp w0, w1, [x28, #SMC_PARAM_W0_OFFS] + ldp w2, w3, [x28, #SMC_PARAM_W2_OFFS] + ldp w4, w5, [x28, #SMC_PARAM_W4_OFFS] + ldp w6, w7, [x28, #SMC_PARAM_W6_OFFS] + smc #0 + stp w0, w1, [x28, #SMC_PARAM_W0_OFFS] + stp w2, w3, [x28, #SMC_PARAM_W2_OFFS] + ldp x28, x30, [sp], #16 + ret +ENDPROC(smccc_call32)
Could we deal with this like we do for PSCI instead? (see __invoke_psci_fn_smc). We could also then rename psci-call.S to fw-call.S and stick this in there too. Will