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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 3/6] xen/arm: add SMC wrapper that is compatible with SMCCC v1.0
On Tue, 25 Sep 2018, Julien Grall wrote:
> From: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>
>
> Existing SMC wrapper call_smc() allows only 4 parameters and
> returns only one value. This is enough for existing
> use in PSCI code, but TEE mediator will need a call that is
> fully compatible with ARM SMCCC v1.0.
>
> This patch adds a wrapper for both arm32 and arm64. In the case of
> arm32, the wrapper is just an alias to the ARM SMCCC v1.1 as the
> convention is the same.
>
> CC: "Edgar E. Iglesias" <edgar.iglesias@xxxxxxxxxx>
> Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>
> [julien: Rework the wrapper to make it closer to SMCC 1.1 wrapper]
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
I have been struggling to find the old doc for SMCCC v1.0, all the
references have been updated to v1.1 online now. Do you have a link?
> ---
> xen/arch/arm/arm64/Makefile | 1 +
> xen/arch/arm/arm64/asm-offsets.c | 5 ++++
> xen/arch/arm/arm64/smc.S | 32 +++++++++++++++++++++++++
> xen/include/asm-arm/smccc.h | 51
> +++++++++++++++++++++++++++++++++++++++-
> 4 files changed, 88 insertions(+), 1 deletion(-)
> create mode 100644 xen/arch/arm/arm64/smc.S
>
> diff --git a/xen/arch/arm/arm64/Makefile b/xen/arch/arm/arm64/Makefile
> index bb5c610b2a..c4f3a28a0d 100644
> --- a/xen/arch/arm/arm64/Makefile
> +++ b/xen/arch/arm/arm64/Makefile
> @@ -8,6 +8,7 @@ obj-y += domain.o
> obj-y += entry.o
> obj-y += insn.o
> obj-$(CONFIG_LIVEPATCH) += livepatch.o
> +obj-y += smc.o
> obj-y += smpboot.o
> obj-y += traps.o
> obj-y += vfp.o
> diff --git a/xen/arch/arm/arm64/asm-offsets.c
> b/xen/arch/arm/arm64/asm-offsets.c
> index 62833d8c8b..280ddb55bf 100644
> --- a/xen/arch/arm/arm64/asm-offsets.c
> +++ b/xen/arch/arm/arm64/asm-offsets.c
> @@ -10,6 +10,7 @@
> #include <xen/bitops.h>
> #include <public/xen.h>
> #include <asm/current.h>
> +#include <asm/smccc.h>
>
> #define DEFINE(_sym, _val) \
> asm volatile ("\n.ascii\"==>#define " #_sym " %0 /* " #_val " */<==\"" \
> @@ -51,6 +52,10 @@ void __dummy__(void)
>
> BLANK();
> OFFSET(INITINFO_stack, struct init_info, stack);
> +
> + BLANK();
> + OFFSET(SMCCC_RES_a0, struct arm_smccc_res, a0);
> + OFFSET(SMCCC_RES_a2, struct arm_smccc_res, a2);
> }
>
> /*
> diff --git a/xen/arch/arm/arm64/smc.S b/xen/arch/arm/arm64/smc.S
> new file mode 100644
> index 0000000000..b0752be57e
> --- /dev/null
> +++ b/xen/arch/arm/arm64/smc.S
> @@ -0,0 +1,32 @@
> +/*
> + * xen/arch/arm/arm64/smc.S
> + *
> + * Wrapper for Secure Monitors Calls
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License.
> + *
> + * 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 <asm/asm_defns.h>
> +#include <asm/macros.h>
> +
> +/*
> + * void __arm_smccc_1_0_smc(register_t a0, register_t a1, register_t a2,
> + * register_t a3, register_t a4, register_t a5,
> + * register_t a6, register_t a7,
> + * struct arm_smccc_res *res)
> + */
> +ENTRY(__arm_smccc_1_0_smc)
> + smc #0
> + ldr x4, [sp]
> + cbz x4, 1f /* No need to store the result */
> + stp x0, x1, [x4, #SMCCC_RES_a0]
> + stp x2, x3, [x4, #SMCCC_RES_a2]
> +1:
> + ret
As I mentioned, I couldn't find the doc, but it looks like the Linux
implementation always copies back the results
(arch/arm64/kernel/smccc-call.S)? Shouldn't we zero x0-x3 at least?
Other than that, it looks fine.
> diff --git a/xen/include/asm-arm/smccc.h b/xen/include/asm-arm/smccc.h
> index 648bef28bd..1ed6cbaa48 100644
> --- a/xen/include/asm-arm/smccc.h
> +++ b/xen/include/asm-arm/smccc.h
> @@ -207,7 +207,56 @@ struct arm_smccc_res {
> *___res = (typeof(*___res)){r0, r1, r2, r3}; \
> } while ( 0 )
>
> -#endif
> +/*
> + * The calling convention for arm32 is the same for both SMCCC v1.0 and
> + * v1.1.
> + */
> +#ifdef CONFIG_ARM_32
> +#define arm_smccc_1_0_smc(...) arm_smccc_1_1_smc(__VA_ARGS__)
> +#else
> +
> +void __arm_smccc_1_0_smc(register_t a0, register_t a1, register_t a2,
> + register_t a3, register_t a4, register_t a5,
> + register_t a6, register_t a7,
> + struct arm_smccc_res *res);
> +
> +/* Macros to handle variadic parameter for SMCCC v1.0 helper */
> +#define __arm_smccc_1_0_smc_7(a0, a1, a2, a3, a4, a5, a6, a7, res) \
> + __arm_smccc_1_0_smc(a0, a1, a2, a3, a4, a5, a6, a7, res)
> +
> +#define __arm_smccc_1_0_smc_6(a0, a1, a2, a3, a4, a5, a6, res) \
> + __arm_smccc_1_0_smc_7(a0, a1, a2, a3, a4, a5, a6, 0, res)
> +
> +#define __arm_smccc_1_0_smc_5(a0, a1, a2, a3, a4, a5, res) \
> + __arm_smccc_1_0_smc_6(a0, a1, a2, a3, a4, a5, 0, res)
> +
> +#define __arm_smccc_1_0_smc_4(a0, a1, a2, a3, a4, res) \
> + __arm_smccc_1_0_smc_5(a0, a1, a2, a3, a4, 0, res)
> +
> +#define __arm_smccc_1_0_smc_3(a0, a1, a2, a3, res) \
> + __arm_smccc_1_0_smc_4(a0, a1, a2, a3, 0, res)
> +
> +#define __arm_smccc_1_0_smc_2(a0, a1, a2, res) \
> + __arm_smccc_1_0_smc_3(a0, a1, a2, 0, res)
> +
> +#define __arm_smccc_1_0_smc_1(a0, a1, res) \
> + __arm_smccc_1_0_smc_2(a0, a1, 0, res)
> +
> +#define __arm_smccc_1_0_smc_0(a0, res) \
> + __arm_smccc_1_0_smc_1(a0, 0, res)
> +
> +#define ___arm_smccc_1_0_smc_count(count, ...) \
> + __arm_smccc_1_0_smc_ ## count(__VA_ARGS__)
> +
> +#define __arm_smccc_1_0_smc_count(count, ...) \
> + ___arm_smccc_1_0_smc_count(count, __VA_ARGS__)
> +
> +#define arm_smccc_1_0_smc(...) \
> + __arm_smccc_1_0_smc_count(__count_args(__VA_ARGS__), __VA_ARGS__)
> +
> +#endif /* CONFIG_ARM_64 */
> +
> +#endif /* __ASSEMBLY__ */
>
> /*
> * Construct function identifier from call type (fast or standard),
> --
> 2.11.0
>
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