[U-Boot] [PATCH v7 3/9] armv8: Add Secure Monitor/Hypervisor Call (SMC/HVC) infrastructure

[Mateusz Kulikowski <mateusz.kulikowski@gmail.com>]

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On 14.10.2015 18:55, Sergey Temerkhanov wrote:
> This commit adds functions issuing calls to secure monitor or
> hypervisore. This allows using services such as Power State
> Coordination Interface (PSCI) provided by firmware, e.g. ARM
> Trusted Firmware (ATF)
> 
> The SMC call can destroy all registers declared temporary by the
> calling conventions. The clobber list is "x0..x17" because of
> this
> 
> Signed-off-by: Sergey Temerkhanov <s.temerkhanov@gmail.com>
> Signed-off-by: Corey Minyard <cminyard@mvista.com>
> Signed-off-by: Radha Mohan Chintakuntla <rchintakuntla@cavium.com>
> Reviewed-by: Simon Glass <sjg@chromium.org>

+1 (I may need it as well)

Tested-by: Mateusz Kulikowski <mateusz.kulikowski@gmail.com>

Tested on: Hikey
Methodology:

Hacked smc handler in arm trusted firmware (x0=x0+x1, x1=x2+x3, x2=x4+x5, x3=x6+2)
+new u-boot command (smc/hvc) using functions from this patch;

I didn't tested hvc code (would need to make some fake hypervisor), but it's basically the same.

Idea: perhaps after this series is merged we can add 2 new commands to u-boot (SMC/HVC) to 
play with hypervisors/secure monitors (and perhaps use some simple functionality if needed).


@Sergey - you probably need to rebase the patch as it doesn't apply to master cleanly

Regards,
Mateusz

> 
> ---
> 
> Changes in v7: None
> Changes in v6: None
> Changes in v5: None
> Changes in v4:
> - Document FW calls
> 
> Changes in v3:
> - Fixed clobber lists (thanks to Corey)
> 
> Changes in v2: None
> 
>  arch/arm/cpu/armv8/Makefile   |  1 +
>  arch/arm/cpu/armv8/fwcall.c   | 75 +++++++++++++++++++++++++++++++++++++++++++
>  arch/arm/include/asm/system.h | 21 ++++++++++++
>  3 files changed, 97 insertions(+)
>  create mode 100644 arch/arm/cpu/armv8/fwcall.c
> 
> diff --git a/arch/arm/cpu/armv8/Makefile b/arch/arm/cpu/armv8/Makefile
> index adb11b3..7579ea7 100644
> --- a/arch/arm/cpu/armv8/Makefile
> +++ b/arch/arm/cpu/armv8/Makefile
> @@ -14,6 +14,7 @@ obj-y	+= exceptions.o
>  obj-y	+= cache.o
>  obj-y	+= tlb.o
>  obj-y	+= transition.o
> +obj-y	+= fwcall.o
>  
>  obj-$(CONFIG_FSL_LSCH3) += fsl-lsch3/
>  obj-$(CONFIG_ARCH_ZYNQMP) += zynqmp/
> diff --git a/arch/arm/cpu/armv8/fwcall.c b/arch/arm/cpu/armv8/fwcall.c
> new file mode 100644
> index 0000000..9efcc5a
> --- /dev/null
> +++ b/arch/arm/cpu/armv8/fwcall.c
> @@ -0,0 +1,75 @@
> +/**
> + * (C) Copyright 2014, Cavium Inc.
> + *
> + * SPDX-License-Identifier:	GPL-2.0+
> +**/
> +
> +#include <asm-offsets.h>
> +#include <config.h>
> +#include <version.h>
> +#include <asm/macro.h>
> +#include <asm/system.h>
> +
> +/*
> + * Issue the hypervisor call
> + *
> + * x0~x7: input arguments
> + * x0~x3: output arguments
> + */
> +void hvc_call(struct pt_regs *args)
> +{
> +	asm volatile(
> +		"ldr x0, %0\n"
> +		"ldr x1, %1\n"
> +		"ldr x2, %2\n"
> +		"ldr x3, %3\n"
> +		"ldr x4, %4\n"
> +		"ldr x5, %5\n"
> +		"ldr x6, %6\n"
> +		"ldr x7, %7\n"
> +		"hvc	#0\n"
> +		"str x0, %0\n"
> +		"str x1, %1\n"
> +		"str x2, %2\n"
> +		"str x3, %3\n"
> +		: "+m" (args->regs[0]), "+m" (args->regs[1]),
> +		  "+m" (args->regs[2]), "+m" (args->regs[3])
> +		: "m" (args->regs[4]), "m" (args->regs[5]),
> +		  "m" (args->regs[6]), "m" (args->regs[7])
> +		: "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7",
> +		  "x8", "x9", "x10", "x11", "x12", "x13", "x14", "x15",
> +		  "x16", "x17");
> +}
> +
> +/*
> + * void smc_call(arg0, arg1...arg7)
> + *
> + * issue the secure monitor call
> + *
> + * x0~x7: input arguments
> + * x0~x3: output arguments
> + */
> +
> +void smc_call(struct pt_regs *args)
> +{
> +	asm volatile(
> +		"ldr x0, %0\n"
> +		"ldr x1, %1\n"
> +		"ldr x2, %2\n"
> +		"ldr x3, %3\n"
> +		"ldr x4, %4\n"
> +		"ldr x5, %5\n"
> +		"ldr x6, %6\n"
> +		"smc	#0\n"
> +		"str x0, %0\n"
> +		"str x1, %1\n"
> +		"str x2, %2\n"
> +		"str x3, %3\n"
> +		: "+m" (args->regs[0]), "+m" (args->regs[1]),
> +		  "+m" (args->regs[2]), "+m" (args->regs[3])
> +		: "m" (args->regs[4]), "m" (args->regs[5]),
> +		  "m" (args->regs[6])
> +		: "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7",
> +		  "x8", "x9", "x10", "x11", "x12", "x13", "x14", "x15",
> +		  "x16", "x17");
> +}
> diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
> index 9288541..f3e2d1b 100644
> --- a/arch/arm/include/asm/system.h
> +++ b/arch/arm/include/asm/system.h
> @@ -1,6 +1,9 @@
>  #ifndef __ASM_ARM_SYSTEM_H
>  #define __ASM_ARM_SYSTEM_H
>  
> +#include <common.h>
> +#include <linux/compiler.h>
> +
>  #ifdef CONFIG_ARM64
>  
>  /*
> @@ -104,6 +107,24 @@ void smp_kick_all_cpus(void);
>  
>  void flush_l3_cache(void);
>  
> +/*
> + *Issue a hypervisor call in accordance with ARM "SMC Calling convention",
> + * DEN0028A
> + *
> + * @args: input and output arguments
> + *
> + */
> +void hvc_call(struct pt_regs *args);
> +
> +/*
> + *Issue a secure monitor call in accordance with ARM "SMC Calling convention",
> + * DEN0028A
> + *
> + * @args: input and output arguments
> + *
> + */
> +void smc_call(struct pt_regs *args);
> +
>  #endif	/* __ASSEMBLY__ */
>  
>  #else /* CONFIG_ARM64 */
> 

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