[U-Boot] [PATCH v3 1/2] arm: add support for semihosting for ARMv7M targets

[U-Boot] [PATCH v3 1/2] arm: add support for semihosting for ARMv7M targets

[Vadzim Dambrouski]

If you enable CONFIG_SEMIHOSTING for STM32F429 target, you will get compile
error looking like this:

arch/arm/lib/semihosting.c: In function 'smh_read':
{standard input}: Assembler messages:
{standard input}:34: Error: invalid swi expression
{standard input}:34: Error: value of 1193046 too large for field of 2 bytes at 0
scripts/Makefile.build:277: recipe for target 'arch/arm/lib/semihosting.o' failed

The source of the problem is "svc #0x123456" instruction. This instruction
can not be encoded using Thumb2 instruction set used by ARMv7M CPUs.
ARM documentation suggests using "bkpt #0xAB" instruction instead [1].
This patch fixes compile errors and adds support for semihosting for
STM32F429 or any other ARMv7M target.
This change was sested on STM32F429-DISCOVERY board using OpenOCD and
"smhload" u-boot command.

[1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0471c/Bgbjhiea.html

Signed-off-by: Vadzim Dambrouski <pftbest@gmail.com>
---

 arch/arm/lib/semihosting.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/lib/semihosting.c b/arch/arm/lib/semihosting.c
index c3e964e..ed5e8e4 100644
--- a/arch/arm/lib/semihosting.c
+++ b/arch/arm/lib/semihosting.c
@@ -31,6 +31,8 @@ static noinline long smh_trap(unsigned int sysnum, void *addr)
 	register long result asm("r0");
 #if defined(CONFIG_ARM64)
 	asm volatile ("hlt #0xf000" : "=r" (result) : "0"(sysnum), "r"(addr));
+#elif defined(CONFIG_CPU_V7M)
+	asm volatile ("bkpt #0xAB" : "=r" (result) : "0"(sysnum), "r"(addr));
 #else
 	/* Note - untested placeholder */
 	asm volatile ("svc #0x123456" : "=r" (result) : "0"(sysnum), "r"(addr));
-- 
2.6.1

[U-Boot] [PATCH v3 2/2] arm: fix compile warnings when semihosting is enabled on ARMv7M target.

[Vadzim Dambrouski]

This patch fixes compile warnings like this:

warning: format '%lu' expects argument of type 'long unsigned int',
         but argument 5 has type 'size_t'

In C99 standard you can use %zu modifier to print size_t values.

Signed-off-by: Vadzim Dambrouski <pftbest@gmail.com>
---

 arch/arm/lib/semihosting.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/lib/semihosting.c b/arch/arm/lib/semihosting.c
index ed5e8e4..e32ad90 100644
--- a/arch/arm/lib/semihosting.c
+++ b/arch/arm/lib/semihosting.c
@@ -92,7 +92,7 @@ static long smh_read(long fd, void *memp, size_t len)
 		size_t len;
 	} read;
 
-	debug("%s: fd %ld, memp %p, len %lu\n", __func__, fd, memp, len);
+	debug("%s: fd %ld, memp %p, len %zu\n", __func__, fd, memp, len);
 
 	read.fd = fd;
 	read.memp = memp;
@@ -106,7 +106,7 @@ static long smh_read(long fd, void *memp, size_t len)
 		 * hard to maintain partial read loops and such, just fail
 		 * with an error message.
 		 */
-		printf("%s: ERROR ret %ld, fd %ld, len %lu memp %p\n",
+		printf("%s: ERROR ret %ld, fd %ld, len %zu memp %p\n",
 		       __func__, ret, fd, len, memp);
 		return -1;
 	}
-- 
2.6.1

[U-Boot] [PATCH v3 1/2] arm: add support for semihosting for ARMv7M targets

[Albert ARIBAUD]

Hello Vadzim,

On Mon, 19 Oct 2015 19:40:14 +0300, Vadzim Dambrouski
<pftbest@gmail.com> wrote:
> If you enable CONFIG_SEMIHOSTING for STM32F429 target, you will get compile
> error looking like this:
> 
> arch/arm/lib/semihosting.c: In function 'smh_read':
> {standard input}: Assembler messages:
> {standard input}:34: Error: invalid swi expression
> {standard input}:34: Error: value of 1193046 too large for field of 2 bytes at 0
> scripts/Makefile.build:277: recipe for target 'arch/arm/lib/semihosting.o' failed
> 
> The source of the problem is "svc #0x123456" instruction. This instruction
> can not be encoded using Thumb2 instruction set used by ARMv7M CPUs.
> ARM documentation suggests using "bkpt #0xAB" instruction instead [1].
> This patch fixes compile errors and adds support for semihosting for
> STM32F429 or any other ARMv7M target.
> This change was sested on STM32F429-DISCOVERY board using OpenOCD and
> "smhload" u-boot command.
> 
> [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0471c/Bgbjhiea.html
> 
> Signed-off-by: Vadzim Dambrouski <pftbest@gmail.com>
> ---

Can someone provide their 'Tested-by' on this?

Amicalement,
-- 
Albert.

[U-Boot] [PATCH v3 1/2] arm: add support for semihosting for ARMv7M targets

[Albert ARIBAUD]

Hello Vadzim,

On Mon, 19 Oct 2015 19:40:14 +0300, Vadzim Dambrouski <pftbest@gmail.com> wrote:
> If you enable CONFIG_SEMIHOSTING for STM32F429 target, you will get compile
> error looking like this:
> 
> arch/arm/lib/semihosting.c: In function 'smh_read':
> {standard input}: Assembler messages:
> {standard input}:34: Error: invalid swi expression
> {standard input}:34: Error: value of 1193046 too large for field of 2 bytes at 0
> scripts/Makefile.build:277: recipe for target 'arch/arm/lib/semihosting.o' failed
> 
> The source of the problem is "svc #0x123456" instruction. This instruction
> can not be encoded using Thumb2 instruction set used by ARMv7M CPUs.
> ARM documentation suggests using "bkpt #0xAB" instruction instead [1].
> This patch fixes compile errors and adds support for semihosting for
> STM32F429 or any other ARMv7M target.
> This change was sested on STM32F429-DISCOVERY board using OpenOCD and
> "smhload" u-boot command.
> 
> [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0471c/Bgbjhiea.html
> 
> Signed-off-by: Vadzim Dambrouski <pftbest@gmail.com>
> ---
> 
>  arch/arm/lib/semihosting.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/arm/lib/semihosting.c b/arch/arm/lib/semihosting.c
> index c3e964e..ed5e8e4 100644
> --- a/arch/arm/lib/semihosting.c
> +++ b/arch/arm/lib/semihosting.c
> @@ -31,6 +31,8 @@ static noinline long smh_trap(unsigned int sysnum, void *addr)
>  	register long result asm("r0");
>  #if defined(CONFIG_ARM64)
>  	asm volatile ("hlt #0xf000" : "=r" (result) : "0"(sysnum), "r"(addr));
> +#elif defined(CONFIG_CPU_V7M)
> +	asm volatile ("bkpt #0xAB" : "=r" (result) : "0"(sysnum), "r"(addr));
>  #else
>  	/* Note - untested placeholder */
>  	asm volatile ("svc #0x123456" : "=r" (result) : "0"(sysnum), "r"(addr));
> -- 
> 2.6.1
> 

Applied to u-boot-arm/master, thanks!

Amicalement,
-- 
Albert.

[U-Boot] [PATCH v3 2/2] arm: fix compile warnings when semihosting is enabled on ARMv7M target.

[Albert ARIBAUD]

Hello Vadzim,

On Mon, 19 Oct 2015 19:40:15 +0300, Vadzim Dambrouski <pftbest@gmail.com> wrote:
> This patch fixes compile warnings like this:
> 
> warning: format '%lu' expects argument of type 'long unsigned int',
>          but argument 5 has type 'size_t'
> 
> In C99 standard you can use %zu modifier to print size_t values.
> 
> Signed-off-by: Vadzim Dambrouski <pftbest@gmail.com>
> ---
> 
>  arch/arm/lib/semihosting.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/lib/semihosting.c b/arch/arm/lib/semihosting.c
> index ed5e8e4..e32ad90 100644
> --- a/arch/arm/lib/semihosting.c
> +++ b/arch/arm/lib/semihosting.c
> @@ -92,7 +92,7 @@ static long smh_read(long fd, void *memp, size_t len)
>  		size_t len;
>  	} read;
>  
> -	debug("%s: fd %ld, memp %p, len %lu\n", __func__, fd, memp, len);
> +	debug("%s: fd %ld, memp %p, len %zu\n", __func__, fd, memp, len);
>  
>  	read.fd = fd;
>  	read.memp = memp;
> @@ -106,7 +106,7 @@ static long smh_read(long fd, void *memp, size_t len)
>  		 * hard to maintain partial read loops and such, just fail
>  		 * with an error message.
>  		 */
> -		printf("%s: ERROR ret %ld, fd %ld, len %lu memp %p\n",
> +		printf("%s: ERROR ret %ld, fd %ld, len %zu memp %p\n",
>  		       __func__, ret, fd, len, memp);
>  		return -1;
>  	}
> -- 
> 2.6.1
> 

Applied to u-boot-arm/master, thanks!

Amicalement,
-- 
Albert.