powerpc: kexec_file: Fix error code when trying to load kdump kernel

kexec_file_load() on powerpc doesn't support kdump kernels yet, so it
returns -ENOTSUPP in that case.

I've recently learned that this errno is internal to the kernel and isn't
supposed to be exposed to userspace. Therefore, change to -EOPNOTSUPP which
is defined in an uapi header.

This does indeed make kexec-tools happier. Before the patch, on ppc64le:

  # ~bauermann/src/kexec-tools/build/sbin/kexec -s -p /boot/vmlinuz
  kexec_file_load failed: Unknown error 524

After the patch:

  # ~bauermann/src/kexec-tools/build/sbin/kexec -s -p /boot/vmlinuz
  kexec_file_load failed: Operation not supported

Fixes: a0458284f062 ("powerpc: Add support code for kexec_file_load()")
Reported-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/machine_kexec_file_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

This is a minor issue, but since it's a simple patch it might be worth
applying it to stable branches.

This is the kexec-tools thread where this problem was brought up:

https://lists.infradead.org/pipermail/kexec/2018-March/020346.html

And this is an instance of a similar fix being applied elsewhere in the
kernel, for the same reasons:

https://patchwork.kernel.org/patch/8490791/

The test shown in the commit log was made using Hari Bathini's patch
adding kexec_file_load() support to kexec-tools in ppc64.

On Thu, Mar 29, 2018 at 04:05:43PM -0300, Thiago Jung Bauermann wrote:
> kexec_file_load() on powerpc doesn't support kdump kernels yet, so it
> returns -ENOTSUPP in that case.
> 
> I've recently learned that this errno is internal to the kernel and isn't
> supposed to be exposed to userspace. Therefore, change to -EOPNOTSUPP which
> is defined in an uapi header.
> 
> This does indeed make kexec-tools happier. Before the patch, on ppc64le:
> 
>   # ~bauermann/src/kexec-tools/build/sbin/kexec -s -p /boot/vmlinuz
>   kexec_file_load failed: Unknown error 524
> 
> After the patch:
> 
>   # ~bauermann/src/kexec-tools/build/sbin/kexec -s -p /boot/vmlinuz
>   kexec_file_load failed: Operation not supported
> 
> Fixes: a0458284f062 ("powerpc: Add support code for kexec_file_load()")
> Reported-by: Dave Young <dyoung@redhat.com>
> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>

Reviewed-by: Simon Horman <horms@verge.net.au>

On 03/29/18 at 04:05pm, Thiago Jung Bauermann wrote:
> kexec_file_load() on powerpc doesn't support kdump kernels yet, so it
> returns -ENOTSUPP in that case.
> 
> I've recently learned that this errno is internal to the kernel and isn't
> supposed to be exposed to userspace. Therefore, change to -EOPNOTSUPP which
> is defined in an uapi header.
> 
> This does indeed make kexec-tools happier. Before the patch, on ppc64le:
> 
>   # ~bauermann/src/kexec-tools/build/sbin/kexec -s -p /boot/vmlinuz
>   kexec_file_load failed: Unknown error 524
> 
> After the patch:
> 
>   # ~bauermann/src/kexec-tools/build/sbin/kexec -s -p /boot/vmlinuz
>   kexec_file_load failed: Operation not supported
> 
> Fixes: a0458284f062 ("powerpc: Add support code for kexec_file_load()")
> Reported-by: Dave Young <dyoung@redhat.com>
> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
> ---
>  arch/powerpc/kernel/machine_kexec_file_64.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> This is a minor issue, but since it's a simple patch it might be worth
> applying it to stable branches.
> 
> This is the kexec-tools thread where this problem was brought up:
> 
> https://lists.infradead.org/pipermail/kexec/2018-March/020346.html
> 
> And this is an instance of a similar fix being applied elsewhere in the
> kernel, for the same reasons:
> 
> https://patchwork.kernel.org/patch/8490791/
> 
> The test shown in the commit log was made using Hari Bathini's patch
> adding kexec_file_load() support to kexec-tools in ppc64.
> 
> diff --git a/arch/powerpc/kernel/machine_kexec_file_64.c b/arch/powerpc/kernel/machine_kexec_file_64.c
> index e4395f937d63..45e0b7d5f200 100644
> --- a/arch/powerpc/kernel/machine_kexec_file_64.c
> +++ b/arch/powerpc/kernel/machine_kexec_file_64.c
> @@ -43,7 +43,7 @@ int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
>  
>  	/* We don't support crash kernels yet. */
>  	if (image->type == KEXEC_TYPE_CRASH)
> -		return -ENOTSUPP;
> +		return -EOPNOTSUPP;
>  
>  	for (i = 0; i < ARRAY_SIZE(kexec_file_loaders); i++) {
>  		fops = kexec_file_loaders[i];
> 
> 
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec

Reviewed-by: Dave Young <dyoung@redhat.com>

Thanks
Dave

On Thu, 2018-03-29 at 19:05:43 UTC, Thiago Jung Bauermann wrote:
> kexec_file_load() on powerpc doesn't support kdump kernels yet, so it
> returns -ENOTSUPP in that case.
> 
> I've recently learned that this errno is internal to the kernel and isn't
> supposed to be exposed to userspace. Therefore, change to -EOPNOTSUPP which
> is defined in an uapi header.
> 
> This does indeed make kexec-tools happier. Before the patch, on ppc64le:
> 
>   # ~bauermann/src/kexec-tools/build/sbin/kexec -s -p /boot/vmlinuz
>   kexec_file_load failed: Unknown error 524
> 
> After the patch:
> 
>   # ~bauermann/src/kexec-tools/build/sbin/kexec -s -p /boot/vmlinuz
>   kexec_file_load failed: Operation not supported
> 
> Fixes: a0458284f062 ("powerpc: Add support code for kexec_file_load()")
> Reported-by: Dave Young <dyoung@redhat.com>
> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
> Reviewed-by: Simon Horman <horms@verge.net.au>
> Reviewed-by: Dave Young <dyoung@redhat.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/bf8a1abc3ddbd6e9a8312ea7d96e5d

cheers