[PATCH 0/2] ARM: zynq: smp improvements

[PATCH 0/2] ARM: zynq: smp improvements

[Luis Araneda]

This series adds support for kernel compiled in Thumb mode
and fixes a kernel panic on smp bring-up when FORTIFY_SOURCE
is enabled.

The series started with the second patch as an RFC, and
the first patch were suggested on the review to complement
the fix.

The changes were run-tested on a Digilent Zybo Z7 board

Luis Araneda (2):
  ARM: zynq: support smp in thumb mode
  ARM: zynq: Use memcpy_toio instead of memcpy on smp bring-up

 arch/arm/mach-zynq/headsmp.S | 2 ++
 arch/arm/mach-zynq/platsmp.c | 4 ++--
 2 files changed, 4 insertions(+), 2 deletions(-)

-- 
2.22.0

[PATCH 1/2] ARM: zynq: support smp in thumb mode

[Luis Araneda]

Add .arm directive to headsmp.S to ensure that the
CPU starts in 32-bit ARM mode and the correct code
size is copied on smp bring-up

Additionally, start secondary CPUs on secondary_startup_arm
to automatically switch from ARM to thumb on a thumb kernel

Suggested-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Luis Araneda <luaraneda@gmail.com>
---
 arch/arm/mach-zynq/headsmp.S | 2 ++
 arch/arm/mach-zynq/platsmp.c | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-zynq/headsmp.S b/arch/arm/mach-zynq/headsmp.S
index ab85003cf9ad..3449e0d1f990 100644
--- a/arch/arm/mach-zynq/headsmp.S
+++ b/arch/arm/mach-zynq/headsmp.S
@@ -7,6 +7,8 @@
 #include <linux/init.h>
 #include <asm/assembler.h>
 
+	.arm
+
 ENTRY(zynq_secondary_trampoline)
 ARM_BE8(setend	be)				@ ensure we are in BE8 mode
 	ldr	r0, zynq_secondary_trampoline_jump
diff --git a/arch/arm/mach-zynq/platsmp.c b/arch/arm/mach-zynq/platsmp.c
index a7cfe07156f4..38728badabd4 100644
--- a/arch/arm/mach-zynq/platsmp.c
+++ b/arch/arm/mach-zynq/platsmp.c
@@ -81,7 +81,7 @@ EXPORT_SYMBOL(zynq_cpun_start);
 
 static int zynq_boot_secondary(unsigned int cpu, struct task_struct *idle)
 {
-	return zynq_cpun_start(__pa_symbol(secondary_startup), cpu);
+	return zynq_cpun_start(__pa_symbol(secondary_startup_arm), cpu);
 }
 
 /*
-- 
2.22.0

[PATCH 2/2] ARM: zynq: Use memcpy_toio instead of memcpy on smp bring-up

[Luis Araneda]

This fixes a kernel panic (read overflow) on memcpy when
FORTIFY_SOURCE is enabled.

The computed size of memcpy args are:
- p_size (dst): 4294967295 = (size_t) -1
- q_size (src): 1
- size (len): 8

Additionally, the memory is marked as __iomem, so one of
the memcpy_* functions should be used for read/write

Signed-off-by: Luis Araneda <luaraneda@gmail.com>
---
 arch/arm/mach-zynq/platsmp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/mach-zynq/platsmp.c b/arch/arm/mach-zynq/platsmp.c
index 38728badabd4..a10085be9073 100644
--- a/arch/arm/mach-zynq/platsmp.c
+++ b/arch/arm/mach-zynq/platsmp.c
@@ -57,7 +57,7 @@ int zynq_cpun_start(u32 address, int cpu)
 			* 0x4: Jump by mov instruction
 			* 0x8: Jumping address
 			*/
-			memcpy((__force void *)zero, &zynq_secondary_trampoline,
+			memcpy_toio(zero, &zynq_secondary_trampoline,
 							trampoline_size);
 			writel(address, zero + trampoline_size);
 
-- 
2.22.0

Re: [PATCH 0/2] ARM: zynq: smp improvements

[Greg KH]

On Mon, Aug 05, 2019 at 11:07:16PM -0400, Luis Araneda wrote:
> This series adds support for kernel compiled in Thumb mode
> and fixes a kernel panic on smp bring-up when FORTIFY_SOURCE
> is enabled.
> 
> The series started with the second patch as an RFC, and
> the first patch were suggested on the review to complement
> the fix.
> 
> The changes were run-tested on a Digilent Zybo Z7 board
> 
> Luis Araneda (2):
>   ARM: zynq: support smp in thumb mode
>   ARM: zynq: Use memcpy_toio instead of memcpy on smp bring-up
> 
>  arch/arm/mach-zynq/headsmp.S | 2 ++
>  arch/arm/mach-zynq/platsmp.c | 4 ++--
>  2 files changed, 4 insertions(+), 2 deletions(-)
> 
> -- 
> 2.22.0
> 

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>

Re: [PATCH 2/2] ARM: zynq: Use memcpy_toio instead of memcpy on smp bring-up

[Greg KH]

On Mon, Aug 05, 2019 at 11:07:18PM -0400, Luis Araneda wrote:
> This fixes a kernel panic (read overflow) on memcpy when
> FORTIFY_SOURCE is enabled.
> 
> The computed size of memcpy args are:
> - p_size (dst): 4294967295 = (size_t) -1
> - q_size (src): 1
> - size (len): 8
> 
> Additionally, the memory is marked as __iomem, so one of
> the memcpy_* functions should be used for read/write
> 
> Signed-off-by: Luis Araneda <luaraneda@gmail.com>
> ---
>  arch/arm/mach-zynq/platsmp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>

Re: [PATCH 1/2] ARM: zynq: support smp in thumb mode

[Greg KH]

On Mon, Aug 05, 2019 at 11:07:17PM -0400, Luis Araneda wrote:
> Add .arm directive to headsmp.S to ensure that the
> CPU starts in 32-bit ARM mode and the correct code
> size is copied on smp bring-up
> 
> Additionally, start secondary CPUs on secondary_startup_arm
> to automatically switch from ARM to thumb on a thumb kernel
> 
> Suggested-by: Michal Simek <michal.simek@xilinx.com>
> Signed-off-by: Luis Araneda <luaraneda@gmail.com>
> ---
>  arch/arm/mach-zynq/headsmp.S | 2 ++
>  arch/arm/mach-zynq/platsmp.c | 2 +-
>  2 files changed, 3 insertions(+), 1 deletion(-)

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>

Re: [PATCH 1/2] ARM: zynq: support smp in thumb mode

[Michal Simek]

On 06. 08. 19 5:07, Luis Araneda wrote:
> Add .arm directive to headsmp.S to ensure that the
> CPU starts in 32-bit ARM mode and the correct code
> size is copied on smp bring-up
> 
> Additionally, start secondary CPUs on secondary_startup_arm
> to automatically switch from ARM to thumb on a thumb kernel
> 
> Suggested-by: Michal Simek <michal.simek@xilinx.com>
> Signed-off-by: Luis Araneda <luaraneda@gmail.com>
> ---
>  arch/arm/mach-zynq/headsmp.S | 2 ++
>  arch/arm/mach-zynq/platsmp.c | 2 +-
>  2 files changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/mach-zynq/headsmp.S b/arch/arm/mach-zynq/headsmp.S
> index ab85003cf9ad..3449e0d1f990 100644
> --- a/arch/arm/mach-zynq/headsmp.S
> +++ b/arch/arm/mach-zynq/headsmp.S
> @@ -7,6 +7,8 @@
>  #include <linux/init.h>
>  #include <asm/assembler.h>
>  
> +	.arm
> +
>  ENTRY(zynq_secondary_trampoline)
>  ARM_BE8(setend	be)				@ ensure we are in BE8 mode
>  	ldr	r0, zynq_secondary_trampoline_jump
> diff --git a/arch/arm/mach-zynq/platsmp.c b/arch/arm/mach-zynq/platsmp.c
> index a7cfe07156f4..38728badabd4 100644
> --- a/arch/arm/mach-zynq/platsmp.c
> +++ b/arch/arm/mach-zynq/platsmp.c
> @@ -81,7 +81,7 @@ EXPORT_SYMBOL(zynq_cpun_start);
>  
>  static int zynq_boot_secondary(unsigned int cpu, struct task_struct *idle)
>  {
> -	return zynq_cpun_start(__pa_symbol(secondary_startup), cpu);
> +	return zynq_cpun_start(__pa_symbol(secondary_startup_arm), cpu);
>  }
>  
>  /*
> 

It is really a question if this should go to stable tree. It is pretty
much new feature.
Will be good to also add link to similar patch for example this one
5616f36713ea77f57ae908bf2fef641364403c9f.

M

Re: [PATCH 2/2] ARM: zynq: Use memcpy_toio instead of memcpy on smp bring-up

[Michal Simek]

On 06. 08. 19 5:07, Luis Araneda wrote:
> This fixes a kernel panic (read overflow) on memcpy when
> FORTIFY_SOURCE is enabled.
> 
> The computed size of memcpy args are:
> - p_size (dst): 4294967295 = (size_t) -1
> - q_size (src): 1
> - size (len): 8
> 
> Additionally, the memory is marked as __iomem, so one of
> the memcpy_* functions should be used for read/write
> 
> Signed-off-by: Luis Araneda <luaraneda@gmail.com>
> ---
>  arch/arm/mach-zynq/platsmp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/mach-zynq/platsmp.c b/arch/arm/mach-zynq/platsmp.c
> index 38728badabd4..a10085be9073 100644
> --- a/arch/arm/mach-zynq/platsmp.c
> +++ b/arch/arm/mach-zynq/platsmp.c
> @@ -57,7 +57,7 @@ int zynq_cpun_start(u32 address, int cpu)
>  			* 0x4: Jump by mov instruction
>  			* 0x8: Jumping address
>  			*/
> -			memcpy((__force void *)zero, &zynq_secondary_trampoline,
> +			memcpy_toio(zero, &zynq_secondary_trampoline,
>  							trampoline_size);
>  			writel(address, zero + trampoline_size);
>  

I would consider this one as stable material. Please also add there link
to the patch which this patch fixes.

M