2018-07-16 13:52:18

by Nicholas Mc Guire

Subject: [PATCH V2] ARM: STi: warn if scu mapping fails

If the device node is not found or the of_iomap() failed, calling
scu_enable would not be safe and could lead to an undefined system
state. So warn in both failure paths before returning.

Signed-off-by: Nicholas Mc Guire <[email protected]>
Link: http://lkml.org/lkml/2018/7/16/219
Fixes: commit 65ebcc115889 ("ARM: sti: Add STiH415 SOC support")
---

V2: replacement of WARN_ON() by a meaningful pr_err as suggested by
Patrice CHOTARD <[email protected]>.

Problem was found by an experimental coccinelle script

Patch was compile tested with: multi_v7_defconfig (implies
CONFIG_ARCH_STI=y, CONFIG_SMP=y)
(with one sparse warning unrelated to the proposed change)

Patch is against 4.18-rc4 (localversion-next is next-20180716)

arch/arm/mach-sti/platsmp.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/arch/arm/mach-sti/platsmp.c b/arch/arm/mach-sti/platsmp.c
index 231f19e..530e9a5 100644
--- a/arch/arm/mach-sti/platsmp.c
+++ b/arch/arm/mach-sti/platsmp.c
@@ -107,12 +107,22 @@ static void __init sti_smp_prepare_cpus(unsigned int max_cpus)

np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");

- if (np) {
- scu_base = of_iomap(np, 0);
- scu_enable(scu_base);
- of_node_put(np);
+ if (!np) {
+ pr_err("SCU not found at %s:%s():%d\n",
+ __FILE__, __func__, __LINE__);
+ return;
}

+ scu_base = of_iomap(np, 0);
+ of_node_put(np);
+ if (!scu_base) {
+ pr_err("SCU remap failed at %s:%s():%d\n",
+ __FILE__, __func__, __LINE__);
+ return;
+ }
+
+ scu_enable(scu_base);
+
if (max_cpus <= 1)
return;

--
2.1.4

2018-07-18 07:19:11

by Patrice CHOTARD

Subject: Re: [PATCH V2] ARM: STi: warn if scu mapping fails

Hi Nicholas

On 07/16/2018 03:46 PM, Nicholas Mc Guire wrote:
> If the device node is not found or the of_iomap() failed, calling
> scu_enable would not be safe and could lead to an undefined system
> state. So warn in both failure paths before returning.
>
> Signed-off-by: Nicholas Mc Guire <[email protected]>
> Link: http://lkml.org/lkml/2018/7/16/219
> Fixes: commit 65ebcc115889 ("ARM: sti: Add STiH415 SOC support")
> ---
>
> V2: replacement of WARN_ON() by a meaningful pr_err as suggested by
> Patrice CHOTARD <[email protected]>.
>
> Problem was found by an experimental coccinelle script
>
> Patch was compile tested with: multi_v7_defconfig (implies
> CONFIG_ARCH_STI=y, CONFIG_SMP=y)
> (with one sparse warning unrelated to the proposed change)
>
> Patch is against 4.18-rc4 (localversion-next is next-20180716)
>
> arch/arm/mach-sti/platsmp.c | 18 ++++++++++++++----
> 1 file changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/mach-sti/platsmp.c b/arch/arm/mach-sti/platsmp.c
> index 231f19e..530e9a5 100644
> --- a/arch/arm/mach-sti/platsmp.c
> +++ b/arch/arm/mach-sti/platsmp.c
> @@ -107,12 +107,22 @@ static void __init sti_smp_prepare_cpus(unsigned int max_cpus)
>
> np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");
>
> - if (np) {
> - scu_base = of_iomap(np, 0);
> - scu_enable(scu_base);
> - of_node_put(np);
> + if (!np) {
> + pr_err("SCU not found at %s:%s():%d\n",
> + __FILE__, __func__, __LINE__);
> + return;
> }
>
> + scu_base = of_iomap(np, 0);
> + of_node_put(np);
> + if (!scu_base) {
> + pr_err("SCU remap failed at %s:%s():%d\n",
> + __FILE__, __func__, __LINE__);
> + return;
> + }
> +
> + scu_enable(scu_base);
> +
> if (max_cpus <= 1)
> return;
>
>
Acked-by: Patrice Chotard <[email protected]>

Patrice