mips: Fix using smp_processor_id() when preemptible

Message ID 1502313950-725-1-git-send-email-minyard@acm.org
State New
Headers show

Commit Message

Corey Minyard Aug. 9, 2017, 9:25 p.m.
From: Corey Minyard <cminyard@mvista.com>


I was getting the following:

BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
caller is pcibios_set_cache_line_size+0x10/0x58

pcibios_set_cache_line_size() used current_cpu_data outside of
an unpreemptible context.

Signed-off-by: Corey Minyard <cminyard@mvista.com>

---
 arch/mips/pci/pci.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

-- 
2.7.4

Comments

Marcin Nowakowski Aug. 10, 2017, 7:57 a.m. | #1
Hi Corey,

This has already been fixed here:
https://git.linux-mips.org/cgit/ralf/upstream-sfr.git/commit/?id=21da5332327b6d183bd93336ecf29c70bc609b7b

https://git.linux-mips.org/cgit/ralf/upstream-sfr.git/commit/?id=735302665c353d6756e7fa2a2cf41b039299f732

Marcin

On 09.08.2017 23:25, minyard@acm.org wrote:
> From: Corey Minyard <cminyard@mvista.com>

> 

> I was getting the following:

> 

> BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1

> caller is pcibios_set_cache_line_size+0x10/0x58

> 

> pcibios_set_cache_line_size() used current_cpu_data outside of

> an unpreemptible context.

> 

> Signed-off-by: Corey Minyard <cminyard@mvista.com>

> ---

>   arch/mips/pci/pci.c | 5 ++++-

>   1 file changed, 4 insertions(+), 1 deletion(-)

> 

> diff --git a/arch/mips/pci/pci.c b/arch/mips/pci/pci.c

> index bd67ac7..afd2f8a 100644

> --- a/arch/mips/pci/pci.c

> +++ b/arch/mips/pci/pci.c

> @@ -28,9 +28,11 @@ EXPORT_SYMBOL(PCIBIOS_MIN_MEM);

>   

>   static int __init pcibios_set_cache_line_size(void)

>   {

> -	struct cpuinfo_mips *c = &current_cpu_data;

> +	struct cpuinfo_mips *c;

>   	unsigned int lsize;

>   

> +	preempt_disable();

> +	c = &current_cpu_data;

>   	/*

>   	 * Set PCI cacheline size to that of the highest level in the

>   	 * cache hierarchy.

> @@ -38,6 +40,7 @@ static int __init pcibios_set_cache_line_size(void)

>   	lsize = c->dcache.linesz;

>   	lsize = c->scache.linesz ? : lsize;

>   	lsize = c->tcache.linesz ? : lsize;

> +	preempt_enable();

>   

>   	BUG_ON(!lsize);

>   

>

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diff --git a/arch/mips/pci/pci.c b/arch/mips/pci/pci.c
index bd67ac7..afd2f8a 100644
--- a/arch/mips/pci/pci.c
+++ b/arch/mips/pci/pci.c
@@ -28,9 +28,11 @@  EXPORT_SYMBOL(PCIBIOS_MIN_MEM);
 
 static int __init pcibios_set_cache_line_size(void)
 {
-	struct cpuinfo_mips *c = &current_cpu_data;
+	struct cpuinfo_mips *c;
 	unsigned int lsize;
 
+	preempt_disable();
+	c = &current_cpu_data;
 	/*
 	 * Set PCI cacheline size to that of the highest level in the
 	 * cache hierarchy.
@@ -38,6 +40,7 @@  static int __init pcibios_set_cache_line_size(void)
 	lsize = c->dcache.linesz;
 	lsize = c->scache.linesz ? : lsize;
 	lsize = c->tcache.linesz ? : lsize;
+	preempt_enable();
 
 	BUG_ON(!lsize);