[v9,4/7] extable: Add function to search only kernel exception table
diff mbox series

Message ID 20190812092236.16648-5-santosh@fossix.org
State Superseded
Headers show
Series
  • powerpc: implement machine check safe memcpy
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Commit Message

Santosh Sivaraj Aug. 12, 2019, 9:22 a.m. UTC
Certain architecture specific operating modes (e.g., in powerpc machine
check handler that is unable to access vmalloc memory), the
search_exception_tables cannot be called because it also searches the
module exception tables if entry is not found in the kernel exception
table.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Santosh Sivaraj <santosh@fossix.org>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
---
 include/linux/extable.h |  2 ++
 kernel/extable.c        | 11 +++++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

Comments

Balbir Singh Aug. 14, 2019, 9:22 a.m. UTC | #1
On 12/8/19 7:22 pm, Santosh Sivaraj wrote:
> Certain architecture specific operating modes (e.g., in powerpc machine
> check handler that is unable to access vmalloc memory), the
> search_exception_tables cannot be called because it also searches the
> module exception tables if entry is not found in the kernel exception
> table.
> 
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Signed-off-by: Santosh Sivaraj <santosh@fossix.org>
> Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>  include/linux/extable.h |  2 ++
>  kernel/extable.c        | 11 +++++++++--
>  2 files changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/extable.h b/include/linux/extable.h
> index 41c5b3a25f67..81ecfaa83ad3 100644
> --- a/include/linux/extable.h
> +++ b/include/linux/extable.h
> @@ -19,6 +19,8 @@ void trim_init_extable(struct module *m);
>  
>  /* Given an address, look for it in the exception tables */
>  const struct exception_table_entry *search_exception_tables(unsigned long add);
> +const struct exception_table_entry *
> +search_kernel_exception_table(unsigned long addr);
> 

Can we find a better name search_kernel still sounds like all of the kernel.
Can we rename it to search_kernel_linear_map_extable?

 
>  #ifdef CONFIG_MODULES
>  /* For extable.c to search modules' exception tables. */
> diff --git a/kernel/extable.c b/kernel/extable.c
> index e23cce6e6092..f6c9406eec7d 100644
> --- a/kernel/extable.c
> +++ b/kernel/extable.c
> @@ -40,13 +40,20 @@ void __init sort_main_extable(void)
>  	}
>  }
>  
> +/* Given an address, look for it in the kernel exception table */
> +const
> +struct exception_table_entry *search_kernel_exception_table(unsigned long addr)
> +{
> +	return search_extable(__start___ex_table,
> +			      __stop___ex_table - __start___ex_table, addr);
> +}
> +
>  /* Given an address, look for it in the exception tables. */
>  const struct exception_table_entry *search_exception_tables(unsigned long addr)
>  {
>  	const struct exception_table_entry *e;
>  
> -	e = search_extable(__start___ex_table,
> -			   __stop___ex_table - __start___ex_table, addr);
> +	e = search_kernel_exception_table(addr);
>  	if (!e)
>  		e = search_module_extables(addr);
>  	return e;
>
Santosh Sivaraj Aug. 14, 2019, 9:39 a.m. UTC | #2
Balbir Singh <bsingharora@gmail.com> writes:

> On 12/8/19 7:22 pm, Santosh Sivaraj wrote:
>> Certain architecture specific operating modes (e.g., in powerpc machine
>> check handler that is unable to access vmalloc memory), the
>> search_exception_tables cannot be called because it also searches the
>> module exception tables if entry is not found in the kernel exception
>> table.
>> 
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Ingo Molnar <mingo@kernel.org>
>> Cc: Nicholas Piggin <npiggin@gmail.com>
>> Signed-off-by: Santosh Sivaraj <santosh@fossix.org>
>> Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
>> ---
>>  include/linux/extable.h |  2 ++
>>  kernel/extable.c        | 11 +++++++++--
>>  2 files changed, 11 insertions(+), 2 deletions(-)
>> 
>> diff --git a/include/linux/extable.h b/include/linux/extable.h
>> index 41c5b3a25f67..81ecfaa83ad3 100644
>> --- a/include/linux/extable.h
>> +++ b/include/linux/extable.h
>> @@ -19,6 +19,8 @@ void trim_init_extable(struct module *m);
>>  
>>  /* Given an address, look for it in the exception tables */
>>  const struct exception_table_entry *search_exception_tables(unsigned long add);
>> +const struct exception_table_entry *
>> +search_kernel_exception_table(unsigned long addr);
>> 
>
> Can we find a better name search_kernel still sounds like all of the kernel.
> Can we rename it to search_kernel_linear_map_extable?

I thought search_kernel_exception_table and search_module_extables were
non-ambiguous enough :-) But If you think name will be confusing, I can
change that as suggested.

Thanks,
Santosh

>
>  
>>  #ifdef CONFIG_MODULES
>>  /* For extable.c to search modules' exception tables. */
>> diff --git a/kernel/extable.c b/kernel/extable.c
>> index e23cce6e6092..f6c9406eec7d 100644
>> --- a/kernel/extable.c
>> +++ b/kernel/extable.c
>> @@ -40,13 +40,20 @@ void __init sort_main_extable(void)
>>  	}
>>  }
>>  
>> +/* Given an address, look for it in the kernel exception table */
>> +const
>> +struct exception_table_entry *search_kernel_exception_table(unsigned long addr)
>> +{
>> +	return search_extable(__start___ex_table,
>> +			      __stop___ex_table - __start___ex_table, addr);
>> +}
>> +
>>  /* Given an address, look for it in the exception tables. */
>>  const struct exception_table_entry *search_exception_tables(unsigned long addr)
>>  {
>>  	const struct exception_table_entry *e;
>>  
>> -	e = search_extable(__start___ex_table,
>> -			   __stop___ex_table - __start___ex_table, addr);
>> +	e = search_kernel_exception_table(addr);
>>  	if (!e)
>>  		e = search_module_extables(addr);
>>  	return e;
>>

Patch
diff mbox series

diff --git a/include/linux/extable.h b/include/linux/extable.h
index 41c5b3a25f67..81ecfaa83ad3 100644
--- a/include/linux/extable.h
+++ b/include/linux/extable.h
@@ -19,6 +19,8 @@  void trim_init_extable(struct module *m);
 
 /* Given an address, look for it in the exception tables */
 const struct exception_table_entry *search_exception_tables(unsigned long add);
+const struct exception_table_entry *
+search_kernel_exception_table(unsigned long addr);
 
 #ifdef CONFIG_MODULES
 /* For extable.c to search modules' exception tables. */
diff --git a/kernel/extable.c b/kernel/extable.c
index e23cce6e6092..f6c9406eec7d 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -40,13 +40,20 @@  void __init sort_main_extable(void)
 	}
 }
 
+/* Given an address, look for it in the kernel exception table */
+const
+struct exception_table_entry *search_kernel_exception_table(unsigned long addr)
+{
+	return search_extable(__start___ex_table,
+			      __stop___ex_table - __start___ex_table, addr);
+}
+
 /* Given an address, look for it in the exception tables. */
 const struct exception_table_entry *search_exception_tables(unsigned long addr)
 {
 	const struct exception_table_entry *e;
 
-	e = search_extable(__start___ex_table,
-			   __stop___ex_table - __start___ex_table, addr);
+	e = search_kernel_exception_table(addr);
 	if (!e)
 		e = search_module_extables(addr);
 	return e;