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SubjectRe: [PATCH v9 4/7] extable: Add function to search only kernel exception table
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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;
>>

--
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#cat ~/notes/quotes | sort -R | head -1 | cut -f2- -d " "

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