Re: [PATCH 09/32] s390/extable: Rework exception handling logic

[Ilya Leoshkevich]

On 10/1/26 12:32, Heiko Carstens wrote:
> Add EX_TABLE_INSN macros which will replace the existing EX_TABLE
> macros. The macros come with new semantics for the whole exception
> handling: with the new exception handling the exception table entries
> always point to the instruction which may cause an exception. This is
> regardless of exception type, and whether an exception is nullifying,
> suppressing, completing, or terminating.
>
> This improves the current situation where exception table entries are
> required which point to the instruction (nullifying) and/or behind the
> instruction (suppressing, completing, or terminating), since depending
> on usage an instruction can generate different exceptions.
>
> The new EX_TABLE_INSN macros are aliases to the existing EX_TABLE
> macros. The exception handling logic is changed to first perform a lookup
> in the exception tables with get_trap_ip() / boot_get_trap_ip(). If that
> finds nothing, it falls back to looking up with instruction_pointer().
>
> This is a temporary solution until all EX_TABLE usages have been
> converted to EX_TABLE_INSN. When that work is complete EX_TABLE will
> be removed, exception tables will only be searched by using the return
> value of get_trap_ip() / boot_get_trap_ip().
>
> Signed-off-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
> ---
>   arch/s390/boot/pgm_check.c          | 35 ++++++++++++++++++++++++-----
>   arch/s390/include/asm/asm-extable.h | 10 +++++++++
>   arch/s390/mm/extable.c              |  4 +++-
>   3 files changed, 42 insertions(+), 7 deletions(-)

Reviewed-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>