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48b4790f05
Provide an inline assembly using alternatives to avoid the need of a base register due to relocatable lowcore when adding or subtracting small constants from preempt_count. Main user is preempt_enable(), which subtracts one from preempt_count and tests if the result is zero. With this the generated code changes from 1000b8: a7 19 00 00 lghi %r1,0 1000bc: eb ff 13 a8 00 6e alsi 936(%r1),-1 1000c2: a7 54 00 05 jnhe 1000cc <__rcu_read_unlock+0x14> to something like this: 1000b8: eb ff 03 a8 00 6e alsi 936,-1 1000be: a7 54 00 05 jnhe 1000c8 <__rcu_read_unlock+0x10> Kernel image size is reduced by 45kb (bloat-o-meter -t, defconfig, gcc15). Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
167 lines
4.9 KiB
167 lines
4.9 KiB