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25876e327e
For AVR, atomic functions generated by LOAD macro turn into load surrounded by up_irq_save and up_irq_restore. The generated code was incorrect as can be seen from disassembly of __atomic_load_4: in r18, 0x3f ; store interrupts enabled flag cli ; disable interrupts out 0x3f, r18 ; restore the flag movw r30, r24 ; copy parameter (address) to pointer register ld r22, Z ; indirect load to return value registers ldd r23, Z+1 ldd r24, Z+2 ldd r25, Z+3 ret ; return The interrupts are disabled to be immediately re-enabled, the load only takes place after that. Both up_irq_save and up_irq_restore are defined in inline assembly. Other architectures (x86/486, Risc-V) mark this assembly with clobbers: memory. Doing the same thing for AVR alleviates the problem: in r18, 0x3f ; store interrupts enabled flag cli ; disable interrupts movw r30, r24 ; copy address ld r22, Z ; load ldd r23, Z+1 ldd r24, Z+2 ldd r25, Z+3 out 0x3f, r18 ; restore interrupts enabled flag ret ; return Besides compiling the code and checking the assembly, this was tested with a custom stress application on AVR128DA28. Assembly of up_irq_enable is marked in the same way with regards to clobbers. This patch also removes two functions that are not called from anywhere (up_irq_disabled, putsreg) Signed-off-by: Kerogit <kr.git@kerogit.eu> |
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