bcef83a00d
POWER ISA v3 defines a new idle processor core mechanism. In summary, a) new instruction named stop is added. This instruction replaces instructions like nap, sleep, rvwinkle. b) new per thread SPR named Processor Stop Status and Control Register (PSSCR) is added which controls the behavior of stop instruction. PSSCR layout: ---------------------------------------------------------- | PLS | /// | SD | ESL | EC | PSLL | /// | TR | MTL | RL | ---------------------------------------------------------- 0 4 41 42 43 44 48 54 56 60 PSSCR key fields: Bits 0:3 - Power-Saving Level Status. This field indicates the lowest power-saving state the thread entered since stop instruction was last executed. Bit 42 - Enable State Loss 0 - No state is lost irrespective of other fields 1 - Allows state loss Bits 44:47 - Power-Saving Level Limit This limits the power-saving level that can be entered into. Bits 60:63 - Requested Level Used to specify which power-saving level must be entered on executing stop instruction This patch adds support for stop instruction and PSSCR handling. Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> |
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| uapi/asm | ||