diff options
Diffstat (limited to '')
| -rw-r--r-- | arch/xtensa/kernel/coprocessor.S | 234 |
1 files changed, 139 insertions, 95 deletions
diff --git a/arch/xtensa/kernel/coprocessor.S b/arch/xtensa/kernel/coprocessor.S index 45cc0ae0af6f..ef33e76e07d8 100644 --- a/arch/xtensa/kernel/coprocessor.S +++ b/arch/xtensa/kernel/coprocessor.S @@ -19,6 +19,26 @@ #include <asm/current.h> #include <asm/regs.h> +/* + * Rules for coprocessor state manipulation on SMP: + * + * - a task may have live coprocessors only on one CPU. + * + * - whether coprocessor context of task T is live on some CPU is + * denoted by T's thread_info->cpenable. + * + * - non-zero thread_info->cpenable means that thread_info->cp_owner_cpu + * is valid in the T's thread_info. Zero thread_info->cpenable means that + * coprocessor context is valid in the T's thread_info. + * + * - if a coprocessor context of task T is live on CPU X, only CPU X changes + * T's thread_info->cpenable, cp_owner_cpu and coprocessor save area. + * This is done by making sure that for the task T with live coprocessor + * on CPU X cpenable SR is 0 when T runs on any other CPU Y. + * When fast_coprocessor exception is taken on CPU Y it goes to the + * C-level do_coprocessor that uses IPI to make CPU X flush T's coprocessors. + */ + #if XTENSA_HAVE_COPROCESSORS /* @@ -29,35 +49,31 @@ .if XTENSA_HAVE_COPROCESSOR(x); \ .align 4; \ .Lsave_cp_regs_cp##x: \ - xchal_cp##x##_store a2 a4 a5 a6 a7; \ - jx a0; \ + xchal_cp##x##_store a2 a3 a4 a5 a6; \ + ret; \ .endif -#define SAVE_CP_REGS_TAB(x) \ - .if XTENSA_HAVE_COPROCESSOR(x); \ - .long .Lsave_cp_regs_cp##x; \ - .else; \ - .long 0; \ - .endif; \ - .long THREAD_XTREGS_CP##x - - #define LOAD_CP_REGS(x) \ .if XTENSA_HAVE_COPROCESSOR(x); \ .align 4; \ .Lload_cp_regs_cp##x: \ - xchal_cp##x##_load a2 a4 a5 a6 a7; \ - jx a0; \ + xchal_cp##x##_load a2 a3 a4 a5 a6; \ + ret; \ .endif -#define LOAD_CP_REGS_TAB(x) \ +#define CP_REGS_TAB(x) \ .if XTENSA_HAVE_COPROCESSOR(x); \ + .long .Lsave_cp_regs_cp##x; \ .long .Lload_cp_regs_cp##x; \ .else; \ - .long 0; \ + .long 0, 0; \ .endif; \ .long THREAD_XTREGS_CP##x +#define CP_REGS_TAB_SAVE 0 +#define CP_REGS_TAB_LOAD 4 +#define CP_REGS_TAB_OFFSET 8 + __XTENSA_HANDLER SAVE_CP_REGS(0) @@ -79,25 +95,15 @@ LOAD_CP_REGS(7) .align 4 -.Lsave_cp_regs_jump_table: - SAVE_CP_REGS_TAB(0) - SAVE_CP_REGS_TAB(1) - SAVE_CP_REGS_TAB(2) - SAVE_CP_REGS_TAB(3) - SAVE_CP_REGS_TAB(4) - SAVE_CP_REGS_TAB(5) - SAVE_CP_REGS_TAB(6) - SAVE_CP_REGS_TAB(7) - -.Lload_cp_regs_jump_table: - LOAD_CP_REGS_TAB(0) - LOAD_CP_REGS_TAB(1) - LOAD_CP_REGS_TAB(2) - LOAD_CP_REGS_TAB(3) - LOAD_CP_REGS_TAB(4) - LOAD_CP_REGS_TAB(5) - LOAD_CP_REGS_TAB(6) - LOAD_CP_REGS_TAB(7) +.Lcp_regs_jump_table: + CP_REGS_TAB(0) + CP_REGS_TAB(1) + CP_REGS_TAB(2) + CP_REGS_TAB(3) + CP_REGS_TAB(4) + CP_REGS_TAB(5) + CP_REGS_TAB(6) + CP_REGS_TAB(7) /* * Entry condition: @@ -115,9 +121,37 @@ ENTRY(fast_coprocessor) + s32i a3, a2, PT_AREG3 + +#ifdef CONFIG_SMP + /* + * Check if any coprocessor context is live on another CPU + * and if so go through the C-level coprocessor exception handler + * to flush it to memory. + */ + GET_THREAD_INFO (a0, a2) + l32i a3, a0, THREAD_CPENABLE + beqz a3, .Lload_local + + /* + * Pairs with smp_wmb in local_coprocessor_release_all + * and with both memws below. + */ + memw + l32i a3, a0, THREAD_CPU + l32i a0, a0, THREAD_CP_OWNER_CPU + beq a0, a3, .Lload_local + + rsr a0, ps + l32i a3, a2, PT_AREG3 + bbci.l a0, PS_UM_BIT, 1f + call0 user_exception +1: call0 kernel_exception +#endif + /* Save remaining registers a1-a3 and SAR */ - s32i a3, a2, PT_AREG3 +.Lload_local: rsr a3, sar s32i a1, a2, PT_AREG1 s32i a3, a2, PT_SAR @@ -125,13 +159,15 @@ ENTRY(fast_coprocessor) rsr a2, depc s32i a2, a1, PT_AREG2 - /* - * The hal macros require up to 4 temporary registers. We use a3..a6. - */ + /* The hal macros require up to 4 temporary registers. We use a3..a6. */ s32i a4, a1, PT_AREG4 s32i a5, a1, PT_AREG5 s32i a6, a1, PT_AREG6 + s32i a7, a1, PT_AREG7 + s32i a8, a1, PT_AREG8 + s32i a9, a1, PT_AREG9 + s32i a10, a1, PT_AREG10 /* Find coprocessor number. Subtract first CP EXCCAUSE from EXCCAUSE */ @@ -148,58 +184,74 @@ ENTRY(fast_coprocessor) wsr a0, cpenable rsync - /* Retrieve previous owner. (a3 still holds CP number) */ + /* Get coprocessor save/load table entry (a7). */ - movi a0, coprocessor_owner # list of owners - addx4 a0, a3, a0 # entry for CP - l32i a4, a0, 0 + movi a7, .Lcp_regs_jump_table + addx8 a7, a3, a7 + addx4 a7, a3, a7 - beqz a4, 1f # skip 'save' if no previous owner + /* Retrieve previous owner (a8). */ - /* Disable coprocessor for previous owner. (a2 = 1 << CP number) */ + rsr a0, excsave1 # exc_table + addx4 a0, a3, a0 # entry for CP + l32i a8, a0, EXC_TABLE_COPROCESSOR_OWNER + + /* Set new owner (a9). */ - l32i a5, a4, THREAD_CPENABLE - xor a5, a5, a2 # (1 << cp-id) still in a2 - s32i a5, a4, THREAD_CPENABLE + GET_THREAD_INFO (a9, a1) + l32i a4, a9, THREAD_CPU + s32i a9, a0, EXC_TABLE_COPROCESSOR_OWNER + s32i a4, a9, THREAD_CP_OWNER_CPU /* - * Get context save area and 'call' save routine. - * (a4 still holds previous owner (thread_info), a3 CP number) + * Enable coprocessor for the new owner. (a2 = 1 << CP number) + * This can be done before loading context into the coprocessor. */ + l32i a4, a9, THREAD_CPENABLE + or a4, a4, a2 - movi a5, .Lsave_cp_regs_jump_table - movi a0, 2f # a0: 'return' address - addx8 a3, a3, a5 # a3: coprocessor number - l32i a2, a3, 4 # a2: xtregs offset - l32i a3, a3, 0 # a3: jump address - add a2, a2, a4 - jx a3 + /* + * Make sure THREAD_CP_OWNER_CPU is in memory before updating + * THREAD_CPENABLE + */ + memw # (2) + s32i a4, a9, THREAD_CPENABLE - /* Note that only a0 and a1 were preserved. */ + beqz a8, 1f # skip 'save' if no previous owner -2: rsr a3, exccause - addi a3, a3, -EXCCAUSE_COPROCESSOR0_DISABLED - movi a0, coprocessor_owner - addx4 a0, a3, a0 + /* Disable coprocessor for previous owner. (a2 = 1 << CP number) */ - /* Set new 'owner' (a0 points to the CP owner, a3 contains the CP nr) */ + l32i a10, a8, THREAD_CPENABLE + xor a10, a10, a2 -1: GET_THREAD_INFO (a4, a1) - s32i a4, a0, 0 + /* Get context save area and call save routine. */ - /* Get context save area and 'call' load routine. */ + l32i a2, a7, CP_REGS_TAB_OFFSET + l32i a3, a7, CP_REGS_TAB_SAVE + add a2, a2, a8 + callx0 a3 - movi a5, .Lload_cp_regs_jump_table - movi a0, 1f - addx8 a3, a3, a5 - l32i a2, a3, 4 # a2: xtregs offset - l32i a3, a3, 0 # a3: jump address - add a2, a2, a4 - jx a3 + /* + * Make sure coprocessor context and THREAD_CP_OWNER_CPU are in memory + * before updating THREAD_CPENABLE + */ + memw # (3) + s32i a10, a8, THREAD_CPENABLE +1: + /* Get context save area and call load routine. */ + + l32i a2, a7, CP_REGS_TAB_OFFSET + l32i a3, a7, CP_REGS_TAB_LOAD + add a2, a2, a9 + callx0 a3 /* Restore all registers and return from exception handler. */ -1: l32i a6, a1, PT_AREG6 + l32i a10, a1, PT_AREG10 + l32i a9, a1, PT_AREG9 + l32i a8, a1, PT_AREG8 + l32i a7, a1, PT_AREG7 + l32i a6, a1, PT_AREG6 l32i a5, a1, PT_AREG5 l32i a4, a1, PT_AREG4 @@ -230,29 +282,21 @@ ENDPROC(fast_coprocessor) ENTRY(coprocessor_flush) - /* reserve 4 bytes on stack to save a0 */ - abi_entry(4) - - s32i a0, a1, 0 - movi a0, .Lsave_cp_regs_jump_table - addx8 a3, a3, a0 - l32i a4, a3, 4 - l32i a3, a3, 0 - add a2, a2, a4 - beqz a3, 1f - callx0 a3 -1: l32i a0, a1, 0 - - abi_ret(4) + abi_entry_default + + movi a4, .Lcp_regs_jump_table + addx8 a4, a3, a4 + addx4 a3, a3, a4 + l32i a4, a3, CP_REGS_TAB_SAVE + beqz a4, 1f + l32i a3, a3, CP_REGS_TAB_OFFSET + add a2, a2, a3 + mov a7, a0 + callx0 a4 + mov a0, a7 +1: + abi_ret_default ENDPROC(coprocessor_flush) - .data - -ENTRY(coprocessor_owner) - - .fill XCHAL_CP_MAX, 4, 0 - -END(coprocessor_owner) - #endif /* XTENSA_HAVE_COPROCESSORS */ |