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Diffstat (limited to 'arch/xtensa/kernel/coprocessor.S')
| -rw-r--r-- | arch/xtensa/kernel/coprocessor.S | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/arch/xtensa/kernel/coprocessor.S b/arch/xtensa/kernel/coprocessor.S new file mode 100644 index 000000000..c7b9f1289 --- /dev/null +++ b/arch/xtensa/kernel/coprocessor.S @@ -0,0 +1,258 @@ +/* + * arch/xtensa/kernel/coprocessor.S + * + * Xtensa processor configuration-specific table of coprocessor and + * other custom register layout information. + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2003 - 2007 Tensilica Inc. + */ + + +#include <linux/linkage.h> +#include <asm/asm-offsets.h> +#include <asm/asmmacro.h> +#include <asm/coprocessor.h> +#include <asm/current.h> +#include <asm/regs.h> + +#if XTENSA_HAVE_COPROCESSORS + +/* + * Macros for lazy context switch. + */ + +#define SAVE_CP_REGS(x) \ + .if XTENSA_HAVE_COPROCESSOR(x); \ + .align 4; \ + .Lsave_cp_regs_cp##x: \ + xchal_cp##x##_store a2 a3 a4 a5 a6; \ + jx a0; \ + .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 a3 a4 a5 a6; \ + jx a0; \ + .endif + +#define LOAD_CP_REGS_TAB(x) \ + .if XTENSA_HAVE_COPROCESSOR(x); \ + .long .Lload_cp_regs_cp##x; \ + .else; \ + .long 0; \ + .endif; \ + .long THREAD_XTREGS_CP##x + + __XTENSA_HANDLER + + SAVE_CP_REGS(0) + SAVE_CP_REGS(1) + SAVE_CP_REGS(2) + SAVE_CP_REGS(3) + SAVE_CP_REGS(4) + SAVE_CP_REGS(5) + SAVE_CP_REGS(6) + SAVE_CP_REGS(7) + + LOAD_CP_REGS(0) + LOAD_CP_REGS(1) + LOAD_CP_REGS(2) + LOAD_CP_REGS(3) + LOAD_CP_REGS(4) + LOAD_CP_REGS(5) + LOAD_CP_REGS(6) + 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) + +/* + * Entry condition: + * + * a0: trashed, original value saved on stack (PT_AREG0) + * a1: a1 + * a2: new stack pointer, original in DEPC + * a3: a3 + * depc: a2, original value saved on stack (PT_DEPC) + * excsave_1: dispatch table + * + * PT_DEPC >= VALID_DOUBLE_EXCEPTION_ADDRESS: double exception, DEPC + * < VALID_DOUBLE_EXCEPTION_ADDRESS: regular exception + */ + +ENTRY(fast_coprocessor) + + /* Save remaining registers a1-a3 and SAR */ + + s32i a3, a2, PT_AREG3 + rsr a3, sar + s32i a1, a2, PT_AREG1 + s32i a3, a2, PT_SAR + mov a1, a2 + rsr a2, depc + s32i a2, a1, PT_AREG2 + + /* + * 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 + + /* Find coprocessor number. Subtract first CP EXCCAUSE from EXCCAUSE */ + + rsr a3, exccause + addi a3, a3, -EXCCAUSE_COPROCESSOR0_DISABLED + + /* Set corresponding CPENABLE bit -> (sar:cp-index, a3: 1<<cp-index)*/ + + ssl a3 # SAR: 32 - coprocessor_number + movi a2, 1 + rsr a0, cpenable + sll a2, a2 + or a0, a0, a2 + wsr a0, cpenable + rsync + + /* Retrieve previous owner. (a3 still holds CP number) */ + + movi a0, coprocessor_owner # list of owners + addx4 a0, a3, a0 # entry for CP + l32i a4, a0, 0 + + beqz a4, 1f # skip 'save' if no previous owner + + /* Disable coprocessor for previous owner. (a2 = 1 << CP number) */ + + l32i a5, a4, THREAD_CPENABLE + xor a5, a5, a2 # (1 << cp-id) still in a2 + s32i a5, a4, THREAD_CPENABLE + + /* + * Get context save area and 'call' save routine. + * (a4 still holds previous owner (thread_info), a3 CP number) + */ + + 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 + + /* Note that only a0 and a1 were preserved. */ + +2: rsr a3, exccause + addi a3, a3, -EXCCAUSE_COPROCESSOR0_DISABLED + movi a0, coprocessor_owner + addx4 a0, a3, a0 + + /* Set new 'owner' (a0 points to the CP owner, a3 contains the CP nr) */ + +1: GET_THREAD_INFO (a4, a1) + s32i a4, a0, 0 + + /* Get context save area and 'call' load routine. */ + + 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 + + /* Restore all registers and return from exception handler. */ + +1: l32i a6, a1, PT_AREG6 + l32i a5, a1, PT_AREG5 + l32i a4, a1, PT_AREG4 + + l32i a0, a1, PT_SAR + l32i a3, a1, PT_AREG3 + l32i a2, a1, PT_AREG2 + wsr a0, sar + l32i a0, a1, PT_AREG0 + l32i a1, a1, PT_AREG1 + + rfe + +ENDPROC(fast_coprocessor) + + .text + +/* + * coprocessor_flush(struct thread_info*, index) + * a2 a3 + * + * Save coprocessor registers for coprocessor 'index'. + * The register values are saved to or loaded from the coprocessor area + * inside the task_info structure. + * + * Note that this function doesn't update the coprocessor_owner information! + * + */ + +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) + +ENDPROC(coprocessor_flush) + + .data + +ENTRY(coprocessor_owner) + + .fill XCHAL_CP_MAX, 4, 0 + +END(coprocessor_owner) + +#endif /* XTENSA_HAVE_COPROCESSORS */ |