/**************************************************************************/ /* Copyright (c) Cadence Design Systems, Inc. */ /* */ /* Permission is hereby granted, free of charge, to any person obtaining */ /* a copy of this software and associated documentation files (the */ /* "Software"), to deal in the Software without restriction, including */ /* without limitation the rights to use, copy, modify, merge, publish, */ /* distribute, sublicense, and/or sell copies of the Software, and to */ /* permit persons to whom the Software is furnished to do so, subject to */ /* the following conditions: */ /* */ /* The above copyright notice and this permission notice shall be */ /* included in all copies or substantial portions of the Software. */ /* */ /* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */ /* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */ /* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */ /* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */ /* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */ /* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */ /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ /**************************************************************************/ /************************************************************************** XTENSA CONTEXT FRAMES AND MACROS FOR RTOS ASSEMBLER SOURCES This header contains definitions and macros for use primarily by Xtensa RTOS assembly source files. It includes and uses the Xtensa hardware abstraction layer (HAL) to deal with config specifics. It may also be included in C source files. NOTE: The Xtensa architecture requires stack pointer alignment to 16 bytes. ***************************************************************************/ #ifndef XTENSA_CONTEXT_H #define XTENSA_CONTEXT_H #ifdef __ASSEMBLER__ #include #endif #include #include #include #if defined (__ASSEMBLER__) #include "tx_api_asm.h" #endif /* Align a value up to nearest n-byte boundary, where n is a power of 2. */ #define ALIGNUP(n, val) (((val) + (n)-1) & -(n)) /* ------------------------------------------------------------------------------- Macros that help define structures for both C and assembler. ------------------------------------------------------------------------------- */ #if defined(_ASMLANGUAGE) || defined(__ASSEMBLER__) #define XSTRUCT_BEGIN .pushsection .text; .struct 0 #define XSTRUCT_FIELD(ctype,size,asname,name) asname: .space size #define XSTRUCT_AFIELD(ctype,size,asname,name,n) asname: .space (size)*(n) #define XSTRUCT_END(sname) sname##Size:; .popsection #else #define XSTRUCT_BEGIN typedef struct { #define XSTRUCT_FIELD(ctype,size,asname,name) ctype name; #define XSTRUCT_AFIELD(ctype,size,asname,name,n) ctype name[n]; #define XSTRUCT_END(sname) } sname; #endif //_ASMLANGUAGE || __ASSEMBLER__ /* ------------------------------------------------------------------------------- INTERRUPT/EXCEPTION STACK FRAME FOR A THREAD OR NESTED INTERRUPT A stack frame of this structure is allocated for any interrupt or exception. It goes on the current stack. If the RTOS has a system stack for handling interrupts, every thread stack must allow space for just one interrupt stack frame, then nested interrupt stack frames go on the system stack. The frame includes basic registers (explicit) and "extra" registers introduced by user TIE or the use of the MAC16 option in the user's Xtensa config. The frame size is minimized by omitting regs not applicable to user's config. For Windowed ABI, this stack frame includes the interruptee's base save area, another base save area to manage gcc nested functions, and a little temporary space to help manage the spilling of the register windows. ------------------------------------------------------------------------------- */ #if XCHAL_HAVE_XEA2 XSTRUCT_BEGIN XSTRUCT_FIELD (long, 4, XT_STK_EXIT, exit) /* exit point for dispatch */ XSTRUCT_FIELD (long, 4, XT_STK_PC, pc) /* return PC */ XSTRUCT_FIELD (long, 4, XT_STK_PS, ps) /* return PS */ XSTRUCT_FIELD (long, 4, XT_STK_A0, a0) XSTRUCT_FIELD (long, 4, XT_STK_A1, a1) /* stack pointer before interrupt */ XSTRUCT_FIELD (long, 4, XT_STK_A2, a2) XSTRUCT_FIELD (long, 4, XT_STK_A3, a3) XSTRUCT_FIELD (long, 4, XT_STK_A4, a4) XSTRUCT_FIELD (long, 4, XT_STK_A5, a5) XSTRUCT_FIELD (long, 4, XT_STK_A6, a6) XSTRUCT_FIELD (long, 4, XT_STK_A7, a7) XSTRUCT_FIELD (long, 4, XT_STK_A8, a8) XSTRUCT_FIELD (long, 4, XT_STK_A9, a9) XSTRUCT_FIELD (long, 4, XT_STK_A10, a10) XSTRUCT_FIELD (long, 4, XT_STK_A11, a11) XSTRUCT_FIELD (long, 4, XT_STK_A12, a12) XSTRUCT_FIELD (long, 4, XT_STK_A13, a13) XSTRUCT_FIELD (long, 4, XT_STK_A14, a14) XSTRUCT_FIELD (long, 4, XT_STK_A15, a15) XSTRUCT_FIELD (long, 4, XT_STK_SAR, sar) XSTRUCT_FIELD (long, 4, XT_STK_EXCCAUSE, exccause) XSTRUCT_FIELD (long, 4, XT_STK_EXCVADDR, excvaddr) #if XCHAL_HAVE_LOOPS XSTRUCT_FIELD (long, 4, XT_STK_LBEG, lbeg) XSTRUCT_FIELD (long, 4, XT_STK_LEND, lend) XSTRUCT_FIELD (long, 4, XT_STK_LCOUNT, lcount) #endif #if XCHAL_HAVE_EXCLUSIVE XSTRUCT_FIELD (long, 4, XT_STK_ATOMCTL, atomctl) #endif #ifndef __XTENSA_CALL0_ABI__ /* Temporary space for saving stuff during window spill */ XSTRUCT_FIELD (long, 4, XT_STK_TMP0, tmp0) XSTRUCT_FIELD (long, 4, XT_STK_TMP1, tmp1) XSTRUCT_FIELD (long, 4, XT_STK_TMP2, tmp2) #endif #ifdef XT_USE_SWPRI /* Storage for virtual priority mask */ XSTRUCT_FIELD (long, 4, XT_STK_VPRI, vpri) #endif #ifdef XT_USE_OVLY /* Storage for overlay state */ XSTRUCT_FIELD (long, 4, XT_STK_OVLY, ovly) #endif XSTRUCT_END(XtExcFrame) #endif /* XCHAL_HAVE_XEA2 */ #if XCHAL_HAVE_XEA3 XSTRUCT_BEGIN XSTRUCT_FIELD (long, 4, XT_STK_ATOMCTL, atomctl) XSTRUCT_FIELD (long, 4, XT_STK_LCOUNT, lcount) XSTRUCT_FIELD (long, 4, XT_STK_LEND, lend) XSTRUCT_FIELD (long, 4, XT_STK_LBEG, lbeg) XSTRUCT_FIELD (long, 4, XT_STK_PC, pc) XSTRUCT_FIELD (long, 4, XT_STK_PS, ps) XSTRUCT_FIELD (long, 4, XT_STK_EXCCAUSE, exccause) XSTRUCT_FIELD (long, 4, XT_STK_EXCVADDR, excvaddr) #ifdef __XTENSA_CALL0_ABI__ XSTRUCT_FIELD (long, 4, XT_STK_A0, a0) XSTRUCT_FIELD (long, 4, XT_STK_A1, a1) XSTRUCT_FIELD (long, 4, XT_STK_A2, a2) XSTRUCT_FIELD (long, 4, XT_STK_A3, a3) XSTRUCT_FIELD (long, 4, XT_STK_A4, a4) XSTRUCT_FIELD (long, 4, XT_STK_A5, a5) XSTRUCT_FIELD (long, 4, XT_STK_A6, a6) XSTRUCT_FIELD (long, 4, XT_STK_A7, a7) #endif XSTRUCT_FIELD (long, 4, XT_STK_A8, a8) XSTRUCT_FIELD (long, 4, XT_STK_A9, a9) XSTRUCT_FIELD (long, 4, XT_STK_A10, a10) XSTRUCT_FIELD (long, 4, XT_STK_A11, a11) XSTRUCT_FIELD (long, 4, XT_STK_A12, a12) XSTRUCT_FIELD (long, 4, XT_STK_A13, a13) XSTRUCT_FIELD (long, 4, XT_STK_A14, a14) XSTRUCT_FIELD (long, 4, XT_STK_A15, a15) #ifdef __XTENSA_WINDOWED_ABI__ XSTRUCT_AFIELD(long, 4, XT_STK_SPILL, spill, 8) #endif XSTRUCT_END(XtExcFrame) #endif /* XCHAL_HAVE_XEA3 */ #if defined(_ASMLANGUAGE) || defined(__ASSEMBLER__) #define XT_STK_NEXT1 XtExcFrameSize #else #define XT_STK_NEXT1 sizeof(XtExcFrame) #endif /* Allocate extra storage if needed for non-CP TIE state. Allow for alignment padding as needed. */ #if XCHAL_EXTRA_SA_SIZE != 0 #if XCHAL_EXTRA_SA_ALIGN <= 16 #define XT_STK_EXTRA ALIGNUP(XCHAL_EXTRA_SA_ALIGN, XT_STK_NEXT1) #else /* If need more alignment than stack, add space for dynamic alignment */ #define XT_STK_EXTRA (ALIGNUP(XCHAL_EXTRA_SA_ALIGN, XT_STK_NEXT1) + XCHAL_EXTRA_SA_ALIGN) #endif #define XT_STK_NEXT2 (XT_STK_EXTRA + XCHAL_EXTRA_SA_SIZE) #else /* No extra storage required */ #define XT_STK_NEXT2 XT_STK_NEXT1 #endif #if XCHAL_HAVE_XEA3 /* Total frame size */ #define XT_STK_FRMSZ (ALIGNUP(0x10, XT_STK_NEXT2)) /* Exception/interrupt frame size */ #define XT_STK_XFRM_SZ XT_STK_NEXT1 /* Extra save area size (including alignment padding) */ #define XT_STK_XTRA_SZ (XT_STK_FRMSZ - XT_STK_XFRM_SZ) /* Alignment padding area size */ #if XCHAL_EXTRA_SA_SIZE != 0 #define XT_STK_ALIGN_SZ (XT_STK_EXTRA - XT_STK_NEXT1) #endif #else /* ------------------------------------------------------------------------------- This is the frame size. Add space for 4 registers (interruptee's base save area) and some space for gcc nested functions if any. ------------------------------------------------------------------------------- */ #define XT_STK_FRMSZ (ALIGNUP(0x10, XT_STK_NEXT2) + 0x20) #endif /* ------------------------------------------------------------------------------- CO-PROCESSOR STATE SAVE AREA FOR A THREAD The RTOS must provide an area per thread to save the state of co-processors when that thread does not have control. Co-processors are context-switched lazily (on demand) only when a new thread uses a co-processor instruction, otherwise a thread retains ownership of the co-processor even when it loses control of the processor. An Xtensa co-processor exception is triggered when any co-processor instruction is executed by a thread that is not the owner, and the context switch of that co-processor is then peformed by the handler. Ownership represents which thread's state is currently in the co-processor. Co-processors may not be used by interrupt or exception handlers. If an co-processor instruction is executed by an interrupt or exception handler, the co-processor exception handler will trigger a kernel panic and freeze. This restriction is introduced to reduce the overhead of saving and restoring co-processor state (which can be quite large) and in particular remove that overhead from interrupt handlers. The co-processor state save area may be in any convenient per-thread location such as in the thread control block or above the thread stack area. It need not be in the interrupt stack frame since interrupts don't use co-processors. Along with the save area for each co-processor, two bitmasks with flags per co-processor (laid out as in the CPENABLE reg) help manage context-switching co-processors as efficiently as possible: XT_CPENABLE The contents of a non-running thread's CPENABLE register. It represents the co-processors owned (and whose state is still needed) by the thread. When a thread is preempted, its CPENABLE is saved here. When a thread solicits a context-swtich, its CPENABLE is cleared - the compiler has saved the (caller-saved) co-proc state if it needs to. When a non-running thread loses ownership of a CP, its bit is cleared. When a thread runs, it's XT_CPENABLE is loaded into the CPENABLE reg. Avoids co-processor exceptions when no change of ownership is needed. XT_CPSTORED A bitmask with the same layout as CPENABLE, a bit per co-processor. Indicates whether the state of each co-processor is saved in the state save area. When a thread enters the kernel, only the state of co-procs still enabled in CPENABLE is saved. When the co-processor exception handler assigns ownership of a co-processor to a thread, it restores the saved state only if this bit is set, and clears this bit. XT_CP_CS_ST A bitmask with the same layout as CPENABLE, a bit per co-processor. Indicates whether callee-saved state is saved in the state save area. Callee-saved state is saved by itself on a solicited context switch, and restored when needed by the coprocessor exception handler. Unsolicited switches will cause the entire coprocessor to be saved when necessary. XT_CP_ASA Pointer to the aligned save area. Allows it to be aligned more than the overall save area (which might only be stack-aligned or TCB-aligned). Especially relevant for Xtensa cores configured with a very large data path that requires alignment greater than 16 bytes (ABI stack alignment). ------------------------------------------------------------------------------- */ #if XCHAL_CP_NUM > 0 /* Offsets of each coprocessor save area within the 'aligned save area': */ #define XT_CP0_SA 0 #define XT_CP1_SA ALIGNUP(XCHAL_CP1_SA_ALIGN, XT_CP0_SA + XCHAL_CP0_SA_SIZE) #define XT_CP2_SA ALIGNUP(XCHAL_CP2_SA_ALIGN, XT_CP1_SA + XCHAL_CP1_SA_SIZE) #define XT_CP3_SA ALIGNUP(XCHAL_CP3_SA_ALIGN, XT_CP2_SA + XCHAL_CP2_SA_SIZE) #define XT_CP4_SA ALIGNUP(XCHAL_CP4_SA_ALIGN, XT_CP3_SA + XCHAL_CP3_SA_SIZE) #define XT_CP5_SA ALIGNUP(XCHAL_CP5_SA_ALIGN, XT_CP4_SA + XCHAL_CP4_SA_SIZE) #define XT_CP6_SA ALIGNUP(XCHAL_CP6_SA_ALIGN, XT_CP5_SA + XCHAL_CP5_SA_SIZE) #define XT_CP7_SA ALIGNUP(XCHAL_CP7_SA_ALIGN, XT_CP6_SA + XCHAL_CP6_SA_SIZE) #define XT_CP_SA_SIZE ALIGNUP(16, XT_CP7_SA + XCHAL_CP7_SA_SIZE) /* Offsets within the overall save area: */ #define XT_CPENABLE 0 /* (2 bytes) coprocessors active for this thread */ #define XT_CPSTORED 2 /* (2 bytes) coprocessors saved for this thread */ #define XT_CP_CS_ST 4 /* (2 bytes) coprocessor callee-saved regs stored for this thread */ #define XT_CP_ASA 8 /* (4 bytes) ptr to aligned save area */ /* Overall size allows for dynamic alignment: */ #define XT_CP_SIZE (12 + XT_CP_SA_SIZE + XCHAL_TOTAL_SA_ALIGN) #else #define XT_CP_SIZE 0 #endif /* ------------------------------------------------------------------------------- MACROS TO HANDLE ABI SPECIFICS OF FUNCTION ENTRY AND RETURN Convenient where the frame size requirements are the same for both ABIs. ENTRY(sz), RET(sz) are for framed functions (have locals or make calls). ENTRY0, RET0 are for frameless functions (no locals, no calls). where size = size of stack frame in bytes (must be >0 and aligned to 16). For framed functions the frame is created and the return address saved at base of frame (Call0 ABI) or as determined by hardware (Windowed ABI). For frameless functions, there is no frame and return address remains in a0. Note: Because CPP macros expand to a single line, macros requiring multi-line expansions are implemented as assembler macros. ------------------------------------------------------------------------------- */ #ifdef __ASSEMBLER__ #ifdef __XTENSA_CALL0_ABI__ /* Call0 */ #define ENTRY(sz) entry1 sz .macro entry1 size=0x10 addi sp, sp, -\size s32i a0, sp, 0 .endm #define ENTRY0 #define RET(sz) ret1 sz .macro ret1 size=0x10 l32i a0, sp, 0 addi sp, sp, \size ret .endm #define RET0 ret #else /* Windowed */ #if XCHAL_HAVE_XEA3 #define ENTRY(sz) entry sp, (sz + 0x20) #define ENTRY0 entry sp, 0x20 #else #define ENTRY(sz) entry sp, (sz + 0x10) #define ENTRY0 entry sp, 0x10 #endif #define RET(sz) retw #define RET0 retw #endif #endif /* ------------------------------------------------------------------------------- This flag is meant for internal use. Have all interrupts be dispatched via a common wrapper, which takes care of doing some OS-specific stuff common to all interrupt handlers. Said stuff cannot safely be handled in the RTOS_ENTER and RTOS_EXIT macros. ------------------------------------------------------------------------------- */ #if (defined TX_ENABLE_EXECUTION_CHANGE_NOTIFY) || (defined XT_INTEXC_HOOKS) #define XT_USE_INT_WRAPPER 1 #else #define XT_USE_INT_WRAPPER 0 #endif #if XCHAL_HAVE_XEA3 #ifdef XT_USE_SWPRI //#warning "Software prioritization of interrupts (XT_USE_SWPRI) not supported for XEA3." #endif #ifdef __ASSEMBLER__ // RTOS-specific entry macro. Use only a8, a12-a14. .macro XT_RTOS_INT_ENTER .endm // RTOS-specific exit macro. Use only a8-a14. // (In call0, a15 holds user SP, must be preserved) .macro XT_RTOS_INT_EXIT // Check nesting count and branch on nest state. movi a8, _tx_thread_system_state movi a9, _tx_thread_execute_ptr // a9 <- &_tx_thread_execute_ptr (new) movi a10, _tx_thread_preempt_disable // a10 <- &_tx_thread_preempt_disable l32i a8, a8, 0 bnez a8, .Lnested // state != 0 means nested movi a8, _tx_thread_current_ptr // a8 <- &_tx_thread_current_ptr (old) l32i a9, a9, 0 // a9 <- _tx_thread_execute_ptr l32i a11, a8, 0 // a11 <- _tx_thread_current_ptr beqz a11, .Lsched // no old thread, go to scheduler l32i a10, a10, 0 // a10 <- _tx_thread_preempt_disable beq a11, a9, .Lnested // no change, restore current thread bgei a10, 1, .Lnested // no preemption, restore current thread // Preemption, save remaining state of current (outgoing) thread movi a12, _tx_timer_time_slice // a12 <- &_tx_timer_time_slice addi a10, a1, -XT_STK_FRMSZ s32i a10, a11, tx_thread_stack_ptr // save outgoing thread stack pointer l32i a10, a12, 0 // a10 <- _tx_timer_time_slice beqz a10, .Ldont_save_ts s32i a10, a11, tx_thread_time_slice // save outgoing time slice value movi a10, 0 s32i a10, a12, 0 // disable time slice .Ldont_save_ts: s32i a10, a11, tx_thread_solicited // mark as preempted s32i a10, a8, 0 // Clear _tx_thread_current_ptr #if XCHAL_CP_NUM > 0 rsr a12, CPENABLE // Save and clear CPENABLE s16i a12, a11, tx_thread_cp_state + XT_CPENABLE wsr a10, CPENABLE #endif // Save non-CP TIE state if any #if XCHAL_EXTRA_SA_SIZE > 0 addi a10, a1, -XT_STK_FRMSZ + XT_STK_ALIGN_SZ // where to save #if XCHAL_EXTRA_SA_ALIGN > 16 movi a12, -XCHAL_EXTRA_SA_ALIGN and a10, a10, a12 // align dynamically >16 bytes #endif xchal_ncp_store a10, a11, a12, a13, a14 #endif // If windowed ABI, a0-a7 was not saved by dispatch code. // These don't go into the exception frame, but below the // exception frame pointer. #ifdef __XTENSA_WINDOWED_ABI__ addi a10, a1, -XT_STK_FRMSZ -32 s32i a0, a10, 0 s32i a2, a10, 8 s32i a3, a10, 12 s32i a4, a10, 16 s32i a5, a10, 20 s32i a6, a10, 24 s32i a7, a10, 28 #endif .Lsched: // When we get here, interrupts are disabled, a8 = &_tx_thread_current_ptr, // a9 = _tx_thread_execute_ptr movi a9, _tx_thread_execute_ptr // a9 <- &_tx_thread_execute_ptr (new) l32i a9, a9, 0 // a9 <- _tx_thread_execute_ptr s32i a9, a8, 0 // _tx_thread_current_ptr = _tx_thread_execute_ptr beqz a9, _xt_idle // go idle if _tx_thread_execute_ptr == 0 l32i a10, a9, tx_thread_run_count l32i a11, a9, tx_thread_time_slice movi a12, _tx_timer_time_slice addi a10, a10, 1 s32i a10, a9, tx_thread_run_count s32i a11, a12, 0 // _tx_timer_time_slice = _tx_thread_current_ptr->tx_thread_time_slice #ifdef TX_THREAD_SAFE_CLIB #if XSHAL_CLIB == XTHAL_CLIB_NEWLIB movi a10, _impure_ptr #elif XSHAL_CLIB == XTHAL_CLIB_XCLIB movi a10, _reent_ptr #else #error TX_THREAD_SAFE_CLIB defined with unsupported C library. #endif l32i a11, a9, tx_thread_clib_ptr s32i a11, a10, 0 #endif #if XCHAL_CP_NUM > 0 l16ui a10, a9, tx_thread_cp_state + XT_CPENABLE wsr a10, CPENABLE // restore CPENABLE #endif l32i a1, a9, tx_thread_stack_ptr // SP = _tx_thread_execute_ptr->tx_thread_stack_ptr #ifdef TX_ENABLE_EXECUTION_CHANGE_NOTIFY // Call the thread entry function to indicate the thread is executing. // SP should be pointing to a safe region at this point. #ifdef __XTENSA_CALL0_ABI__ call0 _tx_execution_thread_enter #else call8 _tx_execution_thread_enter #endif #endif l32i a2, a9, tx_thread_solicited // a2 = solicited flag beqz a2, 1f // Solicited restore addi a1, a1, XT_STK_FRMSZ // restore original SP addi a2, a1, -XT_STK_XFRM_SZ l32i a3, a2, XT_STK_PC // a3 = return PC movi a2, PS_DI xps a2, a2 // disable interrupts movi a2, 0 wsr.ms a2 // restore normal DISPST rsync jx a3 // return to yield point 1: // Preempt restore #if XCHAL_EXTRA_SA_SIZE > 0 addi a10, a1, XT_STK_ALIGN_SZ // where to restore from #if XCHAL_EXTRA_SA_ALIGN > 16 movi a12, -XCHAL_EXTRA_SA_ALIGN and a10, a10, a12 // align dynamically >16 bytes #endif xchal_ncp_load a10, a11, a12, a13, a14 #endif #ifdef __XTENSA_WINDOWED_ABI__ // Restore a0-a7 for windowed ABI addi a8, a1, -32 l32i a0, a8, 0 l32i a2, a8, 8 l32i a3, a8, 12 l32i a4, a8, 16 l32i a5, a8, 20 l32i a6, a8, 24 l32i a7, a8, 28 #else // For call0, dispatch exit code expects a15 = original SP addi a15, a1, XT_STK_FRMSZ #endif addi a1, a1, XT_STK_FRMSZ // set up SP for dispatch exit .Lnested: // Return to the current saved context. .endm #endif /* __ASSEMBLER__ */ #endif /* XCHAL_HAVE_XEA3 */ #endif /* XTENSA_CONTEXT_H */