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author | Chris Zankel <chris@zankel.net> | 2008-02-12 13:17:07 -0800 |
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committer | Chris Zankel <chris@zankel.net> | 2008-02-13 17:41:43 -0800 |
commit | c658eac628aa8df040dfe614556d95e6da3a9ffb (patch) | |
tree | e2211e1d5c894c29e92d4c744f504b38410efe41 /arch/xtensa/kernel/coprocessor.S | |
parent | 71d28e6c285548106f551fde13ca6d589433d843 (diff) | |
download | linux-c658eac628aa8df040dfe614556d95e6da3a9ffb.tar.gz linux-c658eac628aa8df040dfe614556d95e6da3a9ffb.tar.bz2 linux-c658eac628aa8df040dfe614556d95e6da3a9ffb.zip |
[XTENSA] Add support for configurable registers and coprocessors
The Xtensa architecture allows to define custom instructions and
registers. Registers that are bound to a coprocessor are only
accessible if the corresponding enable bit is set, which allows
to implement a 'lazy' context switch mechanism. Other registers
needs to be saved and restore at the time of the context switch
or during interrupt handling.
This patch adds support for these additional states:
- save and restore registers that are used by the compiler upon
interrupt entry and exit.
- context switch additional registers unbound to any coprocessor
- 'lazy' context switch of registers bound to a coprocessor
- ptrace interface to provide access to additional registers
- update configuration files in include/asm-xtensa/variant-fsf
Signed-off-by: Chris Zankel <chris@zankel.net>
Diffstat (limited to 'arch/xtensa/kernel/coprocessor.S')
-rw-r--r-- | arch/xtensa/kernel/coprocessor.S | 443 |
1 files changed, 289 insertions, 154 deletions
diff --git a/arch/xtensa/kernel/coprocessor.S b/arch/xtensa/kernel/coprocessor.S index 01bcb9fcfcbd..2bc1e145c0a4 100644 --- a/arch/xtensa/kernel/coprocessor.S +++ b/arch/xtensa/kernel/coprocessor.S @@ -8,193 +8,328 @@ * License. See the file "COPYING" in the main directory of this archive * for more details. * - * Copyright (C) 2003 - 2005 Tensilica Inc. - * - * Marc Gauthier <marc@tensilica.com> <marc@alumni.uwaterloo.ca> + * Copyright (C) 2003 - 2007 Tensilica Inc. */ -/* - * This module contains a table that describes the layout of the various - * custom registers and states associated with each coprocessor, as well - * as those not associated with any coprocessor ("extra state"). - * This table is included with core dumps and is available via the ptrace - * interface, allowing the layout of such register/state information to - * be modified in the kernel without affecting the debugger. Each - * register or state is identified using a 32-bit "libdb target number" - * assigned when the Xtensa processor is generated. - */ #include <linux/linkage.h> +#include <asm/asm-offsets.h> #include <asm/processor.h> +#include <asm/coprocessor.h> +#include <asm/thread_info.h> +#include <asm/uaccess.h> +#include <asm/unistd.h> +#include <asm/ptrace.h> +#include <asm/current.h> +#include <asm/pgtable.h> +#include <asm/page.h> +#include <asm/signal.h> +#include <asm/tlbflush.h> -#if XCHAL_HAVE_CP +/* + * Entry condition: + * + * a0: trashed, original value saved on stack (PT_AREG0) + * a1: a1 + * a2: new stack pointer, original in DEPC + * a3: dispatch table + * depc: a2, original value saved on stack (PT_DEPC) + * excsave_1: a3 + * + * PT_DEPC >= VALID_DOUBLE_EXCEPTION_ADDRESS: double exception, DEPC + * < VALID_DOUBLE_EXCEPTION_ADDRESS: regular exception + */ -#define CP_LAST ((XCHAL_CP_MAX - 1) * COPROCESSOR_INFO_SIZE) +/* IO protection is currently unsupported. */ -ENTRY(release_coprocessors) +ENTRY(fast_io_protect) + wsr a0, EXCSAVE_1 + movi a0, unrecoverable_exception + callx0 a0 - entry a1, 16 - # a2: task - movi a3, 1 << XCHAL_CP_MAX # a3: coprocessor-bit - movi a4, coprocessor_info+CP_LAST # a4: owner-table - # a5: tmp - movi a6, 0 # a6: 0 - rsil a7, LOCKLEVEL # a7: PS +#if XTENSA_HAVE_COPROCESSORS -1: /* Check if task is coprocessor owner of coprocessor[i]. */ +/* + * Macros for lazy context switch. + */ - l32i a5, a4, COPROCESSOR_INFO_OWNER - srli a3, a3, 1 - beqz a3, 1f - addi a4, a4, -8 - beq a2, a5, 1b +#define SAVE_CP_REGS(x) \ + .align 4; \ + .Lsave_cp_regs_cp##x: \ + .if XTENSA_HAVE_COPROCESSOR(x); \ + xchal_cp##x##_store a2 a4 a5 a6 a7; \ + .endif; \ + jx a0 - /* Found an entry: Clear entry CPENABLE bit to disable CP. */ +#define SAVE_CP_REGS_TAB(x) \ + .if XTENSA_HAVE_COPROCESSOR(x); \ + .long .Lsave_cp_regs_cp##x - .Lsave_cp_regs_jump_table; \ + .else; \ + .long 0; \ + .endif; \ + .long THREAD_XTREGS_CP##x - rsr a5, CPENABLE - s32i a6, a4, COPROCESSOR_INFO_OWNER - xor a5, a3, a5 - wsr a5, CPENABLE - bnez a3, 1b +#define LOAD_CP_REGS(x) \ + .align 4; \ + .Lload_cp_regs_cp##x: \ + .if XTENSA_HAVE_COPROCESSOR(x); \ + xchal_cp##x##_load a2 a4 a5 a6 a7; \ + .endif; \ + jx a0 -1: wsr a7, PS - rsync - retw +#define LOAD_CP_REGS_TAB(x) \ + .if XTENSA_HAVE_COPROCESSOR(x); \ + .long .Lload_cp_regs_cp##x - .Lload_cp_regs_jump_table; \ + .else; \ + .long 0; \ + .endif; \ + .long THREAD_XTREGS_CP##x + 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) -ENTRY(disable_coprocessor) - entry sp, 16 - rsil a7, LOCKLEVEL - rsr a3, CPENABLE - movi a4, 1 - ssl a2 - sll a4, a4 - and a4, a3, a4 - xor a3, a3, a4 - wsr a3, CPENABLE - wsr a7, PS - rsync - retw + 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) -ENTRY(enable_coprocessor) - entry sp, 16 - rsil a7, LOCKLEVEL - rsr a3, CPENABLE - movi a4, 1 - ssl a2 - sll a4, a4 - or a3, a3, a4 - wsr a3, CPENABLE - wsr a7, PS - rsync - retw + .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(save_coprocessor_extra) - entry sp, 16 - xchal_extra_store_funcbody - retw +/* + * coprocessor_save(buffer, index) + * a2 a3 + * coprocessor_load(buffer, index) + * a2 a3 + * + * Save or load coprocessor registers for coprocessor 'index'. + * The register values are saved to or loaded from them 'buffer' address. + * + * Note that these functions don't update the coprocessor_owner information! + * + */ -ENTRY(restore_coprocessor_extra) - entry sp, 16 - xchal_extra_load_funcbody +ENTRY(coprocessor_save) + entry a1, 32 + s32i a0, a1, 0 + movi a0, .Lsave_cp_regs_jump_table + addx8 a3, a3, a0 + l32i a3, a3, 0 + beqz a3, 1f + add a0, a0, a3 + callx0 a0 +1: l32i a0, a1, 0 retw -ENTRY(save_coprocessor_registers) - entry sp, 16 - xchal_cpi_store_funcbody +ENTRY(coprocessor_load) + entry a1, 32 + s32i a0, a1, 0 + movi a0, .Lload_cp_regs_jump_table + addx4 a3, a3, a0 + l32i a3, a3, 0 + beqz a3, 1f + add a0, a0, a3 + callx0 a0 +1: l32i a0, a1, 0 retw -ENTRY(restore_coprocessor_registers) - entry sp, 16 - xchal_cpi_load_funcbody +/* + * coprocessor_flush(struct task_info*, index) + * a2 a3 + * coprocessor_restore(struct task_info*, index) + * a2 a3 + * + * Save or load coprocessor registers for coprocessor 'index'. + * The register values are saved to or loaded from the coprocessor area + * inside the task_info structure. + * + * Note that these functions don't update the coprocessor_owner information! + * + */ + + +ENTRY(coprocessor_flush) + entry a1, 32 + 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 + add a0, a0, a3 + callx0 a0 +1: l32i a0, a1, 0 retw +ENTRY(coprocessor_restore) + entry a1, 32 + s32i a0, a1, 0 + movi a0, .Lload_cp_regs_jump_table + addx4 a3, a3, a0 + l32i a4, a3, 4 + l32i a3, a3, 0 + add a2, a2, a4 + beqz a3, 1f + add a0, a0, a3 + callx0 a0 +1: l32i a0, a1, 0 + retw /* - * The Xtensa compile-time HAL (core.h) XCHAL_*_SA_CONTENTS_LIBDB macros - * describe the contents of coprocessor & extra save areas in terms of - * undefined CONTENTS_LIBDB_{SREG,UREG,REGF} macros. We define these - * latter macros here; they expand into a table of the format we want. - * The general format is: + * Entry condition: * - * CONTENTS_LIBDB_SREG(libdbnum, offset, size, align, rsv1, name, sregnum, - * bitmask, rsv2, rsv3) - * CONTENTS_LIBDB_UREG(libdbnum, offset, size, align, rsv1, name, uregnum, - * bitmask, rsv2, rsv3) - * CONTENTS_LIBDB_REGF(libdbnum, offset, size, align, rsv1, name, index, - * numentries, contentsize, regname_base, - * regfile_name, rsv2, rsv3) + * a0: trashed, original value saved on stack (PT_AREG0) + * a1: a1 + * a2: new stack pointer, original in DEPC + * a3: dispatch table + * depc: a2, original value saved on stack (PT_DEPC) + * excsave_1: a3 * - * For this table, we only care about the <libdbnum>, <offset> and <size> - * fields. + * PT_DEPC >= VALID_DOUBLE_EXCEPTION_ADDRESS: double exception, DEPC + * < VALID_DOUBLE_EXCEPTION_ADDRESS: regular exception */ -/* Map all XCHAL CONTENTS macros to the reg_entry asm macro defined below: */ - -#define CONTENTS_LIBDB_SREG(libdbnum,offset,size,align,rsv1,name,sregnum, \ - bitmask, rsv2, rsv3) \ - reg_entry libdbnum, offset, size ; -#define CONTENTS_LIBDB_UREG(libdbnum,offset,size,align,rsv1,name,uregnum, \ - bitmask, rsv2, rsv3) \ - reg_entry libdbnum, offset, size ; -#define CONTENTS_LIBDB_REGF(libdbnum, offset, size, align, rsv1, name, index, \ - numentries, contentsize, regname_base, \ - regfile_name, rsv2, rsv3) \ - reg_entry libdbnum, offset, size ; - -/* A single table entry: */ - .macro reg_entry libdbnum, offset, size - .ifne (__last_offset-(__last_group_offset+\offset)) - /* padding entry */ - .word (0xFC000000+__last_offset-(__last_group_offset+\offset)) - .endif - .word \libdbnum /* actual entry */ - .set __last_offset, __last_group_offset+\offset+\size - .endm /* reg_entry */ - - -/* Table entry that marks the beginning of a group (coprocessor or "extra"): */ - .macro reg_group cpnum, num_entries, align - .set __last_group_offset, (__last_offset + \align- 1) & -\align - .ifne \num_entries - .word 0xFD000000+(\cpnum<<16)+\num_entries - .endif - .endm /* reg_group */ +ENTRY(fast_coprocessor_double) + wsr a0, EXCSAVE_1 + movi a0, unrecoverable_exception + callx0 a0 -/* - * Register info tables. - */ - .section .rodata, "a" - .globl _xtensa_reginfo_tables - .globl _xtensa_reginfo_table_size - .align 4 -_xtensa_reginfo_table_size: - .word _xtensa_reginfo_table_end - _xtensa_reginfo_tables - -_xtensa_reginfo_tables: - .set __last_offset, 0 - reg_group 0xFF, XCHAL_EXTRA_SA_CONTENTS_LIBDB_NUM, XCHAL_EXTRA_SA_ALIGN - XCHAL_EXTRA_SA_CONTENTS_LIBDB - reg_group 0, XCHAL_CP0_SA_CONTENTS_LIBDB_NUM, XCHAL_CP0_SA_ALIGN - XCHAL_CP0_SA_CONTENTS_LIBDB - reg_group 1, XCHAL_CP1_SA_CONTENTS_LIBDB_NUM, XCHAL_CP1_SA_ALIGN - XCHAL_CP1_SA_CONTENTS_LIBDB - reg_group 2, XCHAL_CP2_SA_CONTENTS_LIBDB_NUM, XCHAL_CP2_SA_ALIGN - XCHAL_CP2_SA_CONTENTS_LIBDB - reg_group 3, XCHAL_CP3_SA_CONTENTS_LIBDB_NUM, XCHAL_CP3_SA_ALIGN - XCHAL_CP3_SA_CONTENTS_LIBDB - reg_group 4, XCHAL_CP4_SA_CONTENTS_LIBDB_NUM, XCHAL_CP4_SA_ALIGN - XCHAL_CP4_SA_CONTENTS_LIBDB - reg_group 5, XCHAL_CP5_SA_CONTENTS_LIBDB_NUM, XCHAL_CP5_SA_ALIGN - XCHAL_CP5_SA_CONTENTS_LIBDB - reg_group 6, XCHAL_CP6_SA_CONTENTS_LIBDB_NUM, XCHAL_CP6_SA_ALIGN - XCHAL_CP6_SA_CONTENTS_LIBDB - reg_group 7, XCHAL_CP7_SA_CONTENTS_LIBDB_NUM, XCHAL_CP7_SA_ALIGN - XCHAL_CP7_SA_CONTENTS_LIBDB - .word 0xFC000000 /* invalid register number,marks end of table*/ -_xtensa_reginfo_table_end: -#endif +ENTRY(fast_coprocessor) + + /* Save remaining registers a1-a3 and SAR */ + + xsr a3, EXCSAVE_1 + 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 offset + add a2, a2, a4 + add a4, a3, a5 # a4: address of save routine + jx a4 + + /* 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 offset + add a2, a2, a4 + add a4, a3, a5 + jx a4 + + /* 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 + + .data +ENTRY(coprocessor_owner) + .fill XCHAL_CP_MAX, 4, 0 + +#endif /* XTENSA_HAVE_COPROCESSORS */ |