From 2d1c645cc50b8f5a718b24bad9eb3931e7105d12 Mon Sep 17 00:00:00 2001 From: Marc Gauthier Date: Sat, 5 Jan 2013 04:57:17 +0400 Subject: [PATCH] xtensa: dispatch medium-priority interrupts Add support for dispatching medium-priority interrupts, that is, interrupts of priority levels 2 to EXCM_LEVEL. IRQ handling may be preempted by higher priority IRQ. Signed-off-by: Marc Gauthier Signed-off-by: Max Filippov Signed-off-by: Chris Zankel --- arch/xtensa/include/asm/atomic.h | 6 +-- arch/xtensa/include/asm/processor.h | 4 +- arch/xtensa/include/asm/regs.h | 1 + arch/xtensa/include/asm/timex.h | 8 ++-- arch/xtensa/kernel/entry.S | 55 ++++++++++++++++++----- arch/xtensa/kernel/head.S | 9 ++-- arch/xtensa/kernel/setup.c | 42 ++++++++++++++++++ arch/xtensa/kernel/traps.c | 55 +++++++++++++++-------- arch/xtensa/kernel/vectors.S | 57 +++++++++++++++++++++++- arch/xtensa/kernel/vmlinux.lds.S | 68 +++++++++++++++++++++++++++-- 10 files changed, 260 insertions(+), 45 deletions(-) diff --git a/arch/xtensa/include/asm/atomic.h b/arch/xtensa/include/asm/atomic.h index c3f289174c10..e7fb447bce8e 100644 --- a/arch/xtensa/include/asm/atomic.h +++ b/arch/xtensa/include/asm/atomic.h @@ -7,7 +7,7 @@ * License. See the file "COPYING" in the main directory of this archive * for more details. * - * Copyright (C) 2001 - 2005 Tensilica Inc. + * Copyright (C) 2001 - 2008 Tensilica Inc. */ #ifndef _XTENSA_ATOMIC_H @@ -24,11 +24,11 @@ /* * This Xtensa implementation assumes that the right mechanism - * for exclusion is for locking interrupts to level 1. + * for exclusion is for locking interrupts to level EXCM_LEVEL. * * Locking interrupts looks like this: * - * rsil a15, 1 + * rsil a15, LOCKLEVEL * * wsr a15, PS * rsync diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h index e5fb6b0abdf4..7e409a5b0ec5 100644 --- a/arch/xtensa/include/asm/processor.h +++ b/arch/xtensa/include/asm/processor.h @@ -5,7 +5,7 @@ * License. See the file "COPYING" in the main directory of this archive * for more details. * - * Copyright (C) 2001 - 2005 Tensilica Inc. + * Copyright (C) 2001 - 2008 Tensilica Inc. */ #ifndef _XTENSA_PROCESSOR_H @@ -68,7 +68,7 @@ /* LOCKLEVEL defines the interrupt level that masks all * general-purpose interrupts. */ -#define LOCKLEVEL 1 +#define LOCKLEVEL XCHAL_EXCM_LEVEL /* WSBITS and WBBITS are the width of the WINDOWSTART and WINDOWBASE * registers diff --git a/arch/xtensa/include/asm/regs.h b/arch/xtensa/include/asm/regs.h index 76096a4e5b8d..b24de6717020 100644 --- a/arch/xtensa/include/asm/regs.h +++ b/arch/xtensa/include/asm/regs.h @@ -88,6 +88,7 @@ #define PS_UM_BIT 5 #define PS_EXCM_BIT 4 #define PS_INTLEVEL_SHIFT 0 +#define PS_INTLEVEL_WIDTH 4 #define PS_INTLEVEL_MASK 0x0000000F /* DBREAKCn register fields. */ diff --git a/arch/xtensa/include/asm/timex.h b/arch/xtensa/include/asm/timex.h index 175b3d5e1b01..9e85ce8bd8dd 100644 --- a/arch/xtensa/include/asm/timex.h +++ b/arch/xtensa/include/asm/timex.h @@ -5,7 +5,7 @@ * License. See the file "COPYING" in the main directory of this archive * for more details. * - * Copyright (C) 2001 - 2005 Tensilica Inc. + * Copyright (C) 2001 - 2008 Tensilica Inc. */ #ifndef _XTENSA_TIMEX_H @@ -19,13 +19,13 @@ #define _INTLEVEL(x) XCHAL_INT ## x ## _LEVEL #define INTLEVEL(x) _INTLEVEL(x) -#if INTLEVEL(XCHAL_TIMER0_INTERRUPT) == 1 +#if INTLEVEL(XCHAL_TIMER0_INTERRUPT) <= XCHAL_EXCM_LEVEL # define LINUX_TIMER 0 # define LINUX_TIMER_INT XCHAL_TIMER0_INTERRUPT -#elif INTLEVEL(XCHAL_TIMER1_INTERRUPT) == 1 +#elif INTLEVEL(XCHAL_TIMER1_INTERRUPT) <= XCHAL_EXCM_LEVEL # define LINUX_TIMER 1 # define LINUX_TIMER_INT XCHAL_TIMER1_INTERRUPT -#elif INTLEVEL(XCHAL_TIMER2_INTERRUPT) == 1 +#elif INTLEVEL(XCHAL_TIMER2_INTERRUPT) <= XCHAL_EXCM_LEVEL # define LINUX_TIMER 2 # define LINUX_TIMER_INT XCHAL_TIMER2_INTERRUPT #else diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S index 3777fec85e7c..0ace2acbbad0 100644 --- a/arch/xtensa/kernel/entry.S +++ b/arch/xtensa/kernel/entry.S @@ -7,7 +7,7 @@ * License. See the file "COPYING" in the main directory of this archive * for more details. * - * Copyright (C) 2004-2007 by Tensilica Inc. + * Copyright (C) 2004 - 2008 by Tensilica Inc. * * Chris Zankel * @@ -349,15 +349,16 @@ common_exception: * so we can allow exceptions and interrupts (*) again. * Set PS(EXCM = 0, UM = 0, RING = 0, OWB = 0, WOE = 1, INTLEVEL = X) * - * (*) We only allow interrupts if PS.INTLEVEL was not set to 1 before - * (interrupts disabled) and if this exception is not an interrupt. + * (*) We only allow interrupts of higher priority than current IRQ */ rsr a3, ps addi a0, a0, -4 movi a2, 1 - extui a3, a3, 0, 1 # a3 = PS.INTLEVEL[0] - moveqz a3, a2, a0 # a3 = 1 iff interrupt exception + extui a3, a3, PS_INTLEVEL_SHIFT, PS_INTLEVEL_WIDTH + # a3 = PS.INTLEVEL + movnez a2, a3, a3 # a2 = 1: level-1, > 1: high priority + moveqz a3, a2, a0 # a3 = IRQ level iff interrupt movi a2, 1 << PS_WOE_BIT or a3, a3, a2 rsr a0, exccause @@ -641,19 +642,51 @@ common_exception_exit: l32i a0, a1, PT_DEPC l32i a3, a1, PT_AREG3 + _bltui a0, VALID_DOUBLE_EXCEPTION_ADDRESS, 1f + + wsr a0, depc l32i a2, a1, PT_AREG2 - _bgeui a0, VALID_DOUBLE_EXCEPTION_ADDRESS, 1f + l32i a0, a1, PT_AREG0 + l32i a1, a1, PT_AREG1 + rfde +1: /* Restore a0...a3 and return */ + rsr a0, ps + extui a2, a0, PS_INTLEVEL_SHIFT, PS_INTLEVEL_WIDTH + movi a0, 2f + slli a2, a2, 4 + add a0, a2, a0 + l32i a2, a1, PT_AREG2 + jx a0 + + .macro irq_exit_level level + .align 16 + .if XCHAL_EXCM_LEVEL >= \level + l32i a0, a1, PT_PC + wsr a0, epc\level l32i a0, a1, PT_AREG0 l32i a1, a1, PT_AREG1 - rfe + rfi \level + .endif + .endm -1: wsr a0, depc + .align 16 +2: l32i a0, a1, PT_AREG0 l32i a1, a1, PT_AREG1 - rfde + rfe + + .align 16 + /* no rfi for level-1 irq, handled by rfe above*/ + nop + + irq_exit_level 2 + irq_exit_level 3 + irq_exit_level 4 + irq_exit_level 5 + irq_exit_level 6 ENDPROC(kernel_exception) @@ -753,7 +786,7 @@ ENTRY(unrecoverable_exception) wsr a1, windowbase rsync - movi a1, (1 << PS_WOE_BIT) | 1 + movi a1, (1 << PS_WOE_BIT) | LOCKLEVEL wsr a1, ps rsync @@ -1474,7 +1507,7 @@ ENTRY(_spill_registers) l32i a1, a3, EXC_TABLE_KSTK wsr a3, excsave1 - movi a4, (1 << PS_WOE_BIT) | 1 + movi a4, (1 << PS_WOE_BIT) | LOCKLEVEL wsr a4, ps rsync diff --git a/arch/xtensa/kernel/head.S b/arch/xtensa/kernel/head.S index 91d9095284de..df88f98737f4 100644 --- a/arch/xtensa/kernel/head.S +++ b/arch/xtensa/kernel/head.S @@ -7,7 +7,7 @@ * License. See the file "COPYING" in the main directory of this archive * for more details. * - * Copyright (C) 2001 - 2005 Tensilica Inc. + * Copyright (C) 2001 - 2008 Tensilica Inc. * * Chris Zankel * Marc Gauthier @@ -128,14 +128,14 @@ ENTRY(_startup) wsr a0, cpenable #endif - /* Set PS.INTLEVEL=1, PS.WOE=0, kernel stack, PS.EXCM=0 + /* Set PS.INTLEVEL=LOCKLEVEL, PS.WOE=0, kernel stack, PS.EXCM=0 * * Note: PS.EXCM must be cleared before using any loop * instructions; otherwise, they are silently disabled, and * at most one iteration of the loop is executed. */ - movi a1, 1 + movi a1, LOCKLEVEL wsr a1, ps rsync @@ -211,7 +211,8 @@ ENTRY(_startup) movi a1, init_thread_union addi a1, a1, KERNEL_STACK_SIZE - movi a2, 0x00040001 # WOE=1, INTLEVEL=1, UM=0 + movi a2, (1 << PS_WOE_BIT) | LOCKLEVEL + # WOE=1, INTLEVEL=LOCKLEVEL, UM=0 wsr a2, ps # (enable reg-windows; progmode stack) rsync diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c index 24c1a57abb40..6dd25ecde3f5 100644 --- a/arch/xtensa/kernel/setup.c +++ b/arch/xtensa/kernel/setup.c @@ -328,6 +328,27 @@ extern char _UserExceptionVector_literal_start; extern char _UserExceptionVector_text_end; extern char _DoubleExceptionVector_literal_start; extern char _DoubleExceptionVector_text_end; +#if XCHAL_EXCM_LEVEL >= 2 +extern char _Level2InterruptVector_text_start; +extern char _Level2InterruptVector_text_end; +#endif +#if XCHAL_EXCM_LEVEL >= 3 +extern char _Level3InterruptVector_text_start; +extern char _Level3InterruptVector_text_end; +#endif +#if XCHAL_EXCM_LEVEL >= 4 +extern char _Level4InterruptVector_text_start; +extern char _Level4InterruptVector_text_end; +#endif +#if XCHAL_EXCM_LEVEL >= 5 +extern char _Level5InterruptVector_text_start; +extern char _Level5InterruptVector_text_end; +#endif +#if XCHAL_EXCM_LEVEL >= 6 +extern char _Level6InterruptVector_text_start; +extern char _Level6InterruptVector_text_end; +#endif + #ifdef CONFIG_S32C1I_SELFTEST @@ -482,6 +503,27 @@ void __init setup_arch(char **cmdline_p) mem_reserve(__pa(&_DoubleExceptionVector_literal_start), __pa(&_DoubleExceptionVector_text_end), 0); +#if XCHAL_EXCM_LEVEL >= 2 + mem_reserve(__pa(&_Level2InterruptVector_text_start), + __pa(&_Level2InterruptVector_text_end), 0); +#endif +#if XCHAL_EXCM_LEVEL >= 3 + mem_reserve(__pa(&_Level3InterruptVector_text_start), + __pa(&_Level3InterruptVector_text_end), 0); +#endif +#if XCHAL_EXCM_LEVEL >= 4 + mem_reserve(__pa(&_Level4InterruptVector_text_start), + __pa(&_Level4InterruptVector_text_end), 0); +#endif +#if XCHAL_EXCM_LEVEL >= 5 + mem_reserve(__pa(&_Level5InterruptVector_text_start), + __pa(&_Level5InterruptVector_text_end), 0); +#endif +#if XCHAL_EXCM_LEVEL >= 6 + mem_reserve(__pa(&_Level6InterruptVector_text_start), + __pa(&_Level6InterruptVector_text_end), 0); +#endif + bootmem_init(); #ifdef CONFIG_OF diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c index 01e0111bf787..9b5c345d2b4f 100644 --- a/arch/xtensa/kernel/traps.c +++ b/arch/xtensa/kernel/traps.c @@ -193,28 +193,49 @@ void do_multihit(struct pt_regs *regs, unsigned long exccause) } /* - * Level-1 interrupt. - * We currently have no priority encoding. + * IRQ handler. + * PS.INTLEVEL is the current IRQ priority level. */ -unsigned long ignored_level1_interrupts; extern void do_IRQ(int, struct pt_regs *); -void do_interrupt (struct pt_regs *regs) +void do_interrupt(struct pt_regs *regs) { - unsigned long intread = get_sr (interrupt); - unsigned long intenable = get_sr (intenable); - int i, mask; - - /* Handle all interrupts (no priorities). - * (Clear the interrupt before processing, in case it's - * edge-triggered or software-generated) - */ + static const unsigned int_level_mask[] = { + 0, + XCHAL_INTLEVEL1_MASK, + XCHAL_INTLEVEL2_MASK, + XCHAL_INTLEVEL3_MASK, + XCHAL_INTLEVEL4_MASK, + XCHAL_INTLEVEL5_MASK, + XCHAL_INTLEVEL6_MASK, + XCHAL_INTLEVEL7_MASK, + }; + unsigned level = get_sr(ps) & PS_INTLEVEL_MASK; + + if (WARN_ON_ONCE(level >= ARRAY_SIZE(int_level_mask))) + return; - for (i=0, mask = 1; i < XCHAL_NUM_INTERRUPTS; i++, mask <<= 1) { - if (mask & (intread & intenable)) { - set_sr (mask, intclear); - do_IRQ (i,regs); + for (;;) { + unsigned intread = get_sr(interrupt); + unsigned intenable = get_sr(intenable); + unsigned int_at_level = intread & intenable & + int_level_mask[level]; + + if (!int_at_level) + return; + + /* + * Clear the interrupt before processing, in case it's + * edge-triggered or software-generated + */ + while (int_at_level) { + unsigned i = __ffs(int_at_level); + unsigned mask = 1 << i; + + int_at_level ^= mask; + set_sr(mask, intclear); + do_IRQ(i, regs); } } } @@ -397,7 +418,7 @@ static inline void spill_registers(void) unsigned int a0, ps; __asm__ __volatile__ ( - "movi a14, " __stringify(PS_EXCM_BIT | 1) "\n\t" + "movi a14, " __stringify(PS_EXCM_BIT | LOCKLEVEL) "\n\t" "mov a12, a0\n\t" "rsr a13, sar\n\t" "xsr a14, ps\n\t" diff --git a/arch/xtensa/kernel/vectors.S b/arch/xtensa/kernel/vectors.S index 68df35f66ce3..82109b42e240 100644 --- a/arch/xtensa/kernel/vectors.S +++ b/arch/xtensa/kernel/vectors.S @@ -10,7 +10,7 @@ * Public License. See the file "COPYING" in the main directory of * this archive for more details. * - * Copyright (C) 2005 Tensilica, Inc. + * Copyright (C) 2005 - 2008 Tensilica, Inc. * * Chris Zankel * @@ -366,6 +366,41 @@ ENTRY(_DebugInterruptVector) ENDPROC(_DebugInterruptVector) + +/* + * Medium priority level interrupt vectors + * + * Each takes less than 16 (0x10) bytes, no literals, by placing + * the extra 8 bytes that would otherwise be required in the window + * vectors area where there is space. With relocatable vectors, + * all vectors are within ~ 4 kB range of each other, so we can + * simply jump (J) to another vector without having to use JX. + * + * common_exception code gets current IRQ level in PS.INTLEVEL + * and preserves it for the IRQ handling time. + */ + + .macro irq_entry_level level + + .if XCHAL_EXCM_LEVEL >= \level + .section .Level\level\()InterruptVector.text, "ax" +ENTRY(_Level\level\()InterruptVector) + wsr a0, epc1 + rsr a0, epc\level + xsr a0, epc1 + # branch to user or kernel vector + j _SimulateUserKernelVectorException + .endif + + .endm + + irq_entry_level 2 + irq_entry_level 3 + irq_entry_level 4 + irq_entry_level 5 + irq_entry_level 6 + + /* Window overflow and underflow handlers. * The handlers must be 64 bytes apart, first starting with the underflow * handlers underflow-4 to underflow-12, then the overflow handlers @@ -396,6 +431,26 @@ ENTRY_ALIGN64(_WindowOverflow4) ENDPROC(_WindowOverflow4) +#if XCHAL_EXCM_LEVEL >= 2 + /* Not a window vector - but a convenient location + * (where we know there's space) for continuation of + * medium priority interrupt dispatch code. + * On entry here, a0 contains PS, and EPC2 contains saved a0: + */ + .align 4 +_SimulateUserKernelVectorException: + wsr a0, excsave2 + movi a0, 4 # LEVEL1_INTERRUPT cause + wsr a0, exccause + rsr a0, ps + bbsi.l a0, PS_UM_BIT, 1f # branch if user mode + rsr a0, excsave2 # restore a0 + j _KernelExceptionVector # simulate kernel vector exception +1: rsr a0, excsave2 # restore a0 + j _UserExceptionVector # simulate user vector exception +#endif + + /* 4-Register Window Underflow Vector (Handler) */ ENTRY_ALIGN64(_WindowUnderflow4) diff --git a/arch/xtensa/kernel/vmlinux.lds.S b/arch/xtensa/kernel/vmlinux.lds.S index 255154f820b7..14695240536d 100644 --- a/arch/xtensa/kernel/vmlinux.lds.S +++ b/arch/xtensa/kernel/vmlinux.lds.S @@ -7,7 +7,7 @@ * License. See the file "COPYING" in the main directory of this archive * for more details. * - * Copyright (C) 2001 - 2005 Tensilica Inc. + * Copyright (C) 2001 - 2008 Tensilica Inc. * * Chris Zankel * Marc Gauthier @@ -134,6 +134,26 @@ SECTIONS RELOCATE_ENTRY(_WindowVectors_text, .WindowVectors.text); +#if XCHAL_EXCM_LEVEL >= 2 + RELOCATE_ENTRY(_Level2InterruptVector_text, + .Level2InterruptVector.text); +#endif +#if XCHAL_EXCM_LEVEL >= 3 + RELOCATE_ENTRY(_Level3InterruptVector_text, + .Level3InterruptVector.text); +#endif +#if XCHAL_EXCM_LEVEL >= 4 + RELOCATE_ENTRY(_Level4InterruptVector_text, + .Level4InterruptVector.text); +#endif +#if XCHAL_EXCM_LEVEL >= 5 + RELOCATE_ENTRY(_Level5InterruptVector_text, + .Level5InterruptVector.text); +#endif +#if XCHAL_EXCM_LEVEL >= 6 + RELOCATE_ENTRY(_Level6InterruptVector_text, + .Level6InterruptVector.text); +#endif RELOCATE_ENTRY(_KernelExceptionVector_text, .KernelExceptionVector.text); RELOCATE_ENTRY(_UserExceptionVector_text, @@ -177,11 +197,53 @@ SECTIONS XCHAL_DEBUG_VECTOR_VADDR, 4, .DebugInterruptVector.literal) +#undef LAST +#define LAST .DebugInterruptVector.text +#if XCHAL_EXCM_LEVEL >= 2 + SECTION_VECTOR (_Level2InterruptVector_text, + .Level2InterruptVector.text, + XCHAL_INTLEVEL2_VECTOR_VADDR, + SIZEOF(LAST), LAST) +# undef LAST +# define LAST .Level2InterruptVector.text +#endif +#if XCHAL_EXCM_LEVEL >= 3 + SECTION_VECTOR (_Level3InterruptVector_text, + .Level3InterruptVector.text, + XCHAL_INTLEVEL3_VECTOR_VADDR, + SIZEOF(LAST), LAST) +# undef LAST +# define LAST .Level3InterruptVector.text +#endif +#if XCHAL_EXCM_LEVEL >= 4 + SECTION_VECTOR (_Level4InterruptVector_text, + .Level4InterruptVector.text, + XCHAL_INTLEVEL4_VECTOR_VADDR, + SIZEOF(LAST), LAST) +# undef LAST +# define LAST .Level4InterruptVector.text +#endif +#if XCHAL_EXCM_LEVEL >= 5 + SECTION_VECTOR (_Level5InterruptVector_text, + .Level5InterruptVector.text, + XCHAL_INTLEVEL5_VECTOR_VADDR, + SIZEOF(LAST), LAST) +# undef LAST +# define LAST .Level5InterruptVector.text +#endif +#if XCHAL_EXCM_LEVEL >= 6 + SECTION_VECTOR (_Level6InterruptVector_text, + .Level6InterruptVector.text, + XCHAL_INTLEVEL6_VECTOR_VADDR, + SIZEOF(LAST), LAST) +# undef LAST +# define LAST .Level6InterruptVector.text +#endif SECTION_VECTOR (_KernelExceptionVector_literal, .KernelExceptionVector.literal, XCHAL_KERNEL_VECTOR_VADDR - 4, - SIZEOF(.DebugInterruptVector.text), - .DebugInterruptVector.text) + SIZEOF(LAST), LAST) +#undef LAST SECTION_VECTOR (_KernelExceptionVector_text, .KernelExceptionVector.text, XCHAL_KERNEL_VECTOR_VADDR, -- 2.20.1