From dc2eb928a1bcf6a48f40c1f2ff21b66bdbf91a3c Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Mon, 23 May 2011 12:22:10 +0100 Subject: [PATCH] ARM: 6938/1: fiq: Refactor {get,set}_fiq_regs() for Thumb-2 * To remove the risk of inconvenient register allocation decisions by the compiler, these functions are separated out as pure assembler. * The apcs frame manipulation code is not applicable for Thumb-2 (and also not easily compatible). Since it's not essential to have a full frame on these leaf assembler functions, the frame manipulation is removed, in the interests of simplicity. * Split up ldm/stm instructions to be compatible with Thumb-2, as well as avoiding instruction forms deprecated on >= ARMv7. Signed-off-by: Dave Martin Reviewed-by: Nicolas Pitre Signed-off-by: Russell King --- arch/arm/include/asm/fiq.h | 16 +++++++++++-- arch/arm/kernel/Makefile | 2 +- arch/arm/kernel/fiq.c | 45 ++-------------------------------- arch/arm/kernel/fiqasm.S | 49 ++++++++++++++++++++++++++++++++++++++ 4 files changed, 66 insertions(+), 46 deletions(-) create mode 100644 arch/arm/kernel/fiqasm.S diff --git a/arch/arm/include/asm/fiq.h b/arch/arm/include/asm/fiq.h index 2242ce22ec6c..45bb3eeeab7c 100644 --- a/arch/arm/include/asm/fiq.h +++ b/arch/arm/include/asm/fiq.h @@ -29,9 +29,21 @@ struct fiq_handler { extern int claim_fiq(struct fiq_handler *f); extern void release_fiq(struct fiq_handler *f); extern void set_fiq_handler(void *start, unsigned int length); -extern void set_fiq_regs(struct pt_regs *regs); -extern void get_fiq_regs(struct pt_regs *regs); extern void enable_fiq(int fiq); extern void disable_fiq(int fiq); +/* helpers defined in fiqasm.S: */ +extern void __set_fiq_regs(unsigned long const *regs); +extern void __get_fiq_regs(unsigned long *regs); + +static inline void set_fiq_regs(struct pt_regs const *regs) +{ + __set_fiq_regs(®s->ARM_r8); +} + +static inline void get_fiq_regs(struct pt_regs *regs) +{ + __get_fiq_regs(®s->ARM_r8); +} + #endif diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index 8d95446150a3..01c0292eea8b 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -24,7 +24,7 @@ obj-$(CONFIG_OC_ETM) += etm.o obj-$(CONFIG_ISA_DMA_API) += dma.o obj-$(CONFIG_ARCH_ACORN) += ecard.o -obj-$(CONFIG_FIQ) += fiq.o +obj-$(CONFIG_FIQ) += fiq.o fiqasm.o obj-$(CONFIG_MODULES) += armksyms.o module.o obj-$(CONFIG_ARTHUR) += arthur.o obj-$(CONFIG_ISA_DMA) += dma-isa.o diff --git a/arch/arm/kernel/fiq.c b/arch/arm/kernel/fiq.c index e72dc34eea1c..4c164ece5891 100644 --- a/arch/arm/kernel/fiq.c +++ b/arch/arm/kernel/fiq.c @@ -89,47 +89,6 @@ void set_fiq_handler(void *start, unsigned int length) flush_icache_range(0x1c, 0x1c + length); } -/* - * Taking an interrupt in FIQ mode is death, so both these functions - * disable irqs for the duration. Note - these functions are almost - * entirely coded in assembly. - */ -void __naked set_fiq_regs(struct pt_regs *regs) -{ - register unsigned long tmp; - asm volatile ( - "mov ip, sp\n\ - stmfd sp!, {fp, ip, lr, pc}\n\ - sub fp, ip, #4\n\ - mrs %0, cpsr\n\ - msr cpsr_c, %2 @ select FIQ mode\n\ - mov r0, r0\n\ - ldmia %1, {r8 - r14}\n\ - msr cpsr_c, %0 @ return to SVC mode\n\ - mov r0, r0\n\ - ldmfd sp, {fp, sp, pc}" - : "=&r" (tmp) - : "r" (®s->ARM_r8), "I" (PSR_I_BIT | PSR_F_BIT | FIQ_MODE)); -} - -void __naked get_fiq_regs(struct pt_regs *regs) -{ - register unsigned long tmp; - asm volatile ( - "mov ip, sp\n\ - stmfd sp!, {fp, ip, lr, pc}\n\ - sub fp, ip, #4\n\ - mrs %0, cpsr\n\ - msr cpsr_c, %2 @ select FIQ mode\n\ - mov r0, r0\n\ - stmia %1, {r8 - r14}\n\ - msr cpsr_c, %0 @ return to SVC mode\n\ - mov r0, r0\n\ - ldmfd sp, {fp, sp, pc}" - : "=&r" (tmp) - : "r" (®s->ARM_r8), "I" (PSR_I_BIT | PSR_F_BIT | FIQ_MODE)); -} - int claim_fiq(struct fiq_handler *f) { int ret = 0; @@ -174,8 +133,8 @@ void disable_fiq(int fiq) } EXPORT_SYMBOL(set_fiq_handler); -EXPORT_SYMBOL(set_fiq_regs); -EXPORT_SYMBOL(get_fiq_regs); +EXPORT_SYMBOL(__set_fiq_regs); /* defined in fiqasm.S */ +EXPORT_SYMBOL(__get_fiq_regs); /* defined in fiqasm.S */ EXPORT_SYMBOL(claim_fiq); EXPORT_SYMBOL(release_fiq); EXPORT_SYMBOL(enable_fiq); diff --git a/arch/arm/kernel/fiqasm.S b/arch/arm/kernel/fiqasm.S new file mode 100644 index 000000000000..207f9d652010 --- /dev/null +++ b/arch/arm/kernel/fiqasm.S @@ -0,0 +1,49 @@ +/* + * linux/arch/arm/kernel/fiqasm.S + * + * Derived from code originally in linux/arch/arm/kernel/fiq.c: + * + * Copyright (C) 1998 Russell King + * Copyright (C) 1998, 1999 Phil Blundell + * Copyright (C) 2011, Linaro Limited + * + * FIQ support written by Philip Blundell , 1998. + * + * FIQ support re-written by Russell King to be more generic + * + * v7/Thumb-2 compatibility modifications by Linaro Limited, 2011. + */ + +#include +#include + +/* + * Taking an interrupt in FIQ mode is death, so both these functions + * disable irqs for the duration. + */ + +ENTRY(__set_fiq_regs) + mov r2, #PSR_I_BIT | PSR_F_BIT | FIQ_MODE + mrs r1, cpsr + msr cpsr_c, r2 @ select FIQ mode + mov r0, r0 @ avoid hazard prior to ARMv4 + ldmia r0!, {r8 - r12} + ldr sp, [r0], #4 + ldr lr, [r0] + msr cpsr_c, r1 @ return to SVC mode + mov r0, r0 @ avoid hazard prior to ARMv4 + mov pc, lr +ENDPROC(__set_fiq_regs) + +ENTRY(__get_fiq_regs) + mov r2, #PSR_I_BIT | PSR_F_BIT | FIQ_MODE + mrs r1, cpsr + msr cpsr_c, r2 @ select FIQ mode + mov r0, r0 @ avoid hazard prior to ARMv4 + stmia r0!, {r8 - r12} + str sp, [r0], #4 + str lr, [r0] + msr cpsr_c, r1 @ return to SVC mode + mov r0, r0 @ avoid hazard prior to ARMv4 + mov pc, lr +ENDPROC(__get_fiq_regs)