From: dave.martin@linaro.org (Dave Martin)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2] ARM: fiq: Refactor {get,set}_fiq_regs() for Thumb-2
Date: Thu, 19 May 2011 14:59:38 +0100 [thread overview]
Message-ID: <1305813578-8113-1-git-send-email-dave.martin@linaro.org> (raw)
* 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.
Tested on omap4 using explicit calls to get_fiq_regs() and
set_fiq_regs().
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org>
---
If anyone else feels able to test/ack this patch, it would be much
appreciated.
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 2242ce2..45bb3ee 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 74554f1..689f4d9 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 e72dc34..4c164ec 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 0000000..207f9d6
--- /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 <philb@gnu.org>, 1998.
+ *
+ * FIQ support re-written by Russell King to be more generic
+ *
+ * v7/Thumb-2 compatibility modifications by Linaro Limited, 2011.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+/*
+ * 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)
--
1.7.1
next reply other threads:[~2011-05-19 13:59 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-19 13:59 Dave Martin [this message]
-- strict thread matches above, loose matches on Subject: below --
2011-04-07 9:39 [PATCH v2] ARM: fiq: Refactor {get,set}_fiq_regs() for Thumb-2 Dave Martin
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