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authorDave Martin <dave.martin@linaro.org>2011-05-23 12:22:10 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-05-26 10:31:06 +0100
commitdc2eb928a1bcf6a48f40c1f2ff21b66bdbf91a3c (patch)
tree3f877569ca481ad79378ed0e5932006434a1cc1e /arch/arm/kernel
parent4db70f73e56961b9bcdfd0c36c62847a18b7dbb5 (diff)
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 <dave.martin@linaro.org> Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel')
-rw-r--r--arch/arm/kernel/Makefile2
-rw-r--r--arch/arm/kernel/fiq.c45
-rw-r--r--arch/arm/kernel/fiqasm.S49
3 files changed, 52 insertions, 44 deletions
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 8d95446150a..01c0292eea8 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 e72dc34eea1..4c164ece589 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" (&regs->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" (&regs->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 00000000000..207f9d65201
--- /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)