[PATCH 10/12] sparc: Make _CPU_ISR_Dispatch_disable per-CPU
Sebastian Huber
sebastian.huber at embedded-brains.de
Mon Aug 5 14:08:17 UTC 2013
This variable must be available for each processor in the system.
---
c/src/lib/libbsp/sparc/shared/irq_asm.S | 42 ++++++++++++++---------------
cpukit/score/cpu/sparc/cpu.c | 14 +++++-----
cpukit/score/cpu/sparc/rtems/score/cpu.h | 24 ++++++++++-------
3 files changed, 41 insertions(+), 39 deletions(-)
diff --git a/c/src/lib/libbsp/sparc/shared/irq_asm.S b/c/src/lib/libbsp/sparc/shared/irq_asm.S
index d0550df..ce276cd 100644
--- a/c/src/lib/libbsp/sparc/shared/irq_asm.S
+++ b/c/src/lib/libbsp/sparc/shared/irq_asm.S
@@ -20,7 +20,7 @@
*/
#include <rtems/asm.h>
-#include <rtems/system.h>
+#include <rtems/score/percpu.h>
#include <bspopts.h>
.macro GET_SELF_CPU_CONTROL REG, TMP
@@ -59,19 +59,11 @@ SYM(_CPU_Context_switch):
std %g4, [%o0 + G4_OFFSET]
std %g6, [%o0 + G6_OFFSET]
- ! load the address of the ISR stack nesting prevention flag
- sethi %hi(SYM(_CPU_ISR_Dispatch_disable)), %g2
- ld [%g2 + %lo(SYM(_CPU_ISR_Dispatch_disable))], %g2
- ! save it a bit later so we do not waste a couple of cycles
-
std %l0, [%o0 + L0_OFFSET] ! save the local registers
std %l2, [%o0 + L2_OFFSET]
std %l4, [%o0 + L4_OFFSET]
std %l6, [%o0 + L6_OFFSET]
- ! Now actually save ISR stack nesting prevention flag
- st %g2, [%o0 + ISR_DISPATCH_DISABLE_STACK_OFFSET]
-
std %i0, [%o0 + I0_OFFSET] ! save the input registers
std %i2, [%o0 + I2_OFFSET]
std %i4, [%o0 + I4_OFFSET]
@@ -82,13 +74,24 @@ SYM(_CPU_Context_switch):
std %o4, [%o0 + O4_OFFSET]
std %o6, [%o0 + O6_SP_OFFSET]
+ ! o3 = self per-CPU control
+ GET_SELF_CPU_CONTROL %o3, %o4
+
+ ! load the ISR stack nesting prevention flag
+ ld [%o3 + SPARC_PER_CPU_ISR_DISPATCH_DISABLE], %o4
+ ! save it a bit later so we do not waste a couple of cycles
+
rd %psr, %o2
st %o2, [%o0 + PSR_OFFSET] ! save status register
+ ! Now actually save ISR stack nesting prevention flag
+ st %o4, [%o0 + ISR_DISPATCH_DISABLE_STACK_OFFSET]
+
/*
* This is entered from _CPU_Context_restore with:
* o1 = context to restore
* o2 = psr
+ * o3 = self per-CPU control
*/
PUBLIC(_CPU_Context_restore_heir)
@@ -196,7 +199,6 @@ done_flushing:
! Load thread specific ISR dispatch prevention flag
ld [%o1 + ISR_DISPATCH_DISABLE_STACK_OFFSET], %o2
- sethi %hi(SYM(_CPU_ISR_Dispatch_disable)), %o3
! Store it to memory later to use the cycles
ldd [%o1 + L0_OFFSET], %l0 ! restore the local registers
@@ -205,7 +207,7 @@ done_flushing:
ldd [%o1 + L6_OFFSET], %l6
! Now restore thread specific ISR dispatch prevention flag
- st %o2,[%o3 + %lo(SYM(_CPU_ISR_Dispatch_disable))]
+ st %o2, [%o3 + SPARC_PER_CPU_ISR_DISPATCH_DISABLE]
ldd [%o1 + I0_OFFSET], %i0 ! restore the output registers
ldd [%o1 + I2_OFFSET], %i2
@@ -235,6 +237,7 @@ done_flushing:
SYM(_CPU_Context_restore):
save %sp, -CPU_MINIMUM_STACK_FRAME_SIZE, %sp
rd %psr, %o2
+ GET_SELF_CPU_CONTROL %o3, %o4
ba SYM(_CPU_Context_restore_heir)
mov %i0, %o1 ! in the delay slot
.align 4
@@ -591,11 +594,10 @@ dont_fix_pil2:
orcc %l6, %g0, %g0 ! Is dispatching disabled?
bnz simple_return ! Yes, then do a "simple" exit
- ! NOTE: Use the delay slot
- sethi %hi(SYM(_CPU_ISR_Dispatch_disable)), %l6
+ nop
! Are we dispatching from a previous ISR in the interrupted thread?
- ld [%l6 + %lo(SYM(_CPU_ISR_Dispatch_disable))], %l7
+ ld [%l5 + SPARC_PER_CPU_ISR_DISPATCH_DISABLE], %l7
orcc %l7, %g0, %g0 ! Is this thread already doing an ISR?
bnz simple_return ! Yes, then do a "simple" exit
nop
@@ -606,9 +608,9 @@ dont_fix_pil2:
* return to the interrupt dispatcher.
*/
- ldub [%l5 + PER_CPU_DISPATCH_NEEDED], %l5
+ ldub [%l5 + PER_CPU_DISPATCH_NEEDED], %l6
- orcc %l5, %g0, %g0 ! Is thread switch necessary?
+ orcc %l6, %g0, %g0 ! Is thread switch necessary?
bz simple_return ! no, then do a simple return
nop
@@ -616,12 +618,9 @@ dont_fix_pil2:
* Invoke interrupt dispatcher.
*/
- PUBLIC(_ISR_Dispatch)
-SYM(_ISR_Dispatch):
! Set ISR dispatch nesting prevention flag
mov 1,%l6
- sethi %hi(SYM(_CPU_ISR_Dispatch_disable)), %l5
- st %l6,[%l5 + %lo(SYM(_CPU_ISR_Dispatch_disable))]
+ st %l6, [%l5 + SPARC_PER_CPU_ISR_DISPATCH_DISABLE]
/*
* The following subtract should get us back on the interrupted
@@ -676,8 +675,7 @@ dispatchAgain:
allow_nest_again:
! Zero out ISR stack nesting prevention flag
- sethi %hi(SYM(_CPU_ISR_Dispatch_disable)), %l5
- st %g0,[%l5 + %lo(SYM(_CPU_ISR_Dispatch_disable))]
+ st %g0, [%l5 + SPARC_PER_CPU_ISR_DISPATCH_DISABLE]
/*
* The CWP in place at this point may be different from
diff --git a/cpukit/score/cpu/sparc/cpu.c b/cpukit/score/cpu/sparc/cpu.c
index baa15c0..1865a21 100644
--- a/cpukit/score/cpu/sparc/cpu.c
+++ b/cpukit/score/cpu/sparc/cpu.c
@@ -19,8 +19,15 @@
#include <rtems/system.h>
#include <rtems/score/isr.h>
+#include <rtems/score/percpu.h>
#include <rtems/rtems/cache.h>
+RTEMS_STATIC_ASSERT(
+ offsetof( Per_CPU_Control, cpu_per_cpu.isr_dispatch_disable)
+ == SPARC_PER_CPU_ISR_DISPATCH_DISABLE,
+ SPARC_PER_CPU_ISR_DISPATCH_DISABLE
+);
+
/*
* This initializes the set of opcodes placed in each trap
* table entry. The routine which installs a handler is responsible
@@ -65,13 +72,6 @@ void _CPU_Initialize(void)
pointer = &_CPU_Null_fp_context;
_CPU_Context_save_fp( &pointer );
#endif
-
- /*
- * Since no tasks have been created yet and no interrupts have occurred,
- * there is no way that the currently executing thread can have an
- * _ISR_Dispatch stack frame on its stack.
- */
- _CPU_ISR_Dispatch_disable = 0;
}
uint32_t _CPU_ISR_Get_level( void )
diff --git a/cpukit/score/cpu/sparc/rtems/score/cpu.h b/cpukit/score/cpu/sparc/rtems/score/cpu.h
index 61f0410..690ddcf 100644
--- a/cpukit/score/cpu/sparc/rtems/score/cpu.h
+++ b/cpukit/score/cpu/sparc/rtems/score/cpu.h
@@ -357,7 +357,13 @@ typedef struct {
/** This defines the size of the minimum stack frame. */
#define CPU_MINIMUM_STACK_FRAME_SIZE 0x60
-#define CPU_PER_CPU_CONTROL_SIZE 0
+#define CPU_PER_CPU_CONTROL_SIZE 4
+
+/**
+ * @brief Offset of the CPU_Per_CPU_control::isr_dispatch_disable field
+ * relative to the Per_CPU_Control begin.
+ */
+#define SPARC_PER_CPU_ISR_DISPATCH_DISABLE 0
/**
* @defgroup Contexts SPARC Context Structures
@@ -383,7 +389,13 @@ typedef struct {
#ifndef ASM
typedef struct {
- /* There is no CPU specific per-CPU state */
+ /**
+ * This flag is context switched with each thread. It indicates
+ * that THIS thread has an _ISR_Dispatch stack frame on its stack.
+ * By using this flag, we can avoid nesting more interrupt dispatching
+ * attempts on a previously interrupted thread's stack.
+ */
+ uint32_t isr_dispatch_disable;
} CPU_Per_CPU_control;
/**
@@ -769,14 +781,6 @@ typedef struct {
SCORE_EXTERN Context_Control_fp _CPU_Null_fp_context CPU_STRUCTURE_ALIGNMENT;
/**
- * This flag is context switched with each thread. It indicates
- * that THIS thread has an _ISR_Dispatch stack frame on its stack.
- * By using this flag, we can avoid nesting more interrupt dispatching
- * attempts on a previously interrupted thread's stack.
- */
-SCORE_EXTERN volatile uint32_t _CPU_ISR_Dispatch_disable;
-
-/**
* The following type defines an entry in the SPARC's trap table.
*
* NOTE: The instructions chosen are RTEMS dependent although one is
--
1.7.7
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