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kernel: tickless: Rename _Swap to allow creation of macro

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Future tickless kernel patches would be inserting some
code before call to Swap. To enable this it will create
a mcro named as the current _Swap which would call first
the tickless kernel code and then call the real __swap()

Jira: ZEP-339
Change-Id: Id778bfcee4f88982c958fcf22d7f04deb4bd572f
Signed-off-by: Ramesh Thomas <ramesh.thomas@intel.com>
This commit is contained in:
Ramesh Thomas 2017-04-06 15:30:27 -07:00 • committed by Anas Nashif
commit 62eea121b3
9 changed files with 70 additions and 68 deletions
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20
arch/arm/core/swap.S
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@ -19,7 +19,7 @@
_ASM_FILE_PROLOGUE
GTEXT(_Swap)
GTEXT(__swap)
#if defined(CONFIG_ARMV6_M)
#elif defined(CONFIG_ARMV7_M)
GTEXT(__svc)
@ -186,7 +186,7 @@ _thread_irq_disabled:
*
* @brief Service call handler
*
* The service call (svc) is only used in _Swap() to enter handler mode so we
* The service call (svc) is only used in __swap() to enter handler mode so we
* can go through the PendSV exception to perform a context switch.
*
* @return N/A
@ -257,13 +257,13 @@ _oops:
*
* @brief Initiate a cooperative context switch
*
* The _Swap() routine is invoked by various kernel services to effect
* a cooperative context context switch. Prior to invoking _Swap(), the caller
* The __swap() routine is invoked by various kernel services to effect
* a cooperative context context switch. Prior to invoking __swap(), the caller
* disables interrupts via irq_lock() and the return 'key' is passed as a
* parameter to _Swap(). The 'key' actually represents the BASEPRI register
* parameter to __swap(). The 'key' actually represents the BASEPRI register
* prior to disabling interrupts via the BASEPRI mechanism.
*
* _Swap() itself does not do much.
* __swap() itself does not do much.
*
* It simply stores the intlock key (the BASEPRI value) parameter into
* current->basepri, and then triggers a service call exception (svc) to setup
@ -273,7 +273,7 @@ _oops:
* __pendsv all come from handling an interrupt, which means we know the
* interrupts were not locked: in that case the BASEPRI value is 0.
*
* Given that _Swap() is called to effect a cooperative context switch,
* Given that __swap() is called to effect a cooperative context switch,
* only the caller-saved integer registers need to be saved in the thread of the
* outgoing thread. This is all performed by the hardware, which stores it in
* its exception stack frame, created when handling the svc exception.
@ -286,18 +286,18 @@ _oops:
*
* C function prototype:
*
* unsigned int _Swap (unsigned int basepri);
* unsigned int __swap (unsigned int basepri);
*
*/
SECTION_FUNC(TEXT, _Swap)
SECTION_FUNC(TEXT, __swap)
ldr r1, =_kernel
ldr r2, [r1, #_kernel_offset_to_current]
str r0, [r2, #_thread_offset_to_basepri]
/*
* Set _Swap()'s default return code to -EAGAIN. This eliminates the need
* Set __swap()'s default return code to -EAGAIN. This eliminates the need
* for the timeout code to set it itself.
*/
ldr r1, =_k_neg_eagain