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riscv: syscall SYS_switch_context and SYS_restore_context use 0 para

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reason:
simplify context switch
sys_call0(SYS_switch_context)
sys_call0(SYS_restore_context)

size nuttx
before
   text    data     bss     dec     hex filename
 148021     921   26944  175886   2af0e nuttx

after
   text    data     bss     dec     hex filename
 147995     921   26928  175844   2aee4 nuttx

size reduce -42

Signed-off-by: hujun5 <hujun5@xiaomi.com>
This commit is contained in:
hujun5 2024-11-29 13:57:00 +08:00 committed by Xiang Xiao
parent 08139fb1db
commit 3c32517b94
6 changed files with 30 additions and 73 deletions
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4
arch/risc-v/include/syscall.h
View file

@ -65,14 +65,14 @@
/* SYS call 1:
*
* void riscv_fullcontextrestore(uintptr_t *restoreregs) noreturn_function;
* void riscv_fullcontextrestore() noreturn_function;
*/
#define SYS_restore_context (1)
/* SYS call 2:
*
* void riscv_switchcontext(uintptr_t **saveregs, uintptr_t *restoreregs);
* void riscv_switchcontext();
*/
#define SYS_switch_context (2)

10
arch/risc-v/src/common/riscv_exit.c
View file

@ -54,25 +54,17 @@
void up_exit(int status)
{
struct tcb_s *tcb = this_task();
/* Destroy the task at the head of the ready to run list. */
nxtask_exit();
/* Now, perform the context switch to the new ready-to-run task at the
* head of the list.
*/
tcb = this_task();
/* Scheduler parameters will update inside syscall */
g_running_tasks[this_cpu()] = NULL;
/* Then switch contexts */
riscv_fullcontextrestore(tcb);
riscv_fullcontextrestore();
/* riscv_fullcontextrestore() should not return but could if the software
* interrupts are disabled.

27
arch/risc-v/src/common/riscv_internal.h
View file

@ -486,36 +486,37 @@ void riscv_jump_to_user(uintptr_t entry, uintreg_t a0, uintreg_t a1,
* Name: riscv_fullcontextrestore
*
* Description:
* Restores the full context of the next task.
*
* Parameters:
* next - Pointer to the next task control block.
* Restores the full context.
*
* Returned Value:
* None
*
****************************************************************************/
#define riscv_fullcontextrestore(next) \
sys_call1(SYS_restore_context, (uintptr_t)next)
#define riscv_fullcontextrestore() \
do \
{ \
sys_call0(SYS_restore_context); \
} \
while (1)
/****************************************************************************
* Name: riscv_switchcontext
*
* Description:
* Switches the context from the previous task to the next task.
*
* Parameters:
* prev - Pointer to the previous task control block.
* next - Pointer to the next task control block.
* Switches the context.
*
* Returned Value:
* None
*
****************************************************************************/
#define riscv_switchcontext(prev, next) \
sys_call2(SYS_switch_context, (uintptr_t)prev, (uintptr_t)next)
#define riscv_switchcontext() \
do \
{ \
sys_call0(SYS_switch_context); \
} \
while (0)
#undef EXTERN
#ifdef __cplusplus

2
arch/risc-v/src/common/riscv_sigdeliver.c
View file

@ -167,5 +167,5 @@ retry:
g_running_tasks[this_cpu()] = NULL;
rtcb->xcp.regs = regs;
riscv_fullcontextrestore(rtcb);
riscv_fullcontextrestore();
}

58
arch/risc-v/src/common/riscv_swint.c
View file

@ -148,7 +148,8 @@ uintptr_t dispatch_syscall(unsigned int nbr, uintptr_t parm1,
int riscv_swint(int irq, void *context, void *arg)
{
uintreg_t *regs = (uintreg_t *)context;
uintreg_t *new_regs = regs;
struct tcb_s *tcb = this_task();
int cpu = this_cpu();
/* Software interrupt 0 is invoked with REG_A0 (REG_X10) = system call
* command and REG_A1-6 = variable number of
@ -164,51 +165,18 @@ int riscv_swint(int irq, void *context, void *arg)
switch (regs[REG_A0])
{
/* A0=SYS_restore_context: This a restore context command:
*
* void
* void riscv_fullcontextrestore(struct tcb_s *prev) noreturn_function;
*
* At this point, the following values are saved in context:
*
* A0 = SYS_restore_context
* A1 = next
*/
case SYS_restore_context:
{
struct tcb_s *next = (struct tcb_s *)(uintptr_t)regs[REG_A1];
DEBUGASSERT(regs[REG_A1] != 0);
new_regs = next->xcp.regs;
riscv_restorecontext(next);
riscv_restorecontext(tcb);
restore_critical_section(tcb, cpu);
}
break;
/* A0=SYS_switch_context: This a switch context command:
*
* void
* riscv_switchcontext(struct tcb_s *prev, struct tcb_s *next);
*
* At this point, the following values are saved in context:
*
* A0 = SYS_switch_context
* A1 = prev
* A2 = next
*
* In this case, we save the context registers to the save register
* area referenced by the saved contents of R5.
*/
case SYS_switch_context:
{
struct tcb_s *prev = (struct tcb_s *)(uintptr_t)regs[REG_A1];
struct tcb_s *next = (struct tcb_s *)(uintptr_t)regs[REG_A2];
DEBUGASSERT(regs[REG_A1] != 0 && regs[REG_A2] != 0);
riscv_savecontext(prev);
new_regs = next->xcp.regs;
riscv_restorecontext(next);
riscv_savecontext(g_running_tasks[cpu]);
riscv_restorecontext(tcb);
restore_critical_section(tcb, cpu);
}
break;
@ -342,21 +310,17 @@ int riscv_swint(int irq, void *context, void *arg)
* switch
*/
if (regs != new_regs)
{
restore_critical_section(this_task(), this_cpu());
#ifdef CONFIG_DEBUG_SYSCALL_INFO
if (cmd <= SYS_switch_context)
{
svcinfo("SWInt Return: Context switch!\n");
up_dump_register(new_regs);
#endif
up_dump_register(tcb.xcp.regs);
}
else
{
#ifdef CONFIG_DEBUG_SYSCALL_INFO
svcinfo("SWInt Return: %" PRIxPTR "\n", regs[REG_A0]);
#endif
}
#endif
return OK;
}

2
arch/risc-v/src/common/riscv_switchcontext.c
View file

@ -80,7 +80,7 @@ void up_switch_context(struct tcb_s *tcb, struct tcb_s *rtcb)
{
/* Then switch contexts */
riscv_switchcontext(rtcb, tcb);
riscv_switchcontext();
/* riscv_switchcontext forces a context switch to the task at the
* head of the ready-to-run list. It does not 'return' in the