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Posted to commits@nuttx.apache.org by GitBox <gi...@apache.org> on 2022/03/25 14:34:47 UTC
[GitHub] [incubator-nuttx] masayuki2009 commented on a change in pull request #5731: arch/risc-v: Improve speed of context switch
masayuki2009 commented on a change in pull request #5731:
URL: https://github.com/apache/incubator-nuttx/pull/5731#discussion_r835328175
##########
File path: arch/risc-v/src/common/riscv_schedulesigaction.c
##########
@@ -265,55 +283,80 @@ void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
* been delivered.
*/
- tcb->xcp.sigdeliver = (void *)sigdeliver;
- tcb->xcp.saved_epc = tcb->xcp.regs[REG_EPC];
- tcb->xcp.saved_int_ctx = tcb->xcp.regs[REG_INT_CTX];
+ tcb->xcp.sigdeliver = sigdeliver;
/* Then set up vector to the trampoline with interrupts
* disabled. We must already be in privileged thread mode
* to be here.
*/
- tcb->xcp.regs[REG_EPC] = (uintptr_t)riscv_sigdeliver;
+ /* Save the current register context location */
+
+ tcb->xcp.saved_regs = tcb->xcp.regs;
+
+ /* Duplicate the register context. These will be
+ * restored by the signal trampoline after the signal has
+ * been delivered.
+ */
+
+ tcb->xcp.regs = (uintptr_t *)((uintptr_t)tcb->xcp.regs -
+ XCPTCONTEXT_SIZE);
- int_ctx = tcb->xcp.regs[REG_INT_CTX];
- int_ctx &= ~MSTATUS_MPIE;
+ memcpy(tcb->xcp.regs, tcb->xcp.saved_regs,
+ XCPTCONTEXT_SIZE);
+ tcb->xcp.regs[REG_SP] = (uintptr_t)tcb->xcp.regs +
+ XCPTCONTEXT_SIZE;
+
+ tcb->xcp.regs[REG_EPC] = (uintptr_t)riscv_sigdeliver;
+ int_ctx = tcb->xcp.regs[REG_INT_CTX];
+ int_ctx &= ~MSTATUS_MPIE;
+#ifdef CONFIG_BUILD_PROTECTED
+ int_ctx |= MSTATUS_MPPM;
+#endif
tcb->xcp.regs[REG_INT_CTX] = int_ctx;
}
else
{
/* tcb is running on the same CPU */
- /* Save the return EPC and STATUS registers. These will be
+ /* Save the context registers. These will be
+ * restored by the signal trampoline after the signal has
+ * been delivered.
+ */
+
+ tcb->xcp.sigdeliver = (void *)sigdeliver;
+
+ tcb->xcp.saved_regs = (uintptr_t *)CURRENT_REGS;
+
+ /* Duplicate the register context. These will be
* restored by the signal trampoline after the signal has
* been delivered.
*/
- tcb->xcp.sigdeliver = (void *)sigdeliver;
- tcb->xcp.saved_epc = CURRENT_REGS[REG_EPC];
- tcb->xcp.saved_int_ctx = CURRENT_REGS[REG_INT_CTX];
+ CURRENT_REGS = (uintptr_t *)((uintptr_t)CURRENT_REGS -
+ XCPTCONTEXT_SIZE);
+
+ memcpy((uintptr_t *)CURRENT_REGS, tcb->xcp.saved_regs,
+ XCPTCONTEXT_SIZE);
+
+ CURRENT_REGS[REG_SP] = (uintptr_t)CURRENT_REGS +
+ XCPTCONTEXT_SIZE;
/* Then set up vector to the trampoline with interrupts
* disabled. The kernel-space trampoline must run in
* privileged thread mode.
*/
- CURRENT_REGS[REG_EPC] = (uintptr_t)riscv_sigdeliver;
+ CURRENT_REGS[REG_EPC] = (uintptr_t)riscv_sigdeliver;
Review comment:
The above line is a style change. (just remove spaces).
##########
File path: arch/risc-v/src/common/riscv_schedulesigaction.c
##########
@@ -265,55 +283,80 @@ void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
* been delivered.
*/
- tcb->xcp.sigdeliver = (void *)sigdeliver;
- tcb->xcp.saved_epc = tcb->xcp.regs[REG_EPC];
- tcb->xcp.saved_int_ctx = tcb->xcp.regs[REG_INT_CTX];
+ tcb->xcp.sigdeliver = sigdeliver;
/* Then set up vector to the trampoline with interrupts
* disabled. We must already be in privileged thread mode
* to be here.
*/
- tcb->xcp.regs[REG_EPC] = (uintptr_t)riscv_sigdeliver;
+ /* Save the current register context location */
+
+ tcb->xcp.saved_regs = tcb->xcp.regs;
+
+ /* Duplicate the register context. These will be
+ * restored by the signal trampoline after the signal has
+ * been delivered.
+ */
+
+ tcb->xcp.regs = (uintptr_t *)((uintptr_t)tcb->xcp.regs -
+ XCPTCONTEXT_SIZE);
- int_ctx = tcb->xcp.regs[REG_INT_CTX];
- int_ctx &= ~MSTATUS_MPIE;
+ memcpy(tcb->xcp.regs, tcb->xcp.saved_regs,
+ XCPTCONTEXT_SIZE);
+ tcb->xcp.regs[REG_SP] = (uintptr_t)tcb->xcp.regs +
+ XCPTCONTEXT_SIZE;
+
+ tcb->xcp.regs[REG_EPC] = (uintptr_t)riscv_sigdeliver;
+ int_ctx = tcb->xcp.regs[REG_INT_CTX];
+ int_ctx &= ~MSTATUS_MPIE;
+#ifdef CONFIG_BUILD_PROTECTED
+ int_ctx |= MSTATUS_MPPM;
+#endif
tcb->xcp.regs[REG_INT_CTX] = int_ctx;
}
else
{
/* tcb is running on the same CPU */
- /* Save the return EPC and STATUS registers. These will be
+ /* Save the context registers. These will be
+ * restored by the signal trampoline after the signal has
+ * been delivered.
+ */
+
+ tcb->xcp.sigdeliver = (void *)sigdeliver;
+
+ tcb->xcp.saved_regs = (uintptr_t *)CURRENT_REGS;
+
+ /* Duplicate the register context. These will be
* restored by the signal trampoline after the signal has
* been delivered.
*/
- tcb->xcp.sigdeliver = (void *)sigdeliver;
- tcb->xcp.saved_epc = CURRENT_REGS[REG_EPC];
- tcb->xcp.saved_int_ctx = CURRENT_REGS[REG_INT_CTX];
+ CURRENT_REGS = (uintptr_t *)((uintptr_t)CURRENT_REGS -
+ XCPTCONTEXT_SIZE);
+
+ memcpy((uintptr_t *)CURRENT_REGS, tcb->xcp.saved_regs,
+ XCPTCONTEXT_SIZE);
+
+ CURRENT_REGS[REG_SP] = (uintptr_t)CURRENT_REGS +
+ XCPTCONTEXT_SIZE;
/* Then set up vector to the trampoline with interrupts
* disabled. The kernel-space trampoline must run in
* privileged thread mode.
*/
- CURRENT_REGS[REG_EPC] = (uintptr_t)riscv_sigdeliver;
+ CURRENT_REGS[REG_EPC] = (uintptr_t)riscv_sigdeliver;
- int_ctx = CURRENT_REGS[REG_INT_CTX];
- int_ctx &= ~MSTATUS_MPIE;
+ int_ctx = CURRENT_REGS[REG_INT_CTX];
+ int_ctx &= ~MSTATUS_MPIE;
#ifndef CONFIG_BUILD_FLAT
- int_ctx |= MSTATUS_MPPM;
+ int_ctx |= MSTATUS_MPPM;
Review comment:
ditto.
##########
File path: arch/risc-v/src/common/riscv_schedulesigaction.c
##########
@@ -370,7 +428,9 @@ void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
int_ctx = tcb->xcp.regs[REG_INT_CTX];
int_ctx &= ~MSTATUS_MPIE;
-
+#ifdef CONFIG_BUILD_PROTECTED
Review comment:
ditto
##########
File path: arch/risc-v/src/common/riscv_sigdeliver.c
##########
@@ -114,7 +110,7 @@ void riscv_sigdeliver(void)
*/
sinfo("Resuming EPC: %" PRIxREG " INT_CTX: %" PRIxREG "\n",
- regs[REG_EPC], regs[REG_INT_CTX]);
+ regs[REG_EPC], regs[REG_INT_CTX]);
Review comment:
ditto.
##########
File path: arch/risc-v/src/common/riscv_schedulesigaction.c
##########
@@ -170,25 +179,34 @@ void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
* been delivered.
*/
- tcb->xcp.sigdeliver = sigdeliver;
- tcb->xcp.saved_epc = tcb->xcp.regs[REG_EPC];
- tcb->xcp.saved_int_ctx = tcb->xcp.regs[REG_INT_CTX];
+ tcb->xcp.sigdeliver = sigdeliver;
- /* Then set up to vector to the trampoline with interrupts
- * disabled. We must already be in privileged thread mode to be
- * here.
+ /* Save the current register context location */
+
+ tcb->xcp.saved_regs = tcb->xcp.regs;
+
+ /* Duplicate the register context. These will be
+ * restored by the signal trampoline after the signal has been
+ * delivered.
*/
- tcb->xcp.regs[REG_EPC] = (uintptr_t)riscv_sigdeliver;
+ tcb->xcp.regs = (uintptr_t *)((uintptr_t)tcb->xcp.regs -
+ XCPTCONTEXT_SIZE);
+
+ memcpy(tcb->xcp.regs, tcb->xcp.saved_regs, XCPTCONTEXT_SIZE);
+ tcb->xcp.regs[REG_SP] = (uintptr_t)tcb->xcp.regs +
+ XCPTCONTEXT_SIZE;
+
+ tcb->xcp.regs[REG_EPC] = (uintptr_t)riscv_sigdeliver;
int_ctx = tcb->xcp.regs[REG_INT_CTX];
int_ctx &= ~MSTATUS_MPIE;
-
tcb->xcp.regs[REG_INT_CTX] = int_ctx;
Review comment:
The above change is a style change. (just remove a blank line)
##########
File path: arch/risc-v/src/common/riscv_schedulesigaction.c
##########
@@ -265,55 +283,80 @@ void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
* been delivered.
*/
- tcb->xcp.sigdeliver = (void *)sigdeliver;
- tcb->xcp.saved_epc = tcb->xcp.regs[REG_EPC];
- tcb->xcp.saved_int_ctx = tcb->xcp.regs[REG_INT_CTX];
+ tcb->xcp.sigdeliver = sigdeliver;
/* Then set up vector to the trampoline with interrupts
* disabled. We must already be in privileged thread mode
* to be here.
*/
- tcb->xcp.regs[REG_EPC] = (uintptr_t)riscv_sigdeliver;
+ /* Save the current register context location */
+
+ tcb->xcp.saved_regs = tcb->xcp.regs;
+
+ /* Duplicate the register context. These will be
+ * restored by the signal trampoline after the signal has
+ * been delivered.
+ */
+
+ tcb->xcp.regs = (uintptr_t *)((uintptr_t)tcb->xcp.regs -
+ XCPTCONTEXT_SIZE);
- int_ctx = tcb->xcp.regs[REG_INT_CTX];
- int_ctx &= ~MSTATUS_MPIE;
+ memcpy(tcb->xcp.regs, tcb->xcp.saved_regs,
+ XCPTCONTEXT_SIZE);
+ tcb->xcp.regs[REG_SP] = (uintptr_t)tcb->xcp.regs +
+ XCPTCONTEXT_SIZE;
+
+ tcb->xcp.regs[REG_EPC] = (uintptr_t)riscv_sigdeliver;
+ int_ctx = tcb->xcp.regs[REG_INT_CTX];
+ int_ctx &= ~MSTATUS_MPIE;
+#ifdef CONFIG_BUILD_PROTECTED
+ int_ctx |= MSTATUS_MPPM;
+#endif
tcb->xcp.regs[REG_INT_CTX] = int_ctx;
}
else
{
/* tcb is running on the same CPU */
- /* Save the return EPC and STATUS registers. These will be
+ /* Save the context registers. These will be
+ * restored by the signal trampoline after the signal has
+ * been delivered.
+ */
+
+ tcb->xcp.sigdeliver = (void *)sigdeliver;
+
+ tcb->xcp.saved_regs = (uintptr_t *)CURRENT_REGS;
+
+ /* Duplicate the register context. These will be
* restored by the signal trampoline after the signal has
* been delivered.
*/
- tcb->xcp.sigdeliver = (void *)sigdeliver;
- tcb->xcp.saved_epc = CURRENT_REGS[REG_EPC];
- tcb->xcp.saved_int_ctx = CURRENT_REGS[REG_INT_CTX];
+ CURRENT_REGS = (uintptr_t *)((uintptr_t)CURRENT_REGS -
+ XCPTCONTEXT_SIZE);
+
+ memcpy((uintptr_t *)CURRENT_REGS, tcb->xcp.saved_regs,
+ XCPTCONTEXT_SIZE);
+
+ CURRENT_REGS[REG_SP] = (uintptr_t)CURRENT_REGS +
+ XCPTCONTEXT_SIZE;
/* Then set up vector to the trampoline with interrupts
* disabled. The kernel-space trampoline must run in
* privileged thread mode.
*/
- CURRENT_REGS[REG_EPC] = (uintptr_t)riscv_sigdeliver;
+ CURRENT_REGS[REG_EPC] = (uintptr_t)riscv_sigdeliver;
- int_ctx = CURRENT_REGS[REG_INT_CTX];
- int_ctx &= ~MSTATUS_MPIE;
+ int_ctx = CURRENT_REGS[REG_INT_CTX];
Review comment:
The above lines are style changes. (just remove spaces).
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