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| author | Kimplul <kimi.h.kuparinen@gmail.com> | 2022-11-13 06:11:43 +0200 |
|---|---|---|
| committer | Kimplul <kimi.h.kuparinen@gmail.com> | 2022-11-13 06:11:43 +0200 |
| commit | 6d3586aa42409fc720e30856cb5df5284329463a (patch) | |
| tree | 571136fdb4f6fb333c1bb4b1274a76eb70263de9 /arch/riscv64/kernel/entry.S | |
| parent | 7da8912c0eee10315dac37cecd4c84f11e5dad59 (diff) | |
| download | kmi-6d3586aa42409fc720e30856cb5df5284329463a.tar.gz kmi-6d3586aa42409fc720e30856cb5df5284329463a.zip | |
~700k ipc requests
+ Eliminated need for save/load_regs, now the register save area is
behind a pointer which _slightly_ increases overall syscall delay, but
speeds up ipc requests by a fair bit.
Diffstat (limited to 'arch/riscv64/kernel/entry.S')
| -rw-r--r-- | arch/riscv64/kernel/entry.S | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/arch/riscv64/kernel/entry.S b/arch/riscv64/kernel/entry.S index 355cd3d..f099065 100644 --- a/arch/riscv64/kernel/entry.S +++ b/arch/riscv64/kernel/entry.S @@ -23,13 +23,9 @@ handle_irq: * now just spin in place */ 1: j 1b _save_context: - /* store user stack pointer and replace it with kernel stack */ - addi tp, tp,-sizeof_registers - sr sp, offsetof_sp(tp) - mv sp, tp - - /* move thread pointer back */ - addi tp, tp, sizeof_registers + sr sp, offsetof_tcbd(tp) + lr sp, offsetof_regs(tp) + addi sp, sp, -sizeof_registers csrrw tp, CSR_SSCRATCH, tp /* save registers */ @@ -67,6 +63,9 @@ _save_context: /* get current tcb into tp and set scratch to 0 so we can figure out if * exception occured in kernel or userspace */ csrrw tp, CSR_SSCRATCH, x0 + lr s0, offsetof_tcbd(tp) + sr s0, offsetof_sp(sp) + addi sp, tp, -sizeof_registers /* load supervisor cause */ csrr s4, CSR_SCAUSE @@ -85,7 +84,7 @@ handle_exception: handle_dispatch: /* store execution continuation point */ csrr s0, CSR_SEPC - sr s0, 0(tp) + sr s0, offsetof_exec(tp) /* allocate space for sys_ret structure on stack and shift argument * registers down one to make room for the pointer to this structure */ addi sp, sp, -sizeof_sys_ret @@ -109,10 +108,10 @@ handle_dispatch: /* if we had a thread switch, load kernel stack of current thread and * restore its context */ /* get associated kernel stack */ - mv sp, tp + lr sp, offsetof_regs(tp) addi sp, sp, -sizeof_registers /* set execution continuation */ - lr s0, 0(tp) + lr s0, offsetof_exec(tp) csrw CSR_SEPC, s0 /* restore system call result */ j restore_noreturn |