From 79822e485edb7b447ab8cb17fdc0f572b598d829 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Wed, 17 Sep 2025 21:20:29 -0400
Subject: kern/amd64: Implement syscall domains and windows

A syscall domain in the L5 kernel is a fixed list of "syscall windows",
each syscall window represents a specific platform and/or syscall model.
A platform latch within each domain determines which window / platform
should be visible. Since syscall domains are per-process, these changes
are local to their respective processes.

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 src/sys/arch/amd64/cpu/trap.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

(limited to 'src/sys/arch/amd64')

diff --git a/src/sys/arch/amd64/cpu/trap.c b/src/sys/arch/amd64/cpu/trap.c
index 6ddc079..d023923 100644
--- a/src/sys/arch/amd64/cpu/trap.c
+++ b/src/sys/arch/amd64/cpu/trap.c
@@ -35,6 +35,7 @@
 #include <sys/param.h>
 #include <sys/cdefs.h>
 #include <sys/panic.h>
+#include <sys/cpuvar.h>
 #include <sys/syslog.h>
 #include <sys/syscall.h>
 #include <machine/trap.h>
@@ -149,6 +150,10 @@ trapframe_dump(struct trapframe *tf)
 void
 trap_syscall(struct trapframe *tf)
 {
+    struct pcore *pcore = this_core();
+    struct syscall_domain *scdp;
+    struct syscall_win *scwp;
+    struct proc *self;
     struct syscall_args scargs = {
         .arg[0] = tf->rdi,
         .arg[1] = tf->rsi,
@@ -159,8 +164,23 @@ trap_syscall(struct trapframe *tf)
         .tf = tf
     };
 
-    if (tf->rax < MAX_SYSCALLS && tf->rax > 0) {
-        tf->rax = g_sctab[tf->rax](&scargs);
+    /* Sanity check */
+    if (__unlikely(pcore == NULL)) {
+        printf("trap_syscall: pcore is NULL\n");
+        return;
+    }
+
+    /* Get the current window */
+    self = pcore->curproc;
+    scdp = &self->scdom;
+    scwp = &scdp->slots[0];
+    if (scwp->sctab == NULL && scwp->p == 0) {
+        printf("trap_syscall: no sctab (platch=%x)\n", scdp->platch);
+        return;
+    }
+
+    if (tf->rax < scwp->nimpl && tf->rax > 0) {
+        tf->rax = scwp->sctab[tf->rax](&scargs);
     }
 }
 
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