From 1a0188fac0c0f265c4495b83592389b8b3645462 Mon Sep 17 00:00:00 2001
From: Kimplul <kimi.h.kuparinen@gmail.com>
Date: Sun, 13 Nov 2022 17:16:28 +0200
Subject: outline rpc stack handling

---
 common/uapi/conf.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++----
 common/uapi/ipc.c  |  3 +++
 2 files changed, 61 insertions(+), 4 deletions(-)

(limited to 'common/uapi')

diff --git a/common/uapi/conf.c b/common/uapi/conf.c
index 2094604..596cb5c 100644
--- a/common/uapi/conf.c
+++ b/common/uapi/conf.c
@@ -16,6 +16,15 @@
  * conf*-syscalls even necessary? */
 size_t __thread_stack_size = SZ_2M;
 size_t __call_stack_size = SZ_2M;
+size_t __rpc_stack_size = SZ_512K;
+
+/** IDs for configuration parameters. */
+/** @todo should probably be moved somewhere so it can be shared with userspace */
+enum conf_param {
+	CONF_THREAD_STACK = 0,
+	CONF_CALL_STACK,
+	CONF_RPC_STACK,
+};
 
 /**
  * Configuration parameter read syscall handler.
@@ -27,7 +36,29 @@ size_t __call_stack_size = SZ_2M;
  */
 SYSCALL_DEFINE1(conf_get)(sys_arg_t param)
 {
-	return SYS_RET1(OK);
+	struct tcb *t = cur_tcb();
+	if (!has_cap(t->caps, CAP_CONF))
+		return SYS_RET1(ERR_PERM);
+
+	long val = 0;
+	switch (param) {
+	case CONF_THREAD_STACK:
+		val = __thread_stack_size;
+		break;
+
+	case CONF_CALL_STACK:
+		val = __call_stack_size;
+		break;
+
+	case CONF_RPC_STACK:
+		val = __rpc_stack_size;
+		break;
+
+	default:
+		return SYS_RET1(ERR_NF);
+	}
+
+	return SYS_RET2(OK, val);
 }
 
 /**
@@ -41,9 +72,32 @@ SYSCALL_DEFINE1(conf_get)(sys_arg_t param)
  */
 SYSCALL_DEFINE2(conf_set)(sys_arg_t param, sys_arg_t val)
 {
-	UNUSED(param);
-	UNUSED(val);
-	/* no parameters supported atm */
+	struct tcb *t = cur_tcb();
+	if (!has_cap(t->caps, CAP_CONF))
+		return SYS_RET1(ERR_PERM);
+
+	size_t size = 0;
+	switch (param) {
+	case CONF_THREAD_STACK:
+		__thread_stack_size = align_up(val, BASE_PAGE_SIZE);
+		break;
+
+	case CONF_CALL_STACK:
+		size = align_up(val, 4 * BASE_PAGE_SIZE);
+		if (size < __rpc_stack_size * 4)
+			return SYS_RET1(ERR_MISC);
+
+		__call_stack_size = size;
+		break;
+
+	case CONF_RPC_STACK:
+		size = align_up(val, BASE_PAGE_SIZE);
+		if (size > __call_stack_size / 4)
+			return SYS_RET1(ERR_MISC);
+
+		__rpc_stack_size = size;
+		break;
+	}
 
 	return SYS_RET1(OK);
 }
diff --git a/common/uapi/ipc.c b/common/uapi/ipc.c
index 052e0ad..5d91588 100644
--- a/common/uapi/ipc.c
+++ b/common/uapi/ipc.c
@@ -41,6 +41,9 @@ static struct sys_ret do_ipc(sys_arg_t pid,
                              bool fwd)
 {
 	struct tcb *t = cur_tcb();
+	if (!enough_rpc_stack(t))
+		return SYS_RET1(ERR_OOMEM);
+
 	struct tcb *r = get_tcb(pid);
 	if (!r)
 		return SYS_RET1(ERR_INVAL);
-- 
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