diff options
Diffstat (limited to 'common/uapi/ipc.c')
| -rw-r--r-- | common/uapi/ipc.c | 69 |
1 files changed, 10 insertions, 59 deletions
diff --git a/common/uapi/ipc.c b/common/uapi/ipc.c index f9b2817..13682c7 100644 --- a/common/uapi/ipc.c +++ b/common/uapi/ipc.c @@ -11,43 +11,6 @@ #include <kmi/ipi.h> #include <kmi/conf.h> -/** - * Mark rpc stack between \p start and \p end inaccessible. - * - * @param t Thread whose rpc stack to modify. - * @param start Start address of rpc stack to mark inaccessible. - * @param end End address of rpc stack to mark inaccessible. - */ -static void mark_rpc_inaccessible(struct tcb *t, vm_t start, vm_t end) -{ - size_t page_size = BASE_PAGE_SIZE; - size_t size = end - start; - size_t pages = size / page_size; - while (pages--) - clear_vpage_flags(t->rpc.vmem, start + pages * page_size, VM_U); -} - -/** - * Mark rpc stack between \p start and \p end accessible. - * - * @param t Thread whose rpc stack to modify. - * @param start Start address of rpc stack to mark accessible. - * @param end End address of rpc stack to mark accessible. - */ -static void mark_rpc_accessible(struct tcb *t, vm_t start, vm_t end) -{ - /** @todo this could still be optimized with arch-specific stuff I would - * imagine, as set_vpage_flags() has to traverse the whole tree for each - * page to mark. Instead it should be possible to mark the pages - * continuously once they've been traversed once. Or maybe even keep - * around a pointer to where the last stack left off? */ - size_t page_size = BASE_PAGE_SIZE; - size_t size = end - start; - size_t pages = size / page_size; - while (pages--) - set_vpage_flags(t->rpc.vmem, start + pages * page_size, VM_U); -} - /** Structure for maintaining the required context data for an rpc call. */ struct call_ctx { /** Execution continuation point. */ @@ -93,7 +56,7 @@ enum ipc_kind { * @param r Process to migrate to. * @param sd RPC stack regions to mark inaccessible. */ -static void finalize_rpc(struct tcb *t, struct tcb *r, struct stack_diff sd) +static void finalize_rpc(struct tcb *t, struct tcb *r, vm_t s) { clone_uvmem(r->proc.vmem, t->rpc.vmem); set_return(t, r->callback); @@ -101,7 +64,7 @@ static void finalize_rpc(struct tcb *t, struct tcb *r, struct stack_diff sd) t->pid = r->rid; /* make sure updates are visible when swapping to the new virtual memory */ - mark_rpc_inaccessible(t, sd.start, sd.end); + mark_rpc_invalid(t, s); use_vmem(t->rpc.vmem); } @@ -115,18 +78,10 @@ static void finalize_rpc(struct tcb *t, struct tcb *r, struct stack_diff sd) * @param kind Kind of IPC we're doing. Essentially toggles kick boolean. * @return RPC stack difference that should be passed to finalize_rpc(). */ -static struct stack_diff enter_rpc(struct tcb *t, struct sys_ret a, +static vm_t enter_rpc(struct tcb *t, struct sys_ret a, enum ipc_kind kind) { - vm_t rpc_stack = t->rpc_stack; - if (is_rpc(t)) - /** @todo what if user uses their own stack? Or is a dick and - * sets the stack pointer to RPC_STACK_TOP or something? It'll - * likely only cause a fuckup in the process who did the dumb - * thing, so maybe just consider it user error? Except by - * causing the stack of the next rpc to run out of memory... */ - rpc_stack = align_down(get_stack(t), BASE_PAGE_SIZE); - + vm_t rpc_stack = rpc_position(t); struct call_ctx *ctx = (struct call_ctx *)(rpc_stack) - 1; ctx->regs = t->regs; @@ -148,7 +103,6 @@ static struct stack_diff enter_rpc(struct tcb *t, struct sys_ret a, * return a status? except it shouldn't happen after we've run * enough_rpc_stack(). */ vm_t new_stack = rpc_stack - BASE_PAGE_SIZE; - struct stack_diff sd = {new_stack, t->rpc_stack}; /** @todo what if each stack is only some number of pages, and if a proc * goes over the limit is is seen as programming error? Possibly user @@ -162,7 +116,7 @@ static struct stack_diff enter_rpc(struct tcb *t, struct sys_ret a, * */ t->rpc_stack = new_stack; set_stack(t, new_stack); - return sd; + return new_stack; } /** @@ -190,7 +144,7 @@ static void leave_rpc(struct tcb *t, struct sys_ret a) set_return(t, ctx->exec); /* if we're returning from a failed rpc, this should essentially be a * no-op */ - mark_rpc_accessible(t, t->rpc_stack, top); + mark_rpc_valid(t, top); t->rpc_stack = ctx->rpc_stack; t->pid = ctx->pid; t->eid = ctx->eid; @@ -211,13 +165,11 @@ static void leave_rpc(struct tcb *t, struct sys_ret a) static bool enough_rpc_stack(struct tcb *t) { /* get top of call stack */ - vm_t top = RPC_STACK_BASE + __call_stack_size; - /* get start of the next rpc stack instance */ - vm_t rpc_stack = t->rpc_stack + BASE_PAGE_SIZE; + vm_t top = rpc_position(t); /* if we can still fit an rpc stack into the call stack, we can safely * do the migration. */ - return top - rpc_stack >= __rpc_stack_size; + return (top - BASE_PAGE_SIZE) >= (t->rpc_stack - __rpc_stack_size); } /** @@ -263,8 +215,7 @@ static void do_ipc(struct tcb *t, if (unlikely(!enough_rpc_stack(t))) return_args1(t, ERR_OOMEM); - struct stack_diff sd = - enter_rpc(t, SYS_RET6(OK, t->eid, d0, d1, d2, d3), kind); + vm_t s = enter_rpc(t, SYS_RET6(OK, t->eid, d0, d1, d2, d3), kind); struct tcb *r = get_tcb(pid); if (unlikely(!r)) { @@ -282,7 +233,7 @@ static void do_ipc(struct tcb *t, if (kind != IPC_REQ) t->eid = t->pid; - finalize_rpc(t, r, sd); + finalize_rpc(t, r, s); /* I tested out passing the return values as arguments to * ret_userspace_fast, but apparently that causes enough stack shuffling * to be slower overall. */ |