From e2b28da32fd2778b1d569457898375ba93241144 Mon Sep 17 00:00:00 2001
From: Tomoki Shirasawa <sira@popeye.cc.u-tokyo.ac.jp>
Date: Sun, 21 Feb 2016 14:55:34 +0900
Subject: [PATCH] signal handler support gdb stepi command

---
 arch/x86/kernel/cpu.c     |  2 ++
 arch/x86/kernel/syscall.c | 23 +++++++++++++++++++++++
 kernel/procfs.c           |  3 +++
 3 files changed, 28 insertions(+)

diff --git a/arch/x86/kernel/cpu.c b/arch/x86/kernel/cpu.c
index d8528c97..058b3e90 100644
--- a/arch/x86/kernel/cpu.c
+++ b/arch/x86/kernel/cpu.c
@@ -893,6 +893,7 @@ void debug_handler(struct x86_user_context *regs)
 	struct siginfo info;
 
 	set_cputime(interrupt_from_user(regs)? 1: 2);
+kprintf("debug_handler rip=%lx\n", regs->gpr.rip);
 #ifdef DEBUG_PRINT_CPU
 	kprintf("debug exception (err: %lx, %lx:%lx)\n",
 	        regs->gpr.error, regs->gpr.cs, regs->gpr.rip);
@@ -920,6 +921,7 @@ void int3_handler(struct x86_user_context *regs)
 	struct siginfo info;
 
 	set_cputime(interrupt_from_user(regs)? 1: 2);
+kprintf("int3_handler rip=%lx\n", regs->gpr.rip);
 #ifdef DEBUG_PRINT_CPU
 	kprintf("int3 exception (err: %lx, %lx:%lx)\n",
 	        regs->gpr.error, regs->gpr.cs, regs->gpr.rip);
diff --git a/arch/x86/kernel/syscall.c b/arch/x86/kernel/syscall.c
index b091e595..957f52dd 100644
--- a/arch/x86/kernel/syscall.c
+++ b/arch/x86/kernel/syscall.c
@@ -32,6 +32,8 @@ int write_process_vm(struct process_vm *vm, void *dst, const void *src, size_t s
 long do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact);
 long syscall(int num, ihk_mc_user_context_t *ctx);
 extern void save_fp_regs(struct thread *proc);
+void set_signal(int sig, void *regs0, siginfo_t *info);
+void check_signal(unsigned long rc, void *regs0, int num);
 
 //#define DEBUG_PRINT_SC
 
@@ -178,6 +180,17 @@ SYSCALL_DECLARE(rt_sigreturn)
 	if(sigsp->restart){
 		return syscall(sigsp->num, (ihk_mc_user_context_t *)regs);
 	}
+	if(regs->gpr.rflags & RFLAGS_TF){
+		struct siginfo info;
+
+		regs->gpr.rax = sigsp->sigrc;
+		memset(&info, '\0', sizeof info);
+		regs->gpr.rflags &= ~RFLAGS_TF;
+		info.si_code = TRAP_TRACE;
+		set_signal(SIGTRAP, regs, &info);
+		check_signal(0, regs, 0);
+		check_need_resched();
+	}
 	return sigsp->sigrc;
 }
 
@@ -595,6 +608,16 @@ do_signal(unsigned long rc, void *regs0, struct thread *thread, struct sig_pendi
 			thread->sigmask.__val[0] |= pending->sigmask.__val[0];
 		kfree(pending);
 		ihk_mc_spinlock_unlock(&thread->sigcommon->lock, irqstate);
+		if(regs->gpr.rflags & RFLAGS_TF){
+			struct siginfo info;
+
+			memset(&info, '\0', sizeof info);
+			regs->gpr.rflags &= ~RFLAGS_TF;
+			info.si_code = TRAP_TRACE;
+			set_signal(SIGTRAP, regs, &info);
+			check_signal(0, regs, 0);
+			check_need_resched();
+		}
 	}
 	else {
 		int	coredumped = 0;
diff --git a/kernel/procfs.c b/kernel/procfs.c
index 76107d0e..894268b6 100644
--- a/kernel/procfs.c
+++ b/kernel/procfs.c
@@ -261,6 +261,9 @@ process_procfs_request(unsigned long rarg)
 		}
 #endif
 
+		if(readwrite == 0)
+			reason = PF_POPULATE | PF_USER;
+
 		while(left){
 			unsigned long pa;
 			char *va;