From 2681fec9240dbcfb3ccda0ccc876fad32b83ec61 Mon Sep 17 00:00:00 2001
From: Mark <alnyan@airmail.cc>
Date: Sun, 29 Dec 2019 02:11:11 +0200
Subject: [PATCH] Dump more information about page faults in userspace

---
 sys/amd64/hw/pfault.c | 30 +++++++++++++++++++++++++-----
 usr/Makefile          |  1 +
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/sys/amd64/hw/pfault.c b/sys/amd64/hw/pfault.c
index 33cb953..7742fc4 100644
--- a/sys/amd64/hw/pfault.c
+++ b/sys/amd64/hw/pfault.c
@@ -6,22 +6,42 @@
 extern void amd64_syscall_yield_stopped();
 
 int amd64_pfault(uintptr_t cr2) {
+    // TODO: would be nice to get error code off the stack and check what kind of
+    // error happened
     struct cpu *cpu = get_cpu();
     _assert(cpu);
 
     struct thread *thr = cpu->thread;
-    kdebug("Page fault in %s thread %u\n",
+    _assert(thr);
+
+    struct cpu_context *ctx = (struct cpu_context *) thr->data.rsp0;
+
+    kerror("Page fault in %s thread %u\n",
         thr->flags & THREAD_KERNEL ? "kernel" : "user",
         thr->pid);
 
-    kdebug("CR2 = %p\n", cr2);
+    kerror("CR2 = %p\n", cr2);
+
+    // Dump registers
+    kerror("RAX = %p, RCX = %p\n", ctx->rax, ctx->rcx);
+    kerror("RDX = %p, RBX = %p\n", ctx->rdx, ctx->rbx);
+    kerror("RSP = %p, RBP = %p\n", ctx->rsp, ctx->rbp);
+    kerror("RSI = %p, RDI = %p\n", ctx->rsi, ctx->rdi);
+    kerror(" R8 = %p,  R9 = %p\n", ctx->r8,  ctx->r9);
+    kerror("R10 = %p, R11 = %p\n", ctx->r10, ctx->r11);
+    kerror("R12 = %p, R13 = %p\n", ctx->r12, ctx->r13);
+    kerror("R14 = %p, R15 = %p\n", ctx->r12, ctx->r15);
+
+    // Can't access IRET-registers (CS/RIP and the likes)
+    // because they're presumably fucked up by error code
+    // push
 
     amd64_syscall_yield_stopped();
     return -1;
 }
 
 void amd64_pfault_kernel(uintptr_t rip, uintptr_t cr2) {
-    kdebug("Kernel-space page fault:\n");
-    kdebug("RIP = %p\n", rip);
-    kdebug("CR2 = %p\n", cr2);
+    kfatal("Kernel-space page fault:\n");
+    kfatal("RIP = %p\n", rip);
+    kfatal("CR2 = %p\n", cr2);
 }
diff --git a/usr/Makefile b/usr/Makefile
index 35b4847..787bbf0 100644
--- a/usr/Makefile
+++ b/usr/Makefile
@@ -13,6 +13,7 @@ CFLAGS=-ffreestanding \
 	   -mno-sse \
 	   -mno-sse2 \
 	   -Ilibc/include \
+	   -ggdb \
 	   -O0 \
 	   -I$(S)/include