[panic] Allow assert/panic to take optional user cpu_state

In places where the "user" state is available, like interrupt handlers,
panic() and kassert() can now take an optional pointer to that user
cpu_state structure, and the panic handler will print that out as well.

src/kernel/assert.cpp

@@ -9,5 +9,5 @@ void const *symbol_table = nullptr;
 
 extern "C"
 void _PDCLIB_assert(const char *message, const char *function, const char *file, unsigned line) {
-    panic::panic(message, function, file, line);
+    panic::panic(message, nullptr, function, file, line);
 }

src/kernel/assert.h

@@ -16,6 +16,7 @@ extern void const *symbol_table;
 __attribute__ ((always_inline))
 inline void panic(
         const char *message = nullptr,
+        const cpu_state *user = nullptr,
         const char *function = __builtin_FUNCTION(),
         const char *file = __builtin_FILE(),
         uint64_t line = __builtin_LINE())
@@ -28,10 +29,13 @@ inline void panic(
     // If we aren't the first CPU to panic, cpu.panic will be null
     if (cpu.panic) {
         cpu.panic->symbol_data = symbol_table;
+        cpu.panic->user_state = user;
+
         cpu.panic->message = message;
         cpu.panic->function = function;
         cpu.panic->file = file;
         cpu.panic->line = line;
+
         cpu.panic->cpus = g_num_cpus;
 
         *apic_icr = send_nmi_command;
@@ -48,12 +52,13 @@ __attribute__ ((always_inline))
 inline void kassert(
         bool check,
         const char *message = nullptr,
+        const cpu_state *user = nullptr,
         const char *function = __builtin_FUNCTION(),
         const char *file = __builtin_FILE(),
         uint64_t line = __builtin_LINE())
 {
     if (!check)
-        panic::panic(message, function, file, line);
+        panic::panic(message, user, function, file, line);
 }
 
 #define assert(x) kassert((x))

src/kernel/cpu.h

@@ -21,11 +21,14 @@ struct cpu_state
 /// Kernel-wide panic information
 struct panic_data
 {
-    void const * symbol_data;
-    char const * message;
-    char const * function;
-    char const * file;
+    void const *symbol_data;
+    cpu_state const *user_state;
+
+    char const *message;
+    char const *function;
+    char const *file;
     uint32_t line;
+
     uint16_t cpus;
 };
 

src/kernel/interrupts.cpp

@@ -91,11 +91,11 @@ isr_handler(cpu_state *regs)
         asm volatile ("mov %%dr5, %%r13" ::: "r13");
         asm volatile ("mov %%dr6, %%r14" ::: "r14");
         asm volatile ("mov %%dr7, %%r15" ::: "r15");
-        kassert(false, "Debug exception");
+        kassert(false, "Debug exception", regs);
         break;
 
     case isr::isrDoubleFault:
-        kassert(false, "Double fault");
+        kassert(false, "Double fault", regs);
         break;
 
     case isr::isrGPFault:
@@ -113,7 +113,7 @@ isr_handler(cpu_state *regs)
             snprintf(message, sizeof(message), "General Protection Fault, error:%lx%s",
                 regs->errorcode, regs->errorcode & 1 ? " external" : "");
         }
-        kassert(false, message);
+        kassert(false, message, regs);
         break;
 
     case isr::isrPageFault: {
@@ -138,7 +138,7 @@ isr_handler(cpu_state *regs)
                 (regs->errorcode & 0x04) ? " user" : "",
                 (regs->errorcode & 0x08) ? " reserved" : "",
                 (regs->errorcode & 0x10) ? " ip" : "");
-            kassert(false, message);
+            kassert(false, message, regs);
         }
         break;
 
@@ -156,7 +156,7 @@ isr_handler(cpu_state *regs)
 
     default:
         snprintf(message, sizeof(message), "Unknown interrupt 0x%lx", regs->interrupt);
-        kassert(false, message);
+        kassert(false, message, regs);
     }
 
     // Return the IST for this vector to what it was

src/kernel/panic.serial/display.cpp

@@ -113,6 +113,13 @@ print_cpu_state(serial_port &out, const cpu_state &regs)
     out.write(clear);
 }
 
+void
+print_user_state(serial_port &out, const cpu_state &regs)
+{
+    out.write("\n\e[1;35m USER:\e[0 ");
+    print_cpu_state(out, regs);
+}
+
 } // namespace panicking
 
 // For printf.c

src/kernel/panic.serial/display.h

@@ -28,5 +28,6 @@ void print_header(
 void print_cpu(serial_port &out, cpu_data &cpu);
 void print_callstack(serial_port &out, symbol_table &syms, frame const *fp);
 void print_cpu_state(serial_port &out, const cpu_state &regs);
+void print_user_state(serial_port &out, const cpu_state &regs);
 
 } // namespace panicking

src/kernel/panic.serial/entry.s

@@ -12,7 +12,7 @@ _panic_entry:
 	push_all
 	check_swap_gs
 
-	mov r9, rsp
+	mov rdi, rsp
 
 	mov rax, [rsp + REGS.rip]
 	push rax

src/kernel/panic.serial/main.cpp

@@ -22,13 +22,7 @@ panicking::symbol_table &syms = __syms_storage.value;
 constexpr int order = __ATOMIC_ACQ_REL;
 
 extern "C"
-void panic_handler(
-        const void *symbol_data,
-        const char *message,
-        const char *function,
-        const char *file,
-        uint64_t line,
-        const cpu_state *regs)
+void panic_handler(const cpu_state *regs)
 {
     cpu_data &cpu = current_cpu();
     panic_data *panic = cpu.panic;
@@ -57,6 +51,9 @@ void panic_handler(
     print_callstack(com1, syms, fp);
     print_cpu_state(com1, *regs);
 
+    if (panic && panic->user_state)
+        print_user_state(com1, *panic->user_state);
+
     __atomic_clear(&asserting_locked, order);
 
     // If we're running on the CPU that panicked, tell the