x86/traps: Clean up printing in {do_reserved,fatal}_trap()

For one, they render the vector in a different base.

Introduce X86_EXC_* constants and vec_name() to refer to exceptions by their
mnemonic, which starts bringing the code/diagnostics in line with the Intel
and AMD manuals.

Provide constants for every archtiecturally defined exception, even those not
implemented by Xen yet, as do_reserved_trap() is a catch-all handler.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

xen/arch/x86/traps.c

@@ -682,6 +682,22 @@ const char *trapstr(unsigned int trapnr)
     return trapnr < ARRAY_SIZE(strings) ? strings[trapnr] : "???";
 }
 
+static const char *vec_name(unsigned int vec)
+{
+    static const char names[][4] = {
+#define P(x) [X86_EXC_ ## x] = "#" #x
+#define N(x) [X86_EXC_ ## x] = #x
+        P(DE),  P(DB),  N(NMI), P(BP),  P(OF),  P(BR),  P(UD),  P(NM),
+        P(DF),  N(CSO), P(TS),  P(NP),  P(SS),  P(GP),  P(PF),  N(SPV),
+        P(MF),  P(AC),  P(MC),  P(XM),  P(VE),  P(CP),
+                                        P(HV),  P(VC),  P(SX),
+#undef N
+#undef P
+    };
+
+    return (vec < ARRAY_SIZE(names) && names[vec][0]) ? names[vec] : "???";
+}
+
 /*
  * This is called for faults at very unexpected times (e.g., when interrupts
  * are disabled). In such situations we can't do much that is safe. We try to
@@ -739,10 +755,9 @@ void fatal_trap(const struct cpu_user_regs *regs, bool show_remote)
         }
     }
 
-    panic("FATAL TRAP: vector = %d (%s)\n"
-          "[error_code=%04x] %s\n",
-          trapnr, trapstr(trapnr), regs->error_code,
-          (regs->eflags & X86_EFLAGS_IF) ? "" : ", IN INTERRUPT CONTEXT");
+    panic("FATAL TRAP: vec %u, %s[%04x]%s\n",
+          trapnr, vec_name(trapnr), regs->error_code,
+          (regs->eflags & X86_EFLAGS_IF) ? "" : " IN INTERRUPT CONTEXT");
 }
 
 static void do_reserved_trap(struct cpu_user_regs *regs)
@@ -753,7 +768,8 @@ static void do_reserved_trap(struct cpu_user_regs *regs)
         return;
 
     show_execution_state(regs);
-    panic("FATAL RESERVED TRAP %#x: %s\n", trapnr, trapstr(trapnr));
+    panic("FATAL RESERVED TRAP: vec %u, %s[%04x]\n",
+          trapnr, vec_name(trapnr), regs->error_code);
 }
 
 static void do_trap(struct cpu_user_regs *regs)

xen/include/asm-x86/processor.h

@@ -43,11 +43,7 @@
 #define TRAP_virtualisation   20
 #define TRAP_nr               32
 
-#define TRAP_HAVE_EC                                                    \
-    ((1u << TRAP_double_fault) | (1u << TRAP_invalid_tss) |             \
-     (1u << TRAP_no_segment) | (1u << TRAP_stack_error) |               \
-     (1u << TRAP_gp_fault) | (1u << TRAP_page_fault) |                  \
-     (1u << TRAP_alignment_check))
+#define TRAP_HAVE_EC X86_EXC_HAVE_EC
 
 /* Set for entry via SYSCALL. Informs return code to use SYSRETQ not IRETQ. */
 /* NB. Same as VGCF_in_syscall. No bits in common with any other TRAP_ defn. */

xen/include/asm-x86/x86-defns.h

@@ -118,4 +118,38 @@
 
 #define X86_NR_VECTORS 256
 
+/* Exception Vectors */
+#define X86_EXC_DE             0 /* Divide Error */
+#define X86_EXC_DB             1 /* Debug Exception */
+#define X86_EXC_NMI            2 /* NMI */
+#define X86_EXC_BP             3 /* Breakpoint */
+#define X86_EXC_OF             4 /* Overflow */
+#define X86_EXC_BR             5 /* BOUND Range */
+#define X86_EXC_UD             6 /* Invalid Opcode */
+#define X86_EXC_NM             7 /* Device Not Available */
+#define X86_EXC_DF             8 /* Double Fault */
+#define X86_EXC_CSO            9 /* Coprocessor Segment Overrun */
+#define X86_EXC_TS            10 /* Invalid TSS */
+#define X86_EXC_NP            11 /* Segment Not Present */
+#define X86_EXC_SS            12 /* Stack-Segment Fault */
+#define X86_EXC_GP            13 /* General Porection Fault */
+#define X86_EXC_PF            14 /* Page Fault */
+#define X86_EXC_SPV           15 /* PIC Spurious Interrupt Vector */
+#define X86_EXC_MF            16 /* Maths fault (x87 FPU) */
+#define X86_EXC_AC            17 /* Alignment Check */
+#define X86_EXC_MC            18 /* Machine Check */
+#define X86_EXC_XM            19 /* SIMD Exception */
+#define X86_EXC_VE            20 /* Virtualisation Exception */
+#define X86_EXC_CP            21 /* Control-flow Protection */
+#define X86_EXC_HV            28 /* Hypervisor Injection */
+#define X86_EXC_VC            29 /* VMM Communication */
+#define X86_EXC_SX            30 /* Security Exception */
+
+/* Bitmap of exceptions which have error codes. */
+#define X86_EXC_HAVE_EC                                             \
+    ((1u << X86_EXC_DF) | (1u << X86_EXC_TS) | (1u << X86_EXC_NP) | \
+     (1u << X86_EXC_SS) | (1u << X86_EXC_GP) | (1u << X86_EXC_PF) | \
+     (1u << X86_EXC_AC) | (1u << X86_EXC_CP) |                      \
+     (1u << X86_EXC_VC) | (1u << X86_EXC_SX))
+
 #endif	/* __XEN_X86_DEFNS_H__ */