[U-Boot] [PATCH 1/2] x86: Display correct CS/EIP/EFLAGS when there is an error code

[Bin Meng]

Some exceptions cause an error code to be saved on the current stack
after the EIP value. We should extract CS/EIP/EFLAGS from different
position on the stack based on the exception number.

Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
---

 arch/x86/cpu/interrupts.c     | 29 ++++++++++++++++++++++++++++-
 arch/x86/include/asm/ptrace.h | 16 +++++++++++++---
 2 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/arch/x86/cpu/interrupts.c b/arch/x86/cpu/interrupts.c
index c777d36..4a6c21f 100644
--- a/arch/x86/cpu/interrupts.c
+++ b/arch/x86/cpu/interrupts.c
@@ -34,12 +34,39 @@ DECLARE_GLOBAL_DATA_PTR;
 
 static void dump_regs(struct irq_regs *regs)
 {
+	unsigned long cs, eip, eflags;
 	unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
 	unsigned long d0, d1, d2, d3, d6, d7;
 	unsigned long sp;
 
+	/*
+	 * Some exceptions cause an error code to be saved on the current stack
+	 * after the EIP value. We should extract CS/EIP/EFLAGS from different
+	 * position on the stack based on the exception number.
+	 */
+	switch (regs->irq_id) {
+	case 8:
+	case 10:
+	case 11:
+	case 12:
+	case 13:
+	case 14:
+	case 17:
+		cs = regs->context.ctx2.xcs;
+		eip = regs->context.ctx2.eip;
+		eflags = regs->context.ctx2.eflags;
+		/* We should fix up the ESP due to error code */
+		regs->esp += 4;
+		break;
+	default:
+		cs = regs->context.ctx1.xcs;
+		eip = regs->context.ctx1.eip;
+		eflags = regs->context.ctx1.eflags;
+		break;
+	}
+
 	printf("EIP: %04x:[<%08lx>] EFLAGS: %08lx\n",
-			(u16)regs->xcs, regs->eip, regs->eflags);
+			(u16)cs, eip, eflags);
 
 	printf("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
 		regs->eax, regs->ebx, regs->ecx, regs->edx);
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index a727dbf..3849bc0 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -63,9 +63,19 @@ struct irq_regs {
 	/* Pushed by vector handler (irq_<num>) */
 	long irq_id;
 	/* Pushed by cpu in response to interrupt */
-	long eip;
-	long xcs;
-	long eflags;
+	union {
+		struct {
+			long eip;
+			long xcs;
+			long eflags;
+		} ctx1;
+		struct {
+			long err;
+			long eip;
+			long xcs;
+			long eflags;
+		} ctx2;
+	} context;
 }  __attribute__ ((packed));
 
 /* Arbitrarily choose the same ptrace numbers as used by the Sparc code. */
-- 
1.8.2.1