PERFORCE change 28737 for review

[Peter Wemm]

http://perforce.freebsd.org/chv.cgi?CH=28737

Change 28737 by peter at peter_daintree on 2003/04/10 14:05:24

	update common_tss.tss.tss_rsp0 on context switch so that we arrive on
	the correct stack when entering the kernel from userland.

Affected files ...

.. //depot/projects/hammer/sys/x86_64/include/tss.h#7 edit
.. //depot/projects/hammer/sys/x86_64/x86_64/genassym.c#16 edit
.. //depot/projects/hammer/sys/x86_64/x86_64/swtch.s#17 edit

Differences ...

==== //depot/projects/hammer/sys/x86_64/include/tss.h#7 (text+ko) ====

@@ -70,4 +70,16 @@
 };
 #pragma pack()
 
+#ifdef _KERNEL
+/*
+ * Nasty hack to arrange internal alignment.
+ * What were they thinking??
+ */
+struct aligned_tss {
+	u_int32_t pad;
+	struct x86_64tss tss  __packed;
+};
+extern struct aligned_tss common_tss;
+#endif
+
 #endif /* _MACHINE_TSS_H_ */

==== //depot/projects/hammer/sys/x86_64/x86_64/genassym.c#16 (text+ko) ====

@@ -133,6 +133,8 @@
 
 ASSYM(PCB_SIZE, sizeof(struct pcb));
 
+ASSYM(COMMON_TSS_RSP0, offsetof(struct aligned_tss, tss.tss_rsp0));
+
 ASSYM(TF_TRAPNO, offsetof(struct trapframe, tf_trapno));
 ASSYM(TF_ERR, offsetof(struct trapframe, tf_err));
 ASSYM(TF_CS, offsetof(struct trapframe, tf_cs));

==== //depot/projects/hammer/sys/x86_64/x86_64/swtch.s#17 (text+ko) ====

@@ -147,6 +147,11 @@
 	 * to load up the rest of the next context.
 	 */
 	movq	TD_PCB(%rsi),%rdx
+
+	/* Update the TSS_RSP0 pointer for the next interrupt */
+	leaq	-16(%rdx), %rbx
+	movq	%rbx, common_tss + COMMON_TSS_RSP0
+
 	/* Restore context. */
 	movq	PCB_RBX(%rdx),%rbx
 	movq	PCB_RSP(%rdx),%rsp