PERFORCE change 31115 for review

[Peter Wemm]

http://perforce.freebsd.org/chv.cgi?CH=31115

Change 31115 by peter at peter_hammer on 2003/05/13 19:38:39

	In theory, the user segment registers are never used while in long
	mode.  But I dont want to have to check during an iret to 32 bit
	compatability mode, so let the sigtramp itself restore the segment
	selectors rather than messing with them in the kernel.

Affected files ...

.. //depot/projects/hammer/sys/amd64/ia32/ia32_genassym.c#2 edit
.. //depot/projects/hammer/sys/amd64/ia32/ia32_signal.c#2 edit
.. //depot/projects/hammer/sys/amd64/ia32/ia32_sigtramp.S#2 edit

Differences ...

==== //depot/projects/hammer/sys/amd64/ia32/ia32_genassym.c#2 (text+ko) ====

@@ -5,13 +5,20 @@
 #include <sys/param.h>
 #include <sys/assym.h>
 #include <sys/systm.h>
+#include <sys/signal.h>
 
 #include <amd64/ia32/ia32_signal.h>
 
 ASSYM(IA32_SIGF_HANDLER, offsetof(struct ia32_sigframe, sf_ah));
 ASSYM(IA32_SIGF_UC, offsetof(struct ia32_sigframe, sf_uc));
 ASSYM(IA32_UC_GS, offsetof(struct ia32_ucontext, uc_mcontext.mc_gs));
+ASSYM(IA32_UC_FS, offsetof(struct ia32_ucontext, uc_mcontext.mc_fs));
+ASSYM(IA32_UC_ES, offsetof(struct ia32_ucontext, uc_mcontext.mc_es));
+ASSYM(IA32_UC_DS, offsetof(struct ia32_ucontext, uc_mcontext.mc_ds));
 #ifdef COMPAT_FREEBSD4
 ASSYM(IA32_SIGF_UC4, offsetof(struct ia32_sigframe, sf_uc));
 ASSYM(IA32_UC4_GS, offsetof(struct ia32_ucontext4, uc_mcontext.mc_gs));
+ASSYM(IA32_UC4_FS, offsetof(struct ia32_ucontext4, uc_mcontext.mc_fs));
+ASSYM(IA32_UC4_ES, offsetof(struct ia32_ucontext4, uc_mcontext.mc_es));
+ASSYM(IA32_UC4_DS, offsetof(struct ia32_ucontext4, uc_mcontext.mc_ds));
 #endif

==== //depot/projects/hammer/sys/amd64/ia32/ia32_signal.c#2 (text+ko) ====

@@ -268,8 +268,10 @@
 	regs->tf_cs = _ucode32sel;
 	regs->tf_ss = _udatasel;
 	load_ds(_udatasel);
+	td->td_pcb->pcb_ds = _udatasel;
 	load_es(_udatasel);
-	load_fs(_udatasel);
+	td->td_pcb->pcb_es = _udatasel;
+	/* leave user %fs and %gs untouched */
 	PROC_LOCK(p);
 }
 #endif	/* COMPAT_FREEBSD4 */
@@ -382,8 +384,10 @@
 	regs->tf_cs = _ucode32sel;
 	regs->tf_ss = _udatasel;
 	load_ds(_udatasel);
+	td->td_pcb->pcb_ds = _udatasel;
 	load_es(_udatasel);
-	load_fs(_udatasel);
+	td->td_pcb->pcb_es = _udatasel;
+	/* leave user %fs and %gs untouched */
 	PROC_LOCK(p);
 }
 
@@ -449,10 +453,7 @@
 		return (EINVAL);
 	}
 
-	/* mc_gs is done by sigtramp.S */
-	load_fs(ucp->uc_mcontext.mc_fs);
-	load_es(ucp->uc_mcontext.mc_es);
-	load_ds(ucp->uc_mcontext.mc_ds);
+	/* Segment selectors restored by sigtramp.S */
 	regs->tf_rdi = ucp->uc_mcontext.mc_edi;
 	regs->tf_rsi = ucp->uc_mcontext.mc_esi;
 	regs->tf_rbp = ucp->uc_mcontext.mc_ebp;
@@ -533,10 +534,7 @@
 	if (ret != 0)
 		return (ret);
 
-	/* mc_gs is done by sigtramp.S */
-	load_fs(ucp->uc_mcontext.mc_fs);
-	load_es(ucp->uc_mcontext.mc_es);
-	load_ds(ucp->uc_mcontext.mc_ds);
+	/* Segment selectors restored by sigtramp.S */
 	regs->tf_rdi = ucp->uc_mcontext.mc_edi;
 	regs->tf_rsi = ucp->uc_mcontext.mc_esi;
 	regs->tf_rbp = ucp->uc_mcontext.mc_ebp;

==== //depot/projects/hammer/sys/amd64/ia32/ia32_sigtramp.S#2 (text+ko) ====

@@ -62,6 +62,9 @@
 	leal	IA32_SIGF_UC(%esp),%eax	/* get ucontext */
 	pushl	%eax
 	movl	IA32_UC_GS(%eax),%gs	/* restore %gs */
+	movl	IA32_UC_FS(%eax),%fs	/* restore %fs */
+	movl	IA32_UC_ES(%eax),%es	/* restore %es */
+	movl	IA32_UC_DS(%eax),%ds	/* restore %ds */
 	movl	$SYS_sigreturn,%eax
 	pushl	%eax			/* junk to fake return addr. */
 	int	$0x80			/* enter kernel with args */
@@ -76,6 +79,9 @@
 	leal	IA32_SIGF_UC4(%esp),%eax/* get ucontext */
 	pushl	%eax
 	movl	IA32_UC4_GS(%eax),%gs	/* restore %gs */
+	movl	IA32_UC4_FS(%eax),%fs	/* restore %fs */
+	movl	IA32_UC4_ES(%eax),%es	/* restore %es */
+	movl	IA32_UC4_DS(%eax),%ds	/* restore %ds */
 	movl	$344,%eax		/* 4.x SYS_sigreturn */
 	pushl	%eax			/* junk to fake return addr. */
 	int	$0x80			/* enter kernel with args */