[src/trunk]: src/sys/arch/amd64/amd64 Declare check_swapgs in an ASM macro. N...

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/f8b9f1436b04
branches:  trunk
changeset: 359628:f8b9f1436b04
user:      maxv <maxv%NetBSD.org@localhost>
date:      Sat Feb 17 21:05:58 2018 +0000

description:
Declare check_swapgs in an ASM macro. No real functional change.

diffstat:

 sys/arch/amd64/amd64/amd64_trap.S |  90 ++++++++++++++++++++------------------
 1 files changed, 48 insertions(+), 42 deletions(-)

diffs (111 lines):

diff -r 90e8f358bdb2 -r f8b9f1436b04 sys/arch/amd64/amd64/amd64_trap.S
--- a/sys/arch/amd64/amd64/amd64_trap.S Sat Feb 17 20:59:14 2018 +0000
+++ b/sys/arch/amd64/amd64/amd64_trap.S Sat Feb 17 21:05:58 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: amd64_trap.S,v 1.30 2018/02/17 20:59:14 maxv Exp $     */
+/*     $NetBSD: amd64_trap.S,v 1.31 2018/02/17 21:05:58 maxv Exp $     */
 
 /*
  * Copyright (c) 1998, 2007, 2008, 2017 The NetBSD Foundation, Inc.
@@ -303,6 +303,52 @@
 IDTVEC_END(\name)
 .endm
 
+#ifndef check_swapgs
+/*
+ * We need to worry about traps in kernel mode while the kernel %gs isn't
+ * loaded. These are either faults on iretq during return to user or loads to
+ * %gs.
+ *
+ * When such traps happen, we have CPL=0 and %gs=userland, and we must perform
+ * an additional swapgs to get %gs=kernel.
+ */
+.macro SWAPGS_HANDLER
+NENTRY(check_swapgs)
+       INTRENTRY_L(3f,1:)
+2:
+       sti
+       jmp     calltrap
+3:
+       /*
+        * Trap in kernel mode.
+        */
+
+       /* Case 1: fault on sysretq? */
+       leaq    do_sysret(%rip),%rdi
+       cmpq    %rdi,TF_RIP(%rsp)
+       je      1b
+
+       /* Case 2: fault on iretq? */
+       leaq    do_iret(%rip),%rdi
+       cmpq    %rdi,TF_RIP(%rsp)
+       jne     5f
+       movq    TF_RSP(%rsp),%rax       /* Must read %rsp, may be a pad word */
+       testb   $SEL_UPL,8(%rax)        /* Check %cs of outer iret frame */
+       je      2b                      /* jump if iret was to kernel  */
+       jmp     1b                      /* to user - must restore %gs */
+5:
+
+       /* Case 3: move to %gs? */
+       movq    TF_RIP(%rsp),%rax
+       movw    (%rax),%ax
+       andb    $070,%ah                /* mask mod/rm from mod/reg/rm */
+       cmpw    $0x8e+050*256,%ax       /* Any move to %gs (reg 5) */
+       jne     2b                      /* No - normal kernel fault */
+       jmp     1b                      /* Yes - restore %gs */
+END(check_swapgs)
+.endm
+#endif
+
        .text
 
        TEXT_USER_BEGIN
@@ -343,47 +389,7 @@
 TRAP_ENTRY_POINT_SPUR  intrspurious,T_ASTFLT,1
 
 #ifndef check_swapgs
-/*
- * We need to worry about traps in kernel mode while the kernel %gs isn't
- * loaded. These are either faults on iretq during return to user or loads to
- * %gs.
- *
- * When such traps happen, we have CPL=0 and %gs=userland, and we must perform
- * an additional swapgs to get %gs=kernel.
- */
-NENTRY(check_swapgs)
-       INTRENTRY_L(3f,1:)
-2:
-       sti
-       jmp     calltrap
-3:
-       /*
-        * Trap in kernel mode.
-        */
-
-       /* Case 1: fault on sysretq? */
-       leaq    do_sysret(%rip),%rdi
-       cmpq    %rdi,TF_RIP(%rsp)
-       je      1b
-
-       /* Case 2: fault on iretq? */
-       leaq    do_iret(%rip),%rdi
-       cmpq    %rdi,TF_RIP(%rsp)
-       jne     5f
-       movq    TF_RSP(%rsp),%rax       /* Must read %rsp, may be a pad word */
-       testb   $SEL_UPL,8(%rax)        /* Check %cs of outer iret frame */
-       je      2b                      /* jump if iret was to kernel  */
-       jmp     1b                      /* to user - must restore %gs */
-5:
-
-       /* Case 3: move to %gs? */
-       movq    TF_RIP(%rsp),%rax
-       movw    (%rax),%ax
-       andb    $070,%ah                /* mask mod/rm from mod/reg/rm */
-       cmpw    $0x8e+050*256,%ax       /* Any move to %gs (reg 5) */
-       jne     2b                      /* No - normal kernel fault */
-       jmp     1b                      /* Yes - restore %gs */
-END(check_swapgs)
+SWAPGS_HANDLER
 #endif
 
        TEXT_USER_END