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authorAleksey Gorelov <Aleksey_Gorelov@Phoenix.com>2006-06-27 02:53:48 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-27 17:32:38 -0700
commit4031ff388138b58e5cd472dccce38828bcb8c706 (patch)
treef2c88fdcdef3ec9880d23ce271f14e95f7aa1cf5 /arch
parentc723e084606ca1c81e91b80b2c0c44bde7bbc4df (diff)
[PATCH] fix broken vm86 interrupt/signal handling
Commit c3ff8ec31c1249d268cd11390649768a12bec1b9 ("[PATCH] i386: Don't miss pending signals returning to user mode after signal processing") meant that vm86 interrupt/signal handling got broken for the case when vm86 is called from kernel space. In this scenario, if signal is pending because of vm86 interrupt, do_notify_resume/do_signal exits immediately due to user_mode() check, without processing any signals. Thus, resume_userspace handler is spinning in a tight loop with signal pending and TIF_SIGPENDING is set. Previously everything worked Ok. No in-tree usage of vm86() from kernel space exists, but I've heard about a number of projects out there which use vm86 calls from kernel, one of them being this, for instance: http://dev.gentoo.org/~spock/projects/vesafb-tng/ The following patch fixes the issue. Signed-off-by: Aleksey Gorelov <aleksey_gorelov@phoenix.com> Cc: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/i386/kernel/entry.S11
1 files changed, 9 insertions, 2 deletions
diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
index 8713e0248a0b..e8d2630fd19a 100644
--- a/arch/i386/kernel/entry.S
+++ b/arch/i386/kernel/entry.S
@@ -83,6 +83,12 @@ VM_MASK = 0x00020000
#define resume_kernel restore_nocheck
#endif
+#ifdef CONFIG_VM86
+#define resume_userspace_sig check_userspace
+#else
+#define resume_userspace_sig resume_userspace
+#endif
+
#define SAVE_ALL \
cld; \
pushl %es; \
@@ -211,6 +217,7 @@ ret_from_exception:
preempt_stop
ret_from_intr:
GET_THREAD_INFO(%ebp)
+check_userspace:
movl EFLAGS(%esp), %eax # mix EFLAGS and CS
movb CS(%esp), %al
testl $(VM_MASK | 3), %eax
@@ -415,7 +422,7 @@ work_notifysig: # deal with pending signals and
# vm86-space
xorl %edx, %edx
call do_notify_resume
- jmp resume_userspace
+ jmp resume_userspace_sig
ALIGN
work_notifysig_v86:
@@ -428,7 +435,7 @@ work_notifysig_v86:
movl %eax, %esp
xorl %edx, %edx
call do_notify_resume
- jmp resume_userspace
+ jmp resume_userspace_sig
#endif
# perform syscall exit tracing