Re: Linux 2.6.16.5

From: Greg KH
Date: Wed Apr 12 2006 - 16:37:29 EST


diff --git a/Makefile b/Makefile
index 29efaa1..cb17131 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
VERSION = 2
PATCHLEVEL = 6
SUBLEVEL = 16
-EXTRAVERSION = .4
+EXTRAVERSION = .5
NAME=Sliding Snow Leopard

# *DOCUMENTATION*
diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S
index 7c10e90..ab6e44d 100644
--- a/arch/x86_64/kernel/entry.S
+++ b/arch/x86_64/kernel/entry.S
@@ -180,6 +180,10 @@ rff_trace:
*
* XXX if we had a free scratch register we could save the RSP into the stack frame
* and report it properly in ps. Unfortunately we haven't.
+ *
+ * When user can change the frames always force IRET. That is because
+ * it deals with uncanonical addresses better. SYSRET has trouble
+ * with them due to bugs in both AMD and Intel CPUs.
*/

ENTRY(system_call)
@@ -254,7 +258,10 @@ sysret_signal:
xorl %esi,%esi # oldset -> arg2
call ptregscall_common
1: movl $_TIF_NEED_RESCHED,%edi
- jmp sysret_check
+ /* Use IRET because user could have changed frame. This
+ works because ptregscall_common has called FIXUP_TOP_OF_STACK. */
+ cli
+ jmp int_with_check

badsys:
movq $-ENOSYS,RAX-ARGOFFSET(%rsp)
@@ -280,7 +287,8 @@ tracesys:
call syscall_trace_leave
RESTORE_TOP_OF_STACK %rbx
RESTORE_REST
- jmp ret_from_sys_call
+ /* Use IRET because user could have changed frame */
+ jmp int_ret_from_sys_call
CFI_ENDPROC

/*
@@ -408,25 +416,9 @@ ENTRY(stub_execve)
CFI_ADJUST_CFA_OFFSET -8
CFI_REGISTER rip, r11
SAVE_REST
- movq %r11, %r15
- CFI_REGISTER rip, r15
FIXUP_TOP_OF_STACK %r11
call sys_execve
- GET_THREAD_INFO(%rcx)
- bt $TIF_IA32,threadinfo_flags(%rcx)
- CFI_REMEMBER_STATE
- jc exec_32bit
RESTORE_TOP_OF_STACK %r11
- movq %r15, %r11
- CFI_REGISTER rip, r11
- RESTORE_REST
- pushq %r11
- CFI_ADJUST_CFA_OFFSET 8
- CFI_REL_OFFSET rip, 0
- ret
-
-exec_32bit:
- CFI_RESTORE_STATE
movq %rax,RAX(%rsp)
RESTORE_REST
jmp int_ret_from_sys_call
-
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