amd64: Fix improper saving of a register.

%esi is not guaranteed to be preserved across function calls.

diff --git a/sys/platform/pc64/amd64/ipl.s b/sys/platform/pc64/amd64/ipl.s
index 9fc2efb..38d6cc7 100644 (file)
--- a/sys/platform/pc64/amd64/ipl.s
+++ b/sys/platform/pc64/amd64/ipl.s
@@ -324,13 +324,13 @@ doreti_soft:
 doreti_ast:
        andl    $~(RQF_AST_SIGNAL|RQF_AST_UPCALL),PCPU(reqflags)
        sti
-       movl    %eax,%esi               /* save cpl (can't use stack) */
+       movl    %eax,%r12d              /* save cpl (can't use stack) */
        movl    $T_ASTFLT,TF_TRAPNO(%rsp)
        movq    %rsp,%rdi               /* pass frame by ref (%edi = C arg) */
        subl    $TDPRI_CRIT,TD_PRI(%rbx)
        call    trap
        addl    $TDPRI_CRIT,TD_PRI(%rbx)
-       movl    %esi,%eax               /* restore cpl for loop */
+       movl    %r12d,%eax              /* restore cpl for loop */
        jmp     doreti_next
 
 #ifdef SMP
@@ -338,7 +338,7 @@ doreti_ast:
         * IPIQ message pending.  We clear RQF_IPIQ automatically.
         */
 doreti_ipiq:
-       movl    %eax,%esi               /* save cpl (can't use stack) */
+       movl    %eax,%r12d              /* save cpl (can't use stack) */
        incl    PCPU(intr_nesting_level)
        andl    $~RQF_IPIQ,PCPU(reqflags)
        subq    $16,%rsp                /* add dummy vec and ppl */
@@ -346,11 +346,11 @@ doreti_ipiq:
        call    lwkt_process_ipiq_frame
        addq    $16,%rsp
        decl    PCPU(intr_nesting_level)
-       movl    %esi,%eax               /* restore cpl for loop */
+       movl    %r12d,%eax              /* restore cpl for loop */
        jmp     doreti_next
 
 doreti_timer:
-       movl    %eax,%esi               /* save cpl (can't use stack) */
+       movl    %eax,%r12d              /* save cpl (can't use stack) */
        incl    PCPU(intr_nesting_level)
        andl    $~RQF_TIMER,PCPU(reqflags)
        subq    $16,%rsp                        /* add dummy vec and ppl */
@@ -358,7 +358,7 @@ doreti_timer:
        call    lapic_timer_process_frame
        addq    $16,%rsp
        decl    PCPU(intr_nesting_level)
-       movl    %esi,%eax               /* restore cpl for loop */
+       movl    %r12d,%eax              /* restore cpl for loop */
        jmp     doreti_next
 
 #endif