Jack Steiner uncovered some opportunities for improvement in
the MCA recovery code.
1) Set bsp to save registers on the kernel stack.
2) Disable interrupts while in the MCA recovery code.
3) Change the way the user process is killed, to avoid
a panic in schedule.
Testing shows that these changes make the recovery code much
more reliable with the 2.6.12 kernel.
Signed-off-by: Russ Anderson <[EMAIL PROTECTED]>
------------------------------------------------------------------------------------
Index: linux/arch/ia64/kernel/mca_drv.c
===================================================================
--- linux.orig/arch/ia64/kernel/mca_drv.c 2005-04-01 13:28:21.897191890
-0600
+++ linux/arch/ia64/kernel/mca_drv.c 2005-04-01 13:29:48.547634088 -0600
@@ -132,8 +132,7 @@
spin_unlock(&mca_bh_lock);
/* This process is about to be killed itself */
- force_sig(SIGKILL, current);
- schedule();
+ do_exit(SIGKILL);
}
/**
@@ -439,6 +438,7 @@
psr2 = (struct ia64_psr *)&pmsa->pmsa_ipsr;
psr2->cpl = 0;
psr2->ri = 0;
+ psr2->i = 0;
return 1;
}
Index: linux/arch/ia64/kernel/mca_drv_asm.S
===================================================================
--- linux.orig/arch/ia64/kernel/mca_drv_asm.S 2005-04-01 13:28:15.696086223
-0600
+++ linux/arch/ia64/kernel/mca_drv_asm.S 2005-04-01 14:31:24.275077908
-0600
@@ -10,6 +10,7 @@
#include <asm/asmmacro.h>
#include <asm/processor.h>
+#include <asm/ptrace.h>
GLOBAL_ENTRY(mca_handler_bhhook)
invala // clear RSE ?
@@ -20,12 +21,21 @@
;;
alloc r16=ar.pfs,0,2,1,0 // make a new frame
;;
+ mov ar.rsc=0
+ ;;
mov r13=IA64_KR(CURRENT) // current task pointer
;;
- adds r12=IA64_TASK_THREAD_KSP_OFFSET,r13
+ mov r2=r13
+ ;;
+ addl r22=IA64_RBS_OFFSET,r2
+ ;;
+ mov ar.bspstore=r22
;;
- ld8 r12=[r12] // stack pointer
+ addl sp=IA64_STK_OFFSET-IA64_PT_REGS_SIZE,r2
;;
+ adds r2=IA64_TASK_THREAD_ON_USTACK_OFFSET,r13
+ ;;
+ st1 [r2]=r0 // clear
current->thread.on_ustack flag
mov loc0=r16
movl loc1=mca_handler_bh // recovery C function
;;
@@ -34,7 +44,9 @@
;;
mov loc1=rp
;;
- br.call.sptk.many rp=b6 // not return ...
+ ssm psr.i
+ ;;
+ br.call.sptk.many rp=b6 // does not return ...
;;
mov ar.pfs=loc0
mov rp=loc1
------------------------------------------------------------------------------------
--
Russ Anderson, OS RAS/Partitioning Project Lead
SGI - Silicon Graphics Inc [EMAIL PROTECTED]
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