From 9ee27c76393394c7fb1ddeca3f1622d4537185a0 Mon Sep 17 00:00:00 2001 From: Takao Indoh Date: Thu, 19 Nov 2009 16:39:22 -0500 Subject: [IA64] Save I-resources to ia64_sal_os_state This is a patch related to this discussion. http://www.spinics.net/lists/linux-ia64/msg07605.html When INIT is sent, ip/psr/pfs register is stored to the I-resources (iip/ipsr/ifs registers), and they are copied in the min-state save area(pmsa_{iip,ipsr,ifs}). Therefore, in creating pt_regs at ia64_mca_modify_original_stack(), cr_{iip,ipsr,ifs} should be derived from pmsa_{iip,ipsr,ifs}. But current code copies pmsa_{xip,xpsr,xfs} to cr_{iip,ipsr,ifs} when PSR.ic is 0. finish_pt_regs(struct pt_regs *regs, const pal_min_state_area_t *ms, unsigned long *nat) { (snip) if (ia64_psr(regs)->ic) { regs->cr_iip = ms->pmsa_iip; regs->cr_ipsr = ms->pmsa_ipsr; regs->cr_ifs = ms->pmsa_ifs; } else { regs->cr_iip = ms->pmsa_xip; regs->cr_ipsr = ms->pmsa_xpsr; regs->cr_ifs = ms->pmsa_xfs; } It's ok when PSR.ic is not 0. But when PSR.ic is 0, this could be a problem when we investigate kernel as the value of regs->cr_iip does not point to where INIT really interrupted. At first I tried to change finish_pt_regs() so that it uses always pmsa_{iip,ipsr,ifs} for cr_{iip,ipsr,ifs}, but Keith Owens pointed out it could cause another problem if I change it. >The only problem I can think of is an MCA/INIT >arriving while code like SAVE_MIN or SAVE_REST is executing. Back >tracing at that point using pmsa_iip is going to be a problem, you have >no idea what state the registers or stack are in. I confirmed he was right, so I decided to keep it as-is and to save pmsa_{iip,ipsr,ifs} to ia64_sal_os_state for debugging. An attached patch is just adding new members into ia64_sal_os_state to save pmsa_{iip,ipsr,ifs}. Signed-off-by: Takao Indoh Signed-off-by: Tony Luck --- arch/ia64/kernel/mca.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'arch/ia64/kernel') diff --git a/arch/ia64/kernel/mca.c b/arch/ia64/kernel/mca.c index 496ac7a99488..32f2639e9b0a 100644 --- a/arch/ia64/kernel/mca.c +++ b/arch/ia64/kernel/mca.c @@ -888,9 +888,10 @@ ia64_mca_modify_comm(const struct task_struct *previous_current) } static void -finish_pt_regs(struct pt_regs *regs, const pal_min_state_area_t *ms, +finish_pt_regs(struct pt_regs *regs, struct ia64_sal_os_state *sos, unsigned long *nat) { + const pal_min_state_area_t *ms = sos->pal_min_state; const u64 *bank; /* If ipsr.ic then use pmsa_{iip,ipsr,ifs}, else use @@ -904,6 +905,10 @@ finish_pt_regs(struct pt_regs *regs, const pal_min_state_area_t *ms, regs->cr_iip = ms->pmsa_xip; regs->cr_ipsr = ms->pmsa_xpsr; regs->cr_ifs = ms->pmsa_xfs; + + sos->iip = ms->pmsa_iip; + sos->ipsr = ms->pmsa_ipsr; + sos->ifs = ms->pmsa_ifs; } regs->pr = ms->pmsa_pr; regs->b0 = ms->pmsa_br0; @@ -1079,7 +1084,7 @@ ia64_mca_modify_original_stack(struct pt_regs *regs, memcpy(old_regs, regs, sizeof(*regs)); old_regs->loadrs = loadrs; old_unat = old_regs->ar_unat; - finish_pt_regs(old_regs, ms, &old_unat); + finish_pt_regs(old_regs, sos, &old_unat); /* Next stack a struct switch_stack. mca_asm.S built a partial * switch_stack, copy it and fill in the blanks using pt_regs and @@ -1150,7 +1155,7 @@ no_mod: mprintk(KERN_INFO "cpu %d, %s %s, original stack not modified\n", smp_processor_id(), type, msg); old_unat = regs->ar_unat; - finish_pt_regs(regs, ms, &old_unat); + finish_pt_regs(regs, sos, &old_unat); return previous_current; } -- cgit v1.2.2