From: "K.Prasad" <prasad@linux.vnet.ibm.com>
To: linuxppc-dev@ozlabs.org
Cc: Michael Neuling <mikey@neuling.org>,
Benjamin Herrenschmidt <benh@au1.ibm.com>,
shaggy@linux.vnet.ibm.com,
Frederic Weisbecker <fweisbec@gmail.com>,
David Gibson <dwg@au1.ibm.com>,
paulus@samba.org, Alan Stern <stern@rowland.harvard.edu>,
"K.Prasad" <prasad@linux.vnet.ibm.com>,
Roland McGrath <roland@redhat.com>
Subject: [RFC Patch 1/2] PPC64-HWBKPT: Disable interrupts for data breakpoint exceptions
Date: Tue, 23 Mar 2010 19:37:02 +0530 [thread overview]
Message-ID: <20100323140702.GB21836@in.ibm.com> (raw)
In-Reply-To: 20100323140008.954823303@pr
Data address breakpoint exceptions are currently handled along with page-faults
which require interrupts to remain in enabled state. Since exception handling
for data breakpoints aren't pre-empt safe, we handle them separately.
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
---
arch/powerpc/kernel/exceptions-64s.S | 12 ++++++++++++
arch/powerpc/mm/fault.c | 2 +-
2 files changed, 13 insertions(+), 1 deletion(-)
Index: linux-2.6.ppc64_test/arch/powerpc/kernel/exceptions-64s.S
===================================================================
--- linux-2.6.ppc64_test.orig/arch/powerpc/kernel/exceptions-64s.S
+++ linux-2.6.ppc64_test/arch/powerpc/kernel/exceptions-64s.S
@@ -735,6 +735,9 @@ _STATIC(do_hash_page)
std r3,_DAR(r1)
std r4,_DSISR(r1)
+ andis. r0,r4,0x0040 /* Data Address Breakpoint match? */
+ bne- handle_dabr_fault
+
andis. r0,r4,0xa450 /* weird error? */
bne- handle_page_fault /* if not, try to insert a HPTE */
BEGIN_FTR_SECTION
@@ -823,6 +826,15 @@ END_FW_FTR_SECTION_IFCLR(FW_FEATURE_ISER
bl .raw_local_irq_restore
b 11f
+/* We have a data breakpoint exception - handle it */
+handle_dabr_fault:
+ /* Populate the pt_regs structure */
+ ld r4,_DAR(r1)
+ ld r5,_DSISR(r1)
+ addi r3,r1,STACK_FRAME_OVERHEAD
+ bl .do_dabr
+ b .ret_from_except_lite
+
/* Here we have a page fault that hash_page can't handle. */
handle_page_fault:
ENABLE_INTS
Index: linux-2.6.ppc64_test/arch/powerpc/mm/fault.c
===================================================================
--- linux-2.6.ppc64_test.orig/arch/powerpc/mm/fault.c
+++ linux-2.6.ppc64_test/arch/powerpc/mm/fault.c
@@ -151,7 +151,7 @@ int __kprobes do_page_fault(struct pt_re
if (!user_mode(regs) && (address >= TASK_SIZE))
return SIGSEGV;
-#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE))
+#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE) || defined(CONFIG_PPC64))
if (error_code & DSISR_DABRMATCH) {
/* DABR match */
do_dabr(regs, address, error_code);
next parent reply other threads:[~2010-03-23 14:07 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20100323140008.954823303@pr>
2010-03-23 14:07 ` K.Prasad [this message]
2010-03-30 5:24 ` [RFC Patch 1/2] PPC64-HWBKPT: Disable interrupts for data breakpoint exceptions Paul Mackerras
2010-03-30 5:32 ` Benjamin Herrenschmidt
2010-03-30 10:19 ` K.Prasad
2010-03-30 10:17 ` K.Prasad
2010-03-23 14:07 ` [RFC Patch 2/2] PPC64-HWBKPT: Implement hw-breakpoints for PPC64 K.Prasad
2010-03-26 21:11 ` Dave Kleikamp
2010-03-29 11:31 ` K.Prasad
2010-03-29 19:53 ` Dave Kleikamp
2010-03-30 10:12 ` K.Prasad
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20100323140702.GB21836@in.ibm.com \
--to=prasad@linux.vnet.ibm.com \
--cc=benh@au1.ibm.com \
--cc=dwg@au1.ibm.com \
--cc=fweisbec@gmail.com \
--cc=linuxppc-dev@ozlabs.org \
--cc=mikey@neuling.org \
--cc=paulus@samba.org \
--cc=roland@redhat.com \
--cc=shaggy@linux.vnet.ibm.com \
--cc=stern@rowland.harvard.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).