== Linus Walleij linusw ==
=== Highlights ===
* Drilled into the RCU lockup. With some help from Paul
McKenney we got a task dump from CPU0 (the CPU that is
locking) but not much more - only the swapper thread is
running there and we need to dump its stack.
* Puffed and pinged on the SPARSE_IRQ patch, yet no reaction
so far.
* Mainlining some stuff in the PL011 driver that has been
sitting internally for some time. Easy stuff went in first and
then we ran into the trickier patches - some odd baudrates
are impossible since th TTY layer will "snap" the baudrate
to a standard baudrate from a table if it's "close enough".
We used to work around this by not calling out to the
TTY layer in the PL011 driver for certain baudrates, but this
is duct-taping. Still debating the real solution with Alan
Cox and Russell King who help out a lot.
* Reviewed and merged various GPIO patches.
* Reviewed and merged various pinctrl patches.
* Reviewed some ux500 patches coming from Lee.
* Reviewed Arnd's iomem cleanups.
* Sent out Patrice Chotard's pinctrl patch for the PL022
SPI driver, Mark has merged it.
=== Plans ===
* Ongoing work on sparse IRQ for Nomadik and Ux500.
* Test the PL08x patches on the Ericsson Research
PB11MPCore and submit platform data for using
pl08x DMA on that platform.
* Look into other Ux500 stuff in need of mainlining...
using an internal tracking sheet for this.
* Look into regmap. Try something out, get to know it.
=== Issues ===
* N/A
Thanks,
Linus Walleij
== Linus Walleij linusw ==
=== Highlights ===
* Finally had the RCU lockup issue fixed - Paul McKenney found
the problem and fixed it. It turns out the same bug has been
seen on the OMAP, where Paul Walmsley, Becy Bruce et al
had reported it.
http://marc.info/?l=linux-kernel&m=134749030206016&w=2
Hunting and testing this took a lot of time.
* To progress on SPARSE_IRQ I proposed a patch to remove
the warning from the GIC, and alerted Rob Herring. He didn't
like that but proposed to fix the problem by fixing all
descriptor allocation, which will take more time.
* Proposed a patch fixing the pinctrl IRQ desc allocations
(these happen really early) and was adviced to introduce a
linear IRQ domain, did this, was proposed to refactor
IRQ domain core, proposed a patch for this, now following
up.
* Found out how to really get rid of the ugly workarounds in
the PL011 driver, only a small ST-Micro derivate-only patch
was needed in the end to adjust baud rate down with ~5%
on high baud rates. The rest of the patches were bogus,
we weren't interfacing the TTY layer correctly. Alan Cox
told me how to do it properly and lo and behold, it just
works now. (All work synchronized back to ST-Ericsson's
internal codebase.)
* Sent out a pinctrl patch for Nomadik I2C, but still
pondering this due to regressions.
* Discussed resource handling for runtime PM and
ordinary suspend/resume in the PL022 SPI driver,
discussion ongoing.
* Reviewed and merged various GPIO patches.
* Reviewed and merged various pinctrl patches.
Pondering PM semantics.
* Reviewed some ux500 patches coming from Lee.
=== Plans ===
* Ongoing work on sparse IRQ for Nomadik and Ux500
with the required IRQ domain refactorings.
* Follow up the rest of the above.
* Test the PL08x patches on the Ericsson Research
PB11MPCore and submit platform data for using
pl08x DMA on that platform.
* Look into other Ux500 stuff in need of mainlining...
using an internal tracking sheet for this.
* Look into regmap. Try something out, get to know it.
=== Issues ===
* N/A
Thanks,
Linus Walleij
Hi all,
Here comes v9...
Greg, patches 1-7 have gotten all the needed acks from Alan and Jason, so
it would be awesome if you could apply them to your tty-next tree.
ARM patches still need Russell's acks, but these can wait, plus if the
core support hits v3.7, it would be much easier to handle the rest
(including the patches that add "kiosk mode" support for KDB).
Thanks!
In v9:
- KGDB patches got their Acked-by tags from Jason Wessel;
- A small 64 bit fixup for kgdb_nmi driver, thanks to Jason;
- Yet again rebased on the latest and greatest tty-next, just to make sure
everything applies cleanly.
These patches can be found in the following repo (based on tty-next):
git://git.infradead.org/users/cbou/linux-nmi-kdb.git master
Old changelogs and rationale for these patches can be found here:
v1-v5, rationale: http://lkml.org/lkml/2012/9/10/2
v6: http://lkml.org/lkml/2012/9/10/2
v7: http://lkml.org/lkml/2012/9/13/367
v8: http://lkml.org/lkml/2012/9/19/525
--
arch/arm/Kconfig | 19 ++
arch/arm/common/vic.c | 28 ++
arch/arm/include/asm/hardware/vic.h | 2 +
arch/arm/include/asm/kgdb.h | 8 +
arch/arm/kernel/Makefile | 1 +
arch/arm/kernel/entry-armv.S | 167 +-----------
arch/arm/kernel/entry-header.S | 170 ++++++++++++
arch/arm/kernel/kgdb_fiq.c | 124 +++++++++
arch/arm/kernel/kgdb_fiq_entry.S | 87 +++++++
arch/arm/mach-versatile/Makefile | 1 +
arch/arm/mach-versatile/kgdb_fiq.c | 31 +++
drivers/tty/serial/Kconfig | 19 ++
drivers/tty/serial/Makefile | 1 +
drivers/tty/serial/amba-pl011.c | 73 +++++-
drivers/tty/serial/kgdb_nmi.c | 402 +++++++++++++++++++++++++++++
drivers/tty/serial/kgdboc.c | 9 +
drivers/tty/serial/serial_core.c | 17 ++
include/linux/kdb.h | 29 ++-
include/linux/kgdb.h | 13 +
include/linux/serial_core.h | 1 +
kernel/debug/debug_core.c | 14 +-
kernel/debug/kdb/kdb_main.c | 31 +++
22 files changed, 1054 insertions(+), 193 deletions(-)
== Highlights ==
* Performed some proof-of-concept tests on the Mel Gorman's idea of using
nr_scanned/(nr_reclaimed+1) ratio for memory pressure detection -- and
the idea seems to work great. Didn't have time to implement it in the
vmevent API, but hopefully this week I'll have something to show;
* Addressed Jason Wessel's comments on KDB FIQ debugger patches, i.e.
now we only register ttyNMI interface and disable_nmi command on arches
that actually support NMI rerouting, plus reworked enable_nmi callback;
* Got a bunch of new ideas from Android folks on KDB FIQ debugger,
cpufreq, low memory handling, and more. Lots of things to investigate
and implement;
* Some power supply and pstore maintenance activity, reviewed over 90
patches in total.
Hi all,
In v8, addressed Jason's comments:
- Changed kgdb_enable_nmi() weak function to kgdb_arch callbck;
- We no longer register disable_nmi command if arch does not register
KGDB NMI handling (i.e. not filling kgdb_arch.enable_nmi callback);
- The same is for ttyNMI: if architecure does not provide us with
enable_nmi call, we don't need the tty device. Of course, there is no
way to tell wether a specific serial device can be used for NMI
debugging, as it is not serial-device specific, but specific to
whether IRQ can be rerouted to an NMI (for most our cases, pretty
much every IRQ can be rerouted, e.g. a hot-pluggable serial device on
a PCI bus).
- Rebased on the latest and greatest tty-next, just in case.
These patches can be found in the following repo (based on tty-next):
git://git.infradead.org/users/cbou/linux-nmi-kdb.git master
Old changelogs and rationale for these patches can be found here:
v1-v5, rationale: http://lkml.org/lkml/2012/9/10/2
v6: http://lkml.org/lkml/2012/9/10/2
v7: http://lkml.org/lkml/2012/9/13/367
Thanks,
--
arch/arm/Kconfig | 19 ++
arch/arm/common/vic.c | 28 +++
arch/arm/include/asm/hardware/vic.h | 2 +
arch/arm/include/asm/kgdb.h | 8 +
arch/arm/kernel/Makefile | 1 +
arch/arm/kernel/entry-armv.S | 167 +------------
arch/arm/kernel/entry-header.S | 170 +++++++++++++
arch/arm/kernel/kgdb_fiq.c | 124 +++++++++
arch/arm/kernel/kgdb_fiq_entry.S | 87 +++++++
arch/arm/mach-versatile/Makefile | 1 +
arch/arm/mach-versatile/kgdb_fiq.c | 31 +++
drivers/tty/serial/Kconfig | 19 ++
drivers/tty/serial/Makefile | 1 +
drivers/tty/serial/amba-pl011.c | 73 +++++-
drivers/tty/serial/kgdb_nmi.c | 402 ++++++++++++++++++++++++++++++
drivers/tty/serial/kgdboc.c | 9 +
drivers/tty/serial/serial_core.c | 17 ++
include/linux/kdb.h | 29 ++-
include/linux/kgdb.h | 13 +
include/linux/serial_core.h | 1 +
kernel/debug/debug_core.c | 14 +-
kernel/debug/kdb/kdb_main.c | 31 +++
22 files changed, 1054 insertions(+), 193 deletions(-)
The Virtualization Extensions introduce the requirement for an ARMv7-A
implementation to include SDIV and UDIV. Any implementation of the
Virtualization Extensions must include the SDIV and UDIV instructions
in the Thumb and ARM instruction sets.
In an ARMv7-A implementation that does not include the Virtualization
Extensions, it is IMPLEMENTATION DEFINED whether:
* SDIV and UDIV are not implemented
* SDIV and UDIV are implemented only in the Thumb instruction set
* SDIV and UDIV are implemented in the Thumb and ARM instruction sets.
This patch adds a handler to trap and emulate unimplemented SDIV and
UDIV instructions in ARM and Thumb modes. Also some basic statistic is
exported via /proc/cpu/idiv_emulation
Signed-off-by: Vladimir Murzin <murzin.v(a)gmail.com>
---
arch/arm/kernel/Makefile | 1 +
arch/arm/kernel/idiv_emulate.c | 194 ++++++++++++++++++++++++++++++++++++++++
arch/arm/mm/Kconfig | 26 ++++++
3 files changed, 221 insertions(+), 0 deletions(-)
create mode 100644 arch/arm/kernel/idiv_emulate.c
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 7ad2d5c..057a630 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -62,6 +62,7 @@ obj-$(CONFIG_OF) += devtree.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_SWP_EMULATE) += swp_emulate.o
CFLAGS_swp_emulate.o := -Wa,-march=armv7-a
+obj-$(CONFIG_IDIV_EMULATE) += idiv_emulate.o
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
obj-$(CONFIG_CPU_XSCALE) += xscale-cp0.o
diff --git a/arch/arm/kernel/idiv_emulate.c b/arch/arm/kernel/idiv_emulate.c
new file mode 100644
index 0000000..f021d0e
--- /dev/null
+++ b/arch/arm/kernel/idiv_emulate.c
@@ -0,0 +1,195 @@
+/*
+ * linux/arch/arm/kernel/idiv_emulate.c
+ *
+ * This code is based on swp_emulate.c
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Implements emulation of the SDIV/UDIV instructions. They are defined for
+ * ARMv7-R and ARMv7-M profiles (in Thumb state only) and are UNDEFINED in the
+ * ARMv7-A profile. SDIV/UDIV are present by default on Cortex-A15.
+ *
+ * This emulation allow using integer divide instructions in case hardware is
+ * not presented
+ *
+ * Syntax of SDIV/UDIV instructions: SDIV/UDIV<c> <Rd>,<Rn>,<Rm>
+ * Where: Rd = the destination register.
+ * Rn = the register that contains the dividend.
+ * Rm = the register that contains the divisor.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/proc_fs.h>
+#include <linux/sched.h>
+#include <linux/syscalls.h>
+#include <linux/perf_event.h>
+
+#include <asm/opcodes.h>
+#include <asm/traps.h>
+#include <asm/uaccess.h>
+
+/*
+ * Macros/defines for extracting register numbers from instruction.
+ */
+#define EXTRACT_REG_NUM(instruction, offset) \
+ (((instruction) & (0xf << (offset))) >> (offset))
+
+/*
+ * Offsets for ARM mode
+ */
+#define RD_OFFSET 16
+#define RN_OFFSET 0
+#define RM_OFFSET 8
+
+/*
+ * Offsets for Thumb mode
+ */
+#define RD_T_OFFSET 8
+#define RN_T_OFFSET 16
+#define RM_T_OFFSET 0
+
+#define TYPE_OF_DIV (1 << 21)
+
+static unsigned long sdivcounter;
+static unsigned long udivcounter;
+static pid_t previous_pid;
+
+#ifdef CONFIG_PROC_FS
+static int proc_read_status(char *page, char **start, off_t off, int count,
+ int *eof, void *data)
+{
+ char *p = page;
+ int len;
+
+ p += sprintf(p, "Emulated UDIV:\t\t%lu\n", udivcounter);
+ p += sprintf(p, "Emulated SDIV:\t\t%lu\n", sdivcounter);
+ if (previous_pid != 0)
+ p += sprintf(p, "Last process:\t\t%d\n", previous_pid);
+
+ len = (p - page) - off;
+ if (len < 0)
+ len = 0;
+
+ *eof = (len <= count) ? 1 : 0;
+ *start = page + off;
+
+ return len;
+}
+#endif
+
+static u32 emulate_udiv(u32 n, u32 base)
+{
+ udivcounter++;
+
+ return n/base;
+}
+
+static s32 emulate_sdiv(s32 n, s32 base)
+{
+ sdivcounter++;
+
+ return n/base;
+}
+
+static int idiv_handler(struct pt_regs *regs, unsigned int instr)
+{
+ long dividend, divisor, dest, res;
+
+ perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->ARM_pc);
+
+ res = arm_check_condition(instr, regs->ARM_cpsr);
+
+ switch (res) {
+ case ARM_OPCODE_CONDTEST_PASS:
+ break;
+ case ARM_OPCODE_CONDTEST_FAIL:
+ /* Condition failed - return to next instruction */
+ regs->ARM_pc += 4;
+ return 0;
+ case ARM_OPCODE_CONDTEST_UNCOND:
+ if (!thumb_mode(regs))
+ return -EFAULT;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (current->pid != previous_pid) {
+ pr_debug("\"%s\" (%ld) uses idiv instruction\n",
+ current->comm, (unsigned long)current->pid);
+ previous_pid = current->pid;
+ }
+
+ if (!thumb_mode(regs)) {
+ dividend = regs->uregs[EXTRACT_REG_NUM(instr, RN_OFFSET)];
+ divisor = regs->uregs[EXTRACT_REG_NUM(instr, RM_OFFSET)];
+ dest = EXTRACT_REG_NUM(instr, RD_OFFSET);
+ } else {
+ dividend = regs->uregs[EXTRACT_REG_NUM(instr, RN_T_OFFSET)];
+ divisor = regs->uregs[EXTRACT_REG_NUM(instr, RM_T_OFFSET)];
+ dest = EXTRACT_REG_NUM(instr, RD_T_OFFSET);
+ }
+
+/*
+ * In an ARMv7-A profile implementation that supports the SDIV and UDIV
+ * instructions, divide-by-zero always returns a zero result.
+ * In fact, integer division emulation provided by gcc lib has already handle
+ * division by zero case sending the signal to the caused process. Emulate this
+ * behavior here as well.
+ */
+ if (!divisor) {
+ siginfo_t info;
+
+ info.si_code = FPE_INTDIV;
+ info.si_signo = SIGFPE;
+ info.si_errno = 0;
+
+ arm_notify_die("Division by zero", regs, &info, 0, 0);
+
+ goto out;
+ }
+
+ if (instr & TYPE_OF_DIV)
+ res = emulate_udiv((u32)dividend, (u32)divisor);
+ else
+ res = emulate_sdiv((s32)dividend, (s32)divisor);
+
+ regs->ARM_pc += 4;
+ regs->uregs[dest] = res;
+
+out:
+ return 0;
+}
+
+static struct undef_hook idiv_hook = {
+ .instr_mask = 0x0310f010,
+ .instr_val = 0x0310f010,
+ .cpsr_mask = MODE_MASK,
+ .cpsr_val = USR_MODE,
+ .fn = idiv_handler
+};
+
+static int __init idiv_emulation_init(void)
+{
+#ifdef CONFIG_PROC_FS
+ struct proc_dir_entry *res;
+
+ res = create_proc_entry("cpu/idiv_emulation", S_IRUGO, NULL);
+
+ if (!res)
+ return -ENOMEM;
+
+ res->read_proc = proc_read_status;
+#endif /* CONFIG_PROC_FS */
+
+ pr_notice("Registering SDIV/UDIV emulation handler\n");
+
+ register_undef_hook(&idiv_hook);
+
+ return 0;
+}
+
+late_initcall(idiv_emulation_init);
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index 101b968..8e2fa94 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -651,6 +651,32 @@ config SWP_EMULATE
If unsure, say Y.
+config IDIV_EMULATE
+ bool "Emulate SDIV/UDIV instructions"
+ depends on !CPU_USE_DOMAINS && CPU_V7
+ select HAVE_PROC_CPU if PROC_FS
+ default y if SMP
+ help
+
+ The Virtualization Extensions introduce the requirement for an
+ ARMv7-A implementation to include SDIV and UDIV. Any
+ implementation of the Virtualization Extensions must include
+ the SDIV and UDIV instructions in the Thumb and ARM
+ instruction sets.
+
+ In an ARMv7-A implementation that does not include the
+ Virtualization Extensions, it is IMPLEMENTATION DEFINED whether:
+ * SDIV and UDIV are not implemented
+ * SDIV and UDIV are implemented only in the Thumb instruction set
+ * SDIV and UDIV are implemented in the Thumb and ARM
+ instruction sets.
+
+ This option allows to handle exeptions due to unimplemented
+ SDIV and UDIV instructions in ARM and Thumb modes.
+
+ If unsure, say Y.
+
+
config CPU_BIG_ENDIAN
bool "Build big-endian kernel"
depends on ARCH_SUPPORTS_BIG_ENDIAN
--
1.7.8.6
Hi all,
Here comes the lucky v7:
- Per Alan Cox's suggestion added hangup method and removed a small
leftover;
- Per Colin Cross' suggestion moved IRQ quiescing logic into
poll_get_char routine. IIUC, Alan is less unhappy about it. As a
result, clear_irq() callback dropped.
These patches can be found in the following repo (based on tty-next):
git://git.infradead.org/users/cbou/linux-nmi-kdb.git master
Old changelogs and rationale for these patches can be found here:
v1-v5, rationale: http://lkml.org/lkml/2012/9/10/2
v6: http://lkml.org/lkml/2012/9/10/2
Thanks,
--
arch/arm/Kconfig | 19 ++
arch/arm/common/vic.c | 28 ++
arch/arm/include/asm/hardware/vic.h | 2 +
arch/arm/include/asm/kgdb.h | 8 +
arch/arm/kernel/Makefile | 1 +
arch/arm/kernel/entry-armv.S | 167 +-----------
arch/arm/kernel/entry-header.S | 170 +++++++++++++
arch/arm/kernel/kgdb_fiq.c | 99 ++++++++
arch/arm/kernel/kgdb_fiq_entry.S | 87 +++++++
arch/arm/mach-versatile/Makefile | 1 +
arch/arm/mach-versatile/kgdb_fiq.c | 31 +++
drivers/tty/serial/Kconfig | 19 ++
drivers/tty/serial/Makefile | 1 +
drivers/tty/serial/amba-pl011.c | 73 +++++-
drivers/tty/serial/kgdb_nmi.c | 396 +++++++++++++++++++++++++++++
drivers/tty/serial/kgdboc.c | 6 +
drivers/tty/serial/serial_core.c | 17 ++
include/linux/kdb.h | 29 ++-
include/linux/kgdb.h | 33 +++
include/linux/serial_core.h | 1 +
kernel/debug/debug_core.c | 36 ++-
kernel/debug/kdb/kdb_main.c | 29 +++
22 files changed, 1060 insertions(+), 193 deletions(-)
Whoops. Sorry this is late.
=== Highlights ===
* Attended a connect planning meeting
* Sent out first pass of refinied jiffies patch (help kill
CLOCK_TICK_RATE for unified-zImage)
* Sent out half of the -stable backports
* Debugged and fixed a 32bit time regression in 3.6-rc, got it merged in
tip for upstream.
* Arve pinged me on an issue they were seeing with the upstream
alarmtimer code. Implemented a solution and will be sending it out for
discussion shortly.
* Discussed with Mel Gorman on his approach to low-memory notification
* Emailed Colin Cross and AntonV to get a coffee meeting scheduled.
=== Plans ===
* Make first pass at sending SIGBUS on accessing purged volatile pages
* Send out alarmtimer fix for discussion
* Send out vsyscall update patches for discussion
* Finish testing and sending -stable backports
=== Issues ===
* NA
== Deepak Saxena <dsaxena> ==
=== Highlights ===
* Got mostly caught up on all email, minus upstream mailing lists
* Had initial discussions with Jakub on project management
* OPSCOM roadmap card review
=== Plans ===
* Update roadmap cards as per OPSCOM review
* Go through all old blueprints and clean them up
* Create BPs for currently untracked work (single zImage, aarch64)
* Catch up on Linux Plumber's Conf and Kernel Summit presentations
* Write up blueprint process for project status tracking
* Get caught up on linux-arm-kernel list
=== Issues ===
=== Travel/Time Off ===
* Travelling to NYC for 1 week,Sept 22nd - 28th, will be working half time
* Copenhagen Connect
