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* fsldma: improved DMA_SLAVE supportIra Snyder2010-10-07
| | | | | | | | | | | | | | | | | Now that the generic DMAEngine API has support for scatterlist to scatterlist copying, the device_prep_slave_sg() portion of the DMA_SLAVE API is no longer necessary and has been removed. However, the device_control() portion of the DMA_SLAVE API is still useful to control device specific parameters, such as externally controlled DMA transfers and maximum burst length. A special dma_ctrl_cmd has been added to enable externally controlled DMA transfers. This is currently specific to the Freescale DMA controller, but can easily be made generic when another user is found. Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* frv: double syscall restarts, syscall restart in sigreturn()Al Viro2010-09-20
| | | | | | | | | | | We need to make sure that only the first do_signal() to be handled on the way out syscall will bother with syscall restarts; additionally, the check on the "signal has user handler" path had been wrong - compare with restart prevention in sigreturn()... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* frv: handling of restart into restart_syscall is fsckedAl Viro2010-09-20
| | | | | | | | | do_signal() should place the syscall number in gr7, not gr8 when handling ERESTART_WOULDBLOCK. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* frv: avoid infinite loop of SIGSEGV deliveryAl Viro2010-09-20
| | | | | | | | | | | Use force_sigsegv() rather than force_sig(SIGSEGV, ...) as the former resets the SEGV handler pointer which will kill the process, rather than leaving it open to an infinite loop if the SEGV handler itself caused a SEGV signal. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* frv: fix address verification holes in setup_frame/setup_rt_frameAl Viro2010-09-20
| | | | | | | | | | | | | | a) sa_handler might be maliciously set to point to kernel memory; blindly dereferencing it in FDPIC case is a Bad Idea(tm). b) I'm not sure you need that set_fs(USER_DS) there at all, but if you do, you'd better do it *before* checking the frame you've decided to use with access_ok(), lest sigaltstack() becomes a convenient roothole. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* frv: restart_block.fn needs to be reset on sigreturnAl Viro2010-09-20
| | | | | | | | | Reset restart_block.fn on executing a sigreturn such that any currently pending system call restarts will be forced to return -EINTR. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2010-09-19
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha-2.6: alpha: deal with multiple simultaneously pending signals alpha: fix a 14 years old bug in sigreturn tracing alpha: unb0rk sigsuspend() and rt_sigsuspend() alpha: belated ERESTART_RESTARTBLOCK race fix alpha: Shift perf event pending work earlier in timer interrupt alpha: wire up fanotify and prlimit64 syscalls alpha: kill big kernel lock alpha: fix build breakage in asm/cacheflush.h alpha: remove unnecessary cast from void* in assignment. alpha: Use static const char * const where possible
| * alpha: deal with multiple simultaneously pending signalsAl Viro2010-09-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Unlike the other targets, alpha sets _one_ sigframe and buggers off until the next syscall/interrupt, even if more signals are pending. It leads to quite a few unpleasant inconsistencies, starting with SIGSEGV potentially arriving not where it should and including e.g. mess with sigsuspend(); consider two pending signals blocked until sigsuspend() unblocks them. We pick the first one; then, if we are hit by interrupt while in the handler, we process the second one as well. If we are not, and if no syscalls had been made, we get out of the first handler and leave the second signal pending; normally sigreturn() would've picked it anyway, but here it starts with restoring the original mask and voila - the second signal is blocked again. On everything else we get both delivered consistently. It's actually easy to fix; the only thing to watch out for is prevention of double syscall restart. Fortunately, the idea I've nicked from arm fix by rmk works just fine... Testcase demonstrating the behaviour in question; on alpha we get one or both flags set (usually one), on everything else both are always set. #include <signal.h> #include <stdio.h> int had1, had2; void f1(int sig) { had1 = 1; } void f2(int sig) { had2 = 1; } main() { sigset_t set1, set2; sigemptyset(&set1); sigemptyset(&set2); sigaddset(&set2, 1); sigaddset(&set2, 2); signal(1, f1); signal(2, f2); sigprocmask(SIG_SETMASK, &set2, NULL); raise(1); raise(2); sigsuspend(&set1); printf("had1:%d had2:%d\n", had1, had2); } Tested-by: Michael Cree <mcree@orcon.net.nz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Matt Turner <mattst88@gmail.com>
| * alpha: fix a 14 years old bug in sigreturn tracingAl Viro2010-09-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The way sigreturn() is implemented on alpha breaks PTRACE_SYSCALL, all way back to 1.3.95 when alpha has grown PTRACE_SYSCALL support. What happens is direct return to ret_from_syscall, in order to bypass mangling of a3 (error indicator) and prevent other mutilations of registers (e.g. by syscall restart). That's fine, but... the entire TIF_SYSCALL_TRACE codepath is kept separate on alpha and post-syscall stopping/notifying the tracer is after the syscall. And the normal path we are forcibly switching to doesn't have it. So we end up with *one* stop in traced sigreturn() vs. two in other syscalls. And yes, strace is visibly broken by that; try to strace the following #include <signal.h> #include <stdio.h> void f(int sig) {} main() { signal(SIGHUP, f); raise(SIGHUP); write(1, "eeeek\n", 6); } and watch the show. The close(1) = 405 in the end of strace output is coming from return value of write() (6 == __NR_close on alpha) and syscall number of exit_group() (__NR_exit_group == 405 there). The fix is fairly simple - the only thing we end up missing is the call of syscall_trace() and we can tell whether we'd been called from the SYSCALL_TRACE path by checking ra value. Since we are setting the switch_stack up (that's what sys_sigreturn() does), we have the right environment for calling syscall_trace() - just before we call undo_switch_stack() and return. Since undo_switch_stack() will overwrite s0 anyway, we can use it to store the result of "has it been called from SYSCALL_TRACE path?" check. The same thing applies in rt_sigreturn(). Tested-by: Michael Cree <mcree@orcon.net.nz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Matt Turner <mattst88@gmail.com>
| * alpha: unb0rk sigsuspend() and rt_sigsuspend()Al Viro2010-09-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Old code used to set regs->r0 and regs->r19 to force the right return value. Leaving that after switch to ERESTARTNOHAND was a Bad Idea(tm), since now that screws the restart - if we hit the case when get_signal_to_deliver() returns 0, we will step back to syscall insn, with v0 set to EINTR and a3 to 1. The latter won't matter, since EINTR is 4, aka __NR_write. Testcase: #include <signal.h> #define _GNU_SOURCE #include <unistd.h> #include <sys/syscall.h> main() { sigset_t mask; sigemptyset(&mask); sigaddset(&mask, SIGCONT); sigprocmask(SIG_SETMASK, &mask, NULL); kill(0, SIGCONT); syscall(__NR_sigsuspend, 1, "b0rken\n", 7); } results on alpha in immediate message to stdout... Fix is obvious; moreover, since we don't need regs anymore, we can switch to normal prototypes for these guys and lose the wrappers. Even better, rt_sigsuspend() is identical to generic version in kernel/signal.c now. Tested-by: Michael Cree <mcree@orcon.net.nz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Matt Turner <mattst88@gmail.com>
| * alpha: belated ERESTART_RESTARTBLOCK race fixAl Viro2010-09-18
| | | | | | | | | | | | | | | | | | same thing as had been done on other targets back in 2003 - move setting ->restart_block.fn into {rt_,}sigreturn(). Tested-by: Michael Cree <mcree@orcon.net.nz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Matt Turner <mattst88@gmail.com>
| * alpha: Shift perf event pending work earlier in timer interruptMichael Cree2010-09-18
| | | | | | | | | | | | | | | | | | | | | | Pending work from the performance event subsystem is executed in the timer interrupt. This patch shifts the call to perf_event_do_pending() before the call to update_process_times() as the latter may call back into the perf event subsystem and it is prudent to have the pending work executed first. Signed-off-by: Michael Cree <mcree@orcon.net.nz> Signed-off-by: Matt Turner <mattst88@gmail.com>
| * alpha: wire up fanotify and prlimit64 syscallsMikael Pettersson2010-09-18
| | | | | | | | | | | | | | | | | | | | | | The 2.6.36-rc kernel added three new system calls: fanotify_init, fanotify_mark, and prlimit64. This patch wires them up on Alpha. Built and booted on an XP900. Untested beyond that. Signed-off-by: Mikael Pettersson <mikpe@it.uu.se> Signed-off-by: Matt Turner <mattst88@gmail.com>
| * alpha: kill big kernel lockArnd Bergmann2010-09-18
| | | | | | | | | | | | | | | | | | | | | | | | All uses of the BKL on alpha are totally bogus, nothing is really protected by this. Remove the remaining users so we don't have to mark alpha as 'depends on BKL'. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: linux-alpha@vger.kernel.org Signed-off-by: Matt Turner <mattst88@gmail.com>
| * alpha: fix build breakage in asm/cacheflush.hTejun Heo2010-09-18
| | | | | | | | | | | | | | | | | | | | | | | | Alpha SMP flush_icache_user_range() is implemented as an inline function inside include/asm/cacheflush.h. It dereferences @current but doesn't include linux/sched.h and thus causes build failure if linux/sched.h wasn't included previously. Fix it by including the needed header file explicitly. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Matt Turner <mattst88@gmail.com>
| * alpha: remove unnecessary cast from void* in assignment.matt mooney2010-09-18
| | | | | | | | | | | | Acked-by: Jan-Benedict Glaw <jbglaw@lug-owl.de> Signed-off-by: matt mooney <mfm@muteddisk.com> Signed-off-by: Matt Turner <mattst88@gmail.com>
| * alpha: Use static const char * const where possibleJoe Perches2010-09-18
| | | | | | | | | | | | Acked-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Matt Turner <mattst88@gmail.com>
* | Merge branch 's5p-fixes-for-linus' of ↵Linus Torvalds2010-09-19
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung * 's5p-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung: ARM: S3C64XX: Add IORESOURCE_IRQ_HIGHLEVEL flag to dm9000 on mach-real6410 ARM: S3C64XX: Fix coding style errors on mach-real6410 ARM: S3C64XX: Prototype SPI devices ARM: S3C64XX: Fix dev-spi build ARM: SAMSUNG: Fix on s5p_gpio_[get,set]_drvstr ARM: SAMSUNG: Fix on drive strength value ARM: S5PV210: Add FIMC clocks ARM: S5PV210: Reduce the iodesc length of systimer ARM: S5PV210: Update I2C-1 Clock Register Property. ARM: S5P: Decrease IO Registers memory region size on FIMC ARM: S5P: Fix DMA coherent mask for FIMC
| * ARM: S3C64XX: Add IORESOURCE_IRQ_HIGHLEVEL flag to dm9000 on mach-real6410Darius Augulis2010-09-17
| | | | | | | | | | | | | | | | | | Add IORESOURCE_IRQ_HIGHLEVEL irq flag to dm9000 driver platform data in board mach-real6410. Signed-off-by: Darius Augulis <augulis.darius@gmail.com> [kgene.kim@samsung.com: minor title fix] Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
| * ARM: S3C64XX: Fix coding style errors on mach-real6410Darius Augulis2010-09-17
| | | | | | | | | | | | | | | | Fix errors reported by checkpatch.pl script Signed-off-by: Darius Augulis <augulis.darius@gmail.com> [kgene.kim@samsung.com: minor title fix] Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
| * ARM: S3C64XX: Prototype SPI devicesMark Brown2010-09-17
| | | | | | | | | | | | | | Avoids build warnings due to the undeclared non-statics. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
| * ARM: S3C64XX: Fix dev-spi buildMark Brown2010-09-14
| | | | | | | | | | | | | | | | The irqs.h usage here got missed in the Samsung platform reorganisation. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Jassi Brar <jassi.brar@samsung.com> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
| * ARM: SAMSUNG: Fix on s5p_gpio_[get,set]_drvstrKukjin Kim2010-09-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes bug on gpio drive strength helper function. The offset should be like follwoing. - off = chip->chip.base - pin; + off = pin - chip->chip.base; In the s5p_gpio_get_drvstr(), the second line is unnecessary, because overwrite drvstr. drvstr = __raw_readl(reg); - drvstr = 0xffff & (0x3 << shift); And need 2bit masking before return the drvstr value. drvstr = drvstr >> shift; + drvstr &= 0x3; In the s5p_gpio_set_drvstr(), need relevant bit clear. tmp = __raw_readl(reg); + tmp &= ~(0x3 << shift); tmp |= drvstr << shift; Reported-by: Jaecheol Lee <jc.lee@samsung.com> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
| * ARM: SAMSUNG: Fix on drive strength valueKukjin Kim2010-09-14
| | | | | | | | | | | | | | | | | | | | This patch fixes on defined drive strength value for GPIO. According to data sheet, if we want drive strength 1x, the value should be 00(b), if 2x should be 10(b), if 3x should be 01(b), and if 4x should be 11(b). Also fixes comment(from S5C to S5P). Reported-by: Janghyuck Kim <janghyuck.kim@samsung.com> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
| * ARM: S5PV210: Add FIMC clocksMarek Szyprowski2010-09-14
| | | | | | | | | | | | | | | | | | | | These clocks enables FIMC driver to operate on machines, which bootloader power gated FIMC devices to save power on boot. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> [kgene.kim@samsung.com: minor title fix] Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
| * ARM: S5PV210: Reduce the iodesc length of systimerKyungmin Park2010-09-14
| | | | | | | | | | | | | | It's enough to use 4KiB. Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
| * ARM: S5PV210: Update I2C-1 Clock Register Property.MyungJoo Ham2010-09-14
| | | | | | | | | | | | | | | | | | | | CLK_GATE_IP3[8] is RESERVED. The port "I2C_HDMI_DDC" of CLK_GATE_IP3[10] is used as another I2C port. Therefore, defined the unused I2C-1 as another I2C there was left undefined but used. Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
| * ARM: S5P: Decrease IO Registers memory region size on FIMCSylwester Nawrocki2010-09-14
| | | | | | | | | | | | | | | | | | | | | | IO registers region size of all FIMC versions is less than 1kB so there is no need to reserve 1M. Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> [kgene.kim@samsung.com: minor title fix] Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
| * ARM: S5P: Fix DMA coherent mask for FIMCMarek Szyprowski2010-09-14
| | | | | | | | | | | | | | | | | | | | FIMC driver uses DMA_coherent allocator, which requires proper dma mask to be set. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> [kgene.kim@samsung.com: minor title fix] Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
* | arm: fix really nasty sigreturn bugAl Viro2010-09-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a signal hits us outside of a syscall and another gets delivered when we are in sigreturn (e.g. because it had been in sa_mask for the first one and got sent to us while we'd been in the first handler), we have a chance of returning from the second handler to location one insn prior to where we ought to return. If r0 happens to contain -513 (-ERESTARTNOINTR), sigreturn will get confused into doing restart syscall song and dance. Incredible joy to debug, since it manifests as random, infrequent and very hard to reproduce double execution of instructions in userland code... The fix is simple - mark it "don't bother with restarts" in wrapper, i.e. set r8 to 0 in sys_sigreturn and sys_rt_sigreturn wrappers, suppressing the syscall restart handling on return from these guys. They can't legitimately return a restart-worthy error anyway. Testcase: #include <unistd.h> #include <signal.h> #include <stdlib.h> #include <sys/time.h> #include <errno.h> void f(int n) { __asm__ __volatile__( "ldr r0, [%0]\n" "b 1f\n" "b 2f\n" "1:b .\n" "2:\n" : : "r"(&n)); } void handler1(int sig) { } void handler2(int sig) { raise(1); } void handler3(int sig) { exit(0); } main() { struct sigaction s = {.sa_handler = handler2}; struct itimerval t1 = { .it_value = {1} }; struct itimerval t2 = { .it_value = {2} }; signal(1, handler1); sigemptyset(&s.sa_mask); sigaddset(&s.sa_mask, 1); sigaction(SIGALRM, &s, NULL); signal(SIGVTALRM, handler3); setitimer(ITIMER_REAL, &t1, NULL); setitimer(ITIMER_VIRTUAL, &t2, NULL); f(-513); /* -ERESTARTNOINTR */ write(1, "buggered\n", 9); return 1; } Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'x86-fixes-for-linus' of ↵Linus Torvalds2010-09-16
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: hpet: Work around hardware stupidity x86, build: Disable -fPIE when compiling with CONFIG_CC_STACKPROTECTOR=y x86, cpufeature: Suppress compiler warning with gcc 3.x x86, UV: Fix initialization of max_pnode
| * | x86: hpet: Work around hardware stupidityThomas Gleixner2010-09-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This more or less reverts commits 08be979 (x86: Force HPET readback_cmp for all ATI chipsets) and 30a564be (x86, hpet: Restrict read back to affected ATI chipsets) to the status of commit 8da854c (x86, hpet: Erratum workaround for read after write of HPET comparator). The delta to commit 8da854c is mostly comments and the change from WARN_ONCE to printk_once as we know the call path of this function already. This needs really in depth explanation: First of all the HPET design is a complete failure. Having a counter compare register which generates an interrupt on matching values forces the software to do at least one superfluous readback of the counter register. While it is nice in theory to program "absolute" time events it is practically useless because the timer runs at some absurd frequency which can never be matched to real world units. So we are forced to calculate a relative delta and this forces a readout of the actual counter value, adding the delta and programming the compare register. When the delta is small enough we run into the danger that we program a compare value which is already in the past. Due to the compare for equal nature of HPET we need to read back the counter value after writing the compare rehgister (btw. this is necessary for absolute timeouts as well) to make sure that we did not miss the timer event. We try to work around that by setting the minimum delta to a value which is larger than the theoretical time which elapses between the counter readout and the compare register write, but that's only true in theory. A NMI or SMI which hits between the readout and the write can easily push us beyond that limit. This would result in waiting for the next HPET timer interrupt until the 32bit wraparound of the counter happens which takes about 306 seconds. So we designed the next event function to look like: match = read_cnt() + delta; write_compare_ref(match); return read_cnt() < match ? 0 : -ETIME; At some point we got into trouble with certain ATI chipsets. Even the above "safe" procedure failed. The reason was that the write to the compare register was delayed probably for performance reasons. The theory was that they wanted to avoid the synchronization of the write with the HPET clock, which is understandable. So the write does not hit the compare register directly instead it goes to some intermediate register which is copied to the real compare register in sync with the HPET clock. That opens another window for hitting the dreaded "wait for a wraparound" problem. To work around that "optimization" we added a read back of the compare register which either enforced the update of the just written value or just delayed the readout of the counter enough to avoid the issue. We unfortunately never got any affirmative info from ATI/AMD about this. One thing is sure, that we nuked the performance "optimization" that way completely and I'm pretty sure that the result is worse than before some HW folks came up with those. Just for paranoia reasons I added a check whether the read back compare register value was the same as the value we wrote right before. That paranoia check triggered a couple of years after it was added on an Intel ICH9 chipset. Venki added a workaround (commit 8da854c) which was reading the compare register twice when the first check failed. We considered this to be a penalty in general and restricted the readback (thus the wasted CPU cycles) to the known to be affected ATI chipsets. This turned out to be a utterly wrong decision. 2.6.35 testers experienced massive problems and finally one of them bisected it down to commit 30a564be which spured some further investigation. Finally we got confirmation that the write to the compare register can be delayed by up to two HPET clock cycles which explains the problems nicely. All we can do about this is to go back to Venki's initial workaround in a slightly modified version. Just for the record I need to say, that all of this could have been avoided if hardware designers and of course the HPET committee would have thought about the consequences for a split second. It's out of my comprehension why designing a working timer is so hard. There are two ways to achieve it: 1) Use a counter wrap around aware compare_reg <= counter_reg implementation instead of the easy compare_reg == counter_reg Downsides: - It needs more silicon. - It needs a readout of the counter to apply a relative timeout. This is necessary as the counter does not run in any useful (and adjustable) frequency and there is no guarantee that the counter which is used for timer events is the same which is used for reading the actual time (and therefor for calculating the delta) Upsides: - None 2) Use a simple down counter for relative timer events Downsides: - Absolute timeouts are not possible, which is not a problem at all in the context of an OS and the expected max. latencies/jitter (also see Downsides of #1) Upsides: - It needs less or equal silicon. - It works ALWAYS - It is way faster than a compare register based solution (One write versus one write plus at least one and up to four reads) I would not be so grumpy about all of this, if I would not have been ignored for many years when pointing out these flaws to various hardware folks. I really hate timers (at least those which seem to be designed by janitors). Though finally we got a reasonable explanation plus a solution and I want to thank all the folks involved in chasing it down and providing valuable input to this. Bisected-by: Nix <nix@esperi.org.uk> Reported-by: Artur Skawina <art.08.09@gmail.com> Reported-by: Damien Wyart <damien.wyart@free.fr> Reported-by: John Drescher <drescherjm@gmail.com> Cc: Venkatesh Pallipadi <venki@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Borislav Petkov <borislav.petkov@amd.com> Cc: stable@kernel.org Acked-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | x86, build: Disable -fPIE when compiling with CONFIG_CC_STACKPROTECTOR=ybasile@opensource.dyc.edu2010-09-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The arch/x86/Makefile uses scripts/gcc-x86_$(BITS)-has-stack-protector.sh to check if cc1 supports -fstack-protector. When -fPIE is passed to cc1, these scripts fail causing stack protection to be disabled even when it is available. This fix is similar to commit c47efe5548abbf53c2f66e06dcb46183b11d6b22 Reported-by: Kai Dietrich <mail@cleeus.de> Signed-off-by: Magnus Granberg <zorry@gentoo.org> LKML-Reference: <20100913101319.748A1148E216@opensource.dyc.edu> Signed-off-by: Anthony G. Basile <basile@opensource.dyc.edu> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * | x86, cpufeature: Suppress compiler warning with gcc 3.xTetsuo Handa2010-09-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Gcc 3.x generates a warning arch/x86/include/asm/cpufeature.h: In function `__static_cpu_has': arch/x86/include/asm/cpufeature.h:326: warning: asm operand 1 probably doesn't match constraints on each file. But static_cpu_has() for gcc 3.x does not need __static_cpu_has(). Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> LKML-Reference: <201008300127.o7U1RC6Z044051@www262.sakura.ne.jp> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * | x86, UV: Fix initialization of max_pnodeJack Steiner2010-09-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix calculation of "max_pnode" for systems where the the highest blade has neither cpus or memory. (And, yes, although rare this does occur). Signed-off-by: Jack Steiner <steiner@sgi.com> LKML-Reference: <20100910150808.GA19802@sgi.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'release' of ↵Linus Torvalds2010-09-16
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6 * 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6: [IA64] Optimize ticket spinlocks in fsys_rt_sigprocmask
| * | | [IA64] Optimize ticket spinlocks in fsys_rt_sigprocmaskPetr Tesarik2010-09-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Tony's fix (f574c843191728d9407b766a027f779dcd27b272) has a small bug, it incorrectly uses "r3" as a scratch register in the first of the two unlock paths ... it is also inefficient. Optimize the fast path again. Signed-off-by: Petr Tesarik <ptesarik@suse.cz> Signed-off-by: Tony Luck <tony.luck@intel.com>
* | | | Merge branch 'stable' of ↵Linus Torvalds2010-09-16
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile * 'stable' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: arch/tile: fix formatting bug in register dumps arch/tile: fix memcpy_fromio()/memcpy_toio() signatures arch/tile: Save and restore extra user state for tilegx arch/tile: Change struct sigcontext to be more useful arch/tile: finish const-ifying sys_execve()
| * | | | arch/tile: fix formatting bug in register dumpsChris Metcalf2010-09-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This cut-and-paste bug was caused by rewriting the register dump code to use only a single printk per line of output. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
| * | | | arch/tile: fix memcpy_fromio()/memcpy_toio() signaturesChris Metcalf2010-09-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This tripped up a driver (not yet committed to git). Fix it now. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
| * | | | arch/tile: Save and restore extra user state for tilegxChris Metcalf2010-09-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | During context switch, save and restore a couple of additional bits of tilegx user state that can be persistently modified by userspace. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
| * | | | arch/tile: Change struct sigcontext to be more usefulChris Metcalf2010-09-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rather than just using pt_regs, it now contains the actual saved state explicitly, similar to pt_regs. By doing it this way, we provide a cleaner API for userspace (or equivalently, we avoid the need for libc to provide its own definition of sigcontext). While we're at it, move PT_FLAGS_xxx to where they are not visible from userspace. And always pass siginfo and mcontext to signal handlers, even if they claim they don't need it, since sometimes they actually try to use it anyway in practice. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
| * | | | arch/tile: finish const-ifying sys_execve()Chris Metcalf2010-09-15
| | |_|/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | The sys_execve() implementation was properly const-ified but not the declaration, the syscall wrappers, or the compat version. This change completes the constification process. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
* | | | Merge ssh://master.kernel.org/home/hpa/tree/secLinus Torvalds2010-09-14
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * ssh://master.kernel.org/home/hpa/tree/sec: x86-64, compat: Retruncate rax after ia32 syscall entry tracing x86-64, compat: Test %rax for the syscall number, not %eax compat: Make compat_alloc_user_space() incorporate the access_ok()
| * | | | x86-64, compat: Retruncate rax after ia32 syscall entry tracingRoland McGrath2010-09-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In commit d4d6715, we reopened an old hole for a 64-bit ptracer touching a 32-bit tracee in system call entry. A %rax value set via ptrace at the entry tracing stop gets used whole as a 32-bit syscall number, while we only check the low 32 bits for validity. Fix it by truncating %rax back to 32 bits after syscall_trace_enter, in addition to testing the full 64 bits as has already been added. Reported-by: Ben Hawkes <hawkes@sota.gen.nz> Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * | | | x86-64, compat: Test %rax for the syscall number, not %eaxH. Peter Anvin2010-09-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On 64 bits, we always, by necessity, jump through the system call table via %rax. For 32-bit system calls, in theory the system call number is stored in %eax, and the code was testing %eax for a valid system call number. At one point we loaded the stored value back from the stack to enforce zero-extension, but that was removed in checkin d4d67150165df8bf1cc05e532f6efca96f907cab. An actual 32-bit process will not be able to introduce a non-zero-extended number, but it can happen via ptrace. Instead of re-introducing the zero-extension, test what we are actually going to use, i.e. %rax. This only adds a handful of REX prefixes to the code. Reported-by: Ben Hawkes <hawkes@sota.gen.nz> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: <stable@kernel.org> Cc: Roland McGrath <roland@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org>
| * | | | compat: Make compat_alloc_user_space() incorporate the access_ok()H. Peter Anvin2010-09-14
| | |/ / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | compat_alloc_user_space() expects the caller to independently call access_ok() to verify the returned area. A missing call could introduce problems on some architectures. This patch incorporates the access_ok() check into compat_alloc_user_space() and also adds a sanity check on the length. The existing compat_alloc_user_space() implementations are renamed arch_compat_alloc_user_space() and are used as part of the implementation of the new global function. This patch assumes NULL will cause __get_user()/__put_user() to either fail or access userspace on all architectures. This should be followed by checking the return value of compat_access_user_space() for NULL in the callers, at which time the access_ok() in the callers can also be removed. Reported-by: Ben Hawkes <hawkes@sota.gen.nz> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Chris Metcalf <cmetcalf@tilera.com> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Tony Luck <tony.luck@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: James Bottomley <jejb@parisc-linux.org> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: <stable@kernel.org>
* / | | MN10300: Fix up the IRQ names for the on-chip serial portsDavid Howells2010-09-14
|/ / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix up the IRQ names for the MN10300 on-chip serial ports in the driver as request_interrupt() no longer allows names containing slashes, giving a warning like the following if one is encountered: ------------[ cut here ]------------ WARNING: at fs/proc/generic.c:323 __xlate_proc_name+0x62/0x7c() name 'ttySM0/Rx' Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | Merge branch 'for-linus' of ↵Linus Torvalds2010-09-13
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k: m68k,m68knommu: Wire up fanotify_init, fanotify_mark, and prlimit64
| * | | m68k,m68knommu: Wire up fanotify_init, fanotify_mark, and prlimit64Geert Uytterhoeven2010-09-13
| |/ / | | | | | | | | | | | | Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Greg Ungerer <gerg@uclinux.org>
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-16 06:48:40 -0500