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* powerpc: Don't corrupt transactional state when using FP/VMX in kernelPaul Mackerras2014-01-151-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, when we have a process using the transactional memory facilities on POWER8 (that is, the processor is in transactional or suspended state), and the process enters the kernel and the kernel then uses the floating-point or vector (VMX/Altivec) facility, we end up corrupting the user-visible FP/VMX/VSX state. This happens, for example, if a page fault causes a copy-on-write operation, because the copy_page function will use VMX to do the copy on POWER8. The test program below demonstrates the bug. The bug happens because when FP/VMX state for a transactional process is stored in the thread_struct, we store the checkpointed state in .fp_state/.vr_state and the transactional (current) state in .transact_fp/.transact_vr. However, when the kernel wants to use FP/VMX, it calls enable_kernel_fp() or enable_kernel_altivec(), which saves the current state in .fp_state/.vr_state. Furthermore, when we return to the user process we return with FP/VMX/VSX disabled. The next time the process uses FP/VMX/VSX, we don't know which set of state (the current register values, .fp_state/.vr_state, or .transact_fp/.transact_vr) we should be using, since we have no way to tell if we are still in the same transaction, and if not, whether the previous transaction succeeded or failed. Thus it is necessary to strictly adhere to the rule that if FP has been enabled at any point in a transaction, we must keep FP enabled for the user process with the current transactional state in the FP registers, until we detect that it is no longer in a transaction. Similarly for VMX; once enabled it must stay enabled until the process is no longer transactional. In order to keep this rule, we add a new thread_info flag which we test when returning from the kernel to userspace, called TIF_RESTORE_TM. This flag indicates that there is FP/VMX/VSX state to be restored before entering userspace, and when it is set the .tm_orig_msr field in the thread_struct indicates what state needs to be restored. The restoration is done by restore_tm_state(). The TIF_RESTORE_TM bit is set by new giveup_fpu/altivec_maybe_transactional helpers, which are called from enable_kernel_fp/altivec, giveup_vsx, and flush_fp/altivec_to_thread instead of giveup_fpu/altivec. The other thing to be done is to get the transactional FP/VMX/VSX state from .fp_state/.vr_state when doing reclaim, if that state has been saved there by giveup_fpu/altivec_maybe_transactional. Having done this, we set the FP/VMX bit in the thread's MSR after reclaim to indicate that that part of the state is now valid (having been reclaimed from the processor's checkpointed state). Finally, in the signal handling code, we move the clearing of the transactional state bits in the thread's MSR a bit earlier, before calling flush_fp_to_thread(), so that we don't unnecessarily set the TIF_RESTORE_TM bit. This is the test program: /* Michael Neuling 4/12/2013 * * See if the altivec state is leaked out of an aborted transaction due to * kernel vmx copy loops. * * gcc -m64 htm_vmxcopy.c -o htm_vmxcopy * */ /* We don't use all of these, but for reference: */ int main(int argc, char *argv[]) { long double vecin = 1.3; long double vecout; unsigned long pgsize = getpagesize(); int i; int fd; int size = pgsize*16; char tmpfile[] = "/tmp/page_faultXXXXXX"; char buf[pgsize]; char *a; uint64_t aborted = 0; fd = mkstemp(tmpfile); assert(fd >= 0); memset(buf, 0, pgsize); for (i = 0; i < size; i += pgsize) assert(write(fd, buf, pgsize) == pgsize); unlink(tmpfile); a = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); assert(a != MAP_FAILED); asm __volatile__( "lxvd2x 40,0,%[vecinptr] ; " // set 40 to initial value TBEGIN "beq 3f ;" TSUSPEND "xxlxor 40,40,40 ; " // set 40 to 0 "std 5, 0(%[map]) ;" // cause kernel vmx copy page TABORT TRESUME TEND "li %[res], 0 ;" "b 5f ;" "3: ;" // Abort handler "li %[res], 1 ;" "5: ;" "stxvd2x 40,0,%[vecoutptr] ; " : [res]"=r"(aborted) : [vecinptr]"r"(&vecin), [vecoutptr]"r"(&vecout), [map]"r"(a) : "memory", "r0", "r3", "r4", "r5", "r6", "r7"); if (aborted && (vecin != vecout)){ printf("FAILED: vector state leaked on abort %f != %f\n", (double)vecin, (double)vecout); exit(1); } munmap(a, size); close(fd); printf("PASSED!\n"); return 0; } Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc: Reclaim two unused thread_info flag bitsPaul Mackerras2014-01-151-4/+0
| | | | | | | | | | TIF_PERFMON_WORK and TIF_PERFMON_CTXSW are completely unused. They appear to be related to the old perfmon2 code, which has been superseded by the perf_event infrastructure. This removes their definitions so that the bits can be used for other purposes. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* Merge branch 'next' of ↵Linus Torvalds2013-11-201-0/+9
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc Pull powerpc LE updates from Ben Herrenschmidt: "With my previous pull request I mentioned some remaining Little Endian patches, notably support for our new ABI, which I was sitting on making sure it was all finalized. The toolchain folks confirmed it now, the new ABI is stable and merged with gcc, so we are all good. Oh and we actually missed the actual Kconfig switch for LE so here it is, along with a couple more bug fixes. I have more fixes but not related to LE so I'll send them as a separate pull request tomorrow, let's get this one out of the way. Note that this supports running user space binaries using the new ABI, but the kernel itself still needs to be built with the old one. We'll bring fixes for that after -rc1. Here's Anton log that goes with this series: This patch series adds support for the new ABI, LPAR support for H_SET_MODE and finally adds a kconfig option and defconfig. ABIv2 support was recently committed to binutils and gcc, and should be merged into glibc soon. There are a number of very nice improvements including the removal of function descriptors. Rusty's kernel patches allow binaries of either ABI to work, easing the transition" * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: powerpc: Wrong DWARF CFI in the kernel vdso for little-endian / ELFv2 powerpc: Add pseries_le_defconfig powerpc: Add CONFIG_CPU_LITTLE_ENDIAN kernel config option. powerpc: Don't use ELFv2 ABI to build the kernel powerpc: ELF2 binaries signal handling powerpc: ELF2 binaries launched directly. powerpc: Set eflags correctly for ELF ABIv2 core dumps. powerpc: Add TIF_ELF2ABI flag. pseries: Add H_SET_MODE to change exception endianness powerpc/pseries: Fix endian issues in pseries EEH code
| * powerpc: Add TIF_ELF2ABI flag.Rusty Russell2013-11-211-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Little endian ppc64 is getting an exciting new ABI. This is reflected by the bottom two bits of e_flags in the ELF header: 0 == legacy binaries (v1 ABI) 1 == binaries using the old ABI (compiled with a new toolchain) 2 == binaries using the new ABI. We store this in a thread flag, because we need to set it in core dumps and for signal delivery. Our chief concern is that it doesn't use function descriptors. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* | preempt: Make PREEMPT_ACTIVE genericThomas Gleixner2013-11-131-2/+0
|/ | | | | | | | No point in having this bit defined by architecture. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20130917183629.090698799@linutronix.de
* powerpc: Syscall hooks for context tracking subsystemLi Zhong2013-05-141-2/+5
| | | | | | | | | | | | | | | | This is the syscall slow path hooks for context tracking subsystem, corresponding to [PATCH] x86: Syscall hooks for userspace RCU extended QS commit bf5a3c13b939813d28ce26c01425054c740d6731 TIF_MEMDIE is moved to the second 16-bits (with value 17), as it seems there is no asm code using it. TIF_NOHZ is added to _TIF_SYCALL_T_OR_A, so it is better for it to be in the same 16 bits with others in the group, so in the asm code, andi. with this group could work. Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* arch: Consolidate tsk_is_polling()Thomas Gleixner2013-04-081-2/+0
| | | | | | | | | | | | | | | Move it to a common place. Preparatory patch for implementing set/clear for the idle need_resched poll implementation. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130321215233.446034505@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Merge branch 'for-linus' of ↵Linus Torvalds2012-10-121-0/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal Pull pile 2 of execve and kernel_thread unification work from Al Viro: "Stuff in there: kernel_thread/kernel_execve/sys_execve conversions for several more architectures plus assorted signal fixes and cleanups. There'll be more (in particular, real fixes for the alpha do_notify_resume() irq mess)..." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (43 commits) alpha: don't open-code trace_report_syscall_{enter,exit} Uninclude linux/freezer.h m32r: trim masks avr32: trim masks tile: don't bother with SIGTRAP in setup_frame microblaze: don't bother with SIGTRAP in setup_rt_frame() mn10300: don't bother with SIGTRAP in setup_frame() frv: no need to raise SIGTRAP in setup_frame() x86: get rid of duplicate code in case of CONFIG_VM86 unicore32: remove pointless test h8300: trim _TIF_WORK_MASK parisc: decide whether to go to slow path (tracesys) based on thread flags parisc: don't bother looping in do_signal() parisc: fix double restarts bury the rest of TIF_IRET sanitize tsk_is_polling() bury _TIF_RESTORE_SIGMASK unicore32: unobfuscate _TIF_WORK_MASK mips: NOTIFY_RESUME is not needed in TIF masks mips: merge the identical "return from syscall" per-ABI code ... Conflicts: arch/arm/include/asm/thread_info.h
| * sanitize tsk_is_polling()Al Viro2012-10-011-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | Make default just return 0. The current default (checking TIF_POLLING_NRFLAG) is taken to architectures that need it; ones that don't do polling in their idle threads don't need to defined TIF_POLLING_NRFLAG at all. ia64 defined both TS_POLLING (used by its tsk_is_polling()) and TIF_POLLING_NRFLAG (not used at all). Killed the latter... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | powerpc/kprobe: Introduce a new thread flagTiejun Chen2012-09-181-0/+3
| | | | | | | | | | | | | | | | We need to add a new thread flag, TIF_EMULATE_STACK_STORE, for emulating stack store operation while exiting exception. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* | powerpc: Uprobes port to powerpcAnanth N Mavinakayanahalli2012-09-051-1/+3
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is the port of uprobes to powerpc. Usage is similar to x86. [root@xxxx ~]# ./bin/perf probe -x /lib64/libc.so.6 malloc Added new event: probe_libc:malloc (on 0xb4860) You can now use it in all perf tools, such as: perf record -e probe_libc:malloc -aR sleep 1 [root@xxxx ~]# ./bin/perf record -e probe_libc:malloc -aR sleep 20 [ perf record: Woken up 22 times to write data ] [ perf record: Captured and wrote 5.843 MB perf.data (~255302 samples) ] [root@xxxx ~]# ./bin/perf report --stdio ... 69.05% tar libc-2.12.so [.] malloc 28.57% rm libc-2.12.so [.] malloc 1.32% avahi-daemon libc-2.12.so [.] malloc 0.58% bash libc-2.12.so [.] malloc 0.28% sshd libc-2.12.so [.] malloc 0.08% irqbalance libc-2.12.so [.] malloc 0.05% bzip2 libc-2.12.so [.] malloc 0.04% sleep libc-2.12.so [.] malloc 0.03% multipathd libc-2.12.so [.] malloc 0.01% sendmail libc-2.12.so [.] malloc 0.01% automount libc-2.12.so [.] malloc The trap_nr addition patch is a prereq. Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc: Use CURRENT_THREAD_INFO instead of open coded assemblyStuart Yoder2012-07-111-0/+6
| | | | | Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* set_restore_sigmask() is never called without SIGPENDING (and never should be)Al Viro2012-06-011-1/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* new helpers: {clear,test,test_and_clear}_restore_sigmask()Al Viro2012-06-011-0/+16
| | | | | | helpers parallel to set_restore_sigmask(), used in the next commits Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'next' of ↵Linus Torvalds2012-05-231-1/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc Pull powerpc updates from Benjamin Herrenschmidt: "Here are the powerpc goodies for 3.5. Main highlights are: - Support for the NX crypto engine in Power7+ - A bunch of Anton goodness, including some micro optimization of our syscall entry on Power7 - I converted a pile of our thermal control drivers to the new i2c APIs (essentially turning the old therm_pm72 into a proper set of windfarm drivers). That's one more step toward removing the deprecated i2c APIs, there's still a few drivers to fix, but we are getting close - kexec/kdump support for 47x embedded cores The big missing thing here is no updates from Freescale. Not sure what's up here, but with Kumar not working for them anymore things are a bit in a state of flux in that area." * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (71 commits) powerpc: Fix irq distribution Revert "powerpc/hw-breakpoint: Use generic hw-breakpoint interfaces for new PPC ptrace flags" powerpc: Fixing a cputhread code documentation powerpc/crypto: Enable the PFO-based encryption device powerpc/crypto: Build files for the nx device driver powerpc/crypto: debugfs routines and docs for the nx device driver powerpc/crypto: SHA512 hash routines for nx encryption powerpc/crypto: SHA256 hash routines for nx encryption powerpc/crypto: AES-XCBC mode routines for nx encryption powerpc/crypto: AES-GCM mode routines for nx encryption powerpc/crypto: AES-ECB mode routines for nx encryption powerpc/crypto: AES-CTR mode routines for nx encryption powerpc/crypto: AES-CCM mode routines for nx encryption powerpc/crypto: AES-CBC mode routines for nx encryption powerpc/crypto: nx driver code supporting nx encryption powerpc/pseries: Enable the PFO-based RNG accelerator powerpc/pseries/hwrng: PFO-based hwrng driver powerpc/pseries: Add PFO support to the VIO bus powerpc/pseries: Add pseries update notifier for OFDT prop changes powerpc/pseries: Add new hvcall constants to support PFO ...
| * powerpc: Remove now unused _TIF_RUNLATCHTiejun Chen2012-05-091-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | 'TIF_RUNLATCH' is already dropped from commit fe1952fc0afb9a2e4c79f103c08aef5d13db1873 powerpc: Rework runlatch code So '_TIF_RUNLATCH' should be removed as well. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* | powerpc: Use common threadinfo allocatorThomas Gleixner2012-05-081-13/+0
|/ | | | | | | | | The core now has a threadinfo allocator which uses a kmemcache when THREAD_SIZE < PAGE_SIZE. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Link: http://lkml.kernel.org/r/20120505150142.059161130@linutronix.de
* powerpc: Rework runlatch codeBenjamin Herrenschmidt2012-03-091-1/+8
| | | | | | | | | | | This moves the inlines into system.h and changes the runlatch code to use the thread local flags (non-atomic) rather than the TIF flags (atomic) to keep track of the latch state. The code to turn it back on in an asynchronous interrupt is now simplified and partially inlined. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* freezer: remove now unused TIF_FREEZETejun Heo2011-11-211-2/+0
| | | | | | Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: linux-arch@vger.kernel.org
* powerpc/ftrace: Implement raw syscall tracepoints on PowerPCIan Munsie2011-05-261-2/+5
| | | | | | | | | | | | | | | | | | | | This patch implements the raw syscall tracepoints on PowerPC and exports them for ftrace syscalls to use. To minimise reworking existing code, I slightly re-ordered the thread info flags such that the new TIF_SYSCALL_TRACEPOINT bit would still fit within the 16 bits of the andi. instruction's UI field. The instructions in question are in /arch/powerpc/kernel/entry_{32,64}.S to and the _TIF_SYSCALL_T_OR_A with the thread flags to see if system call tracing is enabled. In the case of 64bit PowerPC, arch_syscall_addr and arch_syscall_match_sym_name are overridden to allow ftrace syscalls to work given the unusual system call table structure and symbol names that start with a period. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc: mmu_gather reworkPeter Zijlstra2011-05-251-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix up powerpc to the new mmu_gather stuff. PPC has an extra batching queue to RCU free the actual pagetable allocations, use the ARCH extentions for that for now. For the ppc64_tlb_batch, which tracks the vaddrs to unhash from the hardware hash-table, keep using per-cpu arrays but flush on context switch and use a TLF bit to track the lazy_mmu state. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Miller <davem@davemloft.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Tony Luck <tony.luck@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: NUMA aware alloc_thread_info_node()Eric Dumazet2011-03-221-1/+1
| | | | | | | | | | | | | | | | | | | Add a node parameter to alloc_thread_info(), and change its name to alloc_thread_info_node() This change is needed to allow NUMA aware kthread_create_on_cpu() Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: David S. Miller <davem@davemloft.net> Reviewed-by: Andi Kleen <ak@linux.intel.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Tejun Heo <tj@kernel.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: David Howells <dhowells@redhat.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* add descriptive comment for TIF_MEMDIE task flag declaration.Andreas Dilger2010-05-141-1/+1
| | | | | | Signed-off-by: Andreas Dilger <adilger@dilger.ca> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* powerpc: TIF_ABI_PENDING bit removalAndreas Schwab2010-02-011-2/+0
| | | | | | | | Here are the powerpc bits to remove TIF_ABI_PENDING now that set_personality() is called at the appropriate place in exec. Signed-off-by: Andreas Schwab <schwab@linux-m68k.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* sched: INIT_PREEMPT_COUNTPeter Zijlstra2009-07-101-3/+1
| | | | | | | | | | | | | | | | | | | | | Pull the initial preempt_count value into a single definition site. Maintainers for: alpha, ia64 and m68k, please have a look, your arch code is funny. The header magic is a bit odd, but similar to the KERNEL_DS one, CPP waits with expanding these macros until the INIT_THREAD_INFO macro itself is expanded, which is in arch/*/kernel/init_task.c where we've already included sched.h so we're good. Cc: tony.luck@intel.com Cc: rth@twiddle.net Cc: geert@linux-m68k.org Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge commit 'jwb/next' into nextBenjamin Herrenschmidt2009-03-031-1/+3
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| * powerpc/44x: Support for 256KB PAGE_SIZEYuri Tikhonov2009-02-141-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds support for 256KB pages on ppc44x-based boards. For simplification of implementation with 256KB pages we still assume 2-level paging. As a side effect this leads to wasting extra memory space reserved for PTE tables: only 1/4 of pages allocated for PTEs are actually used. But this may be an acceptable trade-off to achieve the high performance we have with big PAGE_SIZEs in some applications (e.g. RAID). Also with 256KB PAGE_SIZE we increase THREAD_SIZE up to 32KB to minimize the risk of stack overflows in the cases of on-stack arrays, which size depends on the page size (e.g. multipage BIOs, NTFS, etc.). With 256KB PAGE_SIZE we need to decrease the PKMAP_ORDER at least down to 9, otherwise all high memory (2 ^ 10 * PAGE_SIZE == 256MB) we'll be occupied by PKMAP addresses leaving no place for vmalloc. We do not separate PKMAP_ORDER for 256K from 16K/64K PAGE_SIZE here; actually that value of 10 in support for 16K/64K had been selected rather intuitively. Thus now for all cases of PAGE_SIZE on ppc44x (including the default, 4KB, one) we have 512 pages for PKMAP. Because ELF standard supports only page sizes up to 64K, then you should use binutils later than 2.17.50.0.3 with '-zmax-page-size' set to 256K for building applications, which are to be run with the 256KB-page sized kernel. If using the older binutils, then you should patch them like follows: --- binutils/bfd/elf32-ppc.c.orig +++ binutils/bfd/elf32-ppc.c -#define ELF_MAXPAGESIZE 0x10000 +#define ELF_MAXPAGESIZE 0x40000 One more restriction we currently have with 256KB page sizes is inability to use shmem safely, so, for now, the 256KB is available only if you turn the CONFIG_SHMEM option off (another variant is to use BROKEN). Though, if you need shmem with 256KB pages, you can always remove the !SHMEM dependency in 'config PPC_256K_PAGES', and use the workaround available here: http://lkml.org/lkml/2008/12/19/20 Signed-off-by: Yuri Tikhonov <yur@emcraft.com> Signed-off-by: Ilya Yanok <yanok@emcraft.com> Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
* | powerpc: Move is_32bit_taskAnton Blanchard2009-02-231-0/+7
|/ | | | | | | | Move is_32bit_task into asm/thread_info.h, that allows us to test for 32/64bit tasks without an ugly CONFIG_PPC64 ifdef. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc: Move include files to arch/powerpc/include/asmStephen Rothwell2008-08-041-0/+161
from include/asm-powerpc. This is the result of a mkdir arch/powerpc/include/asm git mv include/asm-powerpc/* arch/powerpc/include/asm Followed by a few documentation/comment fixups and a couple of places where <asm-powepc/...> was being used explicitly. Of the latter only one was outside the arch code and it is a driver only built for powerpc. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
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