user/sven/linux.git/arch/tile/kernel/intvec_32.S, branch v3.7

arch/tile: fix up some issues in calling do_work_pending()

2012-05-16T20:01:16Z

First, we were at risk of handling thread-info flags, in particular do_signal(), when returning from kernel space. This could happen after a failed kernel_execve(), or when forking a kernel thread. The fix is to test in do_work_pending() for user_mode() and return immediately if so; we already had this test for one of the flags, so I just hoisted it to the top of the function. Second, if a ptraced process updated the callee-saved registers in the ptregs struct and then processed another thread-info flag, we would overwrite the modifications with the original callee-saved registers. To fix this, we add a register to note if we've already saved the registers once, and skip doing it on additional passes through the loop. To avoid a performance hit from the couple of extra instructions involved, I modified the GET_THREAD_INFO() macro to be guaranteed to be one instruction, then bundled it with adjacent instructions, yielding an overall net savings. Reported-By: Al Viro Signed-off-by: Chris Metcalf

arch/tile: avoid accidentally unmasking NMI-type interrupt accidentally

2012-04-02T16:14:03Z

The return path as we reload registers and core state requires that r30 hold a boolean indicating whether we are returning from an NMI, but in a couple of cases we weren't setting this properly, with the result that we could accidentally unmask the NMI interrupt(s), which could cause confusion. Now we set r30 in every place where we jump into the interrupt return path. Signed-off-by: Chris Metcalf

tile: revert change from to in asm files

2011-10-13T12:25:01Z

The 32-bit TILEPro support uses some #defines in for atomic support routines in assembly. To make this more explicit, I've turned those includes into includes of , which should hopefully make it clear that they shouldn't be bombed into in any cleanups. Signed-off-by: Chris Metcalf

atomic: use

2011-07-26T23:49:47Z

This allows us to move duplicated code in (atomic_inc_not_zero() for now) to Signed-off-by: Arun Sharma Reviewed-by: Eric Dumazet Cc: Ingo Molnar Cc: David Miller Cc: Eric Dumazet Acked-by: Mike Frysinger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

arch/tile: allow nonatomic stores to interoperate with fast atomic syscalls

2011-05-04T18:40:07Z

This semantic was already true for atomic operations within the kernel, and this change makes it true for the fast atomic syscalls (__NR_cmpxchg and __NR_atomic_update) as well. Previously, user-space had to use the fast atomic syscalls exclusively to update memory, since raw stores could lose a race with the atomic update code even when the atomic update hadn't actually modified the value. With this change, we no longer write back the value to memory if it hasn't changed. This allows certain types of idioms in user space to work as expected, e.g. "atomic exchange" to acquire a spinlock, followed by a raw store of zero to release the lock. Signed-off-by: Chris Metcalf

arch/tile: support TIF_NOTIFY_RESUME

2011-05-02T22:53:35Z

This support is required for CONFIG_KEYS, NFSv4 kernel DNS, etc. The change is slightly more complex than the minimal thing, since I took advantage of having to go into the assembly code to just move a bunch of stuff into C code: specifically, the schedule(), do_async_page_fault(), do_signal(), and single_step_once() support, in addition to the TIF_NOTIFY_RESUME support. Signed-off-by: Chris Metcalf

arch/tile: support 4KB page size as well as 64KB

2011-03-10T18:17:53Z

The Tilera architecture traditionally supports 64KB page sizes to improve TLB utilization and improve performance when the hardware is being used primarily to run a single application. For more generic server scenarios, it can be beneficial to run with 4KB page sizes, so this commit allows that to be specified (by modifying the arch/tile/include/hv/pagesize.h header). As part of this change, we also re-worked the PTE management slightly so that PTE writes all go through a __set_pte() function where we can do some additional validation. The set_pte_order() function was eliminated since the "order" argument wasn't being used. One bug uncovered was in the PCI DMA code, which wasn't properly flushing the specified range. This was benign with 64KB pages, but with 4KB pages we were getting some larger flushes wrong. The per-cpu memory reservation code also needed updating to conform with the newer percpu stuff; before it always chose 64KB, and that was always correct, but with 4KB granularity we now have to pay closer attention and reserve the amount of memory that will be requested when the percpu code starts allocating. Signed-off-by: Chris Metcalf

arch/tile: fix some comments and whitespace

2011-03-10T18:14:03Z

This is a grab bag of changes with no actual change to generated code. This includes whitespace and comment typos, plus a couple of stale comments being removed. Signed-off-by: Chris Metcalf

arch/tile: stop disabling INTCTRL_1 interrupts during hypervisor downcalls

2011-03-01T21:20:10Z

The problem was that this could lead to IPIs being disabled during the softirq processing after a hypervisor downcall (e.g. for I/O), since both IPI and device interrupts use the INCTRL_1 downcall mechanism. When this happened at the wrong time, it could lead to deadlock. Luckily, we were already maintaining the per-interrupt state we need, and using it in the proper way in the hypervisor, so all we had to do was to change Linux to stop blocking downcall interrupts for the entire length of the downcall. (Now they're blocked while we're executing the downcall routine itself, but not while we're executing any subsequent softirq routines.) The hypervisor is doing a very small amount of work it no longer needs to do (masking INTCTRL_1 on entry to the client interrupt routine), but doing so means that older versions of Tile Linux will continue to work with a current hypervisor, so that seems reasonable. Signed-off-by: Chris Metcalf

arch/tile: handle rt_sigreturn() more cleanly

2010-12-17T21:59:29Z

The current tile rt_sigreturn() syscall pattern uses the common idiom of loading up pt_regs with all the saved registers from the time of the signal, then anticipating the fact that we will clobber the ABI "return value" register (r0) as we return from the syscall by setting the rt_sigreturn return value to whatever random value was in the pt_regs for r0. However, this breaks in our 64-bit kernel when running "compat" tasks, since we always sign-extend the "return value" register to properly handle returned pointers that are in the upper 2GB of the 32-bit compat address space. Doing this to the sigreturn path then causes occasional random corruption of the 64-bit r0 register. Instead, we stop doing the crazy "load the return-value register" hack in sigreturn. We already have some sigreturn-specific assembly code that we use to pass the pt_regs pointer to C code. We extend that code to also set the link register to point to a spot a few instructions after the usual syscall return address so we don't clobber the saved r0. Now it no longer matters what the rt_sigreturn syscall returns, and the pt_regs structure can be cleanly and completely reloaded. Signed-off-by: Chris Metcalf