linux/arch/tile/kernel, branch v2.6.37

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

arch/tile: handle CLONE_SETTLS in copy_thread(), not user space

2010-12-17T21:56:50Z

Previously we were just setting up the "tp" register in the new task as started by clone() in libc. However, this is not quite right, since in principle a signal might be delivered to the new task before it had its TLS set up. (Of course, this race window still exists for resetting the libc getpid() cached value in the new task, in principle. But in any case, we are now doing this exactly the way all other architectures do it.) This change is important for 2.6.37 since the tile glibc we will be submitting upstream will not set TLS in user space any more, so it will only work on a kernel that has this fix. It should also be taken for 2.6.36.x in the stable tree if possible. Signed-off-by: Chris Metcalf Cc: stable

Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile

2010-11-24T22:42:32Z

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: arch/tile: fix memchr() not to dereference memory for zero length arch/tile: make glibc's sysconf(_SC_NPROCESSORS_CONF) work correctly arch/tile: fix rwlock so would-be write lockers don't block new readers

Merge branch 'drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile

2010-11-24T22:42:03Z

* 'drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: pci root complex: support for tile architecture drivers/net/tile/: on-chip network drivers for the tile architecture MAINTAINERS: add drivers/char/hvc_tile.c as maintained by tile

arch/tile: make glibc's sysconf(_SC_NPROCESSORS_CONF) work correctly

2010-11-24T18:42:15Z

glibc assumes that it can count /sys/devices/system/cpu/cpu* to get the number of configured cpus. For this to be valid on tile, we need to generate a "cpu" entry for all cpus, including the ones that are not currently allocated for Linux's use. Signed-off-by: Chris Metcalf

pci root complex: support for tile architecture

2010-11-24T18:13:49Z

This change enables PCI root complex support for TILEPro. Unlike TILE-Gx, TILEPro has no support for memory-mapped I/O, so the PCI support consists of hypervisor upcalls for PIO, DMA, etc. However, the performance is fine for the devices we have tested with so far (1Gb Ethernet, SATA, etc.). The header was tweaked to be a little bit more aggressive about disabling attempts to map/unmap IO port space. The hacky header was rolled into the header and the result was simplified. Both of the latter two headers were preliminary versions not meant for release before now - oh well. There is one quirk for our TILEmpower platform, which accidentally negotiates up to 5GT and needs to be kicked down to 2.5GT. Signed-off-by: Chris Metcalf

BKL: remove extraneous #include

2010-11-17T16:59:32Z

The big kernel lock has been removed from all these files at some point, leaving only the #include. Remove this too as a cleanup. Signed-off-by: Arnd Bergmann Signed-off-by: Linus Torvalds

arch/tile: mark "hardwall" device as non-seekable

2010-11-01T19:31:42Z

Arnd's recent patch series tagged this device with noop_llseek, conservatively. In fact, it should be no_llseek, which we arrange for by opening the device with nonseekable_open(). Signed-off-by: Chris Metcalf

asm-generic/stat.h: support 64-bit file time_t for stat()

2010-11-01T19:31:29Z

The existing asm-generic/stat.h specifies st_mtime, etc., as a 32-value, and works well for 32-bit architectures (currently microblaze, score, and 32-bit tile). However, for 64-bit architectures it isn't sufficient to return 32 bits of time_t; this isn't good insurance against the 2037 rollover. (It also makes glibc support less convenient, since we can't use glibc's handy STAT_IS_KERNEL_STAT mode.) This change extends the two "timespec" fields for each of the three atime, mtime, and ctime fields from "int" to "long". As a result, on 32-bit platforms nothing changes, and 64-bit platforms will now work as expected. The only wrinkle is 32-bit userspace under 64-bit kernels taking advantage of COMPAT mode. For these, we leave the "struct stat64" definitions with the "int" versions of the time_t and nsec fields, so that architectures can implement compat_sys_stat64() and friends with sys_stat64(), etc., and get the expected 32-bit structure layout. This requires a field-by-field copy in the kernel, implemented by the code guarded under __ARCH_WANT_STAT64. This does mean that the shape of the "struct stat" and "struct stat64" structures is different on a 64-bit kernel, but only one of the two structures should ever be used by any given process: "struct stat" is meant for 64-bit userspace only, and "struct stat64" for 32-bit userspace only. (On a 32-bit kernel the two structures continue to have the same shape, since "long" is 32 bits.) The alternative is keeping the two structures the same shape on 64-bit kernels, which means a 64-bit time_t in "struct stat64" for 32-bit processes. This is a little unnatural since 32-bit userspace can't do anything with 64 bits of time_t information, since time_t is just "long", not "int64_t"; and in any case 32-bit userspace might expect to be running under a 32-bit kernel, which can't provide the high 32 bits anyway. In the case of a 32-bit kernel we'd then be extending the kernel's 32-bit time_t to 64 bits, then truncating it back to 32 bits again in userspace, for no particular reason. And, as mentioned above, if we have 64-bit time_t for 32-bit processes we can't easily use glibc's STAT_IS_KERNEL_STAT, since glibc's stat structure requires an embedded "struct timespec", which is a pair of "long" (32-bit) values in a 32-bit userspace. "Inventive" solutions are possible, but are pretty hacky. Signed-off-by: Chris Metcalf Acked-by: Arnd Bergmann

arch/tile: don't allow user code to set the PL via ptrace or signal return

2010-11-01T19:31:17Z

The kernel was allowing any component of the pt_regs to be updated either by signal handlers writing to the stack, or by processes writing via PTRACE_POKEUSR or PTRACE_SETREGS, which meant they could set their PL up from 0 to 1 and get access to kernel code and data (or, in practice, cause a kernel panic). We now always reset the ex1 field, allowing the user to set their ICS bit only. Signed-off-by: Chris Metcalf