linux/arch/tile/kernel/single_step.c, branch v3.13

tile: remove support for TILE64

2013-09-03T18:53:29Z

This chip is no longer being actively developed for (it was superceded by the TILEPro64 in 2008), and in any case the existing compiler and toolchain in the community do not support it. It's unlikely that the kernel works with TILE64 at this point as the configuration has not been tested in years. The support is also awkward as it requires maintaining a significant number of ifdefs. So, just remove it altogether. Signed-off-by: Chris Metcalf

tile: fast-path unaligned memory access for tilegx

2013-08-13T20:04:10Z

This change enables unaligned userspace memory access via a kernel fast path on tilegx. The kernel tracks user PC/instruction pairs per-thread using a direct-mapped cache in userspace. The cache maps those PC/instruction pairs to JIT'ed instruction sequences that load or store using byte-wide load store intructions and then synthesize 2-, 4- or 8-byte load or store results. Once an instruction has been seen to generate an unaligned access once, subsequent hits on that instruction typically require overhead of only around 50 cycles if cache and TLB is hot. We support the prctl() PR_GET_UNALIGN / PR_SET_UNALIGN sys call to enable or disable unaligned fixups on a per-process basis. To do this we pull some of the tilepro unaligned support out of the single_step.c file; tilepro uses instruction disassembly for both single-step and unaligned access support. Since tilegx actually has hardware singlestep support, though, it's cleaner to keep the tilegx unaligned access code in a separate file. While we're at it, properly rename the tilepro-specific types, etc., to have tilepro suffixes instead of generic tile suffixes. Signed-off-by: Chris Metcalf

arch/tile: support building big-endian kernel

2012-05-25T16:48:22Z

The toolchain supports big-endian mode now, so add support for building the kernel to run big-endian as well. Signed-off-by: Chris Metcalf

VM: add "vm_mmap()" helper function

2012-04-21T00:29:13Z

This continues the theme started with vm_brk() and vm_munmap(): vm_mmap() does the same thing as do_mmap(), but additionally does the required VM locking. This uninlines (and rewrites it to be clearer) do_mmap(), which sadly duplicates it in mm/mmap.c and mm/nommu.c. But that way we don't have to export our internal do_mmap_pgoff() function. Some day we hopefully don't have to export do_mmap() either, if all modular users can become the simpler vm_mmap() instead. We're actually very close to that already, with the notable exception of the (broken) use in i810, and a couple of stragglers in binfmt_elf. Signed-off-by: Linus Torvalds

arch/tile: return SIGBUS for addresses that are unaligned AND invalid

2012-04-02T16:13:56Z

Previously we were returning SIGSEGV in this case. It seems cleaner to return SIGBUS since the hardware figures out alignment traps before TLB violations, so SIGBUS is the "more correct" signal. Signed-off-by: Chris Metcalf

Disintegrate asm/system.h for Tile

2012-03-28T17:30:03Z

Disintegrate asm/system.h for Tile. Signed-off-by: David Howells Acked-by: Chris Metcalf

arch/tile: factor out header

2011-11-03T20:58:54Z

The kernel code was using some headers that included a mix of hardware-specific information (typically found in Tilera headers) and structures, enums, and function declarations supporting the disassembly function of the tile-desc.c sources. This change refactors that code so that a hardware-specific, but OS- and application-agnostic header, is created: . This header is then exported to userspace along with the other headers and can be used to build userspace code; in particular, it is used by glibc as part of implementing the backtrace() function. The new header, together with a header that specifically describes the disassembly code ( with _32 and _64 variants), replaces the old and headers. As part of this change, we are also renaming the 32-bit constants from TILE_xxx to TILEPRO_xxx to better reflect the fact that they are specific to the TILEPro architecture, and not to TILE-Gx and any successor "tile" architecture chips. Signed-off-by: Chris Metcalf

arch/tile: support signal "exception-trace" hook

2011-05-20T02:55:59Z

This change adds support for /proc/sys/debug/exception-trace to tile. Like x86 and sparc, by default it is set to "1", generating a one-line printk whenever a user process crashes. By setting it to "2", we get a much more complete userspace diagnostic at crash time, including a user-space backtrace, register dump, and memory dump around the address of the crash. Some vestiges of the Tilera-internal version of this support are removed with this patch (the show_crashinfo variable and the arch_coredump_signal function). We retain a "crashinfo" boot parameter which allows you to set the boot-time value of exception-trace. 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: bug fix: exec'ed task thought it was still single-stepping

2011-03-01T21:19:58Z

To handle single-step, tile mmap's a page of memory in the process space for each thread and uses it to construct a version of the instruction that we want to single step. If the process exec's, though, we lose that mapping, and the kernel needs to be aware that it will need to recreate it if the exec'ed process than tries to single-step as well. Also correct some int32_t to s32 for better kernel style. Signed-off-by: Chris Metcalf