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2015-05-11tile: improve stack backtraceChris Metcalf
This commit fixes a number of issues with the tile backtrace code. - Don't try to identify userspace shared object or executable paths if we are doing a backtrace from an interrupt; it's not legal, and also unlikely to be interesting. Likewise, don't try to do it for other address spaces, since d_path() assumes it is being called in "current" context. - Move "in_backtrace" from thread_struct to thread_info. This way we can access it even if our stack thread_info has been clobbered, which makes backtracing more robust. - Avoid using "current" directly when testing for is_sigreturn(). Since "current" may be corrupt, we're better off using kbt->task explicitly to look up the vdso_base for the current task. Conveniently, this simplifies the internal APIs (we only need one is_sigreturn() function now). - Avoid bogus "Odd fault" warning when pc/sp/ex1 are all zero, as is true for kernel threads above the last frame. - Hook into Tejun Heo's dump_stack() framework in lib/dump_stack.c. - Write last entry in save_stack_trace() as ULONG_MAX, not zero, since ftrace (at least) relies on finding that marker. - Implement save_stack_trace_regs() and save_strack_trace_user(), and set CONFIG_USER_STACKTRACE_SUPPORT. Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
2013-08-13tile: implement gettimeofday() via vDSOChris Metcalf
This change creates the framework for vDSO calls, makes the existing rt_sigreturn() mechanism use it, and adds a fast gettimeofday(). Now that we need to expose the vDSO address to userspace, we add AT_SYSINFO_EHDR to the set of aux entries provided to userspace. (You can disable any extra vDSO support by booting with vdso=0, but the rt_sigreturn vDSO page will still be provided.) Note that glibc has supported the tile vDSO since release 2.17. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-10-20tile: support GENERIC_KERNEL_THREAD and GENERIC_KERNEL_EXECVEChris Metcalf
Also provide an optimized current_pt_regs() while we're at it. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-06tile: remove cpu_idle_on_new_stackChris Metcalf
This routine isn't used unless CONFIG_HOMECACHE is enabled, which isn't even available as a public configuration option yet. Since it no longer links correctly in 3.4, just remove it for now. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-05-25arch/tile: use interrupt critical sections lessChris Metcalf
In general we want to avoid ever touching memory while within an interrupt critical section, since the page fault path goes through a different path from the hypervisor when in an interrupt critical section, and we carefully decided with tilegx that we didn't need to support this path in the kernel. (On tilepro we did implement that path as part of supporting atomic instructions in software.) In practice we always need to touch the kernel stack, since that's where we store the interrupt state before releasing the critical section, but this change cleans up a few things. The IRQ_ENABLE macro is split up so that when we want to enable interrupts in a deferred way (e.g. for cpu_idle or for interrupt return) we can read the per-cpu enable mask before entering the critical section. The cache-migration code is changed to use interrupt masking instead of interrupt critical sections. And, the interrupt-entry code is changed so that we defer loading "tp" from per-cpu data until after we have released the interrupt critical section. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: add "nop" after "nap" to help GX idle power drawChris Metcalf
This avoids the hardware istream prefetcher doing unnecessary work. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01arch/tile: use a cleaner technique to enable interrupt for cpu_idle()Chris Metcalf
Previously we used iret to atomically return to kernel PL with interrupts enabled. However, it turns out that we are architecturally guaranteed that we can just set and clear the "interrupt critical section" and only interrupt on the following instruction, so we now do that instead, since it's cleaner. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01arch/tile: fix __ndelay etc to work betterChris Metcalf
The current implementations of __ndelay and __udelay call a hypervisor service to delay, but the hypervisor service isn't actually implemented very well, and the consensus is that Linux should handle figuring this out natively and not use a hypervisor service. By converting nanoseconds to cycles, and then spinning until the cycle counter reaches the desired cycle, we get several benefits: first, we are sensitive to the actual clock speed; second, we use less power by issuing a slow SPR read once every six cycles while we delay; and third, we properly handle the case of an interrupt by exiting at the target time rather than after some number of cycles. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-10-15arch/tile: parameterize system PLs to support KVM portChris Metcalf
While not a port to KVM (yet), this change modifies the kernel to be able to build either at PL1 or at PL2 with a suitable config switch. Pushing up this change avoids handling branch merge issues going forward with the KVM work. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-10-15arch/tile: add Tilera's <arch/sim.h> header as an open-source headerChris Metcalf
This change adds one of the Tilera standard <arch> headers to the set of headers shipped with Linux. The <arch/sim.h> header provides methods for programmatically interacting with the Tilera simulator. The current <arch/sim.h> provides inline assembly for the _sim_syscall function, so the declaration and definition previously provided manually in Linux are no longer needed. We now use the standard sim_validate_lines_evicted() method from <arch/sim.h> rather than rolling our own direct call to sim_syscall(). Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-07-06arch/tile: Miscellaneous cleanup changes.Chris Metcalf
This commit is primarily changes caused by reviewing "sparse" and "checkpatch" output on our sources, so is somewhat noisy, since things like "printk() -> pr_err()" (or whatever) throughout the codebase tend to get tedious to read. Rather than trying to tease apart precisely which things changed due to which type of code review, this commit includes various cleanups in the code: - sparse: Add declarations in headers for globals. - sparse: Fix __user annotations. - sparse: Using gfp_t consistently instead of int. - sparse: removing functions not actually used. - checkpatch: Clean up printk() warnings by using pr_info(), etc.; also avoid partial-line printks except in bootup code. - checkpatch: Use exposed structs rather than typedefs. - checkpatch: Change some C99 comments to C89 comments. In addition, a couple of minor other changes are rolled in to this commit: - Add support for a "raise" instruction to cause SIGFPE, etc., to be raised. - Remove some compat code that is unnecessary when we fully eliminate some of the deprecated syscalls from the generic syscall ABI. - Update the tile_defconfig to reflect current config contents. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
2010-06-04arch/tile: core support for Tilera 32-bit chips.Chris Metcalf
This change is the core kernel support for TILEPro and TILE64 chips. No driver support (except the console driver) is included yet. This includes the relevant Linux headers in asm/; the low-level low-level "Tile architecture" headers in arch/, which are shared with the hypervisor, etc., and are build-system agnostic; and the relevant hypervisor headers in hv/. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Reviewed-by: Paul Mundt <lethal@linux-sh.org>