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* ARC: gdbserver breakage in Big-Endian configuration #1Vineet Gupta2013-08-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | [Based on mainline commit 502a0c775c7f0a: "ARC: pt_regs update #5"] gdbserver needs @stop_pc, served by ptrace, but fetched from pt_regs differently, based on in_brkpt_traps(), which in turn relies on additional machine state in pt_regs->event bitfield. unsigned long orig_r8:16, event:16; For big endian config, this macro was returning false, despite being in breakpoint Trap exception, causing wrong @stop_pc to be returned to gdb. Issue #1: In BE, @event above is at offset 2 in word, while a STW insn at offset 0 was used to update it. Resort to using ST insn which updates the half-word at right location. Issue #2: The union involving bitfields causes all the members to be laid out at offset 0. So with fix #1 above, ASM was now updating at offset 2, "C" code was still referencing at offset 0. Fixed by wrapping bitfield in a struct. Reported-by: Noam Camus <noamc@ezchip.com> Tested-by: Anton Kolesov <akolesov@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ARC: Fix the typo in event identifier flags used by ptraceVineet Gupta2013-03-20
| | | | | | | | | | | | | | | | orig_r8_IS_EXCPN and orig_r8_IS_BRKPT were same values due to a copy/paste error. Although it looks bad and is wrong, it really doesn't affect gdb working. orig_r8_IS_BRKPT is the one relevant to debugging (breakpoints), since it is used to provide EFA vs. ERET to a ptrace "stop_pc" request. So when gdb has inserted a breakpoint, orig_r8_IS_BRKPT is already set, and anything else (i.e. orig_r8_IS_EXCPN) becoming same as it, really doesn't hurt gdb. The corollary case, could be nasty but nobody uses the ptrace "stop_pc" request in that case Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
* ARC: UAPI Disintegrate arch/arc/include/asmVineet Gupta2013-02-15
| | | | | | | | | | | | | | | | | | | | 1. ./genfilelist.pl arch/arc/include/asm/ 2. Create arch/arc/include/uapi/asm/Kbuild as follows +# UAPI Header export list +include include/uapi/asm-generic/Kbuild.asm 3. ./disintegrate-one.pl arch/arc/include/{,uapi/}asm/<above-list> 4. Edit arch/arc/include/asm/Kbuild to remove ref to asm-generic/Kbuild.asm - To work around empty uapi/asm/setup.h added a placholder comment. - Also a manual #ifdef __ASSEMBLY__ for a late ptrace change Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: David Howells <dhowells@redhat.com>
* ARC: Unaligned access emulationVineet Gupta2013-02-15
| | | | | | | | | | | | | | | | ARC700 doesn't natively support unaligned access, but can be emulated -Unaligned Access Exception -Disassembly at the Fault address to find the exact insn (long/short) Also per Arnd's comment, we runtime control it using 2 sysctl knobs: * SYSCTL_ARCH_UNALIGN_ALLOW: Runtime enable/disble * SYSCTL_ARCH_UNALIGN_NO_WARN: Warn on each emulation attempt Originally contributed by Tim Yao <tim.yao@amlogic.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Tim Yao <tim.yao@amlogic.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
* ARC: kprobes supportVineet Gupta2013-02-15
| | | | | | | Origin port done by Rajeshwar Ranga Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Rajeshwar Ranga <rajeshwar.ranga@gmail.com>
* ARC: [Review] Prevent incorrect syscall restartsVineet Gupta2013-02-15
| | | | | | | | | | | | | | | | | | | | | Per Al Viro's "signals for dummies" https://lkml.org/lkml/2012/12/6/366 there are 3 golden rules for (not) restarting syscalls: " What we need to guarantee is * restarts do not happen on signals caught in interrupts or exceptions * restarts do not happen on signals caught in sigreturn() * restart should happen only once, even if we get through do_signal() many times." ARC Port already handled #1, this patch fixes #2 and #3. We use the additional state in pt_regs->orig_r8 to ckh if restarting has already been done once. Thanks to Al Viro for spotting this. Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Al Viro <viro@ZenIV.linux.org.uk>
* ARC: [Review] Preparing to fix incorrect syscall restarts due to signalsVineet Gupta2013-02-15
| | | | | | | | | | | | | | | | | | | | | | | | To avoid multiple syscall restarts (multiple signals) or no restart at all (sigreturn), we need just an extra bit of state "literally 1 bit" in struct pt_regs. orig_r8 is the best place to do this, however given the way it is encoded currently, we can't add anything simplistically. Current orig_r8: * syscalls -> 1 to NR_SYSCALLS * Exceptions -> NR_SYSCALLS + 1 * Break-point-> NR_SYSCALLS + 2 In new scheme it is a bit-field * lower short word contains the exact event type (and a new bit to represent restart semantics : if syscall was already / can't be restarted) * upper short word optionally containing the syscall num - needed by likes of tracehooks etc This patch only changes how orig_r8 is organised and nothing should change behaviourily. Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Al Viro <viro@ZenIV.linux.org.uk>
* ARC: Process-creation/scheduling/idle-loopVineet Gupta2013-02-11
| | | | | | Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de>
* ARC: Syscall support (no-legacy-syscall ABI)Vineet Gupta2013-02-11
| | | | | | | | | This includes support for generic clone/for/vfork/execve Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Al Viro <viro@ZenIV.linux.org.uk> Acked-by: Arnd Bergmann <arnd@arndb.de>
* ARC: Fundamental ARCH data-types/definesVineet Gupta2013-02-11
* L1_CACHE_SHIFT * PAGE_SIZE, PAGE_OFFSET * struct pt_regs, struct user_regs_struct * struct thread_struct, cpu_relax(), task_pt_regs(), start_thread(), ... * struct thread_info, THREAD_SIZE, INIT_THREAD_INFO(), TIF_*, ... * BUG() * ELF_* * Elf_* To disallow user-space visibility into some of the core kernel data-types such as struct pt_regs, #ifdef __KERNEL__ which also makes the UAPI header spit (further patch in the series) to NOT export it to asm/uapi/ptrace.h Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Jonas Bonn <jonas.bonn@gmail.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Acked-by: Arnd Bergmann <arnd@arndb.de>