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path: root/arch/mips/kernel/uprobes.c
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2016-10-06MIPS: tracing: disable uprobe/kprobe on compact branch instructionsMarcin Nowakowski
Current instruction decoder for uprobe/kprobe handler only handles branches with delay slots. For compact branches the behaviour is rather unpredictable - and depending on the encoding of a compact branch instruction may result in one (or more) of: - executing an instruction that follows a branch which wasn't in a delay slot and shouldn't have been executed - incorrectly emulating a branch leading to a jump to a wrong location - unexpected branching out of the single-stepped code and never reaching the breakpoint that should terminate the probe handler Results of these actions are generally unpredictable, but can end up with a probed application or kernel crash, so disable placing probes on compact branches until they are handled properly. Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14336/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-10-06MIPS: tracing: move insn_has_delay_slot to a shared headerMarcin Nowakowski
Currently both kprobes and uprobes code have definitions of the insn_has_delay_slot method. Move it to a separate header as an inline method that each probe-specific method can later use. No functional change intended, although the methods slightly varied in the constraints they set for the methods - the uprobes one was chosen as it is slightly more specific when filtering opcode fields. Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14335/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-10-04MIPS: uprobes: Flush icache via kernel addressJames Hogan
Update arch_uprobe_copy_ixol() to use the kmap_atomic() based kernel address to flush the icache with flush_icache_range(), rather than the user mapping. We have the kernel mapping available anyway and this avoids having to switch to using the new __flush_icache_user_range() for the sake of Enhanced Virtual Addressing (EVA) where flush_icache_range() will become ineffective on user addresses. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14154/ Patchwork: https://patchwork.linux-mips.org/patch/14308/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-09-29MIPS: uprobes: fix use of uninitialised variableMarcin Nowakowski
arch_uprobe_pre_xol needs to emulate a branch if a branch instruction has been replaced with a breakpoint, but in fact an uninitialised local variable was passed to the emulator routine instead of the original instruction Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com> Fixes: 40e084a506eb ('MIPS: Add uprobes support.') Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14300/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-09-29MIPS: uprobes: remove incorrect set_orig_insnMarcin Nowakowski
Generic kernel code implements a weak version of set_orig_insn that moves cached 'insn' from arch_uprobe to the original code location when the trap is removed. MIPS variant used arch_uprobe->orig_inst which was never initialised properly, so this code only inserted a nop instead of the original instruction. With that change orig_inst can also be safely removed. Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com> Fixes: 40e084a506eb ('MIPS: Add uprobes support.') Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14299/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-09-29MIPS: fix uretprobe implementationMarcin Nowakowski
arch_uretprobe_hijack_return_addr should replace the return address for a call with a trampoline address. Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com> Fixes: 40e084a506eb ('MIPS: Add uprobes support.') Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14298/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-09-13MIPS: uprobes: fix incorrect uprobe brk handlingMarcin Nowakowski
When a uprobe-replacement breakpoint instruction is handled, a notifier is called with DIE_UPROBE argument, but a corresponding exception notify handler for MIPS attempts to handle DIE_BREAK instead. As a result the breakpoint instruction isn't handled by the uprobe code and the probed application terminates with SIGTRAP. Fix this by changing arch_uprobe_exception_notify code to handle DIE_UPROBE as a pre-singlestep condition instead of DIE_BREAK. Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13884/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-09-03MIPS: Add uprobes support.Ralf Baechle
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>