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2018-02-05Drop remaining bits of ia64 host supportPeter Maydell
We dropped support for ia64 host CPUs in the 2.11 release (removing the TCG backend for it, and advertising the support as being completely removed in the changelog). However there are a few bits and pieces of code still floating about. Remove those, too. We can drop the check in configure for "ia64 or hppa host?" entirely, because we don't support hppa hosts either any more. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-Id: <1516897189-11035-1-git-send-email-peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-01-25accel/tcg: add size paremeter in tlb_fill()Laurent Vivier
The MC68040 MMU provides the size of the access that triggers the page fault. This size is set in the Special Status Word which is written in the stack frame of the access fault exception. So we need the size in m68k_cpu_unassigned_access() and m68k_cpu_handle_mmu_fault(). To be able to do that, this patch modifies the prototype of handle_mmu_fault handler, tlb_fill() and probe_write(). do_unassigned_access() already includes a size parameter. This patch also updates handle_mmu_fault handlers and tlb_fill() of all targets (only parameter, no code change). Signed-off-by: Laurent Vivier <laurent@vivier.eu> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20180118193846.24953-2-laurent@vivier.eu>
2018-01-23page_unprotect(): handle calls to pages that are PAGE_WRITEPeter Maydell
If multiple guest threads in user-mode emulation write to a page which QEMU has marked read-only because of cached TCG translations, the threads can race in page_unprotect: * threads A & B both try to do a write to a page with code in it at the same time (ie which we've made non-writeable, so SEGV) * they race into the signal handler with this faulting address * thread A happens to get to page_unprotect() first and takes the mmap lock, so thread B sits waiting for it to be done * A then finds the page, marks it PAGE_WRITE and mprotect()s it writable * A can then continue OK (returns from signal handler to retry the memory access) * ...but when B gets the mmap lock it finds that the page is already PAGE_WRITE, and so it exits page_unprotect() via the "not due to protected translation" code path, and wrongly delivers the signal to the guest rather than just retrying the access In particular, this meant that trying to run 'javac' in user-mode emulation would fail with a spurious guest SIGSEGV. Handle this by making page_unprotect() assume that a call for a page which is already PAGE_WRITE is due to a race of this sort and return a "fault handled" indication. Since this would cause an infinite loop if we ever called page_unprotect() for some other kind of fault than "write failed due to bad access permissions", tighten the condition in handle_cpu_signal() to check the signal number and si_code, and add a comment so that if somebody does ever find themselves debugging an infinite loop of faults they have some clue about why. (The trick for identifying the correct setting for current_tb_invalidated for thread B (needed to handle the precise-SMC case) is due to Richard Henderson. Paolo Bonzini suggested just relying on si_code rather than trying anything more complicated.) Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-Id: <1511879725-9576-3-git-send-email-peter.maydell@linaro.org> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2018-01-23linux-user: Propagate siginfo_t through to handle_cpu_signal()Peter Maydell
Currently all the architecture/OS specific cpu_signal_handler() functions call handle_cpu_signal() without passing it the siginfo_t. We're going to want that so we can look at the si_code to determine whether this is a SEGV_ACCERR access violation or some other kind of fault, so change the functions to pass through the pointer to the siginfo_t rather than just the si_addr value. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <1511879725-9576-2-git-send-email-peter.maydell@linaro.org> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2017-11-21accel/tcg: Handle atomic accesses to notdirty memory correctlyPeter Maydell
To do a write to memory that is marked as notdirty, we need to invalidate any TBs we have cached for that memory, and update the cpu physical memory dirty flags for VGA and migration. The slowpath code in notdirty_mem_write() does all this correctly, but the new atomic handling code in atomic_mmu_lookup() doesn't do anything at all, it just clears the dirty bit in the TLB. The effect of this bug is that if the first write to a notdirty page for which we have cached TBs is by a guest atomic access, we fail to invalidate the TBs and subsequently will execute incorrect code. This can be seen by trying to run 'javac' on AArch64. Use the new notdirty_call_before() and notdirty_call_after() functions to correctly handle the update to notdirty memory in the atomic codepath. Cc: qemu-stable@nongnu.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 1511201308-23580-3-git-send-email-peter.maydell@linaro.org
2017-11-15tcg: Record code_gen_buffer address for user-only memory helpersRichard Henderson
When we handle a signal from a fault within a user-only memory helper, we cannot cpu_restore_state with the PC found within the signal frame. Use a TLS variable, helper_retaddr, to record the unwind start point to find the faulting guest insn. Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reported-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-09-17accel/tcg: move USER code to user-exec.cPhilippe Mathieu-Daudé
Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-Id: <20170912211934.20919-1-f4bug@amsat.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-09-17accel/tcg: move user-exec to accel/tcg/Philippe Mathieu-Daudé
Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-Id: <20170911213328.9701-3-f4bug@amsat.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>