From 0c9ef6f4b33b4ee56c0c8c51b1b9bfbbda62cf64 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Fri, 2 Mar 2018 10:41:17 -0500 Subject: [PATCH] cputlb: Don't assume do_unassigned_access() never returns In get_page_addr_code(), if the guest PC doesn't correspond to RAM then we currently run the CPU's do_unassigned_access() hook if it has one, and otherwise we give up and exit QEMU with a more-or-less useful message. This code assumes that the do_unassigned_access hook will never return, because if it does then we'll plough on attempting to use a non-RAM TLB entry to get a RAM address and will abort() in qemu_ram_addr_from_host_nofail(). Unfortunately some CPU implementations of this hook do return: Microblaze, SPARC and the ARM v7M. Change the code to call report_bad_exec() if the hook returns, as well as if it didn't have one. This means we can tidy it up to use the cpu_unassigned_access() function which wraps the "get the CPU class and call the hook if it has one" work, since we aren't trying to distinguish "no hook" from "hook existed and returned" any more. This brings the handling of this hook into line with the handling used for data accesses, where "hook returned" is treated the same as "no hook existed" and gets you the default behaviour. Backports commit 44d7ce0ef39cb45e13d384574d79799eb3d39834 from qemu --- qemu/cputlb.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) diff --git a/qemu/cputlb.c b/qemu/cputlb.c index f259615c..00208262 100644 --- a/qemu/cputlb.c +++ b/qemu/cputlb.c @@ -313,17 +313,14 @@ tb_page_addr_t get_page_addr_code(CPUArchState *env1, target_ulong addr) pd = iotlbentry->addr & ~TARGET_PAGE_MASK; mr = iotlb_to_region(cpu, pd, iotlbentry->attrs); if (memory_region_is_unassigned(cpu->uc, mr)) { - CPUClass *cc = CPU_GET_CLASS(env1->uc, cpu); - - if (cc->do_unassigned_access) { - cc->do_unassigned_access(cpu, addr, false, true, 0, 4); - } else { - //cpu_abort(cpu, "Trying to execute code outside RAM or ROM at 0x" - // TARGET_FMT_lx "\n", addr); // qq - env1->invalid_addr = addr; - env1->invalid_error = UC_ERR_FETCH_UNMAPPED; - return RAM_ADDR_INVALID; - } + cpu_unassigned_access(cpu, addr, false, true, 0, 4); + /* The CPU's unassigned access hook might have longjumped out + * with an exception. If it didn't (or there was no hook) then + * we can't proceed further. + */ + env1->invalid_addr = addr; + env1->invalid_error = UC_ERR_FETCH_UNMAPPED; + return RAM_ADDR_INVALID; } p = (void *)((uintptr_t)addr + env1->tlb_table[mmu_idx][page_index].addend); ram_addr = qemu_ram_addr_from_host_nofail(cpu->uc, p);