From 44d7ce0ef39cb45e13d384574d79799eb3d39834 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Tue, 28 Feb 2017 12:08:15 +0000 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. Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson --- cputlb.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/cputlb.c b/cputlb.c index 7fa7fefa05..f5d056cc08 100644 --- a/cputlb.c +++ b/cputlb.c @@ -769,14 +769,13 @@ 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(mr)) { - CPUClass *cc = CPU_GET_CLASS(cpu); - - if (cc->do_unassigned_access) { - cc->do_unassigned_access(cpu, addr, false, true, 0, 4); - } else { - report_bad_exec(cpu, addr); - exit(1); - } + 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. + */ + report_bad_exec(cpu, addr); + exit(1); } p = (void *)((uintptr_t)addr + env1->tlb_table[mmu_idx][page_index].addend); return qemu_ram_addr_from_host_nofail(p);