Merge remote-tracking branch 'remotes/amarkovic/tags/mips-queue-sep-12-2019' into staging

MIPS queue for September 12th, 2019

# gpg: Signature made Thu 12 Sep 2019 17:26:10 BST
# gpg:                using RSA key D4972A8967F75A65
# gpg: Good signature from "Aleksandar Markovic <amarkovic@wavecomp.com>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 8526 FBF1 5DA3 811F 4A01  DD75 D497 2A89 67F7 5A65

* remotes/amarkovic/tags/mips-queue-sep-12-2019:
  target/mips: gdbstub: Revert commit 8e0b373
  hw/mips/mips_jazz: Remove no-longer-necessary override of do_unassigned_access
  target/mips: Switch to do_transaction_failed() hook
  hw/mips/mips_jazz: Override do_transaction_failed hook

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 33 insertions, 14 deletions

diff --git a/hw/mips/mips_jazz.c b/hw/mips/mips_jazz.c
index 388c15c376..c967b97d80 100644
--- a/hw/mips/mips_jazz.c
+++ b/hw/mips/mips_jazz.c
@@ -111,16 +111,26 @@ static const MemoryRegionOps dma_dummy_ops = {
 #define MAGNUM_BIOS_SIZE_MAX 0x7e000
 #define MAGNUM_BIOS_SIZE (BIOS_SIZE < MAGNUM_BIOS_SIZE_MAX ? BIOS_SIZE : MAGNUM_BIOS_SIZE_MAX)
 
-static CPUUnassignedAccess real_do_unassigned_access;
-static void mips_jazz_do_unassigned_access(CPUState *cpu, hwaddr addr,
-                                           bool is_write, bool is_exec,
-                                           int opaque, unsigned size)
+static void (*real_do_transaction_failed)(CPUState *cpu, hwaddr physaddr,
+                                          vaddr addr, unsigned size,
+                                          MMUAccessType access_type,
+                                          int mmu_idx, MemTxAttrs attrs,
+                                          MemTxResult response,
+                                          uintptr_t retaddr);
+
+static void mips_jazz_do_transaction_failed(CPUState *cs, hwaddr physaddr,
+                                            vaddr addr, unsigned size,
+                                            MMUAccessType access_type,
+                                            int mmu_idx, MemTxAttrs attrs,
+                                            MemTxResult response,
+                                            uintptr_t retaddr)
 {
-    if (!is_exec) {
+    if (access_type != MMU_INST_FETCH) {
         /* ignore invalid access (ie do not raise exception) */
         return;
     }
-    (*real_do_unassigned_access)(cpu, addr, is_write, is_exec, opaque, size);
+    (*real_do_transaction_failed)(cs, physaddr, addr, size, access_type,
+                                  mmu_idx, attrs, response, retaddr);
 }
 
 static void mips_jazz_init(MachineState *machine,
@@ -157,16 +167,25 @@ static void mips_jazz_init(MachineState *machine,
     env = &cpu->env;
     qemu_register_reset(main_cpu_reset, cpu);
 
-    /* Chipset returns 0 in invalid reads and do not raise data exceptions.
+    /*
+     * Chipset returns 0 in invalid reads and do not raise data exceptions.
      * However, we can't simply add a global memory region to catch
-     * everything, as memory core directly call unassigned_mem_read/write
-     * on some invalid accesses, which call do_unassigned_access on the
-     * CPU, which raise an exception.
-     * Handle that case by hijacking the do_unassigned_access method on
-     * the CPU, and do not raise exceptions for data access. */
+     * everything, as this would make all accesses including instruction
+     * accesses be ignored and not raise exceptions.
+     * So instead we hijack the do_transaction_failed method on the CPU, and
+     * do not raise exceptions for data access.
+     *
+     * NOTE: this behaviour of raising exceptions for bad instruction
+     * fetches but not bad data accesses was added in commit 54e755588cf1e9
+     * to restore behaviour broken by c658b94f6e8c206, but it is not clear
+     * whether the real hardware behaves this way. It is possible that
+     * real hardware ignores bad instruction fetches as well -- if so then
+     * we could replace this hijacking of CPU methods with a simple global
+     * memory region that catches all memory accesses, as we do on Malta.
+     */
     cc = CPU_GET_CLASS(cpu);
-    real_do_unassigned_access = cc->do_unassigned_access;
-    cc->do_unassigned_access = mips_jazz_do_unassigned_access;
+    real_do_transaction_failed = cc->do_transaction_failed;
+    cc->do_transaction_failed = mips_jazz_do_transaction_failed;
 
     /* allocate RAM */
     memory_region_allocate_system_memory(ram, NULL, "mips_jazz.ram",