Am 12.08.2013 21:44, schrieb Aurelien Jarno: > Since commit c658b94f6e8c206c59d02aa6fbac285b86b53d2c, MIPS raises > exceptions when accessing invalid memory. This is not the correct > behaviour for MIPS Malta Core LV, as the GT-64120A system controller > just ignore undecoded access. This feature is used by the Linux kernel > to probe for some devices. > > Emulate the correct behaviour in QEMU by adding an empty slot covering > the entire memory space decoded by the GT-64120A. > > Signed-off-by: Aurelien Jarno <aurel...@aurel32.net> > --- > default-configs/mips-softmmu.mak | 1 + > default-configs/mips64-softmmu.mak | 1 + > default-configs/mips64el-softmmu.mak | 1 + > default-configs/mipsel-softmmu.mak | 1 + > hw/mips/mips_malta.c | 6 ++++++ > 5 files changed, 10 insertions(+) > > diff --git a/default-configs/mips-softmmu.mak > b/default-configs/mips-softmmu.mak > index 926709a..71177ef 100644 > --- a/default-configs/mips-softmmu.mak > +++ b/default-configs/mips-softmmu.mak > @@ -34,3 +34,4 @@ CONFIG_JAZZ_LED=y > CONFIG_MC146818RTC=y > CONFIG_VT82C686=y > CONFIG_ISA_TESTDEV=y > +CONFIG_EMPTY_SLOT=y > diff --git a/default-configs/mips64-softmmu.mak > b/default-configs/mips64-softmmu.mak > index 0ef3f09..617301b 100644 > --- a/default-configs/mips64-softmmu.mak > +++ b/default-configs/mips64-softmmu.mak > @@ -34,3 +34,4 @@ CONFIG_JAZZ_LED=y > CONFIG_MC146818RTC=y > CONFIG_VT82C686=y > CONFIG_ISA_TESTDEV=y > +CONFIG_EMPTY_SLOT=y > diff --git a/default-configs/mips64el-softmmu.mak > b/default-configs/mips64el-softmmu.mak > index 6089318..317b151 100644 > --- a/default-configs/mips64el-softmmu.mak > +++ b/default-configs/mips64el-softmmu.mak > @@ -36,3 +36,4 @@ CONFIG_JAZZ_LED=y > CONFIG_MC146818RTC=y > CONFIG_VT82C686=y > CONFIG_ISA_TESTDEV=y > +CONFIG_EMPTY_SLOT=y > diff --git a/default-configs/mipsel-softmmu.mak > b/default-configs/mipsel-softmmu.mak > index cd59e24..532a9ae 100644 > --- a/default-configs/mipsel-softmmu.mak > +++ b/default-configs/mipsel-softmmu.mak > @@ -34,3 +34,4 @@ CONFIG_JAZZ_LED=y > CONFIG_MC146818RTC=y > CONFIG_VT82C686=y > CONFIG_ISA_TESTDEV=y > +CONFIG_EMPTY_SLOT=y > diff --git a/hw/mips/mips_malta.c b/hw/mips/mips_malta.c > index 0f5de33..61cb3e4 100644 > --- a/hw/mips/mips_malta.c > +++ b/hw/mips/mips_malta.c > @@ -50,6 +50,7 @@ > #include "qemu/host-utils.h" > #include "sysemu/qtest.h" > #include "qemu/error-report.h" > +#include "hw/empty_slot.h" > > //#define DEBUG_BOARD_INIT > > @@ -908,6 +909,11 @@ void mips_malta_init(QEMUMachineInitArgs *args) > DeviceState *dev = qdev_create(NULL, TYPE_MIPS_MALTA); > MaltaState *s = MIPS_MALTA(dev); > > + /* The whole address space decoded by the GT-64120A doesn't generate > + exception when accessing invalid memory. Create an empty slot to > + emulate this feature. */ > + empty_slot_init(0, 0x1fffffff); > + > qdev_init_nofail(dev); > > /* Make sure the first 3 serial ports are associated with a device. */
Hello Aurelien, the patch fixes Linux boot with Malta, therefore Tested-by: Stefan Weil <s...@weilnetz.de> The 2nd parameter of empty_slot_init is not the end address but the length, so I think it should be 0x20000000. With this modification, the patch is good for 1.6. I did not find a hint in the GT-64120A documentation about handling of addresses without connected devices. It is still strange that the exception handler throws a secondary exception with the current code. Regards, Stefan
