| Message ID | 20170529193016.6888-3-aurelien@aurel32.net |
|---|---|
| State | New |
| Headers | show |
On Mon, May 29, 2017 at 09:30:13PM +0200, Aurelien Jarno wrote: > When a masked exception happens, the SH4 CPU generates a non-masked > reset exception, which then jumps to the reset vector at address > 0xA0000000. While this is emulated correctly in QEMU, this does not > work when using a kernel and initrd as this address then contain an > illegal instruction (and there is no guarantee the kernel and initrd > haven't been overwritten). > > Therefore call qemu_system_reset_request to reload the kernel and initrd > and load the program counter to the kernel entry point. > > Reviewed-by: Richard Henderson <rth@twiddle.net> > Signed-off-by: Aurelien Jarno <aurelien@aurel32.net> > --- > target/sh4/helper.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/target/sh4/helper.c b/target/sh4/helper.c > index 4c024f9529..5296e7cf4e 100644 > --- a/target/sh4/helper.c > +++ b/target/sh4/helper.c > @@ -21,6 +21,7 @@ > #include "cpu.h" > #include "exec/exec-all.h" > #include "exec/log.h" > +#include "sysemu/sysemu.h" > > #if !defined(CONFIG_USER_ONLY) > #include "hw/sh4/sh_intc.h" > @@ -92,7 +93,14 @@ void superh_cpu_do_interrupt(CPUState *cs) > > if (env->sr & (1u << SR_BL)) { > if (do_exp && cs->exception_index != 0x1e0) { > - cs->exception_index = 0x000; /* masked exception -> reset */ > + /* In theory a masked exception generates a reset exception, > + which in turn jumps to the reset vector. However this only > + works when using a bootloader. When using a kernel and an > + initrd, they need to be reloaded and the program counter > + should be loaded with the kernel entry point. > + qemu_system_reset_request takes care of that. */ > + qemu_system_reset_request(); > + return; The qemu_system_reset_request() prototype is changing. There is a conflict with another merged pull request. Please rebase onto https://github.com/stefanha/qemu.git staging. target/sh4/helper.c:102:39: error: too few arguments to function call, single argument 'reason' was not specified qemu_system_reset_request(); ~~~~~~~~~~~~~~~~~~~~~~~~~ ^
On 05/30/2017 05:17 AM, Stefan Hajnoczi wrote: > On Mon, May 29, 2017 at 09:30:13PM +0200, Aurelien Jarno wrote: >> When a masked exception happens, the SH4 CPU generates a non-masked >> reset exception, which then jumps to the reset vector at address >> 0xA0000000. While this is emulated correctly in QEMU, this does not >> work when using a kernel and initrd as this address then contain an >> illegal instruction (and there is no guarantee the kernel and initrd >> haven't been overwritten). >> >> + qemu_system_reset_request(); >> + return; > > The qemu_system_reset_request() prototype is changing. There is a > conflict with another merged pull request. Please rebase onto > https://github.com/stefanha/qemu.git staging. > > target/sh4/helper.c:102:39: error: too few arguments to function call, single argument 'reason' was not specified > qemu_system_reset_request(); > ~~~~~~~~~~~~~~~~~~~~~~~~~ ^ You'll probably want SHUTDOWN_CAUSE_GUEST_RESET as the reason, based on the changes made to other target/ files.
On 2017-05-30 10:02, Eric Blake wrote: > On 05/30/2017 05:17 AM, Stefan Hajnoczi wrote: > > On Mon, May 29, 2017 at 09:30:13PM +0200, Aurelien Jarno wrote: > >> When a masked exception happens, the SH4 CPU generates a non-masked > >> reset exception, which then jumps to the reset vector at address > >> 0xA0000000. While this is emulated correctly in QEMU, this does not > >> work when using a kernel and initrd as this address then contain an > >> illegal instruction (and there is no guarantee the kernel and initrd > >> haven't been overwritten). > >> > > >> + qemu_system_reset_request(); > >> + return; > > > > The qemu_system_reset_request() prototype is changing. There is a > > conflict with another merged pull request. Please rebase onto > > https://github.com/stefanha/qemu.git staging. > > > > target/sh4/helper.c:102:39: error: too few arguments to function call, single argument 'reason' was not specified > > qemu_system_reset_request(); > > ~~~~~~~~~~~~~~~~~~~~~~~~~ ^ > > You'll probably want SHUTDOWN_CAUSE_GUEST_RESET as the reason, based on > the changes made to other target/ files. Indeed I confirm. This is the same as the triple fault on x86, which uses SHUTDOWN_CAUSE_GUEST_RESET.
diff --git a/target/sh4/helper.c b/target/sh4/helper.c index 4c024f9529..5296e7cf4e 100644 --- a/target/sh4/helper.c +++ b/target/sh4/helper.c @@ -21,6 +21,7 @@ #include "cpu.h" #include "exec/exec-all.h" #include "exec/log.h" +#include "sysemu/sysemu.h" #if !defined(CONFIG_USER_ONLY) #include "hw/sh4/sh_intc.h" @@ -92,7 +93,14 @@ void superh_cpu_do_interrupt(CPUState *cs) if (env->sr & (1u << SR_BL)) { if (do_exp && cs->exception_index != 0x1e0) { - cs->exception_index = 0x000; /* masked exception -> reset */ + /* In theory a masked exception generates a reset exception, + which in turn jumps to the reset vector. However this only + works when using a bootloader. When using a kernel and an + initrd, they need to be reloaded and the program counter + should be loaded with the kernel entry point. + qemu_system_reset_request takes care of that. */ + qemu_system_reset_request(); + return; } if (do_irq && !env->in_sleep) { return; /* masked */