Re: [Qemu-devel] [PATCH v6 2/2] Add Nios II semihosting support.

2019-03-26 Thread Peter Maydell 
On Thu, 21 Mar 2019 at 18:40, Sandra Loosemore  wrote:
>
> This patch adds support for libgloss semihosting to Nios II bare-metal
> emulation.  The specification for the protocol can be found in the
> libgloss sources.
>
> Signed-off-by: Sandra Loosemore 
> Signed-off-by: Julian Brown 

> --- /dev/null
> +++ b/target/nios2/nios2-semi.c
> @@ -0,0 +1,448 @@
> +/*
> + *  Nios II Semihosting syscall interface.
> + *  This code is derived from m68k-semi.c.
> + *
> + *  Copyright (c) 2017-2019 Mentor Graphics
> + *
> + *  This program is free software; you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation; either version 2 of the License, or
> + *  (at your option) any later version.
> + *
> + *  This program is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with this program; if not, see .

Could we have a URL for the spec of the semihosting ABI,
whereever you decide it should live, please?

Otherwise
Reviewed-by: Peter Maydell 

thanks
-- PMM

[Qemu-devel] [PATCH v6 2/2] Add Nios II semihosting support.

2019-03-21 Thread Sandra Loosemore 
This patch adds support for libgloss semihosting to Nios II bare-metal
emulation.  The specification for the protocol can be found in the
libgloss sources.

Signed-off-by: Sandra Loosemore 
Signed-off-by: Julian Brown 
---
 qemu-options.hx|   8 +-
 target/nios2/Makefile.objs |   2 +-
 target/nios2/cpu.h |   4 +-
 target/nios2/helper.c  |  13 ++
 target/nios2/nios2-semi.c  | 448 +
 5 files changed, 469 insertions(+), 6 deletions(-)
 create mode 100644 target/nios2/nios2-semi.c

diff --git a/qemu-options.hx b/qemu-options.hx
index 08749a3..4135d5d 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3968,21 +3968,21 @@ ETEXI
 DEF("semihosting", 0, QEMU_OPTION_semihosting,
 "-semihostingsemihosting mode\n",
 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
-QEMU_ARCH_MIPS)
+QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2)
 STEXI
 @item -semihosting
 @findex -semihosting
-Enable semihosting mode (ARM, M68K, Xtensa, MIPS only).
+Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II only).
 ETEXI
 DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config,
 "-semihosting-config 
[enable=on|off][,target=native|gdb|auto][,arg=str[,...]]\n" \
 "semihosting configuration\n",
 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
-QEMU_ARCH_MIPS)
+QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2)
 STEXI
 @item -semihosting-config 
[enable=on|off][,target=native|gdb|auto][,arg=str[,...]]
 @findex -semihosting-config
-Enable and configure semihosting (ARM, M68K, Xtensa, MIPS only).
+Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II only).
 @table @option
 @item target=@code{native|gdb|auto}
 Defines where the semihosting calls will be addressed, to QEMU (@code{native})
diff --git a/target/nios2/Makefile.objs b/target/nios2/Makefile.objs
index 2a11c5c..010de0e 100644
--- a/target/nios2/Makefile.objs
+++ b/target/nios2/Makefile.objs
@@ -1,4 +1,4 @@
-obj-y += translate.o op_helper.o helper.o cpu.o mmu.o
+obj-y += translate.o op_helper.o helper.o cpu.o mmu.o nios2-semi.o
 obj-$(CONFIG_SOFTMMU) += monitor.o
 
 $(obj)/op_helper.o: QEMU_CFLAGS += $(HELPER_CFLAGS)
diff --git a/target/nios2/cpu.h b/target/nios2/cpu.h
index 047f376..afd30d5 100644
--- a/target/nios2/cpu.h
+++ b/target/nios2/cpu.h
@@ -141,7 +141,7 @@ typedef struct Nios2CPUClass {
 #define R_PC 64
 
 /* Exceptions */
-#define EXCP_BREAK-1
+#define EXCP_BREAK0x1000
 #define EXCP_RESET0
 #define EXCP_PRESET   1
 #define EXCP_IRQ  2
@@ -223,6 +223,8 @@ void nios2_cpu_do_unaligned_access(CPUState *cpu, vaddr 
addr,
 qemu_irq *nios2_cpu_pic_init(Nios2CPU *cpu);
 void nios2_check_interrupts(CPUNios2State *env);
 
+void do_nios2_semihosting(CPUNios2State *env);
+
 #define TARGET_PHYS_ADDR_SPACE_BITS 32
 #ifdef CONFIG_USER_ONLY
 # define TARGET_VIRT_ADDR_SPACE_BITS 31
diff --git a/target/nios2/helper.c b/target/nios2/helper.c
index a8b8ec6..bb0a784 100644
--- a/target/nios2/helper.c
+++ b/target/nios2/helper.c
@@ -23,8 +23,10 @@
 #include "cpu.h"
 #include "qemu/host-utils.h"
 #include "exec/exec-all.h"
+#include "exec/cpu_ldst.h"
 #include "exec/log.h"
 #include "exec/helper-proto.h"
+#include "exec/semihost.h"
 
 #if defined(CONFIG_USER_ONLY)
 
@@ -169,6 +171,17 @@ void nios2_cpu_do_interrupt(CPUState *cs)
 break;
 
 case EXCP_BREAK:
+qemu_log_mask(CPU_LOG_INT, "BREAK exception at pc=%x\n",
+  env->regs[R_PC]);
+/* The semihosting instruction is "break 1".  */
+if (semihosting_enabled() &&
+cpu_ldl_code(env, env->regs[R_PC]) == 0x003da07a)  {
+qemu_log_mask(CPU_LOG_INT, "Entering semihosting\n");
+env->regs[R_PC] += 4;
+do_nios2_semihosting(env);
+break;
+}
+
 if ((env->regs[CR_STATUS] & CR_STATUS_EH) == 0) {
 env->regs[CR_BSTATUS] = env->regs[CR_STATUS];
 env->regs[R_BA] = env->regs[R_PC] + 4;
diff --git a/target/nios2/nios2-semi.c b/target/nios2/nios2-semi.c
new file mode 100644
index 000..4e45a27
--- /dev/null
+++ b/target/nios2/nios2-semi.c
@@ -0,0 +1,448 @@
+/*
+ *  Nios II Semihosting syscall interface.
+ *  This code is derived from m68k-semi.c.
+ *
+ *  Copyright (c) 2017-2019 Mentor Graphics
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see