[Qemu-devel] [PATCH] armv7m: optional -kernel if -gdb present
For standalone emulation, the image must be specified via -kernel,
but when using QEMU as a GDB server, the presence of -kernel is
no longer mandatory, since the image can be loaded by the GDB client.
Signed-off-by: Liviu Ionescu i...@livius.net
---
hw/arm/armv7m.c | 3 ++-
include/sysemu/sysemu.h | 1 +
vl.c| 7 ++-
3 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/hw/arm/armv7m.c b/hw/arm/armv7m.c
index 696de12..9d1669c 100644
--- a/hw/arm/armv7m.c
+++ b/hw/arm/armv7m.c
@@ -14,6 +14,7 @@
#include sysemu/qtest.h
#include qemu/error-report.h
#include hw/boards.h
+#include sysemu/sysemu.h
static struct arm_boot_info armv7m_binfo;
@@ -241,7 +242,7 @@ qemu_irq *armv7m_init(MemoryRegion *system_memory,
big_endian = 0;
#endif
-if (!kernel_filename !qtest_enabled()) {
+if (!kernel_filename !qtest_enabled() !with_gdb) {
fprintf(stderr, Guest image must be specified (using -kernel)\n);
exit(1);
}
diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index c145d94..08bbe71 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -104,6 +104,7 @@ typedef enum DisplayType
} DisplayType;
extern int autostart;
+extern int with_gdb;
typedef enum {
VGA_NONE, VGA_STD, VGA_CIRRUS, VGA_VMWARE, VGA_XENFB, VGA_QXL,
diff --git a/vl.c b/vl.c
index a88e5da..4a03fb8 100644
--- a/vl.c
+++ b/vl.c
@@ -138,6 +138,7 @@ bool enable_mlock = false;
int nb_nics;
NICInfo nd_table[MAX_NICS];
int autostart;
+int with_gdb;
static int rtc_utc = 1;
static int rtc_date_offset = -1; /* -1 means no change */
QEMUClockType rtc_clock;
@@ -2797,6 +2798,7 @@ int main(int argc, char **argv, char **envp)
uint64_t ram_slots = 0;
FILE *vmstate_dump_file = NULL;
Error *main_loop_err = NULL;
+with_gdb = false;
atexit(qemu_run_exit_notifiers);
error_set_progname(argv[0]);
@@ -3241,9 +3243,11 @@ int main(int argc, char **argv, char **envp)
break;
case QEMU_OPTION_s:
add_device_config(DEV_GDB, tcp:: DEFAULT_GDBSTUB_PORT);
+with_gdb = true;
break;
case QEMU_OPTION_gdb:
add_device_config(DEV_GDB, optarg);
+with_gdb = true;
break;
case QEMU_OPTION_L:
if (data_dir_idx ARRAY_SIZE(data_dir)) {
@@ -4443,7 +4447,8 @@ int main(int argc, char **argv, char **envp)
error_free(local_err);
exit(1);
}
-} else if (autostart) {
+} else if (autostart kernel_filename) {
+/* If an image is defined and no -S is requested, start it. */
vm_start();
}
--
1.9.3 (Apple Git-50)
Re: [Qemu-devel] [PATCH] armv7m: optional -kernel if -gdb present
On 20 November 2014 12:05, Liviu Ionescu i...@livius.net wrote:
For standalone emulation, the image must be specified via -kernel,
but when using QEMU as a GDB server, the presence of -kernel is
no longer mandatory, since the image can be loaded by the GDB client.
I think the correct fix for this issue is:
-if (!kernel_filename !qtest_enabled()) {
+if (!kernel_filename !qtest_enabled() !with_gdb) {
fprintf(stderr, Guest image must be specified (using -kernel)\n);
exit(1);
}
just delete this entire if() statement. This is how we've handled
similar issues with the ARM A profile boards. (Some of the boards
still have those checks but that's just because nobody's bothered
to fix them yet.)
thanks
-- PMM
Re: [Qemu-devel] [PATCH] armv7m: optional -kernel if -gdb present
On 20 Nov 2014, at 14:29, Peter Maydell peter.mayd...@linaro.org wrote:
-if (!kernel_filename !qtest_enabled()) {
+if (!kernel_filename !qtest_enabled() !with_gdb) {
fprintf(stderr, Guest image must be specified (using -kernel)\n);
exit(1);
}
just delete this entire if() statement. This is how we've handled
similar issues with the ARM A profile boards. (Some of the boards
still have those checks but that's just because nobody's bothered
to fix them yet.)
I'm a bit confused. if not running with gdb, what is the expected behaviour if
the image is missing?
Liviu
Re: [Qemu-devel] [PATCH] armv7m: optional -kernel if -gdb present
On 20 November 2014 12:34, Liviu Ionescu i...@livius.net wrote:
On 20 Nov 2014, at 14:29, Peter Maydell peter.mayd...@linaro.org wrote:
-if (!kernel_filename !qtest_enabled()) {
+if (!kernel_filename !qtest_enabled() !with_gdb) {
fprintf(stderr, Guest image must be specified (using -kernel)\n);
exit(1);
}
just delete this entire if() statement. This is how we've handled
similar issues with the ARM A profile boards. (Some of the boards
still have those checks but that's just because nobody's bothered
to fix them yet.)
I'm a bit confused. if not running with gdb, what is the expected
behaviour if the image is missing?
Same thing as if you start a hardware board with nothing loaded
into the flash. (Probably this means go into an infinite loop
of taking exceptions.)
-- PMM
Re: [Qemu-devel] [PATCH] armv7m: optional -kernel if -gdb present
On 20 Nov 2014, at 14:50, Peter Maydell peter.mayd...@linaro.org wrote: Same thing as if you start a hardware board with nothing loaded into the flash. (Probably this means go into an infinite loop of taking exceptions.) hmmm... and you consider this behaviour to meet the user-friendly requirements? I tried it, and the program simply hangs, without any stdout/stderr messages. if you find this behaviour acceptable for unix users, ok, you don't have to update the other profiles, but for most cortex-m users it is confusing, and user-friendliness is not only appreciated, but required. I would appreciate you reconsider the patch. thank you, Liviu
Re: [Qemu-devel] [PATCH] armv7m: optional -kernel if -gdb present
On 20 November 2014 13:09, Liviu Ionescu i...@livius.net wrote: On 20 Nov 2014, at 14:50, Peter Maydell peter.mayd...@linaro.org wrote: Same thing as if you start a hardware board with nothing loaded into the flash. (Probably this means go into an infinite loop of taking exceptions.) hmmm... and you consider this behaviour to meet the user-friendly requirements? I tried it, and the program simply hangs, without any stdout/stderr messages. Yes. That's what hardware does in that situation. I don't think that whether or not a debugger has been connected should change our behaviour. (And even with your patch, if you connect a debugger and just hit its 'run' button without loading an image then we'll do the same exception-loop.) if you find this behaviour acceptable for unix users, ok, you don't have to update the other profiles, but for most cortex-m users it is confusing, and user-friendliness is not only appreciated, but required. I agree it's not very user friendly. But I don't like inconsistency between our behaviour for different boards either. (And for some boards we're going to have a bios or other firmware which will run if you don't specify -kernel.) In general I think many of the concerns you're raising here are real problems, and our user-friendliness is indeed poor in a lot of places. However the solutions you're proposing are often specific to M-profile ARM, whereas I have to consider the whole project and would prefer solutions which clean up and deal with an issue for all boards and all CPUs. That's obviously harder than a more local and restricted fix, but the benefit is greater. thanks -- PMM
Re: [Qemu-devel] [PATCH] armv7m: optional -kernel if -gdb present
On 20 Nov 2014, at 15:20, Peter Maydell peter.mayd...@linaro.org wrote: ... However the solutions you're proposing are often specific to M-profile ARM, ok, I'll keep this local to my branch. what about the previous patch, is it acceptable? regards, Liviu
