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gem5: add m5 fail 1 to /m5op.out

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Document that m5 fail is not actually exiting status 1 on fs.py.
This commit is contained in:
Ciro Santilli
2018-08-24 10:48:02 +01:00
parent 6fadc5ec93
commit 6d51da52bb
2 changed files with 63 additions and 16 deletions
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44
README.adoc
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@@ -8221,16 +8221,36 @@ It is possible to guess what most tools do from the corresponding <<m5ops>>, but
===== m5 exit
Quit gem5 with exit status 0.
End the simulation.
Sane Python scripts will exit gem5 with status 0, which is what `fs.py` does.
===== m5 fail
Quit gem5 with the given exit status.
End the simulation with a failure exit event:
....
m5 fail 1
....
Sane Python scripts would use that as the exit status of gem5, which would be useful for testing purposes, but `fs.py` at 200281b08ca21f0d2678e23063f088960d3c0819 just prints an error message:
....
Simulated exit code not 0! Exit code is 1
....
and exits with status 0.
TODO: it used to exit non 0, be like that, but it actually got changed to just print the message. Why? https://gem5-review.googlesource.com/c/public/gem5/+/4880
`m5 fail` is just a superset of `m5 exit`, which is just:
....
m5 fail 0
....
as can be seen from the source: https://github.com/gem5/gem5/blob/50a57c0376c02c912a978c4443dd58caebe0f173/src/sim/pseudo_inst.cc#L303
===== m5 writefile
Send a guest file to the host. <<9p>> is a more advanced alternative.
@@ -8294,10 +8314,13 @@ The executable `/m5ops.out` illustrates how to hard code with inline assembly th
....
# checkpoint
/m5ops.out c
# dumpstats
/m5ops.out d
# dump exit
# exit
/m5ops.out e
# dump resetstats
/m5ops.out r
....
@@ -8359,7 +8382,20 @@ Finally, `m5.c` calls the defined functions as in:
m5_exit(ints[0]);
....
Therefore, the runtime "argument" that gets passed to the instruction, e.g. the desired exit status in the case of `exit`, gets passed directly through the link:https://en.wikipedia.org/wiki/Calling_convention#ARM_(A64)[aarch64 calling convention].
Therefore, the runtime "argument" that gets passed to the instruction, e.g. the delay in ticks until the exit for `m5 exit`, gets passed directly through the link:https://en.wikipedia.org/wiki/Calling_convention#ARM_(A64)[aarch64 calling convention].
Keep in mind that for all archs, `m5.c` does the calls with 64-bit integers:
....
uint64_t ints[2] = {0,0};
parse_int_args(argc, argv, ints, argc);
m5_fail(ints[1], ints[0]);
....
Therefore, for example:
* aarch64 uses `x0` for the first argument and `x1` for the second, since each is 64 bits log already
* arm uses `r0` and `r1` for the first argument, and `r2` and `r3` for the second, since each register is only 32 bits long
That convention specifies that `x0` to `x7` contain the function arguments, so `x0` contains the first argument, and `x1` the second.

35
kernel_module/user/m5ops.c
View File

@@ -6,36 +6,44 @@
#define ENABLED 1
#if defined(__arm__)
static void m5_checkpoint()
static void m5_checkpoint(void)
{
__asm__ __volatile__ ("mov r0, #0; mov r1, #0; .inst 0xEE000110 | (0x43 << 16);");
__asm__ __volatile__ ("mov r0, #0; mov r1, #0; mov r2, #0; mov r3, #0; .inst 0xEE000110 | (0x43 << 16);");
};
static void m5_dump_stats()
static void m5_dump_stats(void)
{
__asm__ __volatile__ ("mov r0, #0; mov r1, #0; .inst 0xEE000110 | (0x41 << 16);");
__asm__ __volatile__ ("mov r0, #0; mov r1, #0; mov r2, #0; mov r3, #0; .inst 0xEE000110 | (0x41 << 16);");
};
static void m5_exit()
{
__asm__ __volatile__ ("mov r0, #0; .inst 0xEE000110 | (0x21 << 16);");
};
static void m5_reset_stats()
static void m5_fail_1(void)
{
__asm__ __volatile__ ("mov r0, #0; mov r1, #0; .inst 0xEE000110 | (0x40 << 16);");
__asm__ __volatile__ ("mov r0, #0; mov r1, #0; mov r2, #1; mov r3, #0; .inst 0xEE000110 | (0x22 << 16);");
};
static void m5_reset_stats(void)
{
__asm__ __volatile__ ("mov r0, #0; mov r1, #0; mov r2, #0; mov r3, #0; .inst 0xEE000110 | (0x40 << 16);");
};
#elif defined(__aarch64__)
static void m5_checkpoint()
static void m5_checkpoint(void)
{
__asm__ __volatile__ ("mov x0, #0; mov x1, #0; .inst 0xFF000110 | (0x43 << 16);");
};
static void m5_dump_stats()
static void m5_dump_stats(void)
{
__asm__ __volatile__ ("mov x0, #0; mov x1, #0; .inst 0xFF000110 | (0x41 << 16);");
};
static void m5_exit()
static void m5_exit(void)
{
__asm__ __volatile__ ("mov x0, #0; .inst 0XFF000110 | (0x21 << 16);");
};
static void m5_reset_stats()
static void m5_fail_1(void)
{
__asm__ __volatile__ ("mov x0, #0; mov x1, #1; .inst 0xFF000110 | (0x22 << 16);");
};
static void m5_reset_stats(void)
{
__asm__ __volatile__ ("mov x0, #0; mov x1, #0; .inst 0XFF000110 | (0x40 << 16);");
};
@@ -62,14 +70,17 @@ void
switch (action)
{
case 'c':
m5_checkpoint(0, 0);
m5_checkpoint();
break;
case 'd':
m5_dump_stats(0, 0);
m5_dump_stats();
break;
case 'e':
m5_exit();
break;
case 'f':
m5_fail_1();
break;
case 'r':
m5_reset_stats();
break;