Re: [PATCH v1 12/22] plugins: stxp test case from Aaron (!upstream)

[Aaron Lindsay]

On Feb 01 15:29, Alex Bennée wrote:
> 
> Aaron Lindsay <aaron@os.amperecomputing.com> writes:
> 
> > On Jan 24 20:15, Alex Bennée wrote:
> >> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> >> Cc: Aaron Lindsay <aaron@os.amperecomputing.com>
> >> Message-ID: <YXCA62xdRDeueQR6@strawberry.localdomain>
> >> 
> >> ---
> >> [AJB] this was for testing, I think you can show the same stuff with
> >> the much more complete execlog now.
> >
> > Is it true that execlog can also reproduce the duplicate loads which are
> > still an outstanding issue?
> 
> Are we still seeing duplicate loads? I thought that had been fixed.

I have not explicitly tested for the duplicate loads on atomics lately
(though I have seen some transient behavior related to atomics that I
have struggled to reliably reproduce, but I believe that's a different
issue). I hadn't seen a subsequent fix come through after the initial
fix for stores and assumed it was still an issue. Sorry for my
assumption, particularly if I just missed it.

-Aaron

> >> ---
> >>  contrib/plugins/stxp-plugin.c     | 50 +++++++++++++++++++++++++++++++
> >>  tests/tcg/aarch64/stxp.c          | 28 +++++++++++++++++
> >>  contrib/plugins/Makefile          |  1 +
> >>  tests/tcg/aarch64/Makefile.target |  3 ++
> >>  4 files changed, 82 insertions(+)
> >>  create mode 100644 contrib/plugins/stxp-plugin.c
> >>  create mode 100644 tests/tcg/aarch64/stxp.c
> >> 
> >> diff --git a/contrib/plugins/stxp-plugin.c b/contrib/plugins/stxp-plugin.c
> >> new file mode 100644
> >> index 0000000000..432cf8c1ed
> >> --- /dev/null
> >> +++ b/contrib/plugins/stxp-plugin.c
> >> @@ -0,0 +1,50 @@
> >> +#include <stdio.h>
> >> +#include <stdarg.h>
> >> +#include <qemu-plugin.h>
> >> +
> >> +QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION;
> >> +
> >> +void qemu_logf(const char *str, ...)
> >> +{
> >> +    char message[1024];
> >> +    va_list args;
> >> +    va_start(args, str);
> >> +    vsnprintf(message, 1023, str, args);
> >> +
> >> +    qemu_plugin_outs(message);
> >> +
> >> +    va_end(args);
> >> +}
> >> +
> >> +void before_insn_cb(unsigned int cpu_index, void *udata)
> >> +{
> >> +    uint64_t pc = (uint64_t)udata;
> >> +    qemu_logf("Executing PC: 0x%" PRIx64 "\n", pc);
> >> +}
> >> +
> >> +static void mem_cb(unsigned int cpu_index, qemu_plugin_meminfo_t meminfo, 
> >> uint64_t va, void *udata)
> >> +{
> >> +    uint64_t pc = (uint64_t)udata;
> >> +    qemu_logf("PC 0x%" PRIx64 " accessed memory at 0x%" PRIx64 "\n", pc, 
> >> va);
> >> +}
> >> +
> >> +static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
> >> +{
> >> +    size_t n = qemu_plugin_tb_n_insns(tb);
> >> +
> >> +    for (size_t i = 0; i < n; i++) {
> >> +        struct qemu_plugin_insn *insn = qemu_plugin_tb_get_insn(tb, i);
> >> +        uint64_t pc = qemu_plugin_insn_vaddr(insn);
> >> +
> >> +        qemu_plugin_register_vcpu_insn_exec_cb(insn, before_insn_cb, 
> >> QEMU_PLUGIN_CB_R_REGS, (void *)pc);
> >> +        qemu_plugin_register_vcpu_mem_cb(insn, mem_cb, 
> >> QEMU_PLUGIN_CB_NO_REGS, QEMU_PLUGIN_MEM_RW, (void*)pc);
> >> +    }
> >> +}
> >> +
> >> +QEMU_PLUGIN_EXPORT
> >> +int qemu_plugin_install(qemu_plugin_id_t id, const qemu_info_t *info,
> >> +                        int argc, char **argv)
> >> +{
> >> +    qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans);
> >> +    return 0;
> >> +}
> >> diff --git a/tests/tcg/aarch64/stxp.c b/tests/tcg/aarch64/stxp.c
> >> new file mode 100644
> >> index 0000000000..fb8ef6a46d
> >> --- /dev/null
> >> +++ b/tests/tcg/aarch64/stxp.c
> >> @@ -0,0 +1,28 @@
> >> +
> >> +
> >> +void stxp_issue_demo(void *arr)
> >> +{
> >> +    asm(".align 8\n\t"
> >> +        "    mov x0, %[in]\n\t"
> >> +        "    mov x18, 0x1000\n\t"
> >> +        "    mov x2, 0x0\n\t"
> >> +        "    mov x3, 0x0\n\t"
> >> +        "loop:\n\t"
> >> +        "    prfm  pstl1strm, [x0]\n\t"
> >> +        "    ldxp  x16, x17, [x0]\n\t"
> >> +        "    stxp  w16, x2, x3, [x0]\n\t"
> >> +        "\n\t"
> >> +        "    subs x18, x18, 1\n\t"
> >> +        "    beq done\n\t"
> >> +        "    b loop\n\t"
> >> +        "done:\n\t"
> >> +        : /* none out */
> >> +        : [in] "r" (arr) /* in */
> >> +        : "x0", "x2", "x3", "x16", "x17", "x18"); /* clobbers */
> >> +}
> >> +
> >> +int main()
> >> +{
> >> +    char arr[16];
> >> +    stxp_issue_demo(&arr);
> >> +}
> >> diff --git a/contrib/plugins/Makefile b/contrib/plugins/Makefile
> >> index 54ac5ccd9f..576ed5875a 100644
> >> --- a/contrib/plugins/Makefile
> >> +++ b/contrib/plugins/Makefile
> >> @@ -20,6 +20,7 @@ NAMES += howvec
> >>  NAMES += lockstep
> >>  NAMES += hwprofile
> >>  NAMES += cache
> >> +NAMES += stxp-plugin
> >>  
> >>  SONAMES := $(addsuffix .so,$(addprefix lib,$(NAMES)))
> >>  
> >> diff --git a/tests/tcg/aarch64/Makefile.target 
> >> b/tests/tcg/aarch64/Makefile.target
> >> index 1d967901bd..54b2e90d00 100644
> >> --- a/tests/tcg/aarch64/Makefile.target
> >> +++ b/tests/tcg/aarch64/Makefile.target
> >> @@ -72,4 +72,7 @@ endif
> >>  
> >>  endif
> >>  
> >> +# Load/Store exclusive test
> >> +AARCH64_TESTS += stxp
> >> +
> >>  TESTS += $(AARCH64_TESTS)
> >> -- 
> >> 2.30.2
> >> 
> 
> 
> -- 
> Alex Bennée