/*
* Ptrace test for TAR, PPR, DSCR registers in the TM context
*
* Copyright (C) 2015 Anshuman Khandual, IBM Corporation.
*
* 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.
*/
#include "ptrace.h"
#include "tm.h"
#include "ptrace-tar.h"
int shm_id;
unsigned long *cptr, *pptr;
void tm_tar(void)
{
unsigned long result, texasr;
unsigned long regs[3];
int ret;
cptr = (unsigned long *)shmat(shm_id, NULL, 0);
trans:
cptr[1] = 0;
asm __volatile__(
"li 4, %[tar_1];"
"mtspr %[sprn_tar], 4;" /* TAR_1 */
"li 4, %[dscr_1];"
"mtspr %[sprn_dscr], 4;" /* DSCR_1 */
"or 31,31,31;" /* PPR_1*/
"1: ;"
"tbegin.;"
"beq 2f;"
"li 4, %[tar_2];"
"mtspr %[sprn_tar], 4;" /* TAR_2 */
"li 4, %[dscr_2];"
"mtspr %[sprn_dscr], 4;" /* DSCR_2 */
"or 1,1,1;" /* PPR_2 */
"tsuspend.;"
"li 0, 1;"
"stw 0, 0(%[cptr1]);"
"tresume.;"
"b .;"
"tend.;"
"li 0, 0;"
"ori %[res], 0, 0;"
"b 3f;"
/* Transaction abort handler */
"2: ;"
"li 0, 1;"
"ori %[res], 0, 0;"
"mfspr %[texasr], %[sprn_texasr];"
"3: ;"
: [res] "=r" (result), [texasr] "=r" (texasr)
: [sprn_dscr]"i"(SPRN_DSCR), [sprn_tar]"i"(SPRN_TAR),
[sprn_ppr]"i"(SPRN_PPR), [sprn_texasr]"i"(SPRN_TEXASR),
[tar_1]"i"(TAR_1), [dscr_1]"i"(DSCR_1), [tar_2]"i"(TAR_2),
[dscr_2]"i"(DSCR_2), [cptr1] "r" (&cptr[1])
: "memory", "r0", "r1", "r3", "r4", "r5", "r6"
);
/* TM failed, analyse */
if (result) {
if (!cptr[0])
goto trans;
regs[0] = mfspr(SPRN_TAR);
regs[1] = mfspr(SPRN_PPR);
regs[2] = mfspr(SPRN_DSCR);
shmdt(&cptr);
printf("%-30s TAR: %lu PPR: %lx DSCR: %lu\n",
user_read, regs[0], regs[1], regs[2]);
ret = validate_tar_registers(regs, TAR_4, PPR_4, DSCR_4);
if (ret)
exit(1);
exit(0);
}
shmdt(&cptr);
exit(1);
}
int trace_tm_tar(pid_t child)
{
unsigned long regs[3];
FAIL_IF(start_trace(child));
FAIL_IF(show_tar_registers(child, regs));
printf("%-30s TAR: %lu PPR: %lx DSCR: %lu\n",
ptrace_read_running, regs[0], regs[1], regs[2]);
FAIL_IF(validate_tar_registers(regs, TAR_2, PPR_2, DSCR_2));
FAIL_IF(show_tm_checkpointed_state(child, regs));
printf("%-30s TAR: %lu PPR: %lx DSCR: %lu\n",
ptrace_read_ckpt, regs[0], regs[1], regs[2]);
FAIL_IF(validate_tar_registers(regs, TAR_1, PPR_1, DSCR_1));
FAIL_IF(write_ckpt_tar_registers(child, TAR_4, PPR_4, DSCR_4));
printf("%-30s TAR: %u PPR: %lx DSCR: %u\n",
ptrace_write_ckpt, TAR_4, PPR_4, DSCR_4);
pptr[0] = 1;
FAIL_IF(stop_trace(child));
return TEST_PASS;
}
int ptrace_tm_tar(void)
{
pid_t pid;
int ret, status;
SKIP_IF(!have_htm());
shm_id = shmget(IPC_PRIVATE, sizeof(int) * 2, 0777|IPC_CREAT);
pid = fork();
if (pid == 0)
tm_tar();
pptr = (unsigned long *)shmat(shm_id, NULL, 0);
pptr[0] = 0;
if (pid) {
while (!pptr[1])
asm volatile("" : : : "memory");
ret = trace_tm_tar(pid);
if (ret) {
kill(pid, SIGTERM);
shmdt(&pptr);
shmctl(shm_id, IPC_RMID, NULL);
return TEST_FAIL;
}
shmdt(&pptr);
ret = wait(&status);
shmctl(shm_id, IPC_RMID, NULL);
if (ret != pid) {
printf("Child's exit status not captured\n");
return TEST_FAIL;
}
return (WIFEXITED(status) && WEXITSTATUS(status)) ? TEST_FAIL :
TEST_PASS;
}
return TEST_PASS;
}
int main(int argc, char *argv[])
{
return test_harness(ptrace_tm_tar, "ptrace_tm_tar");
}
lue='4'>45 6 7 8 9 10 15 20 25 30 35 40 space: include ignore mode: unified ssdiff stat only tracing: Fix hwlat kthread migration
The hwlat tracer creates a kernel thread at start of the tracer. It is
pinned to a single CPU and will move to the next CPU after each period of
running. If the user modifies the migration thread's affinity, it will not
change after that happens.
The original code created the thread at the first instance it was called,
but later was changed to destroy the thread after the tracer was finished,
and would not be created until the next instance of the tracer was
established. The code that initialized the affinity was only called on the
initial instantiation of the tracer. After that, it was not initialized, and
the previous affinity did not match the current newly created one, making
it appear that the user modified the thread's affinity when it did not, and
the thread failed to migrate again.
Cc: stable@vger.kernel.org
Fixes: 0330f7aa8ee6 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>