Re: [PATCH V10 17/28] selftests, powerpc: Add ptrace tests for EBB

From: Cyril Bur
Date: Tue Mar 01 2016 - 19:33:04 EST

On Tue, 16 Feb 2016 14:29:47 +0530
Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx> wrote:

> This patch adds ptrace interface test for EBB specific
> registers. This also adds some generic ptrace interface
> based helper functions to be used by other patches later
> on in the series.
>
> Signed-off-by: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
> ---
> tools/testing/selftests/powerpc/Makefile | 3 +-
> tools/testing/selftests/powerpc/ptrace/Makefile | 7 +
> .../testing/selftests/powerpc/ptrace/ptrace-ebb.c | 150 ++++++++++++++
> .../testing/selftests/powerpc/ptrace/ptrace-ebb.h | 103 ++++++++++
> tools/testing/selftests/powerpc/ptrace/ptrace.h | 225 +++++++++++++++++++++
> 5 files changed, 487 insertions(+), 1 deletion(-)
> create mode 100644 tools/testing/selftests/powerpc/ptrace/Makefile
> create mode 100644 tools/testing/selftests/powerpc/ptrace/ptrace-ebb.c
> create mode 100644 tools/testing/selftests/powerpc/ptrace/ptrace-ebb.h
> create mode 100644 tools/testing/selftests/powerpc/ptrace/ptrace.h
>
> diff --git a/tools/testing/selftests/powerpc/Makefile b/tools/testing/selftests/powerpc/Makefile
> index 0c2706b..5b3c62c 100644
> --- a/tools/testing/selftests/powerpc/Makefile
> +++ b/tools/testing/selftests/powerpc/Makefile
> @@ -22,7 +22,8 @@ SUB_DIRS = benchmarks \
> switch_endian \
> syscalls \
> tm \
> - vphn
> + vphn \
> + ptrace
>
> endif
>
> diff --git a/tools/testing/selftests/powerpc/ptrace/Makefile b/tools/testing/selftests/powerpc/ptrace/Makefile
> new file mode 100644
> index 0000000..8666ac0
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/ptrace/Makefile
> @@ -0,0 +1,7 @@
> +TEST_PROGS := ptrace-ebb
> +all: $(TEST_PROGS)
> +
> +$(TEST_PROGS): ../harness.c ptrace.S ../utils.c
> +ptrace-ebb: ../pmu/event.c ../pmu/lib.c ../pmu/ebb/ebb_handler.S ../pmu/ebb/busy_loop.S
> +clean:
> + rm -f $(TEST_PROGS) *.o

If you:
include ../../lib.mk

Then this Makefile just works with run_tests and install targets from the
base Makefile

> diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-ebb.c b/tools/testing/selftests/powerpc/ptrace/ptrace-ebb.c
> new file mode 100644
> index 0000000..e1ca608
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/ptrace/ptrace-ebb.c
> @@ -0,0 +1,150 @@
> +/*
> + * Ptrace interface test for EBB
> + *
> + * 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 "../pmu/ebb/ebb.h"
> +#include "ptrace.h"
> +#include "ptrace-ebb.h"
> +

Check out tools/testing/selftests/powerpc/utils.h which provides a nice (and
super hacky) FAIL_IF() macro.

> +void ebb(void)
> +{
> + struct event event;
> +
> + event_init_named(&event, 0x1001e, "cycles");
> + event.attr.config |= (1ull << 63);
> + event.attr.exclusive = 1;
> + event.attr.pinned = 1;
> + event.attr.exclude_kernel = 1;
> + event.attr.exclude_hv = 1;
> + event.attr.exclude_idle = 1;
> +
> + if (event_open(&event)) {
> + perror("event_open() failed");
> + exit(1);
> + }
> +
> + setup_ebb_handler(standard_ebb_callee);
> + mtspr(SPRN_BESCR, 0x8000000100000000ull);
> +
> + mb();
> +
> + if (ebb_event_enable(&event)) {
> + perror("ebb_event_handler() failed");
> + exit(1);
> + }
> +
> + mtspr(SPRN_PMC1, pmc_sample_period(SAMPLE_PERIOD));
> + while(1)
> + core_busy_loop();
> + exit(0);
> +}
> +
> +int validate_ebb(struct ebb_regs *regs)
> +{
> + #if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
> + struct opd *opd = (struct opd *) ebb_handler;
> + #endif
> +
> + printf("EBBRR: %lx\n", regs->ebbrr);
> + printf("EBBHR: %lx\n", regs->ebbhr);
> + printf("BESCR: %lx\n", regs->bescr);
> + printf("SIAR: %lx\n", regs->siar);
> + printf("SDAR: %lx\n", regs->sdar);
> + printf("SIER: %lx\n", regs->sier);
> + printf("MMCR2: %lx\n", regs->mmcr2);
> + printf("MMCR0: %lx\n", regs->mmcr0);
> +
> + /* Validate EBBHR */
> + #if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
> + if (regs->ebbhr != opd->entry)
> + return TEST_FAIL;
> + #else
> + if (regs->ebbhr != (unsigned long) ebb_handler)
> + return TEST_FAIL;
> + #endif
> +
> + /* Validate SIER */
> + if (regs->sier != SIER_EXP)
> + return TEST_FAIL;
> +
> + /* Validate MMCR2 */
> + if (regs->mmcr2 != MMCR2_EXP)
> + return TEST_FAIL;
> +
> + /* Validate MMCR0 */
> + if (regs->mmcr0 != MMCR0_EXP)
> + return TEST_FAIL;
> +
> + return TEST_PASS;
> +}
> +
> +int trace_ebb(pid_t child)
> +{
> + struct ebb_regs regs;
> + int ret;
> +
> + sleep(2);
> + ret = start_trace(child);
> + if (ret)
> + return TEST_FAIL;
> +
> + ret = show_ebb_registers(child, &regs);
> + if (ret)
> + return TEST_FAIL;
> +
> + ret = validate_ebb(&regs);
> + if (ret)
> + return TEST_FAIL;
> +
> + ret = stop_trace(child);
> + if (ret)
> + return TEST_FAIL;
> +
> + return TEST_PASS;
> +}
> +
> +int ptrace_ebb(void)
> +{
> + pid_t pid;
> + int ret, status;
> +
> + pid = fork();
> + if (pid < 0) {
> + perror("fork() failed");
> + return TEST_FAIL;
> + }
> +
> + if (pid == 0)
> + ebb();
> +
> + if (pid) {
> + ret = trace_ebb(pid);
> + if (ret)
> + return TEST_FAIL;
> +
> + kill(pid, SIGKILL);
> + ret = wait(&status);
> + if (ret != pid) {
> + printf("Child's exit status not captured\n");
> + return TEST_FAIL;
> + }
> +
> + if (WIFEXITED(status)) {
> + if(WEXITSTATUS(status))
> + return TEST_FAIL;
> + }
> + return TEST_PASS;
> + }
> + return TEST_PASS;
> +}
> +
> +int main(int argc, char *argv[])
> +{
> + return test_harness(ptrace_ebb, "ptrace_ebb");
> +}
> diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-ebb.h b/tools/testing/selftests/powerpc/ptrace/ptrace-ebb.h
> new file mode 100644
> index 0000000..9b38edc
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/ptrace/ptrace-ebb.h
> @@ -0,0 +1,103 @@
> +/*
> + * Inspired mostly from the EBB selftest
> + *
> + * 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.
> + */
> +#define SAMPLE_PERIOD 100 /* EBB event sample persiod */
> +
> +/* Standard expected values */
> +#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
> +#define MMCR0_EXP 0x8000008000000001
> +#else
> +#define MMCR0_EXP 0x180000080
> +#endif
> +
> +#define MMCR2_EXP 0
> +#define SIER_EXP 0x2000000
> +
> +struct opd
> +{
> + u64 entry;
> + u64 toc;
> +};
> +
> +void (*ebb_user_func)(void);
> +extern void ebb_handler(void); /* Defined in ebb_handle.S */
> +
> +void ebb_hook(void) /* Called by ebb_handler */
> +{
> + if (ebb_user_func)
> + ebb_user_func();
> +}
> +
> +void setup_ebb_handler(void (*callee)(void))
> +{
> + u64 entry;
> +
> +#if defined(_CALL_ELF) && _CALL_ELF == 2
> + entry = (u64)ebb_handler;
> +#else
> + struct opd *opd;
> +
> + opd = (struct opd *)ebb_handler;
> + entry = opd->entry;
> +#endif
> + ebb_user_func = callee;
> +
> + /* Ensure ebb_user_func is set before we set the handler */
> + mb();
> + mtspr(SPRN_EBBHR, entry);
> +
> + /* Make sure the handler is set before we return */
> + mb();
> +}
> +
> +void reset_ebb_with_clear_mask(unsigned long mmcr0_clear_mask)
> +{
> + u64 val;
> +
> + /* 2) clear MMCR0[PMAO] - docs say BESCR[PMEO] should do this */
> + /* 3) set MMCR0[PMAE] - docs say BESCR[PME] should do this */
> + val = mfspr(SPRN_MMCR0);
> + mtspr(SPRN_MMCR0, (val & ~mmcr0_clear_mask) | MMCR0_PMAE);
> +
> + /* 4) clear BESCR[PMEO] */
> + mtspr(SPRN_BESCRR, BESCR_PMEO);
> +
> + /* 5) set BESCR[PME] */
> + mtspr(SPRN_BESCRS, BESCR_PME);
> +
> + /* 6) rfebb 1 - done in our caller */
> +}
> +
> +void standard_ebb_callee(void)
> +{
> + u64 val;
> +
> + val = mfspr(SPRN_BESCR);
> + if (!(val & BESCR_PMEO))
> + printf("Spurious interrupt\n");
> +
> + mtspr(SPRN_PMC1, pmc_sample_period(SAMPLE_PERIOD));
> + reset_ebb_with_clear_mask(MMCR0_PMAO | MMCR0_FC);
> +}
> +
> +int ebb_event_enable(struct event *e)
> +{
> + int rc;
> +
> + mb();
> +
> + rc = ioctl(e->fd, PERF_EVENT_IOC_ENABLE);
> + if (rc)
> + return rc;
> + rc = event_read(e);
> +
> + mb();
> + return rc;
> +}
> diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace.h b/tools/testing/selftests/powerpc/ptrace/ptrace.h
> new file mode 100644
> index 0000000..44256d2
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/ptrace/ptrace.h
> @@ -0,0 +1,225 @@
> +/*
> + * Ptrace interface test helper functions
> + *
> + * 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 <inttypes.h>
> +#include <unistd.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <malloc.h>
> +#include <errno.h>
> +#include <time.h>
> +#include <sys/ptrace.h>
> +#include <sys/ioctl.h>
> +#include <sys/uio.h>
> +#include <sys/types.h>
> +#include <sys/wait.h>
> +#include <sys/signal.h>
> +#include <sys/ipc.h>
> +#include <sys/shm.h>
> +#include <sys/user.h>
> +#include <linux/elf.h>
> +#include <linux/types.h>
> +#include <linux/auxvec.h>
> +#include "../reg.h"
> +#include "utils.h"
> +
> +/* ELF core note sections */
> +#define NT_PPC_TAR 0x103 /* Target Address Register */
> +#define NT_PPC_PPR 0x104 /* Program Priority Register */
> +#define NT_PPC_DSCR 0x105 /* Data Stream Control Register */
> +#define NT_PPC_EBB 0x106 /* Event Based Branch Registers */
> +#define NT_PPC_TM_CGPR 0x107 /* TM checkpointed GPR Registers */
> +#define NT_PPC_TM_CFPR 0x108 /* TM checkpointed FPR Registers */
> +#define NT_PPC_TM_CVMX 0x109 /* TM checkpointed VMX Registers */
> +#define NT_PPC_TM_CVSX 0x10a /* TM checkpointed VSX Registers */
> +#define NT_PPC_TM_SPR 0x10b /* TM Special Purpose Registers */
> +#define NT_PPC_TM_CTAR 0x10c /* TM checkpointed Target Address Register */
> +#define NT_PPC_TM_CPPR 0x10d /* TM checkpointed Program Priority Register */
> +#define NT_PPC_TM_CDSCR 0x10e /* TM checkpointed Data Stream Control Register */
> +
> +/* TEXASR register bits */
> +#define TEXASR_FC 0xFE00000000000000
> +#define TEXASR_FP 0x0100000000000000
> +#define TEXASR_DA 0x0080000000000000
> +#define TEXASR_NO 0x0040000000000000
> +#define TEXASR_FO 0x0020000000000000
> +#define TEXASR_SIC 0x0010000000000000
> +#define TEXASR_NTC 0x0008000000000000
> +#define TEXASR_TC 0x0004000000000000
> +#define TEXASR_TIC 0x0002000000000000
> +#define TEXASR_IC 0x0001000000000000
> +#define TEXASR_IFC 0x0000800000000000
> +#define TEXASR_ABT 0x0000000100000000
> +#define TEXASR_SPD 0x0000000080000000
> +#define TEXASR_HV 0x0000000020000000
> +#define TEXASR_PR 0x0000000010000000
> +#define TEXASR_FS 0x0000000008000000
> +#define TEXASR_TE 0x0000000004000000
> +#define TEXASR_ROT 0x0000000002000000
> +
> +#define TEST_PASS 0
> +#define TEST_FAIL 1
> +
> +struct ebb_regs {
> + unsigned long ebbrr;
> + unsigned long ebbhr;
> + unsigned long bescr;
> + unsigned long siar;
> + unsigned long sdar;
> + unsigned long sier;
> + unsigned long mmcr2;
> + unsigned long mmcr0;
> +};
> +
> +struct fpr_regs {
> + unsigned long fpr[32];
> + unsigned long fpscr;
> +};
> +
> +
> +/* Basic ptrace operations */
> +int start_trace(pid_t child)
> +{
> + int ret;
> +
> + ret = ptrace(PTRACE_ATTACH, child, NULL, NULL);
> + if (ret) {
> + perror("ptrace(PTRACE_ATTACH) failed");
> + return TEST_FAIL;
> + }
> + ret = waitpid(child, NULL, 0);
> + if (ret != child) {
> + perror("waitpid() failed");
> + return TEST_FAIL;
> + }
> + return TEST_PASS;
> +}
> +
> +int stop_trace(pid_t child)
> +{
> + int ret;
> +
> + ret = ptrace(PTRACE_DETACH, child, NULL, NULL);
> + if (ret) {
> + perror("ptrace(PTRACE_DETACH) failed");
> + return TEST_FAIL;
> + }
> + return TEST_PASS;
> +}
> +
> +int cont_trace(pid_t child)
> +{
> + int ret;
> +
> + ret = ptrace(PTRACE_CONT, child, NULL, NULL);
> + if (ret) {
> + perror("ptrace(PTRACE_CONT) failed");
> + return TEST_FAIL;
> + }
> + return TEST_PASS;
> +}
> +
> +/* EBB */
> +int show_ebb_registers(pid_t child, struct ebb_regs *regs)
> +{
> + struct ebb_regs *ebb;
> + struct iovec iov;
> + int ret;
> +
> + ebb = malloc(sizeof(struct ebb_regs));
> + if (!ebb) {
> + perror("malloc() failed");
> + return TEST_FAIL;
> + }
> +
> + iov.iov_base = (struct ebb_regs *) ebb;
> + iov.iov_len = sizeof(struct ebb_regs);
> + ret = ptrace(PTRACE_GETREGSET, child, NT_PPC_EBB, &iov);
> + if (ret) {
> + perror("ptrace(PTRACE_GETREGSET) failed");
> + goto fail;
> + }
> +
> + if (regs)
> + memcpy(regs, ebb, sizeof(struct ebb_regs));
> +
> + free(ebb);
> + return TEST_PASS;
> +fail:
> + free(ebb);
> + return TEST_FAIL;
> +}
> +
> +/* Analyse TEXASR after TM failure */
> +inline unsigned long get_tfiar(void)
> +{
> + unsigned long ret;
> +
> + asm volatile("mfspr %0,%1" : "=r" (ret): "i" (SPRN_TFIAR));
> + return ret;
> +}
> +
> +void analyse_texasr(unsigned long texasr)
> +{
> + printf("TEXASR: %16lx\t", texasr);
> +
> + if (texasr & TEXASR_FP)
> + printf("TEXASR_FP ");
> +
> + if (texasr & TEXASR_DA)
> + printf("TEXASR_DA ");
> +
> + if (texasr & TEXASR_NO)
> + printf("TEXASR_NO ");
> +
> + if (texasr & TEXASR_FO)
> + printf("TEXASR_FO ");
> +
> + if (texasr & TEXASR_SIC)
> + printf("TEXASR_SIC ");
> +
> + if (texasr & TEXASR_NTC)
> + printf("TEXASR_NTC ");
> +
> + if (texasr & TEXASR_TC)
> + printf("TEXASR_TC ");
> +
> + if (texasr & TEXASR_TIC)
> + printf("TEXASR_TIC ");
> +
> + if (texasr & TEXASR_IC)
> + printf("TEXASR_IC ");
> +
> + if (texasr & TEXASR_IFC)
> + printf("TEXASR_IFC ");
> +
> + if (texasr & TEXASR_ABT)
> + printf("TEXASR_ABT ");
> +
> + if (texasr & TEXASR_SPD)
> + printf("TEXASR_SPD ");
> +
> + if (texasr & TEXASR_HV)
> + printf("TEXASR_HV ");
> +
> + if (texasr & TEXASR_PR)
> + printf("TEXASR_PR ");
> +
> + if (texasr & TEXASR_FS)
> + printf("TEXASR_FS ");
> +
> + if (texasr & TEXASR_TE)
> + printf("TEXASR_TE ");
> +
> + if (texasr & TEXASR_ROT)
> + printf("TEXASR_ROT ");
> +
> + printf("TFIAR :%lx\n", get_tfiar());
> +}