Re: [PATCH] perf cs-etm: Improve completeness for kernel address space

On Mon, 24 Jun 2019 at 13:00, Arnaldo Carvalho de Melo arnaldo.melo@gmail.com wrote:

Em Thu, Jun 20, 2019 at 08:58:29AM +0800, Leo Yan escreveu:

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Hi Mathieu,

On Wed, Jun 19, 2019 at 11:49:44AM -0600, Mathieu Poirier wrote:

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diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config index 51dd00f65709..4776c2c1fb6d 100644 --- a/tools/perf/Makefile.config +++ b/tools/perf/Makefile.config @@ -418,6 +418,30 @@ ifdef CORESIGHT endif LDFLAGS += $(LIBOPENCSD_LDFLAGS) EXTLIBS += $(OPENCSDLIBS)

• ifneq ($(wildcard $(srctree)/arch/arm64/kernel/vmlinux.lds),)

•  # Extract info from lds:
  

•  #  . = ((((((((0xffffffffffffffff)) - (((1)) << (48)) + 1) + (0)) + (0x08000000))) + (0x08000000))) + 0x00080000;
  

•  # ARM64_PRE_START_SIZE := (0x08000000 + 0x08000000 + 0x00080000)
  

•  ARM64_PRE_START_SIZE := $(shell egrep ' \. \= \({8}0x[0-9a-fA-F]+\){2}' \
  

•    $(srctree)/arch/arm64/kernel/vmlinux.lds | \
  

•    sed -e 's/[(|)|.|=|+|<|;|-]//g' -e 's/ \+/ /g' -e 's/^[ \t]*//' | \
  

•    awk -F' ' '{print "("$$6 "+"  $$7 "+" $$8")"}' 2>/dev/null)
  

• else

•  ARM64_PRE_START_SIZE := 0
  

• endif
• CFLAGS += -DARM64_PRE_START_SIZE="$(ARM64_PRE_START_SIZE)"
• ifneq ($(wildcard $(srctree)/arch/arm/kernel/vmlinux.lds),)

•  # Extract info from lds:
  

•  #   . = ((0xC0000000)) + 0x00208000;
  

•  # ARM_PRE_START_SIZE := 0x00208000
  

•  ARM_PRE_START_SIZE := $(shell egrep ' \. \= \({2}0x[0-9a-fA-F]+\){2}' \
  

•    $(srctree)/arch/arm/kernel/vmlinux.lds | \
  

•    sed -e 's/[(|)|.|=|+|<|;|-]//g' -e 's/ \+/ /g' -e 's/^[ \t]*//' | \
  

•    awk -F' ' '{print "("$$2")"}' 2>/dev/null)
  

• else

•  ARM_PRE_START_SIZE := 0
  

• endif
• CFLAGS += -DARM_PRE_START_SIZE="$(ARM_PRE_START_SIZE)" $(call detected,CONFIG_LIBOPENCSD) ifdef CSTRACE_RAW CFLAGS += -DCS_DEBUG_RAW

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 0c7776b51045..ae831f836c70 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -613,10 +613,34 @@ static void cs_etm__free(struct perf_session *session) static u8 cs_etm__cpu_mode(struct cs_etm_queue *etmq, u64 address) { struct machine *machine;

•   u64 fixup_kernel_start = 0;
  

•   const char *arch;
  
    machine = etmq->etm->machine;
  

•   arch = perf_env__arch(machine->env);
  
  

•   if (address >= etmq->etm->kernel_start) {
  

•   /*
  

•    * Since arm and arm64 specify some memory regions prior to
  

•    * 'kernel_start', kernel addresses can be less than 'kernel_start'.
  

•    *
  

•    * For arm architecture, the 16MB virtual memory space prior to
  

•    * 'kernel_start' is allocated to device modules, a PMD table if
  

•    * CONFIG_HIGHMEM is enabled and a PGD table.
  

•    *
  

•    * For arm64 architecture, the root PGD table, device module memory
  

•    * region and BPF jit region are prior to 'kernel_start'.
  

•    *
  

•    * To reflect the complete kernel address space, compensate these
  

•    * pre-defined regions for kernel start address.
  

•    */
  

•   if (!strcmp(arch, "arm64"))
  

•           fixup_kernel_start = etmq->etm->kernel_start -
  

•                                ARM64_PRE_START_SIZE;
  

•   else if (!strcmp(arch, "arm"))
  

•           fixup_kernel_start = etmq->etm->kernel_start -
  

•                                ARM_PRE_START_SIZE;
  

I will test your work but from a quick look wouldn't it be better to have a single define name here? From looking at the modifications you did to Makefile.config there doesn't seem to be a reason to have two.

Thanks for suggestion. I changed to use single define ARM_PRE_START_SIZE and sent patch v2 [1].

If possible, please test patch v2.

Thanks, Leo Yan

So just for the record, I'm waiting for Mathieu on this one, i.e. for him to test/ack v3.

Right, please give me some time to test this. As Leo indicated the procedure is time consuming.

Thanks, Mathieu

• Arnaldo

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[1] https://lore.kernel.org/linux-arm-kernel/20190620005428.20883-1-leo.yan@lina...

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•   if (address >= fixup_kernel_start) {
            if (machine__is_host(machine))
                    return PERF_RECORD_MISC_KERNEL;
            else
  

-- 2.17.1

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• Arnaldo