Re: [PATCH v2] perf cs-etm: Improve completeness for kernel address space

Hi all,

On Thu, Jun 20, 2019 at 08:54:28AM +0800, Leo Yan wrote:

[...]

diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config index 51dd00f65709..cf5906d667aa 100644 --- a/tools/perf/Makefile.config +++ b/tools/perf/Makefile.config @@ -418,6 +418,26 @@ ifdef CORESIGHT endif LDFLAGS += $(LIBOPENCSD_LDFLAGS) EXTLIBS += $(OPENCSDLIBS)

• ARM_PRE_START_SIZE := 0
• ifeq ($(SRCARCH),arm64)

•  # Extract info from lds:
  

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

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

•  ARM_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)
  

• endif
• ifeq ($(SRCARCH),arm)

•  # 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)
  

• endif
• CFLAGS += -DARM_PRE_START_SIZE="$(ARM_PRE_START_SIZE)"

I did testing for building perf with this patch, this patch is fragile and easily introduce the building warning:

<command-line>: error: "ARM_PRE_START_SIZE" redefined [-Werror] <command-line>: note: this is the location of the previous definition

To dismiss this error, I need to change the macro define as below:

+ CFLAGS += -DARM_PRE_START_SIZE=$(ARM_PRE_START_SIZE)

So I sent patch v3 to address this issue and please directly reivew patch v3. Sorry for spamming.

Thanks, Leo Yan

 $(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..5fa0be3a3904 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -613,10 +613,27 @@ 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;

machine = etmq->etm->machine;

• 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.
  

• */
  

• fixup_kernel_start = etmq->etm->kernel_start - ARM_PRE_START_SIZE;
• if (address >= fixup_kernel_start) { if (machine__is_host(machine)) return PERF_RECORD_MISC_KERNEL; else

-- 2.17.1