perf symbols: Slightly improve module file executable section mappings

Currently perf does not record module section addresses except for
the .text section. In general that means perf cannot get module section
mappings correct (except for .text) when loading symbols from a kernel
module file. (Note using --kcore does not have this issue)

Improve that situation slightly by identifying executable sections that
use the same mapping as the .text section. That happens when an
executable section comes directly after the .text section, both in memory
and on file, something that can be determined by following the same layout
rules used by the kernel, refer kernel layout_sections(). Note whether
that happens is somewhat arbitrary, so this is not a final solution.

Example from tracing a virtual machine process:

 Before:

  $ perf script | grep unknown
         CPU 0/KVM    1718   203.511270:     318341 cpu-cycles:P:  ffffffffc13e8a70 [unknown] (/lib/modules/6.7.2-local/kernel/arch/x86/kvm/kvm-intel.ko)
  $ perf script -vvv 2>&1 >/dev/null | grep kvm.intel | grep 'noinstr.text\|ffff'
  Map: 0-7e0 41430 [kvm_intel].noinstr.text
  Map: ffffffffc13a7000-ffffffffc1421000 a0 /lib/modules/6.7.2-local/kernel/arch/x86/kvm/kvm-intel.ko

 After:

  $ perf script | grep 203.511270
         CPU 0/KVM    1718   203.511270:     318341 cpu-cycles:P:  ffffffffc13e8a70 vmx_vmexit+0x0 (/lib/modules/6.7.2-local/kernel/arch/x86/kvm/kvm-intel.ko)
  $ perf script -vvv 2>&1 >/dev/null | grep kvm.intel | grep 'noinstr.text\|ffff'
  Map: ffffffffc13a7000-ffffffffc1421000 a0 /lib/modules/6.7.2-local/kernel/arch/x86/kvm/kvm-intel.ko

Reported-by: Like Xu <[email protected]>
Signed-off-by: Adrian Hunter <[email protected]>
Acked-by: Namhyung Kim <[email protected]>
Signed-off-by: Namhyung Kim <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

0 files changed, 0 insertions, 0 deletions