linux.git/tools/perf/util/disasm.c, branch v6.16

perf annotate: Return errors from disasm_line__parse_powerpc()

2025-03-07T00:52:24+00:00

In disasm_line__parse_powerpc() , return code from function
disasm_line__parse() is ignored. This will result in bad results
if the disasm_line__parse() fails to disasm the line. Use
the return code to fix this.

Signed-off-by: Athira Rajeev 
Tested-By: Venkat Rao Bagalkote 
Link: https://lore.kernel.org/r/20250304154114.62093-2-atrajeev@linux.ibm.com
Signed-off-by: Namhyung Kim

perf annotate: Add annotation_options.disassembler_used

2025-03-07T00:51:22+00:00

When doing "perf annotate", perf tool provides option to
use specific disassembler like llvm/objdump/capstone. The
order picked is to use llvm first and if that fails fallback
to objdump ie to use PERF_DISASM_LLVM, PERF_DISASM_CAPSTONE
and PERF_DISASM_OBJDUMP

In powerpc, when using "data type" sort keys, first preferred
approach is to read the raw instruction from the DSO. In objdump
is specified in "--objdump" option, it picks the symbol disassemble
using objdump. Currently disasm_line__parse_powerpc() function
uses length of the "line" to determine if objdump is used.
But there are few cases, where if objdump doesn't recognise the
instruction, the disassembled string will be empty.

Example:

     134cdc:	c4 05 82 41 	beq     1352a0 
     134ce0:	ac 00 8e 40 	bne     cr3,134d8c 
     134ce4:	0f 00 10 04 	pld     r9,1028308
====>134ce8:	d4 b0 20 e5
     134cec:	16 00 40 39 	li      r10,22
     134cf0:	48 01 21 ea 	ld      r17,328(r1)

So depending on length of line will give bad results.

Add a new filed to annotation options structure,
"struct annotation_options" to save the disassembler used.
Use this info to determine if disassembly is done while
parsing the disasm line.

Reported-by: Tejas Manhas 
Signed-off-by: Athira Rajeev 
Tested-By: Venkat Rao Bagalkote 
Link: https://lore.kernel.org/r/20250304154114.62093-1-atrajeev@linux.ibm.com
Signed-off-by: Namhyung Kim

perf annotate: Use an array for the disassembler preference

2025-01-27T23:58:01+00:00

Prior to this change a string was used which could cause issues with
an unrecognized disassembler in symbol__disassembler. Change to
initializing an array of perf_disassembler enum values. If a value
already exists then adding it a second time is ignored to avoid array
out of bounds problems present in the previous code, it also allows a
statically sized array and removes memory allocation needs. Errors in
the disassembler string are reported when the config is parsed during
perf annotate or perf top start up. If the array is uninitialized
after processing the config file the default llvm, capstone then
objdump values are added but without a need to parse a string.

Fixes: a6e8a58de629 ("perf disasm: Allow configuring what disassemblers to use")
Closes: https://lore.kernel.org/lkml/CAP-5=fUdfCyxmEiTpzS2uumUp3-SyQOseX2xZo81-dQtWXj6vA@mail.gmail.com/
Signed-off-by: Ian Rogers 
Tested-by: Namhyung Kim 
Link: https://lore.kernel.org/r/20250124043856.1177264-1-irogers@google.com
Signed-off-by: Namhyung Kim

perf disasm: Return a proper error when not determining the file type

2024-12-09T20:51:53+00:00

Before:

  ⬢ [acme@toolbox a]$ perf annotate --stdio2 -i acme-perf-injected.data 'java.lang.String com.fasterxml.jackson.core.sym.CharsToNameCanonicalizer.findSymbol(char[], int, int, int)'
  Error:
  Couldn't annotate java.lang.String com.fasterxml.jackson.core.sym.CharsToNameCanonicalizer.findSymbol(char[], int, int, int):
  Internal error: Invalid -1 error code
  ⬢ [acme@toolbox a]$

After:

  ⬢ [acme@toolbox a]$ perf annotate --stdio2 -i acme-perf-injected.data 'java.lang.String com.fasterxml.jackson.core.sym.CharsToNameCanonicalizer.findSymbol(char[], int, int, int)'
  Error:
  Couldn't annotate java.lang.String com.fasterxml.jackson.core.sym.CharsToNameCanonicalizer.findSymbol(char[], int, int, int):
  Couldn't determine the file /tmp/perf-3308868.map type.
  ⬢ [acme@toolbox a]$

Reported-by: Francesco Nigro 
Reported-by: Ilan Green 
Cc: Adrian Hunter 
Cc: Ian Rogers 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Namhyung Kim 
Cc: Stephane Eranian 
Cc: Yonatan Goldschmidt 
Link: https://lore.kernel.org/lkml/Z092D9-r_iOgwIWM@x1
Signed-off-by: Arnaldo Carvalho de Melo

perf disasm: Allow configuring what disassemblers to use

2024-11-13T19:27:35+00:00

The perf tools annotation code used for a long time parsing the output
of binutils's objdump (or its reimplementations, like llvm's) to then
parse and augment it with samples, allow navigation, etc.

More recently disassemblers from the capstone and llvm (libraries, not
parsing the output of tools using those libraries to mimic binutils's
objdump output) were introduced.

So when all those methods are available, there is a static preference
for a series of attempts of disassembling a binary, with the 'llvm,
capstone, objdump' sequence being hard coded.

This patch allows users to change that sequence, specifying via a 'perf
config' 'annotate.disassemblers' entry which and in what order
disassemblers should be attempted.

As alluded to in the comments in the source code of this series, this
flexibility is useful for users and developers alike, elliminating the
requirement to rebuild the tool with some specific set of libraries to
see how the output of disassembling would be for one of these methods.

  root@x1:~# rm -f ~/.perfconfig
  root@x1:~# perf annotate -v --stdio2 update_load_avg
  
  symbol__disassemble:
    filename=/usr/lib/debug/lib/modules/6.11.4-201.fc40.x86_64/vmlinux,
    sym=update_load_avg, start=0xffffffffb6148fe0, en>
  annotating [0x6ff7170]
    /usr/lib/debug/lib/modules/6.11.4-201.fc40.x86_64/vmlinux :
    [0x7407ca0] update_load_avg
  Disassembled with llvm
  annotate.disassemblers=llvm,capstone,objdump
  Samples: 66  of event 'cpu_atom/cycles/P', 10000 Hz,
	Event count (approx.): 5185444, [percent: local period]
  update_load_avg()
    /usr/lib/debug/lib/modules/6.11.4-201.fc40.x86_64/vmlinux
  Percent       0xffffffff81148fe0 :
     1.61         pushq   %r15
                  pushq   %r14
     1.00         pushq   %r13
                  movl    %edx,%r13d
     1.90         pushq   %r12
                  pushq   %rbp
                  movq    %rsi,%rbp
                  pushq   %rbx
                  movq    %rdi,%rbx
                  subq    $0x18,%rsp
    15.14         movl    0x1a4(%rdi),%eax

  root@x1:~# perf config annotate.disassemblers=capstone
  root@x1:~# cat ~/.perfconfig
  # this file is auto-generated.
  [annotate]
	  disassemblers = capstone
  root@x1:~#
  root@x1:~# perf annotate -v --stdio2 update_load_avg
  
  Disassembled with capstone
  annotate.disassemblers=capstone
  Samples: 66  of event 'cpu_atom/cycles/P', 10000 Hz,
  Event count (approx.): 5185444, [percent: local period]
  update_load_avg()
  /usr/lib/debug/lib/modules/6.11.4-201.fc40.x86_64/vmlinux
  Percent       0xffffffff81148fe0 :
     1.61         pushq   %r15
                  pushq   %r14
     1.00         pushq   %r13
                  movl    %edx,%r13d
     1.90         pushq   %r12
                  pushq   %rbp
                  movq    %rsi,%rbp
                  pushq   %rbx
                  movq    %rdi,%rbx
                  subq    $0x18,%rsp
    15.14         movl    0x1a4(%rdi),%eax
  root@x1:~# perf config annotate.disassemblers=objdump,capstone
  root@x1:~# perf config annotate.disassemblers
  annotate.disassemblers=objdump,capstone
  root@x1:~# cat ~/.perfconfig
  # this file is auto-generated.
  [annotate]
	  disassemblers = objdump,capstone
  root@x1:~# perf annotate -v --stdio2 update_load_avg
  Executing: objdump  --start-address=0xffffffff81148fe0 \
		      --stop-address=0xffffffff811497aa  \
		      -d --no-show-raw-insn -S -C "$1"
  Disassembled with objdump
  annotate.disassemblers=objdump,capstone
  Samples: 66  of event 'cpu_atom/cycles/P', 10000 Hz,
  Event count (approx.): 5185444, [percent: local period]
  update_load_avg()
  /usr/lib/debug/lib/modules/6.11.4-201.fc40.x86_64/vmlinux
  Percent

                Disassembly of section .text:

                ffffffff81148fe0 :
                #define DO_ATTACH       0x4

                ffffffff81148fe0 :
                #define DO_ATTACH       0x4
                #define DO_DETACH       0x8

                /* Update task and its cfs_rq load average */
                static inline void update_load_avg(struct cfs_rq *cfs_rq,
						   struct sched_entity *se,
						   int flags)
                {
     1.61         push   %r15
                  push   %r14
     1.00         push   %r13
                  mov    %edx,%r13d
     1.90         push   %r12
                  push   %rbp
                  mov    %rsi,%rbp
                  push   %rbx
                  mov    %rdi,%rbx
                  sub    $0x18,%rsp
                }

                /* rq->task_clock normalized against any time
		   this cfs_rq has spent throttled */
                static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
                {
                if (unlikely(cfs_rq->throttle_count))
    15.14         mov    0x1a4(%rdi),%eax
  root@x1:~#

After adding a way to select the disassembler from the command line a
'perf test' comparing the output of the various diassemblers should be
introduced, to test these codebases.

Acked-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Athira Rajeev 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Namhyung Kim 
Cc: Steinar H. Gunderson 
Link: https://lore.kernel.org/r/20241111151734.1018476-4-acme@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf disasm: Define stubs for the LLVM and capstone disassemblers

2024-11-13T19:20:32+00:00

This reduces the number of ifdefs in the main symbol__disassemble()
method and paves the way for allowing the user to configure the
disassemblers of preference.

Acked-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Aditya Bodkhe 
Cc: Athira Rajeev 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Masami Hiramatsu (Google) 
Cc: Namhyung Kim 
Cc: Steinar H. Gunderson 
Link: https://lore.kernel.org/r/20241111151734.1018476-3-acme@kernel.org
[ Applied fixes from Masami Hiramatsu and Aditya Bodkhe for when capstone devel files are not available ]
Link: https://lore.kernel.org/r/B78FB6DF-24E9-4A3C-91C9-535765EC0E2A@ibm.com
Link: https://lore.kernel.org/r/173145729034.2747044.453926054000880254.stgit@mhiramat.roam.corp.google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf disasm: Introduce symbol__disassemble_objdump()

2024-11-11T17:26:37+00:00

With the first disassemble method in perf, the parsing of objdump
output, just like we have for llvm and capstone.

This paves the way to allow the user to specify what disassemblers are
preferred and to also to at some point allow building without the
objdump method.

Acked-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Athira Rajeev 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Namhyung Kim 
Cc: Steinar H. Gunderson 
Link: https://lore.kernel.org/r/20241111151734.1018476-2-acme@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf dwarf-regs: Add EM_HOST and EF_HOST defines

2024-11-09T16:39:13+00:00

Computed from the build architecture defines, EM_HOST and EF_HOST give
values that can be used in dwarf register lookup. Place in
dwarf-regs.h so the value can be shared. Move some dwarf-regs.c
constants used for EM_HOST to dwarf-regs.h. Add CSky constants that
may be missing.

In disasm.c add an include of dwarf-regs.h as the included
arch/*/annotate/instructions.c files make use of the constants and we
want the elf.h/dwarf-regs.h dependency to be explicit.

Reviewed-by: Masami Hiramatsu (Google) 
Signed-off-by: Ian Rogers 
Cc: Anup Patel 
Cc: Yang Jihong 
Cc: Palmer Dabbelt 
Cc: David S. Miller 
Cc: Albert Ou 
Cc: Shenlin Liang 
Cc: Nick Terrell 
Cc: Guilherme Amadio 
Cc: Steinar H. Gunderson 
Cc: Changbin Du 
Cc: Alexander Lobakin 
Cc: Przemek Kitszel 
Cc: Huacai Chen 
Cc: Guo Ren 
Cc: Masahiro Yamada 
Cc: Will Deacon 
Cc: James Clark 
Cc: Mike Leach 
Cc: Chen Pei 
Cc: Leo Yan 
Cc: Oliver Upton 
Cc: Aditya Gupta 
Cc: Kajol Jain 
Cc: Athira Rajeev 
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-riscv@lists.infradead.org
Cc: Bibo Mao 
Cc: John Garry 
Cc: Atish Patra 
Cc: Dima Kogan 
Cc: Paul Walmsley 
Cc: Dr. David Alan Gilbert 
Cc: linux-csky@vger.kernel.org
Link: https://lore.kernel.org/r/20241108234606.429459-4-irogers@google.com
Signed-off-by: Namhyung Kim

perf disasm: Fix not cleaning up disasm_line in symbol__disassemble_raw()

2024-10-23T22:36:14+00:00

In symbol__disassemble_raw(), the created disasm_line should be
discarded before returning an error. When creating disasm_line fails,
break the loop and then release the created lines.

Fixes: 0b971e6bf1c3 ("perf annotate: Add support to capture and parse raw instruction in powerpc using dso__data_read_offset utility")
Signed-off-by: Li Huafei 
Tested-by: Athira Rajeev 
Cc: sesse@google.com
Cc: kjain@linux.ibm.com
Link: https://lore.kernel.org/r/20241019154157.282038-3-lihuafei1@huawei.com
Signed-off-by: Namhyung Kim

perf disasm: Use disasm_line__free() to properly free disasm_line

2024-10-23T22:36:06+00:00

symbol__disassemble_capstone_powerpc() goto the 'err' label when it
failed in the loop that created disasm_line, and then used free()
directly to free disasm_line. Since the structure disasm_line contains
members that allocate memory dynamically, this can result in a memory
leak. In fact, we can simply break the loop when it fails in the middle
of the loop, and disasm_line__free() will then be called to properly
free the created line. Other error paths do not need to consider freeing
disasm_line.

Fixes: c5d60de1813a ("perf annotate: Add support to use libcapstone in powerpc")
Signed-off-by: Li Huafei 
Tested-by: Athira Rajeev 
Cc: sesse@google.com
Cc: kjain@linux.ibm.com
Link: https://lore.kernel.org/r/20241019154157.282038-2-lihuafei1@huawei.com
Signed-off-by: Namhyung Kim