pm24.git/tools/perf/arch/x86/annotate, branch master

perf disasm: Add e_machine/e_flags to struct arch

2024-11-09T16:39:13Z

Currently functions like get_dwarf_regnum only work with the host architecture. Carry the elf machine and flags in struct arch so that in disassembly these can be used to allow cross platform disassembly. 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/20241108234606.429459-5-irogers@google.com Signed-off-by: Namhyung Kim

perf build: Rename HAVE_DWARF_SUPPORT to HAVE_LIBDW_SUPPORT

2024-10-18T17:17:40Z

In Makefile.config for unwinding the name dwarf implies either libunwind or libdw. Make it clearer that HAVE_DWARF_SUPPORT is really just defined when libdw is present by renaming to HAVE_LIBDW_SUPPORT. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Tested-by: Leo Yan 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: Masami Hiramatsu (Google) 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/20241017001354.56973-11-irogers@google.com Signed-off-by: Namhyung Kim

perf annotate-data: Copy back variable types after move

2024-08-22T15:38:18Z

In some cases, compilers don't set the location expression in DWARF precisely. For instance, it may assign a variable to a register after copying it from a different register. Then it should use the register for the new type but still uses the old register. This makes hard to track the type information properly. This is an example I found in __tcp_transmit_skb(). The first argument (sk) of this function is a pointer to sock and there's a variable (tp) for tcp_sock. static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it, gfp_t gfp_mask, u32 rcv_nxt) { ... struct tcp_sock *tp; BUG_ON(!skb || !tcp_skb_pcount(skb)); tp = tcp_sk(sk); prior_wstamp = tp->tcp_wstamp_ns; tp->tcp_wstamp_ns = max(tp->tcp_wstamp_ns, tp->tcp_clock_cache); ... So it basically calls tcp_sk(sk) to get the tcp_sock pointer from sk. But it turned out to be the same value because tcp_sock embeds sock as the first member. The sk is located in reg5 (RDI) and tp is in reg3 (RBX). The offset of tcp_wstamp_ns is 0x748 and tcp_clock_cache is 0x750. So you need to use RBX (reg3) to access the fields in the tcp_sock. But the code used RDI (reg5) as it has the same value. $ pahole --hex -C tcp_sock vmlinux | grep -e 748 -e 750 u64 tcp_wstamp_ns; /* 0x748 0x8 */ u64 tcp_clock_cache; /* 0x750 0x8 */ And this is the disassembly of the part of the function. <__tcp_transmit_skb>: ... 44: mov %rdi, %rbx 47: mov 0x748(%rdi), %rsi 4e: mov 0x750(%rdi), %rax 55: cmp %rax, %rsi Because compiler put the debug info to RBX, it only knows RDI is a pointer to sock and accessing those two fields resulted in error due to offset being beyond the type size. ----------------------------------------------------------- find data type for 0x748(reg5) at __tcp_transmit_skb+0x63 CU for net/ipv4/tcp_output.c (die:0x817f543) frame base: cfa=0 fbreg=6 scope: [1/1] (die:81aac3e) bb: [0 - 30] var [0] -0x98(stack) type='struct tcp_out_options' size=0x28 (die:0x81af3df) var [5] reg8 type='unsigned int' size=0x4 (die:0x8180ed6) var [5] reg2 type='unsigned int' size=0x4 (die:0x8180ed6) var [5] reg1 type='int' size=0x4 (die:0x818059e) var [5] reg4 type='struct sk_buff*' size=0x8 (die:0x8181360) var [5] reg5 type='struct sock*' size=0x8 (die:0x8181a0c) <<<--- the first argument ('sk' at %RDI) mov [19] reg8 -> -0xa8(stack) type='unsigned int' size=0x4 (die:0x8180ed6) mov [20] stack canary -> reg0 mov [29] reg0 -> -0x30(stack) stack canary bb: [36 - 3e] mov [36] reg4 -> reg15 type='struct sk_buff*' size=0x8 (die:0x8181360) bb: [44 - 63] mov [44] reg5 -> reg3 type='struct sock*' size=0x8 (die:0x8181a0c) <<<--- calling tcp_sk() var [47] reg3 type='struct tcp_sock*' size=0x8 (die:0x819eead) <<<--- new variable ('tp' at %RBX) var [4e] reg4 type='unsigned long long' size=0x8 (die:0x8180edd) mov [58] reg4 -> -0xc0(stack) type='unsigned long long' size=0x8 (die:0x8180edd) chk [63] reg5 offset=0x748 ok=1 kind=1 (struct sock*) : offset bigger than size <<<--- access with old variable final result: offset bigger than size While it's a fault in the compiler, we could work around this issue by using the type of new variable when it's copied directly. So I've added copied_from field in the register state to track those direct register to register copies. After that new register gets a new type and the old register still has the same type, it'll update (copy it back) the type of the old register. For example, if we can update type of reg5 at __tcp_transmit_skb+0x47, we can find the target type of the instruction at 0x63 like below: ----------------------------------------------------------- find data type for 0x748(reg5) at __tcp_transmit_skb+0x63 ... bb: [44 - 63] mov [44] reg5 -> reg3 type='struct sock*' size=0x8 (die:0x8181a0c) var [47] reg3 type='struct tcp_sock*' size=0x8 (die:0x819eead) var [47] copyback reg5 type='struct tcp_sock*' size=0x8 (die:0x819eead) <<<--- here mov [47] 0x748(reg5) -> reg4 type='unsigned long long' size=0x8 (die:0x8180edd) mov [4e] 0x750(reg5) -> reg0 type='unsigned long long' size=0x8 (die:0x8180edd) mov [58] reg4 -> -0xc0(stack) type='unsigned long long' size=0x8 (die:0x8180edd) chk [63] reg5 offset=0x748 ok=1 kind=1 (struct tcp_sock*) : Good! <<<--- new type found by insn track: 0x748(reg5) type-offset=0x748 final result: type='struct tcp_sock' size=0xa98 (die:0x819eeb2) Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Athira Rajeev Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20240821232628.353177-5-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf annotate-data: Fix percpu pointer check

2024-08-21T14:30:38Z

In check_matching_type(), it checks the type state of the register in a wrong order. When it's the percpu pointer, it should check the type for the pointer, but it checks the CFA bit first and thought it has no type in the stack slot. This resulted in no type info. ----------------------------------------------------------- find data type for 0x28(reg1) at hrtimer_reprogram+0x88 CU for kernel/time/hrtimer.c (die:0x18f219f) frame base: cfa=1 fbreg=7 ... add [72] percpu 0x24500 -> reg1 pointer type='struct hrtimer_cpu_base' size=0x240 (die:0x18f6d46) bb: [7a - 7e] bb: [80 - 86] (here) bb: [88 - 88] vvv chk [88] reg1 offset=0x28 ok=1 kind=4 cfa : no type information no type information Here, instruction at 0x72 found reg1 has a (percpu) pointer and got the correct type. But when it checks the final result, it wrongly thought it was stack variable because it checks the cfa bit first. After changing the order of state check: ----------------------------------------------------------- find data type for 0x28(reg1) at hrtimer_reprogram+0x88 CU for kernel/time/hrtimer.c (die:0x18f219f) frame base: cfa=1 fbreg=7 ... (here) vvvvvvvvvv chk [88] reg1 offset=0x28 ok=1 kind=4 percpu ptr : Good! found by insn track: 0x28(reg1) type-offset=0x28 final type: type='struct hrtimer_cpu_base' size=0x240 (die:0x18f6d46) Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Athira Rajeev Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20240821065408.285548-3-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf annotate-data: Fix missing constant copy

2024-08-21T14:27:18Z

I found it missed to copy the immediate constant when it moves the register value. This could result in a wrong type inference since the address for the per-cpu variable would be 0 always. Fixes: eb9190afaed6afd5 ("perf annotate-data: Handle ADD instructions") Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Athira Rajeev Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20240821065408.285548-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Add "update_insn_state" callback function to handle arch specific instruction tracking

2024-07-31T19:12:59Z

Add "update_insn_state" callback to "struct arch" to handle instruction tracking. Currently updating instruction state is handled by static function "update_insn_state_x86" which is defined in "annotate-data.c". Make this as a callback for specific arch and move to archs specific file "arch/x86/annotate/instructions.c" . This will help to add helper function for other platforms in file: "arch//annotate/instructions.c" and make changes/updates easier. Define callback "update_insn_state" as part of "struct arch", also make some of the debug functions non-static so that it can be referenced from other places. Reviewed-by: Kajol Jain Reviewed-by: Namhyung Kim Signed-off-by: Athira Rajeev Tested-by: Kajol Jain Cc: Adrian Hunter Cc: Akanksha J N Cc: Christophe Leroy Cc: Disha Goel Cc: Hari Bathini Cc: Ian Rogers Cc: Jiri Olsa Cc: Madhavan Srinivasan Cc: Segher Boessenkool Link: https://lore.kernel.org/lkml/20240718084358.72242-3-atrajeev@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Add more x86 mov instruction cases

2023-09-15T23:46:40Z

Instructions with sign- and zero- extention like movsbl and movzwq were not handled properly. As it can check different size suffix (-b, -w, -l or -q) we can omit that and add the common parts even though some combinations are not possible. Reviewed-by: Ian Rogers Link: https://lore.kernel.org/r/20230908052216.566148-1-namhyung@kernel.org Signed-off-by: Namhyung Kim

perf annotate: Remove x86 instructions with suffix

2023-06-09T13:56:05Z

Now the suffix is handled in the general code. Let's get rid of them. Reviewed-by: Adrian Hunter Reviewed-by: Masami Hiramatsu Signed-off-by: Namhyung Kim Cc: Andi Kleen Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20230524205054.3087004-2-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Handle "decq", "incq", "testq", "tzcnt" instructions on x86

2023-05-15T20:50:01Z

I found that the "decq", "incq", "testq", "tzcnt" instructions didn't parse the operands properly. Add them to the "x86__instructions" table to fix the issue. Signed-off-by: Namhyung Kim Acked-by: Ian Rogers Cc: Adrian Hunter Cc: Andi Kleen Cc: Ingo Molnar Cc: Jiri Olsa Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20230511062725.514752-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Add fusion logic for AMD microarchs

2021-09-15T20:54:52Z

AMD family 15h and above microarchs fuse a subset of cmp/test/ALU instructions with branch instructions[1][2]. Add perf annotate fused instruction support for these microarchs. Before: │ testb $0x80,0x51(%rax) │ ┌──jne 5b3 0.78 │ │ mov %r13,%rdi │ │→ callq mark_page_accessed 1.08 │5b3:└─→mov 0x8(%r13),%rax After: │ ┌──testb $0x80,0x51(%rax) │ ├──jne 5b3 0.78 │ │ mov %r13,%rdi │ │→ callq mark_page_accessed 1.08 │5b3:└─→mov 0x8(%r13),%rax [1] https://bugzilla.kernel.org/attachment.cgi?id=298553 [2] https://bugzilla.kernel.org/attachment.cgi?id=298555 Committer testing: On a: $ grep -m1 "model name" /proc/cpuinfo model name : AMD Ryzen 9 3900X 12-Core Processor $ Samples: 44K of event 'cycles', 4000 Hz, Event count (approx.): 7533249650 _int_malloc /usr/lib64/libc-2.33.so [Percent: local period] Percent│ ┌──test %eax,%eax │ ├──jne 884 │ │↓ jmpq 943 │ │ nop │878:│ add $0x10,%rdx 0.64 │ │ add %eax,%eax 0.57 │ │↓ je cc9 0.77 │884:└─→test %esi,%eax │ ↑ je 878 │ mov 0x18(%rdx),%r15 Reported-by: Kim Phillips Signed-off-by: Ravi Bangoria Tested-by: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Jin Yao Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Link: https //lore.kernel.org/r/20210911043854.8373-2-ravi.bangoria@amd.com Signed-off-by: Arnaldo Carvalho de Melo