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Message-ID: <85dd05e1-055d-4dc2-87a6-3221e327fd67@oracle.com>
Date: Thu, 13 Nov 2025 10:21:50 +0100
From: Alexandre Chartre <alexandre.chartre@...cle.com>
To: linux-kernel@...r.kernel.org, mingo@...nel.org, jpoimboe@...nel.org,
peterz@...radead.org
Cc: alexandre.chartre@...cle.com
Subject: Re: [PATCH v3 00/28] objtool: Function validation tracing
kernel test robot has reported a build error on ppc for two patches. I am
fixing this (forgot to test build when there's no support for disassembly).
Sorry about that.
alex.
On 11/12/25 17:02, Alexandre Chartre wrote:
> Hi,
>
> These patches change objtool to disassemble code with libopcodes instead
> of running objdump. You will find below:
>
> - Changes: changes made in this version
> - Overview: overview of the changes
> - Notes: description of some particular behavior
> - Examples: output examples
>
> Thanks,
>
> alex.
>
> -----
>
> Changes:
> ========
>
> This new version addresses comments from Josh and Peter, in particular:
>
> - Josh: replace ERROR in disas_context_create with WARN
> - Josh: do not change offstr() outside the disassembler
> - Josh: duplicated "falls through to next function" warning
> - Josh: validate_symbol() has extra newline before return
> - Josh: "make -s" should be completely silent
> - Josh: instructions with unwinding state changes are printing twice
> - Josh: explain TRACE_INSN(insn, NULL): this prints an instruction with no
> additional message.
>
> - Peter: display alternative on a single line
> - Peter: display nop-like instruction as NOP<n>
> - Peter: in alternative show differences between jmp.d8 and jmp.d32 (jmp/jmpq is used now)
> - Peter: show alternative feature name and flags
> - Peter: alternative jumps to altinstr_aux - see NOTE below:
> Disassembly can show default alternative jumping to .altinstr_aux
> - Peter: some jump label target seems wrong (jmp +0) - NOTE below:
> Disassembly can show alternative jumping to the next instruction
>
> Other improvements:
>
> - An alternatives is displayed on single line if each alternative has a
> single instruction. Otherwise alternatives are dispayed side-by-side,
> with one column for each lternative.
>
> - Each alternative of a group alternative is displayed with its feature
> name and flags: <flags><feature-name>
>
> <flags> is made of the following characters:
>
> '!' : ALT_FLAG_NOT
> '+' : ALT_FLAG_DIRECT_CALL
> '?' : unknown flag (i.e. any other flags)
>
> - If an alternative is a jump table then "JUMP" is used as the feature
> name.
>
> - If an alternative is an exception table then "EXCEPTION" is used as the
> feature name.
>
> - Print the destination name of pv_ops calls when we can figure out if
> XENPV mode is used or not. If the PV mode can't be predicted then print
> the default pv_ops destination as a destination example.
>
> - If a group alternative is a direct call then print the corresponding
> pv_ops call.
>
> Examples are shown below.
>
>
> Overview:
> =========
>
> This provides the following changes to objtool.
>
> - Disassemble code with libopcodes instead of running objdump
>
> objtool executes the objdump command to disassemble code. In particular,
> if objtool fails to validate a function then it will use objdump to
> disassemble the entire file which is not very helpful when processing
> a large file (like vmlinux.o).
>
> Using libopcodes provides more control about the disassembly scope and
> output, and it is possible to disassemble a single instruction or
> a single function. Now when objtool fails to validate a function it
> will disassemble that single function instead of disassembling the
> entire file.
>
> - Add the --trace <function> option to trace function validation
>
> Figuring out why a function validation has failed can be difficult because
> objtool checks all code flows (including alternatives) and maintains
> instructions states (in particular call frame information).
>
> The trace option allows to follow the function validation done by objtool
> instruction per instruction, see what objtool is doing and get function
> validation information. An output example is shown below.
>
> - Add the --disas <function> option to disassemble functions
>
> Disassembly is done using libopcodes and it will show the different code
> alternatives.
>
> Note: some changes are architecture specific (x86, powerpc, loongarch). Any
> feedback about the behavior on powerpc and loongarch is welcome.
>
>
> Notes:
> ======
>
> Disassembly can show default alternative jumping to .altinstr_aux
> -----------------------------------------------------------------
> Disassembly can show a default alternative jumping to .altinstr_aux. This
> happens when the _static_cpu_has() function is used. Its default code
> jumps to .altinstr_aux where a test sequence is executed (test; jnz; jmp).
>
> At runtime, this sequence is not used because the _static_cpu_has()
> an alternative with the X86_FEATURE_ALWAYS feature.
>
>
> debc: perf_get_x86_pmu_capability+0xc jmpq 0xdec1 <.altinstr_aux+0xfc> | NOP5 (X86_FEATURE_HYBRID_CPU) | jmpq 0x61a <perf_get_x86_pmu_capability+0x37> (X86_FEATURE_ALWAYS) # <alternative.debc>
> dec1: perf_get_x86_pmu_capability+0x11 ud2
>
>
> Disassembly can show alternative jumping to the next instruction
> ----------------------------------------------------------------
>
> The disassembly can show jump tables with an alternative which jumps
> to the next instruction.
>
> For example:
>
> def9: perf_get_x86_pmu_capability+0x49 NOP2 | jmp defb <perf_get_x86_pmu_capability+0x4b> (JUMP) # <alternative.def9>
> defb: perf_get_x86_pmu_capability+0x4b mov 0x0(%rip),%rdi # 0xdf02 <x86_pmu+0xd8>
>
> This disassembly is correct. These instructions come from:
>
> cap->num_counters_gp = x86_pmu_num_counters(NULL)):
>
> which will end up executing this statement:
>
> if (static_branch_unlikely(&perf_is_hybrid) && NULL)
> <do something>;
>
> This statement is optimized to do nothing because the condition is
> always false. But static_branch_unlikely() is implemented with a jump
> table inside an "asm goto" statement, and "asm goto" statements are
> not optimized.
>
> So basically the code is optimized like this:
>
> if (static_branch_unlikely(&perf_is_hybrid))
> ;
>
> And this translates to the assembly code above.
>
>
> Examples:
> =========
>
> Example 1 (--trace option): Trace the validation of the os_save() function
> --------------------------------------------------------------------------
>
> $ ./tools/objtool/objtool --hacks=jump_label --hacks=noinstr --hacks=skylake --ibt --orc --retpoline --rethunk --sls --static-call --uaccess --prefix=16 --link --trace os_xsave -v vmlinux.o
> os_xsave: validation begin
> 59b20: os_xsave+0x0 push %r12 - state: cfa=rsp+16 r12=(cfa-16) stack_size=16
> 59b22: os_xsave+0x2 mov 0x0(%rip),%eax # 0x59b28 <alternatives_patched>
> 59b28: os_xsave+0x8 push %rbp - state: cfa=rsp+24 rbp=(cfa-24) stack_size=24
> 59b29: os_xsave+0x9 mov %rdi,%rbp
> 59b2c: os_xsave+0xc push %rbx - state: cfa=rsp+32 rbx=(cfa-32) stack_size=32
> 59b2d: os_xsave+0xd mov 0x8(%rdi),%rbx
> 59b31: os_xsave+0x11 mov %rbx,%r12
> 59b34: os_xsave+0x14 shr $0x20,%r12
> 59b38: os_xsave+0x18 test %eax,%eax
> 59b3a: os_xsave+0x1a je 0x59b62 <os_xsave+0x42> - jump taken
> 59b62: os_xsave+0x42 | ud2
> 59b64: os_xsave+0x44 | jmp 0x59b3c <os_xsave+0x1c> - unconditional jump
> 59b3c: os_xsave+0x1c | | xor %edx,%edx
> 59b3e: os_xsave+0x1e | | mov %rbx,%rsi
> 59b41: os_xsave+0x21 | | mov %rbp,%rdi
> 59b44: os_xsave+0x24 | | callq 0x59b49 <xfd_validate_state> - call
> 59b49: os_xsave+0x29 | | mov %ebx,%eax
> 59b4b: os_xsave+0x2b | | mov %r12d,%edx
> | | / <alternative.59b4e> EXCEPTION for instruction at 0x59b4e <os_xsave+0x2e>
> 59b55: os_xsave+0x35 | | | test %ebx,%ebx
> 59b57: os_xsave+0x37 | | | jne 0x59b66 <os_xsave+0x46> - jump taken
> 59b66: os_xsave+0x46 | | | | ud2
> 59b68: os_xsave+0x48 | | | | pop %rbx - state: cfa=rsp+24 rbx=<undef> stack_size=24
> 59b69: os_xsave+0x49 | | | | pop %rbp - state: cfa=rsp+16 rbp=<undef> stack_size=16
> 59b6a: os_xsave+0x4a | | | | pop %r12 - state: cfa=rsp+8 r12=<undef> stack_size=8
> 59b6c: os_xsave+0x4c | | | | jmpq 0x59b71 <__x86_return_thunk> - return
> 59b57: os_xsave+0x37 | | | jne 0x59b66 <os_xsave+0x46> - jump not taken
> 59b59: os_xsave+0x39 | | | pop %rbx - state: cfa=rsp+24 rbx=<undef> stack_size=24
> 59b5a: os_xsave+0x3a | | | pop %rbp - state: cfa=rsp+16 rbp=<undef> stack_size=16
> 59b5b: os_xsave+0x3b | | | pop %r12 - state: cfa=rsp+8 r12=<undef> stack_size=8
> 59b5d: os_xsave+0x3d | | | jmpq 0x59b62 <__x86_return_thunk> - return
> | | \ <alternative.59b4e> EXCEPTION end
> | | / <alternative.59b4e> X86_FEATURE_XSAVES
> 1b2b: .altinstr_replacement+0x1b2b | | | xsaves64 0x40(%rbp)
> 59b53: os_xsave+0x33 | | | xor %ebx,%ebx
> 59b55: os_xsave+0x35 | | | test %ebx,%ebx - already visited
> | | \ <alternative.59b4e> X86_FEATURE_XSAVES end
> | | / <alternative.59b4e> X86_FEATURE_XSAVEC
> 1b26: .altinstr_replacement+0x1b26 | | | xsavec64 0x40(%rbp)
> 59b53: os_xsave+0x33 | | | xor %ebx,%ebx - already visited
> | | \ <alternative.59b4e> X86_FEATURE_XSAVEC end
> | | / <alternative.59b4e> X86_FEATURE_XSAVEOPT
> 1b21: .altinstr_replacement+0x1b21 | | | xsaveopt64 0x40(%rbp)
> 59b53: os_xsave+0x33 | | | xor %ebx,%ebx - already visited
> | | \ <alternative.59b4e> X86_FEATURE_XSAVEOPT end
> | | / <alternative.59b4e> DEFAULT
> 59b4e: os_xsave+0x2e | | xsave64 0x40(%rbp)
> 59b53: os_xsave+0x33 | | xor %ebx,%ebx - already visited
> 59b3a: os_xsave+0x1a je 0x59b62 <os_xsave+0x42> - jump not taken
> 59b3c: os_xsave+0x1c xor %edx,%edx - already visited
> os_xsave: validation end
>
>
> Example 2 (--disas option): Single Instruction Alternatives
> -----------------------------------------------------------
> Alternatives with single instructions are displayed on a single line.
> Instructions of the different alternatives are separated with a vertical
> bar (|).
>
>
> $ ./tools/objtool/objtool --disas=perf_get_x86_pmu_capability --link vmlinux.o
> perf_get_x86_pmu_capability:
> deb0: perf_get_x86_pmu_capability+0x0 endbr64
> deb4: perf_get_x86_pmu_capability+0x4 callq 0xdeb9 <__fentry__>
> deb9: perf_get_x86_pmu_capability+0x9 mov %rdi,%rdx
> debc: perf_get_x86_pmu_capability+0xc jmpq 0xdec1 <.altinstr_aux+0xfc> | NOP5 (X86_FEATURE_HYBRID_CPU) | jmpq 0x61a <perf_get_x86_pmu_capability+0x37> (X86_FEATURE_ALWAYS) # <alternative.debc>
> dec1: perf_get_x86_pmu_capability+0x11 ud2
> dec3: perf_get_x86_pmu_capability+0x13 movq $0x0,(%rdx)
> deca: perf_get_x86_pmu_capability+0x1a movq $0x0,0x8(%rdx)
> ded2: perf_get_x86_pmu_capability+0x22 movq $0x0,0x10(%rdx)
> deda: perf_get_x86_pmu_capability+0x2a movq $0x0,0x18(%rdx)
> dee2: perf_get_x86_pmu_capability+0x32 jmpq 0xdee7 <__x86_return_thunk>
> dee7: perf_get_x86_pmu_capability+0x37 cmpq $0x0,0x0(%rip) # 0xdeef <x86_pmu+0x10>
> deef: perf_get_x86_pmu_capability+0x3f je 0xdec3 <perf_get_x86_pmu_capability+0x13>
> def1: perf_get_x86_pmu_capability+0x41 mov 0x0(%rip),%eax # 0xdef7 <x86_pmu+0x8>
> def7: perf_get_x86_pmu_capability+0x47 mov %eax,(%rdi)
> def9: perf_get_x86_pmu_capability+0x49 NOP2 | jmp defb <perf_get_x86_pmu_capability+0x4b> (JUMP) # <alternative.def9>
> defb: perf_get_x86_pmu_capability+0x4b mov 0x0(%rip),%rdi # 0xdf02 <x86_pmu+0xd8>
> df02: perf_get_x86_pmu_capability+0x52 callq 0xdf07 <__sw_hweight64> | popcnt %rdi,%rax (X86_FEATURE_POPCNT) # <alternative.df02>
> df07: perf_get_x86_pmu_capability+0x57 mov %eax,0x4(%rdx)
> df0a: perf_get_x86_pmu_capability+0x5a NOP2 | jmp df0c <perf_get_x86_pmu_capability+0x5c> (JUMP) # <alternative.df0a>
> df0c: perf_get_x86_pmu_capability+0x5c mov 0x0(%rip),%rdi # 0xdf13 <x86_pmu+0xe0>
> df13: perf_get_x86_pmu_capability+0x63 callq 0xdf18 <__sw_hweight64> | popcnt %rdi,%rax (X86_FEATURE_POPCNT) # <alternative.df13>
> df18: perf_get_x86_pmu_capability+0x68 mov %eax,0x8(%rdx)
> df1b: perf_get_x86_pmu_capability+0x6b mov 0x0(%rip),%eax # 0xdf21 <x86_pmu+0xf8>
> df21: perf_get_x86_pmu_capability+0x71 mov %eax,0xc(%rdx)
> df24: perf_get_x86_pmu_capability+0x74 mov %eax,0x10(%rdx)
> df27: perf_get_x86_pmu_capability+0x77 mov 0x0(%rip),%rax # 0xdf2e <x86_pmu+0x108>
> df2e: perf_get_x86_pmu_capability+0x7e mov %eax,0x14(%rdx)
> df31: perf_get_x86_pmu_capability+0x81 mov 0x0(%rip),%eax # 0xdf37 <x86_pmu+0x110>
> df37: perf_get_x86_pmu_capability+0x87 mov %eax,0x18(%rdx)
> df3a: perf_get_x86_pmu_capability+0x8a movzbl 0x0(%rip),%ecx # 0xdf41 <x86_pmu+0x1d1>
> df41: perf_get_x86_pmu_capability+0x91 movzbl 0x1c(%rdx),%eax
> df45: perf_get_x86_pmu_capability+0x95 shr %cl
> df47: perf_get_x86_pmu_capability+0x97 and $0x1,%ecx
> df4a: perf_get_x86_pmu_capability+0x9a and $0xfffffffe,%eax
> df4d: perf_get_x86_pmu_capability+0x9d or %ecx,%eax
> df4f: perf_get_x86_pmu_capability+0x9f mov %al,0x1c(%rdx)
> df52: perf_get_x86_pmu_capability+0xa2 jmpq 0xdf57 <__x86_return_thunk>
>
>
> Example 3 (--disas option): Alternatives with multiple instructions
> -------------------------------------------------------------------
> Alternatives with multiple instructions are displayed side-by-side, with
> an header describing the alternative. The code in the first column is the
> default code of the alternative.
>
>
> $ ./tools/objtool/objtool --disas=__switch_to_asm --link vmlinux.o
> __switch_to_asm:
> 82c0: __switch_to_asm+0x0 push %rbp
> 82c1: __switch_to_asm+0x1 push %rbx
> 82c2: __switch_to_asm+0x2 push %r12
> 82c4: __switch_to_asm+0x4 push %r13
> 82c6: __switch_to_asm+0x6 push %r14
> 82c8: __switch_to_asm+0x8 push %r15
> 82ca: __switch_to_asm+0xa mov %rsp,0x1670(%rdi)
> 82d1: __switch_to_asm+0x11 mov 0x1670(%rsi),%rsp
> 82d8: __switch_to_asm+0x18 mov 0xad8(%rsi),%rbx
> 82df: __switch_to_asm+0x1f mov %rbx,%gs:0x0(%rip) # 0x82e7 <__stack_chk_guard>
> 82e7: __switch_to_asm+0x27 | <alternative.82e7> | !X86_FEATURE_ALWAYS | X86_FEATURE_RSB_CTXSW
> 82e7: __switch_to_asm+0x27 | jmp 0x8312 <__switch_to_asm+0x52> | NOP1 | mov $0x10,%r12
> 82e8: __switch_to_asm+0x28 | | NOP1 |
> 82e9: __switch_to_asm+0x29 | NOP1 | callq 0x82ef <__switch_to_asm+0x2f> |
> 82ea: __switch_to_asm+0x2a | NOP1 | |
> 82eb: __switch_to_asm+0x2b | NOP1 | |
> 82ec: __switch_to_asm+0x2c | NOP1 | |
> 82ed: __switch_to_asm+0x2d | NOP1 | |
> 82ee: __switch_to_asm+0x2e | NOP1 | int3 | callq 0x82f4 <__switch_to_asm+0x34>
> 82ef: __switch_to_asm+0x2f | NOP1 | add $0x8,%rsp |
> 82f0: __switch_to_asm+0x30 | NOP1 | |
> 82f1: __switch_to_asm+0x31 | NOP1 | |
> 82f2: __switch_to_asm+0x32 | NOP1 | |
> 82f3: __switch_to_asm+0x33 | NOP1 | lfence | int3
> 82f4: __switch_to_asm+0x34 | NOP1 | | callq 0x82fa <__switch_to_asm+0x3a>
> 82f5: __switch_to_asm+0x35 | NOP1 | |
> 82f6: __switch_to_asm+0x36 | NOP1 | |
> 82f7: __switch_to_asm+0x37 | NOP1 | |
> 82f8: __switch_to_asm+0x38 | NOP1 | |
> 82f9: __switch_to_asm+0x39 | NOP1 | | int3
> 82fa: __switch_to_asm+0x3a | NOP1 | | add $0x10,%rsp
> 82fb: __switch_to_asm+0x3b | NOP1 | |
> 82fc: __switch_to_asm+0x3c | NOP1 | |
> 82fd: __switch_to_asm+0x3d | NOP1 | |
> 82fe: __switch_to_asm+0x3e | NOP1 | | dec %r12
> 82ff: __switch_to_asm+0x3f | NOP1 | |
> 8300: __switch_to_asm+0x40 | NOP1 | |
> 8301: __switch_to_asm+0x41 | NOP1 | | jne 0x82ee <__switch_to_asm+0x2e>
> 8302: __switch_to_asm+0x42 | NOP1 | |
> 8303: __switch_to_asm+0x43 | NOP1 | | lfence
> 8304: __switch_to_asm+0x44 | NOP1 | |
> 8305: __switch_to_asm+0x45 | NOP1 | |
> 8306: __switch_to_asm+0x46 | NOP1 | | movq $0xffffffffffffffff,%gs:0x0(%rip) # 0x20b <__x86_call_depth>
> 8307: __switch_to_asm+0x47 | NOP1 | |
> 8308: __switch_to_asm+0x48 | NOP1 | |
> 8309: __switch_to_asm+0x49 | NOP1 | |
> 830a: __switch_to_asm+0x4a | NOP1 | |
> 830b: __switch_to_asm+0x4b | NOP1 | |
> 830c: __switch_to_asm+0x4c | NOP1 | |
> 830d: __switch_to_asm+0x4d | NOP1 | |
> 830e: __switch_to_asm+0x4e | NOP1 | |
> 830f: __switch_to_asm+0x4f | NOP1 | |
> 8310: __switch_to_asm+0x50 | NOP1 | |
> 8311: __switch_to_asm+0x51 | NOP1 | |
> 8312: __switch_to_asm+0x52 pop %r15
> 8314: __switch_to_asm+0x54 pop %r14
> 8316: __switch_to_asm+0x56 pop %r13
> 8318: __switch_to_asm+0x58 pop %r12
> 831a: __switch_to_asm+0x5a pop %rbx
> 831b: __switch_to_asm+0x5b pop %rbp
> 831c: __switch_to_asm+0x5c jmpq 0x8321 <__switch_to>
>
>
> Example 4 (--disas option): Alternative with direct call
> --------------------------------------------------------
> An alternative with a direct call show the pv_ops call and
> the default pv_ops function for this call.
>
> $ ./tools/objtool/objtool --disas=paravirt_read_msr --link vmlinux.o
> paravirt_read_msr:
> c3d0: paravirt_read_msr+0x0 mov %edi,%edi
> c3d2: paravirt_read_msr+0x2 callq *0x0(%rip) # 0xc3d8 <pv_ops+0xb0> | callq pv_ops[22] ~ native_read_msr (+X86_FEATURE_ALWAYS) # <alternative.c3d2>
> c3d8: paravirt_read_msr+0x8 jmpq 0xc3dd <__x86_return_thunk>
>
>
> Example 5 (--disas option): Alternative with direct call for XENPV
> ------------------------------------------------------------------
> An alternative with a direct call in the XENPV case show the pv_ops
> function for XEN.
>
> early_ioremap_pmd:
> 332d0: early_ioremap_pmd+0x0 push %rbx
> 332d1: early_ioremap_pmd+0x1 mov %rdi,%rbx
> 332d4: early_ioremap_pmd+0x4 callq *0x0(%rip) # 0x332da <pv_ops+0x150> | mov %cr3,%rax (!X86_FEATURE_XENPV) | callq xen_read_cr3 (+X86_FEATURE_ALWAYS) # <alternative.332d4>
> 332da: early_ioremap_pmd+0xa mov 0x0(%rip),%rdx # 0x332e1 <sme_me_mask>
> 332e1: early_ioremap_pmd+0x11 mov 0x0(%rip),%ecx # 0x332e7 <pgdir_shift>
> 332e7: early_ioremap_pmd+0x17 mov %rbx,%rsi
> 332ea: early_ioremap_pmd+0x1a and 0x0(%rip),%rax # 0x332f1 <physical_mask>
> 332f1: early_ioremap_pmd+0x21 not %rdx
> 332f4: early_ioremap_pmd+0x24 and %rdx,%rax
> 332f7: early_ioremap_pmd+0x27 mov %rbx,%rdx
> 332fa: early_ioremap_pmd+0x2a shr %cl,%rdx
> 332fd: early_ioremap_pmd+0x2d and $0xfffffffffffff000,%rax
> 33303: early_ioremap_pmd+0x33 add 0x0(%rip),%rax # 0x3330a <page_offset_base>
> 3330a: early_ioremap_pmd+0x3a and $0x1ff,%edx
> 33310: early_ioremap_pmd+0x40 lea (%rax,%rdx,8),%rdi
> 33314: early_ioremap_pmd+0x44 callq 0x33319 <p4d_offset+0x0>
> 33319: early_ioremap_pmd+0x49 mov (%rax),%rdi
> 3331c: early_ioremap_pmd+0x4c callq *0x0(%rip) # 0x33322 <pv_ops+0x228> | mov %rdi,%rax (!X86_FEATURE_XENPV) | callq __raw_callee_save_xen_p4d_val (+X86_FEATURE_ALWAYS) # <alternative.3331c>
> 33322: early_ioremap_pmd+0x52 mov 0x0(%rip),%rdx # 0x33329 <page_offset_base>
> 33329: early_ioremap_pmd+0x59 and 0x0(%rip),%rax # 0x33330 <physical_mask>
> 33330: early_ioremap_pmd+0x60 and $0xfffffffffffff000,%rax
> 33336: early_ioremap_pmd+0x66 mov 0xff8(%rax,%rdx,1),%rdi
> 3333e: early_ioremap_pmd+0x6e callq *0x0(%rip) # 0x33344 <pv_ops+0x210> | mov %rdi,%rax (!X86_FEATURE_XENPV) | callq __raw_callee_save_xen_pud_val (+X86_FEATURE_ALWAYS) # <alternative.3333e>
> 33344: early_ioremap_pmd+0x74 mov 0x0(%rip),%rcx # 0x3334b <physical_mask>
> 3334b: early_ioremap_pmd+0x7b mov %rcx,%rdx
> 3334e: early_ioremap_pmd+0x7e and $0xfffffffffffff000,%rdx
> 33355: early_ioremap_pmd+0x85 and $0x80,%dil
> 33359: early_ioremap_pmd+0x89 je 0x33365 <early_ioremap_pmd+0x95>
> 3335b: early_ioremap_pmd+0x8b and $0xffffffffc0000000,%rcx
> 33362: early_ioremap_pmd+0x92 mov %rcx,%rdx
> 33365: early_ioremap_pmd+0x95 and %rax,%rdx
> 33368: early_ioremap_pmd+0x98 add 0x0(%rip),%rdx # 0x3336f <page_offset_base>
> 3336f: early_ioremap_pmd+0x9f pop %rbx
> 33370: early_ioremap_pmd+0xa0 lea 0xfc8(%rdx),%rax
> 33377: early_ioremap_pmd+0xa7 jmpq 0x3337c <__x86_return_thunk>
>
> -----
>
> Alexandre Chartre (28):
> objtool: Move disassembly functions to a separated file
> objtool: Create disassembly context
> objtool: Disassemble code with libopcodes instead of running objdump
> tool build: Remove annoying newline in build output
> objtool: Print symbol during disassembly
> objtool: Store instruction disassembly result
> objtool: Disassemble instruction on warning or backtrace
> objtool: Extract code to validate instruction from the validate branch
> loop
> objtool: Record symbol name max length
> objtool: Add option to trace function validation
> objtool: Trace instruction state changes during function validation
> objtool: Improve register reporting during function validation
> objtool: Identify the different types of alternatives
> objtool: Improve tracing of alternative instructions
> objtool: Do not validate IBT for .return_sites and .call_sites
> objtool: Add the --disas=<function-pattern> action
> objtool: Print headers for alternatives
> objtool: Disassemble group alternatives
> objtool: Print addresses with alternative instructions
> objtool: Disassemble exception table alternatives
> objtool: Disassemble jump table alternatives
> objtool: Fix address references in alternatives
> objtool: Provide access to feature and flags of group alternatives
> objtool: Function to get the name of a CPU feature
> objtool: Improve naming of group alternatives
> objtool: Get the destination name of a PV call
> objtool: Improve the disassembly of the pv_ops call
> objtool: Print single line for alternatives with one instruction
>
> .../x86/tools/gen-cpu-feature-names-x86.awk | 33 +
> tools/build/Makefile.feature | 4 +-
> tools/objtool/Build | 3 +
> tools/objtool/Makefile | 23 +
> tools/objtool/arch/loongarch/decode.c | 30 +
> tools/objtool/arch/loongarch/special.c | 5 +
> tools/objtool/arch/powerpc/decode.c | 31 +
> tools/objtool/arch/powerpc/special.c | 5 +
> tools/objtool/arch/x86/Build | 8 +
> tools/objtool/arch/x86/decode.c | 36 +-
> tools/objtool/arch/x86/special.c | 10 +
> tools/objtool/builtin-check.c | 5 +-
> tools/objtool/check.c | 745 ++++++-----
> tools/objtool/disas.c | 1137 +++++++++++++++++
> tools/objtool/include/objtool/arch.h | 14 +-
> tools/objtool/include/objtool/builtin.h | 2 +
> tools/objtool/include/objtool/check.h | 41 +-
> tools/objtool/include/objtool/disas.h | 71 +
> tools/objtool/include/objtool/elf.h | 7 +
> tools/objtool/include/objtool/objtool.h | 6 +-
> tools/objtool/include/objtool/special.h | 4 +-
> tools/objtool/include/objtool/trace.h | 121 ++
> tools/objtool/include/objtool/warn.h | 17 +-
> tools/objtool/objtool.c | 27 +-
> tools/objtool/special.c | 2 +
> tools/objtool/trace.c | 204 +++
> 26 files changed, 2271 insertions(+), 320 deletions(-)
> create mode 100644 tools/arch/x86/tools/gen-cpu-feature-names-x86.awk
> create mode 100644 tools/objtool/disas.c
> create mode 100644 tools/objtool/include/objtool/disas.h
> create mode 100644 tools/objtool/include/objtool/trace.h
> create mode 100644 tools/objtool/trace.c
>
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