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Message-ID: <20251124110425.GAaSQ7uSffz7xDayLJ@fat_crate.local>
Date: Mon, 24 Nov 2025 12:04:25 +0100
From: Borislav Petkov <bp@...en8.de>
To: Alexandre Chartre <alexandre.chartre@...cle.com>
Cc: linux-kernel@...r.kernel.org, mingo@...nel.org, jpoimboe@...nel.org,
peterz@...radead.org, david.laight.linux@...il.com
Subject: Re: [PATCH v6 00/30] objtool: Function validation tracing
On Fri, Nov 21, 2025 at 10:53:10AM +0100, Alexandre Chartre wrote:
> Notes:
> ======
So those examples below look very useful and cool. Can you pls document them
so that I can find the breadcrumbs next time and use them?
:-)
Thx.
> 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
> 59be0: os_xsave+0x0 push %r12 - state: cfa=rsp+16 r12=(cfa-16) stack_size=16
> 59be2: os_xsave+0x2 mov 0x0(%rip),%eax # 0x59be8 <alternatives_patched>
> 59be8: os_xsave+0x8 push %rbp - state: cfa=rsp+24 rbp=(cfa-24) stack_size=24
> 59be9: os_xsave+0x9 mov %rdi,%rbp
> 59bec: os_xsave+0xc push %rbx - state: cfa=rsp+32 rbx=(cfa-32) stack_size=32
> 59bed: os_xsave+0xd mov 0x8(%rdi),%rbx
> 59bf1: os_xsave+0x11 mov %rbx,%r12
> 59bf4: os_xsave+0x14 shr $0x20,%r12
> 59bf8: os_xsave+0x18 test %eax,%eax
> 59bfa: os_xsave+0x1a je 0x59c22 <os_xsave+0x42> - jump taken
> 59c22: os_xsave+0x42 | ud2
> 59c24: os_xsave+0x44 | jmp 0x59bfc <os_xsave+0x1c> - unconditional jump
> 59bfc: os_xsave+0x1c | | xor %edx,%edx
> 59bfe: os_xsave+0x1e | | mov %rbx,%rsi
> 59c01: os_xsave+0x21 | | mov %rbp,%rdi
> 59c04: os_xsave+0x24 | | callq 0x59c09 <xfd_validate_state> - call
> 59c09: os_xsave+0x29 | | mov %ebx,%eax
> 59c0b: os_xsave+0x2b | | mov %r12d,%edx
> | | / <alternative.59c0e> X86_FEATURE_XSAVEOPT
> 1b29: .altinstr_replacement+0x1b29 | | | xsaveopt64 0x40(%rbp)
> 59c13: os_xsave+0x33 | | | xor %ebx,%ebx
> 59c15: os_xsave+0x35 | | | test %ebx,%ebx
> 59c17: os_xsave+0x37 | | | jne 0x59c26 <os_xsave+0x46> - jump taken
> 59c26: os_xsave+0x46 | | | | ud2
> 59c28: os_xsave+0x48 | | | | pop %rbx - state: cfa=rsp+24 rbx=<undef> stack_size=24
> 59c29: os_xsave+0x49 | | | | pop %rbp - state: cfa=rsp+16 rbp=<undef> stack_size=16
> 59c2a: os_xsave+0x4a | | | | pop %r12 - state: cfa=rsp+8 r12=<undef> stack_size=8
> 59c2c: os_xsave+0x4c | | | | jmpq 0x59c31 <__x86_return_thunk> - return
> 59c17: os_xsave+0x37 | | | jne 0x59c26 <os_xsave+0x46> - jump not taken
> 59c19: os_xsave+0x39 | | | pop %rbx - state: cfa=rsp+24 rbx=<undef> stack_size=24
> 59c1a: os_xsave+0x3a | | | pop %rbp - state: cfa=rsp+16 rbp=<undef> stack_size=16
> 59c1b: os_xsave+0x3b | | | pop %r12 - state: cfa=rsp+8 r12=<undef> stack_size=8
> 59c1d: os_xsave+0x3d | | | jmpq 0x59c22 <__x86_return_thunk> - return
> | | \ <alternative.59c0e> X86_FEATURE_XSAVEOPT
> | | / <alternative.59c0e> X86_FEATURE_XSAVEC
> 1b2e: .altinstr_replacement+0x1b2e | | | xsavec64 0x40(%rbp)
> 59c13: os_xsave+0x33 | | | xor %ebx,%ebx - already visited
> | | \ <alternative.59c0e> X86_FEATURE_XSAVEC
> | | / <alternative.59c0e> X86_FEATURE_XSAVES
> 1b33: .altinstr_replacement+0x1b33 | | | xsaves64 0x40(%rbp)
> 59c13: os_xsave+0x33 | | | xor %ebx,%ebx - already visited
> | | \ <alternative.59c0e> X86_FEATURE_XSAVES
> | | / <alternative.59c0e> EXCEPTION for instruction at 0x59c0e <os_xsave+0x2e>
> 59c15: os_xsave+0x35 | | | test %ebx,%ebx - already visited
> | | \ <alternative.59c0e> EXCEPTION
> | | / <alternative.59c0e> DEFAULT
> 59c0e: os_xsave+0x2e | | xsave64 0x40(%rbp)
> 59c13: os_xsave+0x33 | | xor %ebx,%ebx - already visited
> 59bfa: os_xsave+0x1a je 0x59c22 <os_xsave+0x42> - jump not taken
> 59bfc: os_xsave+0x1c xor %edx,%edx - already visited
> os_xsave: validation end
>
>
> Example 2 (--disas option): Single Instruction Alternatives
> -----------------------------------------------------------
>
> Compact Output (default):
>
> Alternatives with single instructions are displayed each on one line,
> with the instruction and a description of the alternative.
>
> $ ./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 <alternative.debc>
> = jmpq 0xdec1 <.altinstr_aux+0xfc> (if DEFAULT)
> = jmpq 0x622 <perf_get_x86_pmu_capability+0x37> (if X86_FEATURE_ALWAYS)
> = nop5 (if X86_FEATURE_HYBRID_CPU)
> 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 <jump_table.def9>
> = nop2 (if DEFAULT)
> = jmp defb <perf_get_x86_pmu_capability+0x4b> (if JUMP)
> defb: perf_get_x86_pmu_capability+0x4b mov 0x0(%rip),%rdi # 0xdf02 <x86_pmu+0xd8>
> df02: perf_get_x86_pmu_capability+0x52 <alternative.df02>
> = callq 0xdf07 <__sw_hweight64> (if DEFAULT)
> = popcnt %rdi,%rax (if X86_FEATURE_POPCNT)
> df07: perf_get_x86_pmu_capability+0x57 mov %eax,0x4(%rdx)
> df0a: perf_get_x86_pmu_capability+0x5a <jump_table.df0a>
> = nop2 (if DEFAULT)
> = jmp df0c <perf_get_x86_pmu_capability+0x5c> (if JUMP)
> df0c: perf_get_x86_pmu_capability+0x5c mov 0x0(%rip),%rdi # 0xdf13 <x86_pmu+0xe0>
> df13: perf_get_x86_pmu_capability+0x63 <alternative.df13>
> = callq 0xdf18 <__sw_hweight64> (if DEFAULT)
> = popcnt %rdi,%rax (if X86_FEATURE_POPCNT)
> 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>
>
>
> Wide Output (--wide option):
>
> Alternatives with single instructions are displayed side-by-side,
> with an header.
>
> $ ./tools/objtool/objtool --disas=perf_get_x86_pmu_capability --wide --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 | <alternative.debc> | X86_FEATURE_ALWAYS | X86_FEATURE_HYBRID_CPU
> debc: perf_get_x86_pmu_capability+0xc | jmpq 0xdec1 <.altinstr_aux+0xfc> | jmpq 0x622 <perf_get_x86_pmu_capability+0x37> | nop5
> 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 | <jump_table.def9> | JUMP
> def9: perf_get_x86_pmu_capability+0x49 | nop2 | jmp defb <perf_get_x86_pmu_capability+0x4b>
> defb: perf_get_x86_pmu_capability+0x4b mov 0x0(%rip),%rdi # 0xdf02 <x86_pmu+0xd8>
> df02: perf_get_x86_pmu_capability+0x52 | <alternative.df02> | X86_FEATURE_POPCNT
> df02: perf_get_x86_pmu_capability+0x52 | callq 0xdf07 <__sw_hweight64> | popcnt %rdi,%rax
> df07: perf_get_x86_pmu_capability+0x57 mov %eax,0x4(%rdx)
> df0a: perf_get_x86_pmu_capability+0x5a | <jump_table.df0a> | JUMP
> df0a: perf_get_x86_pmu_capability+0x5a | nop2 | jmp df0c <perf_get_x86_pmu_capability+0x5c>
> df0c: perf_get_x86_pmu_capability+0x5c mov 0x0(%rip),%rdi # 0xdf13 <x86_pmu+0xe0>
> df13: perf_get_x86_pmu_capability+0x63 | <alternative.df13> | X86_FEATURE_POPCNT
> df13: perf_get_x86_pmu_capability+0x63 | callq 0xdf18 <__sw_hweight64> | popcnt %rdi,%rax
> 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
> -------------------------------------------------------------------
>
> Compact Output (default):
>
> Alternatives with multiple instructions are displayed one above the other,
> with an header describing 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>
> = DEFAULT
> 82e7: __switch_to_asm+0x27 | jmp 0x8312 <__switch_to_asm+0x52>
> 82e9: __switch_to_asm+0x29 | nop*41
> |
> = X86_FEATURE_RSB_CTXSW
> 82e7: __switch_to_asm+0x27 | mov $0x10,%r12
> 82ee: __switch_to_asm+0x2e | callq 0x82f4 <__switch_to_asm+0x34>
> 82f3: __switch_to_asm+0x33 | int3
> 82f4: __switch_to_asm+0x34 | callq 0x82fa <__switch_to_asm+0x3a>
> 82f9: __switch_to_asm+0x39 | int3
> 82fa: __switch_to_asm+0x3a | add $0x10,%rsp
> 82fe: __switch_to_asm+0x3e | dec %r12
> 8301: __switch_to_asm+0x41 | jne 0x82ee <__switch_to_asm+0x2e>
> 8303: __switch_to_asm+0x43 | lfence
> 8306: __switch_to_asm+0x46 | movq $0xffffffffffffffff,%gs:0x0(%rip) # 0x20b <__x86_call_depth>
> |
> = !X86_FEATURE_ALWAYS
> 82e7: __switch_to_asm+0x27 | nop1
> 82e8: __switch_to_asm+0x28 | nop1
> 82e9: __switch_to_asm+0x29 | callq 0x82ef <__switch_to_asm+0x2f>
> 82ee: __switch_to_asm+0x2e | int3
> 82ef: __switch_to_asm+0x2f | add $0x8,%rsp
> 82f3: __switch_to_asm+0x33 | lfence
> |
> 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>
>
>
> Wide Output (--wide option):
>
> 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 --wide --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_RSB_CTXSW | !X86_FEATURE_ALWAYS
> 82e7: __switch_to_asm+0x27 | jmp 0x8312 <__switch_to_asm+0x52> | mov $0x10,%r12 | nop1
> 82e8: __switch_to_asm+0x28 | | | nop1
> 82e9: __switch_to_asm+0x29 | nop*41 | | callq 0x82ef <__switch_to_asm+0x2f>
> 82ee: __switch_to_asm+0x2e | | callq 0x82f4 <__switch_to_asm+0x34> | int3
> 82ef: __switch_to_asm+0x2f | | | add $0x8,%rsp
> 82f3: __switch_to_asm+0x33 | | int3 | lfence
> 82f4: __switch_to_asm+0x34 | | callq 0x82fa <__switch_to_asm+0x3a> |
> 82f9: __switch_to_asm+0x39 | | int3 |
> 82fa: __switch_to_asm+0x3a | | add $0x10,%rsp |
> 82fe: __switch_to_asm+0x3e | | dec %r12 |
> 8301: __switch_to_asm+0x41 | | jne 0x82ee <__switch_to_asm+0x2e> |
> 8303: __switch_to_asm+0x43 | | lfence |
> 8306: __switch_to_asm+0x46 | | movq $0xffffffffffffffff,%gs:0x0(%rip) # 0x20b <__x86_call_depth> |
> 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>
>
> -----
>
> Alexandre Chartre (30):
> 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: Add functions to better name 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: Preserve alternatives order
> 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: Compact output for alternatives with one instruction
> objtool: Add wide output for disassembly
> objtool: Trim trailing NOPs in alternative
>
> .../x86/tools/gen-cpu-feature-names-x86.awk | 33 +
> tools/build/Makefile.feature | 4 +-
> tools/objtool/.gitignore | 3 +
> tools/objtool/Build | 3 +
> tools/objtool/Makefile | 26 +
> tools/objtool/arch/loongarch/decode.c | 23 +
> tools/objtool/arch/loongarch/special.c | 5 +
> tools/objtool/arch/powerpc/decode.c | 24 +
> tools/objtool/arch/powerpc/special.c | 5 +
> tools/objtool/arch/x86/Build | 8 +
> tools/objtool/arch/x86/decode.c | 20 +
> tools/objtool/arch/x86/special.c | 10 +
> tools/objtool/builtin-check.c | 4 +
> tools/objtool/check.c | 648 +++++----
> tools/objtool/disas.c | 1245 +++++++++++++++++
> tools/objtool/include/objtool/arch.h | 11 +
> tools/objtool/include/objtool/builtin.h | 3 +
> tools/objtool/include/objtool/check.h | 35 +-
> tools/objtool/include/objtool/disas.h | 81 ++
> tools/objtool/include/objtool/special.h | 4 +-
> tools/objtool/include/objtool/trace.h | 141 ++
> tools/objtool/include/objtool/warn.h | 17 +-
> tools/objtool/special.c | 2 +
> tools/objtool/trace.c | 203 +++
> 24 files changed, 2259 insertions(+), 299 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
>
> --
> 2.43.5
>
>
>
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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