Re: [tip:x86/tdx 8/12] vmlinux.o: warning: objtool: __tdx_hypercall+0x128: __tdx_hypercall_failed() is missing a __noreturn annotation

From: Huang, Kai
Date: Wed Sep 13 2023 - 21:24:04 EST

On Thu, 2023-09-14 at 09:05 +0800, kernel test robot wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/tdx
> head: 7b804135d4d1f0a2b9dda69c6303d3f2dcbe9d37
> commit: c641cfb5c157b6c3062a824fd8ba190bf06fb952 [8/12] x86/tdx: Make TDX_HYPERCALL asm similar to TDX_MODULE_CALL
> config: x86_64-rhel-8.3-bpf (https://download.01.org/0day-ci/archive/20230914/202309140828.9RdmlH2Z-lkp@xxxxxxxxx/config)
> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230914/202309140828.9RdmlH2Z-lkp@xxxxxxxxx/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > Closes: https://lore.kernel.org/oe-kbuild-all/202309140828.9RdmlH2Z-lkp@xxxxxxxxx/
>
> All warnings (new ones prefixed by >>):
>
> > > vmlinux.o: warning: objtool: __tdx_hypercall+0x128: __tdx_hypercall_failed() is missing a __noreturn annotation
>

Hmm.. The __tdx_hypercall_failed() is already annotated with __noreturn (I
explicitly added it to silent such warning):

/* Called from __tdx_hypercall() for unrecoverable failure */
noinstr void __noreturn __tdx_hypercall_failed(void)
{
instrumentation_begin();
panic("TDVMCALL failed. TDX module bug?");
}

Not sure why the objtool is still complaining this?

>
> objdump-func vmlinux.o __tdx_hypercall:
> 0000 0000000000000050 <__tdx_hypercall_failed>:
> 0000 50: f3 0f 1e fa endbr64
> 0004 54: 48 c7 c7 00 00 00 00 mov $0x0,%rdi 57: R_X86_64_32S .rodata.str1.8+0xe18
> 000b 5b: e8 00 00 00 00 call 60 <__tdx_hypercall> 5c: R_X86_64_PLT32 panic-0x4
> 0000 0000000000000060 <__tdx_hypercall>:
> 0000 60: f3 0f 1e fa endbr64
> 0004 64: 53 push %rbx
> 0005 65: 48 89 fb mov %rdi,%rbx
> 0008 68: 48 83 ec 70 sub $0x70,%rsp
> 000c 6c: 65 48 8b 04 25 28 00 00 00 mov %gs:0x28,%rax
> 0015 75: 48 89 44 24 68 mov %rax,0x68(%rsp)
> 001a 7a: 31 c0 xor %eax,%eax
> 001c 7c: 48 8b 47 58 mov 0x58(%rdi),%rax
> 0020 80: 48 89 e6 mov %rsp,%rsi
> 0023 83: 48 c7 04 24 cc ff 00 00 movq $0xffcc,(%rsp)
> 002b 8b: 48 89 44 24 08 mov %rax,0x8(%rsp)
> 0030 90: 48 8b 07 mov (%rdi),%rax
> 0033 93: 48 89 44 24 10 mov %rax,0x10(%rsp)
> 0038 98: 48 8b 47 08 mov 0x8(%rdi),%rax
> 003c 9c: 48 89 44 24 18 mov %rax,0x18(%rsp)
> 0041 a1: 48 8b 47 10 mov 0x10(%rdi),%rax
> 0045 a5: 48 89 44 24 20 mov %rax,0x20(%rsp)
> 004a aa: 48 8b 47 18 mov 0x18(%rdi),%rax
> 004e ae: 48 89 44 24 28 mov %rax,0x28(%rsp)
> 0053 b3: 48 8b 47 20 mov 0x20(%rdi),%rax
> 0057 b7: 48 89 44 24 30 mov %rax,0x30(%rsp)
> 005c bc: 48 8b 47 28 mov 0x28(%rdi),%rax
> 0060 c0: 48 89 44 24 38 mov %rax,0x38(%rsp)
> 0065 c5: 48 8b 47 30 mov 0x30(%rdi),%rax
> 0069 c9: 48 89 44 24 40 mov %rax,0x40(%rsp)
> 006e ce: 48 8b 47 38 mov 0x38(%rdi),%rax
> 0072 d2: 48 89 44 24 48 mov %rax,0x48(%rsp)
> 0077 d7: 48 8b 47 50 mov 0x50(%rdi),%rax
> 007b db: 48 89 44 24 50 mov %rax,0x50(%rsp)
> 0080 e0: 48 8b 47 40 mov 0x40(%rdi),%rax
> 0084 e4: 48 89 44 24 58 mov %rax,0x58(%rsp)
> 0089 e9: 48 8b 47 48 mov 0x48(%rdi),%rax
> 008d ed: 31 ff xor %edi,%edi
> 008f ef: 48 89 44 24 60 mov %rax,0x60(%rsp)
> 0094 f4: e8 00 00 00 00 call f9 <__tdx_hypercall+0x99> f5: R_X86_64_PLT32 __tdcall_hypercall-0x4
> 0099 f9: 48 85 c0 test %rax,%rax
> 009c fc: 0f 85 81 00 00 00 jne 183 <__tdx_hypercall+0x123>
> 00a2 102: 48 8b 54 24 28 mov 0x28(%rsp),%rdx
> 00a7 107: 48 8b 44 24 10 mov 0x10(%rsp),%rax
> 00ac 10c: 48 89 53 18 mov %rdx,0x18(%rbx)
> 00b0 110: 48 8b 54 24 30 mov 0x30(%rsp),%rdx
> 00b5 115: 48 89 03 mov %rax,(%rbx)
> 00b8 118: 48 8b 44 24 18 mov 0x18(%rsp),%rax
> 00bd 11d: 48 89 53 20 mov %rdx,0x20(%rbx)
> 00c1 121: 48 8b 54 24 38 mov 0x38(%rsp),%rdx
> 00c6 126: 48 89 43 08 mov %rax,0x8(%rbx)
> 00ca 12a: 48 8b 44 24 20 mov 0x20(%rsp),%rax
> 00cf 12f: 48 89 53 28 mov %rdx,0x28(%rbx)
> 00d3 133: 48 8b 54 24 40 mov 0x40(%rsp),%rdx
> 00d8 138: 48 89 43 10 mov %rax,0x10(%rbx)
> 00dc 13c: 48 89 53 30 mov %rdx,0x30(%rbx)
> 00e0 140: 48 8b 54 24 48 mov 0x48(%rsp),%rdx
> 00e5 145: 48 89 53 38 mov %rdx,0x38(%rbx)
> 00e9 149: 48 8b 54 24 58 mov 0x58(%rsp),%rdx
> 00ee 14e: 48 89 53 40 mov %rdx,0x40(%rbx)
> 00f2 152: 48 8b 54 24 60 mov 0x60(%rsp),%rdx
> 00f7 157: 48 89 53 48 mov %rdx,0x48(%rbx)
> 00fb 15b: 48 8b 54 24 50 mov 0x50(%rsp),%rdx
> 0100 160: 48 89 53 50 mov %rdx,0x50(%rbx)
> 0104 164: 48 8b 54 24 08 mov 0x8(%rsp),%rdx
> 0109 169: 48 89 53 58 mov %rdx,0x58(%rbx)
> 010d 16d: 48 8b 54 24 68 mov 0x68(%rsp),%rdx
> 0112 172: 65 48 2b 14 25 28 00 00 00 sub %gs:0x28,%rdx
> 011b 17b: 75 10 jne 18d <__tdx_hypercall+0x12d>
> 011d 17d: 48 83 c4 70 add $0x70,%rsp
> 0121 181: 5b pop %rbx
> 0122 182: c3 ret
> 0123 183: e8 00 00 00 00 call 188 <__tdx_hypercall+0x128> 184: R_X86_64_PLT32 __tdx_hypercall_failed-0x4
> 0128 188: e9 75 ff ff ff jmp 102 <__tdx_hypercall+0xa2>
> 012d 18d: e8 00 00 00 00 call 192 <__tdx_hypercall+0x132> 18e: R_X86_64_PLT32 __stack_chk_fail-0x4
> 0132 192: 66 2e 0f 1f 84 00 00 00 00 00 cs nopw 0x0(%rax,%rax,1)
> 013c 19c: 0f 1f 40 00 nopl 0x0(%rax)
>