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| author | Peter Zijlstra <peterz@infradead.org> | 2022-03-08 18:30:50 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-13 21:59:13 +0300 |
| commit | e3c961c56ad522eaf2716afa42c59346675ee4b1 (patch) | |
| tree | 90f01214a01930bc2d0e0ed83b6dd54b2ab25869 /arch | |
| parent | 6bb2270223a8128efdcaf1654ba416f693eb4623 (diff) | |
| download | linux-e3c961c56ad522eaf2716afa42c59346675ee4b1.tar.xz | |
x86: Annotate call_on_stack()
[ Upstream commit be0075951fde739f14ee2b659e2fd6e2499c46c0 ]
vmlinux.o: warning: objtool: page_fault_oops()+0x13c: unreachable instruction
0000 000000000005b460 <page_fault_oops>:
...
0128 5b588: 49 89 23 mov %rsp,(%r11)
012b 5b58b: 4c 89 dc mov %r11,%rsp
012e 5b58e: 4c 89 f2 mov %r14,%rdx
0131 5b591: 48 89 ee mov %rbp,%rsi
0134 5b594: 4c 89 e7 mov %r12,%rdi
0137 5b597: e8 00 00 00 00 call 5b59c <page_fault_oops+0x13c> 5b598: R_X86_64_PLT32 handle_stack_overflow-0x4
013c 5b59c: 5c pop %rsp
vmlinux.o: warning: objtool: sysvec_reboot()+0x6d: unreachable instruction
0000 00000000000033f0 <sysvec_reboot>:
...
005d 344d: 4c 89 dc mov %r11,%rsp
0060 3450: e8 00 00 00 00 call 3455 <sysvec_reboot+0x65> 3451: R_X86_64_PLT32 irq_enter_rcu-0x4
0065 3455: 48 89 ef mov %rbp,%rdi
0068 3458: e8 00 00 00 00 call 345d <sysvec_reboot+0x6d> 3459: R_X86_64_PC32 .text+0x47d0c
006d 345d: e8 00 00 00 00 call 3462 <sysvec_reboot+0x72> 345e: R_X86_64_PLT32 irq_exit_rcu-0x4
0072 3462: 5c pop %rsp
Both cases are due to a call_on_stack() calling a __noreturn function.
Since that's an inline asm, GCC can't do anything about the
instructions after the CALL. Therefore put in an explicit
ASM_REACHABLE annotation to make sure objtool and gcc are consistently
confused about control flow.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154319.468805622@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/irq_stack.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/include/asm/irq_stack.h b/arch/x86/include/asm/irq_stack.h index 8d55bd11848c..e087cd7837c3 100644 --- a/arch/x86/include/asm/irq_stack.h +++ b/arch/x86/include/asm/irq_stack.h @@ -99,7 +99,8 @@ } #define ASM_CALL_ARG0 \ - "call %P[__func] \n" + "call %P[__func] \n" \ + ASM_REACHABLE #define ASM_CALL_ARG1 \ "movq %[arg1], %%rdi \n" \ |