On Tue, Apr 28, 2020 at 10:19:46PM +0200, Arnd Bergmann wrote:
> On Tue, Apr 28, 2020 at 6:10 PM Josh Poimboeuf <jpoim...@redhat.com> wrote:
> > On Tue, Apr 28, 2020 at 04:49:15PM +0200, Arnd Bergmann wrote:
> > > ==> build/x86/0xFD7B7323_defconfig/log <==
> > > arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x991:
> > > unreachable instruction
> >
> > This warning looks correct, did you make a change to entry_64.S?
>
> I bisected my local patches and found that I had a local hack that turned
> off CONFIG_RETPOLINE for testing something unrelated. I can reproduce
> it on linux-next with this patch:
>
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -447,8 +447,7 @@ config GOLDFISH
> depends on X86_GOLDFISH
>
> config RETPOLINE
> - bool "Avoid speculative indirect branches in kernel"
> - default y
> + def_bool n
> select STACK_VALIDATION if HAVE_STACK_VALIDATION
> help
> Compile kernel with the retpoline compiler options to guard against
Thanks, that worked.
This one makes no sense to me. It looks like the assembler is inserting
a jump as part of the alignment padding??? WTH.
0000000000000980 <common_spurious>:
980: 48 83 04 24 80 addq $0xffffffffffffff80,(%rsp)
985: e8 00 00 00 00 callq 98a <common_spurious+0xa>
986: R_X86_64_PLT32 interrupt_entry-0x4
98a: e8 00 00 00 00 callq 98f <common_spurious+0xf>
98b: R_X86_64_PLT32 smp_spurious_interrupt-0x4
98f: eb 7e jmp a0f <ret_from_intr>
991: eb 6d jmp a00 <common_interrupt>
993: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
99a: 00 00 00 00
99e: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
9a5: 00 00 00 00
9a9: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
9b0: 00 00 00 00
9b4: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
9bb: 00 00 00 00
9bf: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
9c6: 00 00 00 00
9ca: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
9d1: 00 00 00 00
9d5: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
9dc: 00 00 00 00
9e0: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
9e7: 00 00 00 00
9eb: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
9f2: 00 00 00 00
9f6: 66 2e 0f 1f 84 00 00 nopw %cs:0x0(%rax,%rax,1)
9fd: 00 00 00
0000000000000a00 <common_interrupt>:
a00: 48 83 04 24 80 addq $0xffffffffffffff80,(%rsp)
--
Josh
