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SubjectRe: [RFC 24/30] x86/entry/32: Switch INT80 to the new C syscall path
On Thu, Sep 3, 2015 at 9:45 AM, Brian Gerst <brgerst@gmail.com> wrote:
> On Tue, Sep 1, 2015 at 6:41 PM, Andy Lutomirski <luto@kernel.org> wrote:
>> Signed-off-by: Andy Lutomirski <luto@kernel.org>
>> ---
>> arch/x86/entry/entry_32.S | 34 +++++++++++++---------------------
>> 1 file changed, 13 insertions(+), 21 deletions(-)
>>
>> diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
>> index 36b6beb181f6..02881e528945 100644
>> --- a/arch/x86/entry/entry_32.S
>> +++ b/arch/x86/entry/entry_32.S
>> @@ -153,13 +153,13 @@
>>
>> #endif /* CONFIG_X86_32_LAZY_GS */
>>
>> -.macro SAVE_ALL
>> +.macro SAVE_ALL pt_regs_ax=%eax
>> cld
>> PUSH_GS
>> pushl %fs
>> pushl %es
>> pushl %ds
>> - pushl %eax
>> + pushl \pt_regs_ax
>> pushl %ebp
>> pushl %edi
>> pushl %esi
>> @@ -370,20 +370,17 @@ ENDPROC(entry_SYSENTER_32)
>> # system call handler stub
>> ENTRY(entry_INT80_32)
>> ASM_CLAC
>> - pushl %eax # save orig_eax
>> - SAVE_ALL
>> - GET_THREAD_INFO(%ebp)
>> - # system call tracing in operation / emulation
>> - testl $_TIF_WORK_SYSCALL_ENTRY, TI_flags(%ebp)
>> - jnz syscall_trace_entry
>> - cmpl $(NR_syscalls), %eax
>> - jae syscall_badsys
>> -syscall_call:
>> - call *sys_call_table(, %eax, 4)
>> -syscall_after_call:
>> - movl %eax, PT_EAX(%esp) # store the return value
>> -syscall_exit:
>> - jmp syscall_exit_work
>> + pushl %eax /* pt_regs->orig_ax */
>> + SAVE_ALL pt_regs_ax=$-ENOSYS /* save rest, load -ENOSYS into ax */
>> +
>> + /*
>> + * User mode is traced as though IRQs are on, and the interrupt gate
>> + * turned them off.
>> + */
>> + TRACE_IRQS_OFF
>> +
>> + movl %esp, %eax
>> + call do_int80_syscall_32
>>
>> restore_all:
>> TRACE_IRQS_IRET
>> @@ -491,11 +488,6 @@ syscall_fault:
>> jmp resume_userspace
>> END(syscall_fault)
>>
>> -syscall_badsys:
>> - movl $-ENOSYS, %eax
>> - jmp syscall_after_call
>> -END(syscall_badsys)
>> -
>> sysenter_badsys:
>> movl $-ENOSYS, %eax
>> jmp sysenter_after_call
>> --
>> 2.4.3
>>
>
> While bisecting a boot failure on the 32-bit native kernel I came
> across this build error:
> arch/x86/built-in.o: In function `syscall_trace_entry':
> /home/bgerst/kernel/linux/arch/x86/entry/entry_32.S:468: undefined
> reference to `syscall_call'
> /home/bgerst/kernel/linux/arch/x86/entry/entry_32.S:469: undefined
> reference to `syscall_exit'
>

Whoops! I'll fix that up for v2.

--Andy


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