Re: [PATCH] x86/asm/entry/64: Merge the field offset into the THREAD_INFO() macro

[Andy Lutomirski]

On Tue, Mar 24, 2015 at 11:44 AM, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
> From 11e2761ba0969466299b7109eba749d2292e8796 Mon Sep 17 00:00:00 2001
> From: Ingo Molnar <mingo@xxxxxxxxxx>
> Date: Tue, 24 Mar 2015 19:18:41 +0100
> Subject: [PATCH] x86/asm/entry/64: Merge the field offset into the THREAD_INFO() macro
>
> Before:
>
>    TI_sysenter_return+THREAD_INFO(%rsp,3*8),%r10d
>
> After:
>
>    movl    THREAD_INFO(TI_sysenter_return, %rsp, 3*8), %r10d
>
> to turn it into a clear thread_info accessor.

LGTM (in either order), but I'd fix the nice docs that you just introduced, too.

Acked-by: Andy Lutomirski <luto@xxxxxxxxxx>

>
> No code changed:
>
>  md5:
>    fb4cb2b3ce05d89940ca304efc8ff183  ia32entry.o.before.asm
>    fb4cb2b3ce05d89940ca304efc8ff183  ia32entry.o.after.asm
>
>    e39f2958a5d1300158e276e4f7663263  entry_64.o.before.asm
>    e39f2958a5d1300158e276e4f7663263  entry_64.o.after.asm
>
> Cc: Alexei Starovoitov <ast@xxxxxxxxxxxx>
> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
> Cc: Andy Lutomirski <luto@xxxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxx>
> Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> Cc: H. Peter Anvin <hpa@xxxxxxxxx>
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Cc: Will Drewry <wad@xxxxxxxxxxxx>
> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
> ---
>  arch/x86/ia32/ia32entry.S          | 30 +++++++++++++++---------------
>  arch/x86/include/asm/thread_info.h |  4 ++--
>  arch/x86/kernel/entry_64.S         |  4 ++--
>  3 files changed, 19 insertions(+), 19 deletions(-)
>
> diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
> index acbff3fb96a1..32e94aec6073 100644
> --- a/arch/x86/ia32/ia32entry.S
> +++ b/arch/x86/ia32/ia32entry.S
> @@ -127,7 +127,7 @@ ENTRY(ia32_sysenter_target)
>         CFI_REL_OFFSET rsp,0
>         pushfq_cfi
>         /*CFI_REL_OFFSET rflags,0*/
> -       movl    TI_sysenter_return+THREAD_INFO(%rsp,3*8),%r10d
> +       movl    THREAD_INFO(TI_sysenter_return, %rsp, 3*8), %r10d
>         CFI_REGISTER rip,r10
>         pushq_cfi $__USER32_CS
>         /*CFI_REL_OFFSET cs,0*/
> @@ -159,8 +159,8 @@ ENTRY(ia32_sysenter_target)
>         jnz sysenter_fix_flags
>  sysenter_flags_fixed:
>
> -       orl     $TS_COMPAT,TI_status+THREAD_INFO(%rsp,SIZEOF_PTREGS)
> -       testl   $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,SIZEOF_PTREGS)
> +       orl     $TS_COMPAT, THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
> +       testl   $_TIF_WORK_SYSCALL_ENTRY, THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
>         CFI_REMEMBER_STATE
>         jnz  sysenter_tracesys
>         cmpq    $(IA32_NR_syscalls-1),%rax
> @@ -177,10 +177,10 @@ ENTRY(ia32_sysenter_target)
>         movq    %rax,RAX(%rsp)
>         DISABLE_INTERRUPTS(CLBR_NONE)
>         TRACE_IRQS_OFF
> -       testl   $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,SIZEOF_PTREGS)
> +       testl   $_TIF_ALLWORK_MASK, THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
>         jnz     sysexit_audit
>  sysexit_from_sys_call:
> -       andl    $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,SIZEOF_PTREGS)
> +       andl    $~TS_COMPAT,THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
>         /* clear IF, that popfq doesn't enable interrupts early */
>         andl    $~0x200,EFLAGS(%rsp)
>         movl    RIP(%rsp),%edx          /* User %eip */
> @@ -225,7 +225,7 @@ ENTRY(ia32_sysenter_target)
>         .endm
>
>         .macro auditsys_exit exit
> -       testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,SIZEOF_PTREGS)
> +       testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
>         jnz ia32_ret_from_sys_call
>         TRACE_IRQS_ON
>         ENABLE_INTERRUPTS(CLBR_NONE)
> @@ -240,7 +240,7 @@ ENTRY(ia32_sysenter_target)
>         movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi
>         DISABLE_INTERRUPTS(CLBR_NONE)
>         TRACE_IRQS_OFF
> -       testl %edi,TI_flags+THREAD_INFO(%rsp,SIZEOF_PTREGS)
> +       testl %edi, THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
>         jz \exit
>         CLEAR_RREGS
>         jmp int_with_check
> @@ -262,7 +262,7 @@ ENTRY(ia32_sysenter_target)
>
>  sysenter_tracesys:
>  #ifdef CONFIG_AUDITSYSCALL
> -       testl   $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,SIZEOF_PTREGS)
> +       testl   $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
>         jz      sysenter_auditsys
>  #endif
>         SAVE_EXTRA_REGS
> @@ -346,8 +346,8 @@ ENTRY(ia32_cstar_target)
>  1:     movl    (%r8),%r9d
>         _ASM_EXTABLE(1b,ia32_badarg)
>         ASM_CLAC
> -       orl     $TS_COMPAT,TI_status+THREAD_INFO(%rsp,SIZEOF_PTREGS)
> -       testl   $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,SIZEOF_PTREGS)
> +       orl     $TS_COMPAT, THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
> +       testl   $_TIF_WORK_SYSCALL_ENTRY, THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
>         CFI_REMEMBER_STATE
>         jnz   cstar_tracesys
>         cmpq $IA32_NR_syscalls-1,%rax
> @@ -364,10 +364,10 @@ ENTRY(ia32_cstar_target)
>         movq %rax,RAX(%rsp)
>         DISABLE_INTERRUPTS(CLBR_NONE)
>         TRACE_IRQS_OFF
> -       testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,SIZEOF_PTREGS)
> +       testl $_TIF_ALLWORK_MASK, THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
>         jnz sysretl_audit
>  sysretl_from_sys_call:
> -       andl $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,SIZEOF_PTREGS)
> +       andl $~TS_COMPAT, THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
>         RESTORE_RSI_RDI_RDX
>         movl RIP(%rsp),%ecx
>         CFI_REGISTER rip,rcx
> @@ -402,7 +402,7 @@ ENTRY(ia32_cstar_target)
>
>  cstar_tracesys:
>  #ifdef CONFIG_AUDITSYSCALL
> -       testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,SIZEOF_PTREGS)
> +       testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
>         jz cstar_auditsys
>  #endif
>         xchgl %r9d,%ebp
> @@ -469,8 +469,8 @@ ENTRY(ia32_syscall)
>            this could be a problem. */
>         ALLOC_PT_GPREGS_ON_STACK
>         SAVE_C_REGS_EXCEPT_R891011
> -       orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,SIZEOF_PTREGS)
> -       testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,SIZEOF_PTREGS)
> +       orl $TS_COMPAT, THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
> +       testl $_TIF_WORK_SYSCALL_ENTRY, THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
>         jnz ia32_tracesys
>         cmpq $(IA32_NR_syscalls-1),%rax
>         ja ia32_badsys
> diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
> index 813dfbb867a7..224285b674ca 100644
> --- a/arch/x86/include/asm/thread_info.h
> +++ b/arch/x86/include/asm/thread_info.h
> @@ -222,7 +222,7 @@ static inline unsigned long current_stack_pointer(void)
>   * currently at exactly SIZEOF_PTREGS bytes away from the top of the
>   * stack:
>   *
> - *      mov TI_flags+THREAD_INFO(%rsp, SIZEOF_PTREGS), %eax
> + *      mov THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS), %eax
>   *
>   * will translate to:
>   *
> @@ -230,7 +230,7 @@ static inline unsigned long current_stack_pointer(void)
>   *
>   * which is below the current RSP by almost 16K.
>   */
> -#define THREAD_INFO(reg, off) ((off)-THREAD_SIZE)(reg)
> +#define THREAD_INFO(field, reg, off) ((field)+(off)-THREAD_SIZE)(reg)
>
>  #endif
>
> diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
> index df04ee069b1f..8f01a4f1cf9e 100644
> --- a/arch/x86/kernel/entry_64.S
> +++ b/arch/x86/kernel/entry_64.S
> @@ -249,7 +249,7 @@ GLOBAL(system_call_after_swapgs)
>         pushq_cfi_reg   r11                     /* pt_regs->r11 */
>         sub     $(6*8),%rsp /* pt_regs->bp,bx,r12-15 not saved */
>
> -       testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,SIZEOF_PTREGS)
> +       testl $_TIF_WORK_SYSCALL_ENTRY, THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
>         jnz tracesys
>  system_call_fastpath:
>  #if __SYSCALL_MASK == ~0
> @@ -267,7 +267,7 @@ GLOBAL(system_call_after_swapgs)
>   * Has incompletely filled pt_regs, iret frame is also incomplete.
>   */
>  ret_from_sys_call:
> -       testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,SIZEOF_PTREGS)
> +       testl $_TIF_ALLWORK_MASK, THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
>         jnz int_ret_from_sys_call       /* Go the slow path */
>
>         LOCKDEP_SYS_EXIT



-- 
Andy Lutomirski
AMA Capital Management, LLC
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/