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Message-ID: <CALCETrU53POrE__fWSZYJ9mkRm-AQBuPftsZFtJ19c-T+kseHQ@mail.gmail.com>
Date: Tue, 24 Mar 2015 12:08:32 -0700
From: Andy Lutomirski <luto@...capital.net>
To: Ingo Molnar <mingo@...nel.org>
Cc: Denys Vlasenko <dvlasenk@...hat.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Steven Rostedt <rostedt@...dmis.org>,
Borislav Petkov <bp@...en8.de>,
"H. Peter Anvin" <hpa@...or.com>, Oleg Nesterov <oleg@...hat.com>,
Frederic Weisbecker <fweisbec@...il.com>,
Alexei Starovoitov <ast@...mgrid.com>,
Will Drewry <wad@...omium.org>,
Kees Cook <keescook@...omium.org>, X86 ML <x86@...nel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86/asm/entry/64: Merge the field offset into the
THREAD_INFO() macro
On Tue, Mar 24, 2015 at 11:44 AM, Ingo Molnar <mingo@...nel.org> wrote:
> From 11e2761ba0969466299b7109eba749d2292e8796 Mon Sep 17 00:00:00 2001
> From: Ingo Molnar <mingo@...nel.org>
> 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@...nel.org>
>
> 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@...mgrid.com>
> Cc: Andy Lutomirski <luto@...capital.net>
> Cc: Andy Lutomirski <luto@...nel.org>
> Cc: Borislav Petkov <bp@...en8.de>
> Cc: Borislav Petkov <bp@...e.de>
> Cc: Denys Vlasenko <dvlasenk@...hat.com>
> Cc: Frederic Weisbecker <fweisbec@...il.com>
> Cc: H. Peter Anvin <hpa@...or.com>
> Cc: Kees Cook <keescook@...omium.org>
> Cc: Linus Torvalds <torvalds@...ux-foundation.org>
> Cc: Oleg Nesterov <oleg@...hat.com>
> Cc: Steven Rostedt <rostedt@...dmis.org>
> Cc: Will Drewry <wad@...omium.org>
> Signed-off-by: Ingo Molnar <mingo@...nel.org>
> ---
> 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
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