Re: [PATCH 0/5] Live patching for powerpc
From: Josh Poimboeuf
Date: Thu Apr 14 2016 - 12:41:29 EST
On Thu, Apr 14, 2016 at 05:20:29PM +0200, Torsten Duwe wrote:
> On Thu, Apr 14, 2016 at 11:08:02PM +1000, Michael Ellerman wrote:
> > On Thu, 2016-04-14 at 14:57 +0200, Torsten Duwe wrote:
> >
> > > FTR: then I still have a few ppc64 hunks floating around to support certain consistency
> > > models...
> >
> > OK. I'm not quite sure what you mean but post them and we'll see I guess :)
>
> It's *roughly* the ppc64 equivalent of Josh Poimboeuf's Mar 25
> | [RFC PATCH v1.9 14/14] livepatch: update task universe when exiting kernel
> which only considers x86.
>
> It's forward ported from an earlier code base; there's some glue missing,
> but here it is, for reference.
>
> Signed-off-by: Torsten Duwe <duwe@xxxxxxx>
Hi Torsten,
Thanks for sharing. This is quite fortuitous as Miroslav just today
mentioned to me that we would need something like this. If you don't
mind, I may pull this patch or some variant of it into v2 of the
consistency model.
>
>
> diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
> index b034ecd..3e749f4 100644
> --- a/arch/powerpc/include/asm/thread_info.h
> +++ b/arch/powerpc/include/asm/thread_info.h
> @@ -92,6 +92,7 @@ static inline struct thread_info *current_thread_info(void)
> TIF_NEED_RESCHED */
> #define TIF_32BIT 4 /* 32 bit binary */
> #define TIF_RESTORE_TM 5 /* need to restore TM FP/VEC/VSX */
> +#define TIF_KLP_NEED_UPDATE 6 /* kGraft patching in progress */
> #define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
> #define TIF_SINGLESTEP 8 /* singlestepping active */
> #define TIF_NOHZ 9 /* in adaptive nohz mode */
> @@ -115,8 +116,10 @@ static inline struct thread_info *current_thread_info(void)
> #define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
> #define _TIF_32BIT (1<<TIF_32BIT)
> #define _TIF_RESTORE_TM (1<<TIF_RESTORE_TM)
> +#define _TIF_KLP_NEED_UPDATE (1<<TIF_KLP_NEED_UPDATE)
> #define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
> #define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP)
> +#define _TIF_NOHZ (1<<TIF_NOHZ)
> #define _TIF_SECCOMP (1<<TIF_SECCOMP)
> #define _TIF_RESTOREALL (1<<TIF_RESTOREALL)
> #define _TIF_NOERROR (1<<TIF_NOERROR)
> @@ -124,7 +127,7 @@ static inline struct thread_info *current_thread_info(void)
> #define _TIF_UPROBE (1<<TIF_UPROBE)
> #define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)
> #define _TIF_EMULATE_STACK_STORE (1<<TIF_EMULATE_STACK_STORE)
> -#define _TIF_NOHZ (1<<TIF_NOHZ)
> +
> #define _TIF_SYSCALL_DOTRACE (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
> _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT | \
> _TIF_NOHZ)
> @@ -132,7 +135,8 @@ static inline struct thread_info *current_thread_info(void)
> #define _TIF_USER_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
> _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
> _TIF_RESTORE_TM)
> -#define _TIF_PERSYSCALL_MASK (_TIF_RESTOREALL|_TIF_NOERROR)
> +
> +#define _TIF_PERSYSCALL_MASK (_TIF_RESTOREALL|_TIF_NOERROR|_TIF_KLP_NEED_UPDATE)
>
> /* Bits in local_flags */
> /* Don't move TLF_NAPPING without adjusting the code in entry_32.S */
> diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
> index 5bbd1bc..17f8a18 100644
> --- a/arch/powerpc/kernel/entry_64.S
> +++ b/arch/powerpc/kernel/entry_64.S
> @@ -151,8 +151,8 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
>
> CURRENT_THREAD_INFO(r11, r1)
> ld r10,TI_FLAGS(r11)
> - andi. r11,r10,_TIF_SYSCALL_DOTRACE
> - bne syscall_dotrace /* does not return */
> + andi. r10,r10,(_TIF_SYSCALL_DOTRACE|_TIF_KLP_NEED_UPDATE)
> + bne- syscall_precall /* does not return */
> cmpldi 0,r0,NR_syscalls
> bge- syscall_enosys
>
> @@ -245,6 +245,17 @@ syscall_error:
> neg r3,r3
> std r5,_CCR(r1)
> b .Lsyscall_error_cont
> +
> +syscall_precall:
> + andi. r10,r10,(_TIF_KLP_NEED_UPDATE)
> + beq+ syscall_dotrace
> +
> + addi r11,r11,TI_FLAGS
> +1: ldarx r12,0,r11
> + andc r12,r12,r10
> + stdcx. r12,0,r11
> + bne- 1b
> + subi r11,r11,TI_FLAGS
>
> /* Traced system call support */
> syscall_dotrace:
--
Josh