Re: [update] Re: new execve/kernel_thread design
From: Al Viro <viro@ZenIV.linux.org.uk>
Date: 2012-10-29 13:25:40
Also in:
lkml
Subsystem:
s390 architecture, the rest · Maintainers:
Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Linus Torvalds
On Mon, Oct 29, 2012 at 08:53:39AM +0100, Martin Schwidefsky wrote:
Oops, sorry. I tested this weeks ago but it seems I never wrote a mail to indicate success. The current git kernel works just fine.
"Current git" being what? Linus' tree? linux-next? signal.git#arch-s390? FWIW, the relevant diff against mainline is below, linux-next already contains it.
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 3f3d9ca..3cdc0f1 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig@@ -136,6 +136,7 @@ config S390 select KTIME_SCALAR if 32BIT select HAVE_ARCH_SECCOMP_FILTER select GENERIC_KERNEL_THREAD + select GENERIC_KERNEL_EXECVE select HAVE_MOD_ARCH_SPECIFIC select MODULES_USE_ELF_RELA
diff --git a/arch/s390/include/asm/unistd.h b/arch/s390/include/asm/unistd.h
index bbbae41..ccbcab7 100644
--- a/arch/s390/include/asm/unistd.h
+++ b/arch/s390/include/asm/unistd.h@@ -54,7 +54,6 @@ # define __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND # endif #define __ARCH_WANT_SYS_EXECVE -#define __ARCH_WANT_KERNEL_EXECVE /* * "Conditional" syscalls
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index ef46f66..aa8f2ba 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S@@ -330,40 +330,18 @@ ENTRY(ret_from_fork) la %r11,STACK_FRAME_OVERHEAD(%r15) l %r12,__LC_THREAD_INFO l %r13,__LC_SVC_NEW_PSW+4 - tm __PT_PSW+1(%r11),0x01 # forking a kernel thread ? - je 1f l %r1,BASED(.Lschedule_tail) basr %r14,%r1 # call schedule_tail TRACE_IRQS_ON ssm __LC_SVC_NEW_PSW # reenable interrupts - j sysc_tracenogo - -1: # it's a kernel thread - st %r15,__PT_R15(%r11) # store stack pointer for new kthread - l %r1,BASED(.Lschedule_tail) - basr %r14,%r1 # call schedule_tail - TRACE_IRQS_ON - ssm __LC_SVC_NEW_PSW # reenable interrupts - lm %r9,%r11,__PT_R9(%r11) # load gprs + tm __PT_PSW+1(%r11),0x01 # forking a kernel thread ? + jne sysc_tracenogo + # it's a kernel thread + lm %r9,%r10,__PT_R9(%r11) # load gprs ENTRY(kernel_thread_starter) la %r2,0(%r10) basr %r14,%r9 - la %r2,0 - br %r11 # do_exit - -# -# kernel_execve function needs to deal with pt_regs that is not -# at the usual place -# -ENTRY(ret_from_kernel_execve) - ssm __LC_PGM_NEW_PSW # disable I/O and ext. interrupts - lr %r15,%r2 - lr %r11,%r2 - ahi %r15,-STACK_FRAME_OVERHEAD - xc __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15) - l %r12,__LC_THREAD_INFO - ssm __LC_SVC_NEW_PSW # reenable interrupts - j sysc_return + j sysc_tracenogo /* * Program check handler routine
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index 07d8de3..499e95e 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S@@ -352,33 +352,17 @@ sysc_tracenogo: ENTRY(ret_from_fork) la %r11,STACK_FRAME_OVERHEAD(%r15) lg %r12,__LC_THREAD_INFO - tm __PT_PSW+1(%r11),0x01 # forking a kernel thread ? - je 1f brasl %r14,schedule_tail TRACE_IRQS_ON ssm __LC_SVC_NEW_PSW # reenable interrupts - j sysc_tracenogo -1: # it's a kernel thread - stg %r15,__PT_R15(%r11) # store stack pointer for new kthread - brasl %r14,schedule_tail - TRACE_IRQS_ON - ssm __LC_SVC_NEW_PSW # reenable interrupts - lmg %r9,%r11,__PT_R9(%r11) # load gprs + tm __PT_PSW+1(%r11),0x01 # forking a kernel thread ? + jne sysc_tracenogo + # it's a kernel thread + lmg %r9,%r10,__PT_R9(%r11) # load gprs ENTRY(kernel_thread_starter) la %r2,0(%r10) basr %r14,%r9 - la %r2,0 - br %r11 # do_exit - -ENTRY(ret_from_kernel_execve) - ssm __LC_PGM_NEW_PSW # disable I/O and ext. interrupts - lgr %r15,%r2 - lgr %r11,%r2 - aghi %r15,-STACK_FRAME_OVERHEAD - xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) - lg %r12,__LC_THREAD_INFO - ssm __LC_SVC_NEW_PSW # reenable interrupts - j sysc_return + j sysc_tracenogo /* * Program check handler routine