Thread (11 messages) 11 messages, 6 authors, 2012-09-24

Re: sys_kcmp (was: Re: [PATCH 1/2] ARM: add finit_module syscall to ARM)

From: Cyrill Gorcunov <hidden>
Date: 2012-09-24 16:49:48
Also in: lkml

On Mon, Sep 24, 2012 at 12:21:46PM -0400, Mark Salter wrote:
quoted hunk ↗ jump to hunk
diff --git a/include/asm-generic/unistd.h b/include/asm-generic/unistd.h
index 991ef01..3748ec9 100644
--- a/include/asm-generic/unistd.h
+++ b/include/asm-generic/unistd.h
@@ -691,9 +691,11 @@ __SC_COMP(__NR_process_vm_readv, sys_process_vm_readv, \
 #define __NR_process_vm_writev 271
 __SC_COMP(__NR_process_vm_writev, sys_process_vm_writev, \
           compat_sys_process_vm_writev)
+#define __NR_kcmp 272
+__SYSCALL(__NR_kcmp, sys_kcmp)
 
 #undef __NR_syscalls
-#define __NR_syscalls 272
+#define __NR_syscalls 273
quoted
I have that queued for 3.7.  There is of course a little risk here.  We
do have a test in tools/testing/selftests/kcmp/ - I suggest that arch
people run it!  In fact all the tools/testing/selftests should execute
successfully on all architectures - if not, please let's fix things
up.
I ran into a build error on C6X (no-MMU) when I enabled CHECKPOINT_RESTORE:

  linux-next/kernel/sys.c: In function 'prctl_set_mm':
  linux-next/kernel/sys.c:1869:34: error: 'mmap_min_addr' undeclared (first use in this function)

I got past that with:
diff --git a/include/linux/security.h b/include/linux/security.h
index 01ef030..14e394d 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -118,6 +118,7 @@ void reset_security_ops(void);
 extern unsigned long mmap_min_addr;
 extern unsigned long dac_mmap_min_addr;
 #else
+#define mmap_min_addr          0UL
 #define dac_mmap_min_addr      0UL
 #endif
Looking at kcmp_test.c, it uses fork, so won't work without MMU. Is
the kcmp syscall even meaningful for no-MMU? I suppose some of the
tests in kcmp_test.c could be accomplished using clone directly
rather than fork.
Hi Mark, good catch! I think it should be two patches then. As to kcmp_test.c,
I've been using fork there simply because it was simplier. The clone could
be used as well. (kcmp should work even with mmu emulated i think).
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