Subject: [PATCH] remove bogus ppc_select syscall

From: Arnd Bergmann <[email-masked]>
Date: Wed, 24 Sep 2008 08:39:14 +0200

The ppc_select function was introduced in linux-2.3.48 in order to support
code confusing the legacy select() calling convention with the standard one.
Even 11 years ago, all correctly built code should not have done this and
could have easily been phased out. Nothing that was compiled later should
actually try to use the old_select interface, and it would have been broken
already on all ppc64 kernels with the syscall emulation layer.

This patch brings the 32 bit compat ABI and the native 32 bit ABI for
powerpc into a consistent state, by removing support for both the
old_select system call number and the handler for it.

The bug report triggering this came from Halesh Sadashiiv <[email-masked]>, who discovered that the 32 bit
implementation of ppc_select would in case of a negative number
of file descriptors incorrectly return -EFAULT instead of -EINVAL.
There seems to be no way to fix this problem in a way that would
keep broken pre-1997 binaries running.

Signed-off-by: Arnd Bergmann <[email-masked]>
Cc: Halesh Sadashiiv <[email-masked]>
---

Halesh, please test this patch to make sure it fixes the problem
you reported. I do not have a ppc32 machine I can try this on.

diff --git a/arch/powerpc/include/asm/unistd.h b/arch/powerpc/include/asm/unistd.h
index e07d0c7..46107cc 100644
--- a/arch/powerpc/include/asm/unistd.h
+++ b/arch/powerpc/include/asm/unistd.h
@@ -92,7 +92,7 @@
 #define __NR_settimeofday       79
 #define __NR_getgroups          80
 #define __NR_setgroups          81
-#define __NR_select             82
+/* Number 82 was the old (pre-1.3.x) select */
 #define __NR_symlink            83
 #define __NR_oldlstat           84
 #define __NR_readlink           85
diff --git a/arch/powerpc/include/asm/systbl.h b/arch/powerpc/include/asm/systbl.h
index f6cc7a4..5a69b32 100644
--- a/arch/powerpc/include/asm/systbl.h
+++ b/arch/powerpc/include/asm/systbl.h
@@ -85,7 +85,7 @@ COMPAT_SYS_SPU(gettimeofday)
 COMPAT_SYS_SPU(settimeofday)
 COMPAT_SYS_SPU(getgroups)
 COMPAT_SYS_SPU(setgroups)
-SYSX(sys_ni_syscall,sys_ni_syscall,ppc_select)
+SYSCALL(sys_ni_syscall)
 SYSCALL_SPU(symlink)
 OLDSYS(lstat)
 COMPAT_SYS_SPU(readlink)
@@ -145,7 +145,7 @@ SYSCALL_SPU(setfsuid)
 SYSCALL_SPU(setfsgid)
 SYSCALL_SPU(llseek)
 COMPAT_SYS_SPU(getdents)
-SYSX_SPU(sys_select,ppc32_select,ppc_select)
+SYSX_SPU(sys_select,ppc32_select,sys_select)
 SYSCALL_SPU(flock)
 SYSCALL_SPU(msync)
 COMPAT_SYS_SPU(readv)
diff --git a/arch/powerpc/kernel/syscalls.c b/arch/powerpc/kernel/syscalls.c
index c04832c..c2e6a74 100644
--- a/arch/powerpc/kernel/syscalls.c
+++ b/arch/powerpc/kernel/syscalls.c
@@ -183,31 +183,6 @@ unsigned long sys_mmap(unsigned long addr, size_t len,
 	return do_mmap2(addr, len, prot, flags, fd, offset, PAGE_SHIFT);
 }
 
-#ifdef CONFIG_PPC32
-/*
- * Due to some executables calling the wrong select we sometimes
- * get wrong args.  This determines how the args are being passed
- * (a single ptr to them all args passed) then calls
- * sys_select() with the appropriate args. -- Cort
- */
-int
-ppc_select(int n, fd_set __user *inp, fd_set __user *outp, fd_set __user *exp, struct timeval __user *tvp)
-{
-	if ( (unsigned long)n >= 4096 )
-	{
-		unsigned long __user *buffer = (unsigned long __user *)n;
-		if (!access_ok(VERIFY_READ, buffer, 5*sizeof(unsigned long))
-		    || __get_user(n, buffer)
-		    || __get_user(inp, ((fd_set __user * __user *)(buffer+1)))
-		    || __get_user(outp, ((fd_set  __user * __user *)(buffer+2)))
-		    || __get_user(exp, ((fd_set  __user * __user *)(buffer+3)))
-		    || __get_user(tvp, ((struct timeval  __user * __user *)(buffer+4))))
-			return -EFAULT;
-	}
-	return sys_select(n, inp, outp, exp, tvp);
-}
-#endif
-
 #ifdef CONFIG_PPC64
 long ppc64_personality(unsigned long personality)
 {