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[PATCH] Remove ioperm etc. support for arm (was: Re: _ioperm support for Arm)
* Phil Blundell:
> On Wed, May 29, 2019 at 04:03:26PM +0200, Florian Weimer wrote:
>> There's this bug:
>>
>> Remove ARM old-ABI support
>> <https://sourceware.org/bugzilla/show_bug.cgi?id=13556>
>>
>> I believe this removed core support for non-EABI platforms.
>
> That's not quite the same thing. The old ABI differed from the EABI
> in several ways, including the stack alignment rules and the way
> that system calls were done. I think the bug you mentioned above
> was to remove the support in glibc for those specific "old ABI"
> mechanisms.
>
> What you currently get if you build glibc for ARMv4 is an "almost-EABI"
> configuration which does everything in the same way as the EABI except
> that there is no interworking support. I think we still have a certain
> amount of #ifdef __ARM_ARCH_4__ for that purpose. If we wanted to clean
> things up there then removing support for the half-baked V4T interworking
> would probably be more of a win since I think that accounts for a larger
> amount of #ifdef scar tissue.
>
>> All the target triplets we test upstream have gnueabi in them, and these
>> days, anything that is not built by build-many-glibcs.py in at least
>> variant is not considered supported, I think.
>
> For the reasons above, even when building glibc for armv4 you still put
> "gnueabi" in the triplet. But I think you're still correct that
> build-many-glibcs.py doesn't actually test anything older than ARMv5TE.
For libc.so.6 on arm-linux-gnueabi (as built by build-many-glibcs.py),
readelf shows this:
Attribute Section: aeabi
File Attributes
Tag_CPU_name: "5T"
Tag_CPU_arch: v5T
Tag_ARM_ISA_use: Yes
Tag_THUMB_ISA_use: Thumb-1
Tag_ABI_PCS_wchar_t: 4
Tag_ABI_FP_rounding: Needed
Tag_ABI_FP_denormal: Needed
Tag_ABI_FP_exceptions: Needed
Tag_ABI_FP_user_exceptions: Needed
Tag_ABI_FP_number_model: IEEE 754
Tag_ABI_align_needed: 8-byte
Tag_ABI_align_preserved: 8-byte, except leaf SP
Tag_ABI_enum_size: int
So it looks like to me like a later architectue version.
I would welcome comments on the commit message. The patch itself has
been “tested” with build-many-glibcs.py on all 32-bit Arm architectures.
Thanks,
Florian
arm: Remove ioperm/iopl/inb/inw/inl/outb/outw/outl support
Linux only supports the required ISA sysctls on StrongARM devices,
which are armv4 and no longer tested during glibc development
and probably bit-rotted by this point. (No reported test results,
and the last discussion of armv4 support was in the glibc 2.19
release notes.)
2019-05-29 Florian Weimer <fweimer@redhat.com>
arm: Remove ioperm/iopl/inb/inw/inl/outb/outw/outl support.
* sysdeps/unix/sysv/linux/arm/Makefile
[$(subdir) == misc] (sysdep_headers): Remove sys/io.h.
* sysdeps/unix/sysv/linux/arm/sys/io.h: Remove file.
* sysdeps/unix/sysv/linux/arm/ioperm.c: Rewrite file.
(ioperm, iopl, inb, inw, inl, outb, outw, outl): Turn into
compatibility symbols.
diff --git a/NEWS b/NEWS
index c885b960ca..31ead24851 100644
--- a/NEWS
+++ b/NEWS
@@ -58,6 +58,9 @@ Deprecated and removed features, and other changes affecting compatibility:
configurations) has been removed, following the deprecation of this
subarchitecture in version 8 of GCC, and its removal in version 9.
+* On 32-bit Arm, support for the port-based I/O emulation and the <sys/io.h>
+ header have been removed.
+
Changes to build and runtime requirements:
* GCC 6.2 or later is required to build the GNU C Library.
diff --git a/sysdeps/unix/sysv/linux/arm/Makefile b/sysdeps/unix/sysv/linux/arm/Makefile
index 4adc35de04..d7a2f6a8a7 100644
--- a/sysdeps/unix/sysv/linux/arm/Makefile
+++ b/sysdeps/unix/sysv/linux/arm/Makefile
@@ -5,7 +5,7 @@ endif
ifeq ($(subdir),misc)
sysdep_routines += ioperm
-sysdep_headers += sys/elf.h sys/io.h
+sysdep_headers += sys/elf.h
endif
ifeq ($(subdir),signal)
diff --git a/sysdeps/unix/sysv/linux/arm/ioperm.c b/sysdeps/unix/sysv/linux/arm/ioperm.c
index 0e338c4504..e832a6605e 100644
--- a/sysdeps/unix/sysv/linux/arm/ioperm.c
+++ b/sysdeps/unix/sysv/linux/arm/ioperm.c
@@ -17,167 +17,71 @@
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
-/* I/O port access on the ARM is something of a fiction. What we do is to
- map an appropriate area of /dev/mem into user space so that a program
- can blast away at the hardware in such a way as to generate I/O cycles
- on the bus. To insulate user code from dependencies on particular
- hardware we don't allow calls to inb() and friends to be inlined, but
- force them to come through code in here every time. Performance-critical
- registers tend to be memory mapped these days so this should be no big
- problem. */
+#include <shlib-compat.h>
-/* Once upon a time this file used mprotect to enable and disable
- access to particular areas of I/O space. Unfortunately the
- mprotect syscall also has the side effect of enabling caching for
- the area affected (this is a kernel limitation). So we now just
- enable all the ports all of the time. */
+#if SHLIB_COMPAT (libc, GLIBC_2_4, GLIBC_2_30)
+# include <errno.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <ctype.h>
-#include <stdlib.h>
-#include <unistd.h>
-
-#include <sys/types.h>
-#include <sys/mman.h>
-
-#include <sys/sysctl.h>
-
-#define MAX_PORT 0x10000
-
-static struct {
- unsigned long int base;
- unsigned long int io_base;
- unsigned int shift;
- unsigned int initdone; /* since all the above could be 0 */
-} io;
-
-#define IO_ADDR(port) (io.base + ((port) << io.shift))
-
-/*
- * Initialize I/O system. The io_bae and port_shift values are fetched
- * using sysctl (CTL_BUS, CTL_BUS_ISA, ISA_*).
- */
-
-static int
-init_iosys (void)
+int
+ioperm (unsigned long int from, unsigned long int num, int turn_on)
{
- static int iobase_name[] = { CTL_BUS, CTL_BUS_ISA, BUS_ISA_PORT_BASE };
- static int ioshift_name[] = { CTL_BUS, CTL_BUS_ISA, BUS_ISA_PORT_SHIFT };
- size_t len = sizeof (io.base);
-
- if (! __sysctl (iobase_name, 3, &io.io_base, &len, NULL, 0)
- && ! __sysctl (ioshift_name, 3, &io.shift, &len, NULL, 0))
- {
- io.initdone = 1;
- return 0;
- }
-
- /* sysctl has failed... */
- __set_errno (ENODEV);
+ __set_errno (ENOSYS);
return -1;
}
+compat_symbol (libc, ioperm, ioperm, GLIBC_2_4);
int
-_ioperm (unsigned long int from, unsigned long int num, int turn_on)
+iopl (unsigned int level)
{
- if (! io.initdone && init_iosys () < 0)
- return -1;
-
- /* this test isn't as silly as it may look like; consider overflows! */
- if (from >= MAX_PORT || from + num > MAX_PORT)
- {
- __set_errno (EINVAL);
- return -1;
- }
-
- if (turn_on)
- {
- if (! io.base)
- {
- int fd;
-
- fd = __open ("/dev/mem", O_RDWR);
- if (fd < 0)
- return -1;
-
- io.base =
- (unsigned long int) __mmap (0, MAX_PORT << io.shift,
- PROT_READ | PROT_WRITE,
- MAP_SHARED, fd, io.io_base);
- __close (fd);
- if ((long) io.base == -1)
- return -1;
- }
- }
-
- return 0;
+ __set_errno (ENOSYS);
+ return -1;
}
+compat_symbol (libc, iopl, iopl, GLIBC_2_4);
-int
-_iopl (unsigned int level)
-{
- if (level > 3)
- {
- __set_errno (EINVAL);
- return -1;
- }
- if (level)
- {
- return _ioperm (0, MAX_PORT, 1);
- }
- return 0;
-}
-
+/* The remaining functions do not have any way to indicate failure.
+ However, it is only valid to call them after calling ioperm/iopl,
+ which will have indicated failure. */
void
-_outb (unsigned char b, unsigned long int port)
+outb (unsigned char b, unsigned long int port)
{
- *((volatile unsigned char *)(IO_ADDR (port))) = b;
}
-
+compat_symbol (libc, outb, outb, GLIBC_2_4);
void
-_outw (unsigned short b, unsigned long int port)
+outw (unsigned short b, unsigned long int port)
{
- *((volatile unsigned short *)(IO_ADDR (port))) = b;
}
-
+compat_symbol (libc, outw, outw, GLIBC_2_4);
void
-_outl (unsigned int b, unsigned long int port)
+outl (unsigned int b, unsigned long int port)
{
- *((volatile unsigned long *)(IO_ADDR (port))) = b;
}
-
+compat_symbol (libc, outl, outl, GLIBC_2_4);
unsigned int
-_inb (unsigned long int port)
+inb (unsigned long int port)
{
- return *((volatile unsigned char *)(IO_ADDR (port)));
+ return 0;
}
+compat_symbol (libc, inb, inb, GLIBC_2_4);
unsigned int
-_inw (unsigned long int port)
+inw (unsigned long int port)
{
- return *((volatile unsigned short *)(IO_ADDR (port)));
+ return 0;
}
+compat_symbol (libc, inw, inw, GLIBC_2_4);
unsigned int
-_inl (unsigned long int port)
+inl (unsigned long int port)
{
- return *((volatile unsigned long *)(IO_ADDR (port)));
+ return 0;
}
+compat_symbol (libc, inl, inl, GLIBC_2_4);
-weak_alias (_ioperm, ioperm);
-weak_alias (_iopl, iopl);
-weak_alias (_inb, inb);
-weak_alias (_inw, inw);
-weak_alias (_inl, inl);
-weak_alias (_outb, outb);
-weak_alias (_outw, outw);
-weak_alias (_outl, outl);
+#endif /* SHLIB_COMAT */
diff --git a/sysdeps/unix/sysv/linux/arm/sys/io.h b/sysdeps/unix/sysv/linux/arm/sys/io.h
deleted file mode 100644
index 6f5ae5079a..0000000000
--- a/sysdeps/unix/sysv/linux/arm/sys/io.h
+++ /dev/null
@@ -1,47 +0,0 @@
-/* Copyright (C) 1996-2019 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
-
- The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
-
- The GNU C Library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library. If not, see
- <http://www.gnu.org/licenses/>. */
-
-#ifndef _SYS_IO_H
-
-#define _SYS_IO_H 1
-#include <features.h>
-
-__BEGIN_DECLS
-
-/* If TURN_ON is TRUE, request for permission to do direct i/o on the
- port numbers in the range [FROM,FROM+NUM-1]. Otherwise, turn I/O
- permission off for that range. This call requires root privileges. */
-extern int ioperm (unsigned long int __from, unsigned long int __num,
- int __turn_on) __THROW;
-
-/* Set the I/O privilege level to LEVEL. If LEVEL is nonzero,
- permission to access any I/O port is granted. This call requires
- root privileges. */
-extern int iopl (int __level) __THROW;
-
-/* The functions that actually perform reads and writes. */
-extern unsigned char inb (unsigned long int __port) __THROW;
-extern unsigned short int inw (unsigned long int __port) __THROW;
-extern unsigned long int inl (unsigned long int __port) __THROW;
-
-extern void outb (unsigned char __value, unsigned long int __port) __THROW;
-extern void outw (unsigned short __value, unsigned long int __port) __THROW;
-extern void outl (unsigned long __value, unsigned long int __port) __THROW;
-
-__END_DECLS
-
-#endif /* _SYS_IO_H */