Background: I've implemented 1K/2K page tables for s390. These sub-page
page tables are required to properly support the s390 virtualization
instruction with KVM. The SIE instruction requires that the page tables
have 256 page table entries (pte) followed by 256 page status table entries
(pgste). The pgstes are only required if the process is using the SIE
instruction. The pgstes are updated by the hardware and by the hypervisor
for a number of reasons, one of them is dirty and reference bit tracking.
To avoid wasting memory the standard pte table allocation should return
1K/2K (31/64 bit) and 2K/4K if the process is using SIE.
Problem: Page size on s390 is 4K, page table size is 1K or 2K. That means
the s390 version for pte_alloc_one cannot return a pointer to a struct
page. Trouble is that with the CONFIG_HIGHPTE feature on x86 pte_alloc_one
cannot return a pointer to a pte either, since that would require more than
32 bit for the return value of pte_alloc_one (and the pte * would not be
accessible since its not kmapped).
Solution: The only solution I found to this dilemma is a new typedef: a
pgtable_t. For s390 pgtable_t will be a (pte *) - to be introduced with a
later patch. For everybody else it will be a (struct page *). The
additional problem with the initialization of the ptl lock and the
NR_PAGETABLE accounting is solved with a constructor pgtable_page_ctor and
a destructor pgtable_page_dtor. The page table allocation and free
functions need to call these two whenever a page table page is allocated or
freed. pmd_populate will get a pgtable_t instead of a struct page pointer.
To get the pgtable_t back from a pmd entry that has been installed with
pmd_populate a new function pmd_pgtable is added. It replaces the pmd_page
call in free_pte_range and apply_to_pte_range.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the conversion factor between jiffies and milli- or microseconds is
not a single multiply or divide, as for the case of HZ == 300, we currently
do a multiply followed by a divide. The intervening result, however, is
subject to overflows, especially since the fraction is not simplified (for
HZ == 300, we multiply by 300 and divide by 1000).
This is exposed to the user when passing a large timeout to poll(), for
example.
This patch replaces the multiply-divide with a reciprocal multiplication on
32-bit platforms. When the input is an unsigned long, there is no portable
way to do this on 64-bit platforms there is no portable way to do this
since it requires a 128-bit intermediate result (which gcc does support on
64-bit platforms but may generate libgcc calls, e.g. on 64-bit s390), but
since the output is a 32-bit integer in the cases affected, just simplify
the multiply-divide (*3/10 instead of *300/1000).
The reciprocal multiply used can have off-by-one errors in the upper half
of the valid output range. This could be avoided at the expense of having
to deal with a potential 65-bit intermediate result. Since the intent is
to avoid overflow problems and most of the other time conversions are only
semiexact, the off-by-one errors were considered an acceptable tradeoff.
At Ralf Baechle's suggestion, this version uses a Perl script to compute
the necessary constants. We already have dependencies on Perl for kernel
compiles. This does, however, require the Perl module Math::BigInt, which
is included in the standard Perl distribution starting with version 5.8.0.
In order to support older versions of Perl, include a table of canned
constants in the script itself, and structure the script so that
Math::BigInt isn't required if pulling values from said table.
Running the script requires that the HZ value is available from the
Makefile. Thus, this patch also adds the Kconfig variable CONFIG_HZ to the
architectures which didn't already have it (alpha, cris, frv, h8300, m32r,
m68k, m68knommu, sparc, v850, and xtensa.) It does *not* touch the sh or
sh64 architectures, since Paul Mundt has dealt with those separately in the
sh tree.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Ralf Baechle <ralf@linux-mips.org>,
Cc: Sam Ravnborg <sam@ravnborg.org>,
Cc: Paul Mundt <lethal@linux-sh.org>,
Cc: Richard Henderson <rth@twiddle.net>,
Cc: Michael Starvik <starvik@axis.com>,
Cc: David Howells <dhowells@redhat.com>,
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>,
Cc: Hirokazu Takata <takata@linux-m32r.org>,
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Cc: Roman Zippel <zippel@linux-m68k.org>,
Cc: William L. Irwin <sparclinux@vger.kernel.org>,
Cc: Chris Zankel <chris@zankel.net>,
Cc: H. Peter Anvin <hpa@zytor.com>,
Cc: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
the #endif /* CONFIG_SMP */ should cover the default condition, or it may cause
bad parameter to be silently missed.
To make it work correctly, we have to remove the ifdef CONFIG SMP surrounding
__xchg_called_with_bad_pointer declaration. Thanks to Adrian Bunk for detecting
this.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Hirokazu Takata <takata@linux-m32r.org>
Cc: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add __xchg_local, xchg_local (define), __cmpxchg_local_u32, __cmpxchg_local,
cmpxchg_local(macro).
cmpxchg_local and cmpxchg64_local will use the architecture specific
__cmpxchg_local_u32 for 32 bits arguments, and use the generic
__cmpxchg_local_generic for 8, 16 and 64 bits arguments.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
asm/elf.h, asm/page.h and asm/user.h don't export to userspace now, so we can
drop #ifdef __KERNEL__ for them.
[k.shutemov@gmail.com: remove #ifdef __KERNEL_]
Signed-off-by: Kirill A. Shutemov <k.shutemov@gmail.com>
Reviewed-by: David Woodhouse <dwmw2@infradead.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Kirill A. Shutemov <k.shutemov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The declaration and implementation of __const_udelay use different
names for the parameter on a number of architectures:
include/asm-avr32/delay.h:15:extern void __const_udelay(unsigned long usecs);
arch/avr32/lib/delay.c:39:inline void __const_udelay(unsigned long xloops)
include/asm-sh/delay.h:15:extern void __const_udelay(unsigned long usecs);
arch/sh/lib/delay.c:22:inline void __const_udelay(unsigned long xloops)
include/asm-m32r/delay.h:15:extern void __const_udelay(unsigned long usecs);
arch/m32r/lib/delay.c:58:void __const_udelay(unsigned long xloops)
include/asm-x86/delay.h:16:extern void __const_udelay(unsigned long usecs);
arch/x86/lib/delay_32.c:82:inline void __const_udelay(unsigned long xloops)
arch/x86/lib/delay_64.c:46:inline void __const_udelay(unsigned long xloops)
The units of the parameter isn't usecs, so that name is definitely
wrong. It's also not exactly loops, so I suppose xloops is an OK
name.
This patch changes these names from usecs to xloops.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(with Martin Schwidefsky <schwidefsky@de.ibm.com>)
The pgd/pud/pmd/pte page table allocation functions get a mm_struct pointer as
first argument. The free functions do not get the mm_struct argument. This
is 1) asymmetrical and 2) to do mm related page table allocations the mm
argument is needed on the free function as well.
[kamalesh@linux.vnet.ibm.com: i386 fix]
[akpm@linux-foundation.org: coding-syle fixes]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A userspace program may wish to set the mark for each packets its send
without using the netfilter MARK target. Changing the mark can be used
for mark based routing without netfilter or for packet filtering.
It requires CAP_NET_ADMIN capability.
Signed-off-by: Laszlo Attila Toth <panther@balabit.hu>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Update sys_rt_sigsuspend() of arch/m32r/signal.c.
This modification is derived from generic one of kernel/signal.c.
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
checksyscalls.sh reports warnings for missing syscalls.
But, on m32r, some legacy syscalls were removed elaborately.
This patch kills warnings for obsolete syscalls, which are
no longer used in the m32r kernel.
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Change the page member of the scatterlist structure to be an unsigned
long, and encode more stuff in the lower bits:
- Bits 0 and 1 zero: this is a normal sg entry. Next sg entry is located
at sg + 1.
- Bit 0 set: this is a chain entry, the next real entry is at ->page_link
with the two low bits masked off.
- Bit 1 set: this is the final entry in the sg entry. sg_next() will return
NULL when passed such an entry.
It's thus important that sg table users use the proper accessors to get
and set the page member.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Add CONFIG_IDE_ARCH_OBSOLETE_INIT to drivers/ide/Kconfig and use it instead
of defining IDE_ARCH_OBSOLETE_INIT in <arch/ide.h>.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
forbid asm/bitops.h direct inclusion
Because of compile errors that may occur after bit changes if asm/bitops.h is
included directly without e.g. linux/kernel.h which includes linux/bitops.h,
forbid direct inclusion of asm/bitops.h. Thanks to Adrian Bunk.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
remove asm/bitops.h includes
including asm/bitops directly may cause compile errors. don't include it
and include linux/bitops instead. next patch will deny including asm header
directly.
Cc: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
