Commit Graph

1113 Commits

Author SHA1 Message Date
Nishanth Aravamudan 5c888d5318 [PATCH] xtensa: use ssleep() instead of schedule_timeout()
Replace schedule_timeout() with ssleep() to guarantee the task delays as
expected.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-12 16:01:01 -07:00
Chris Zankel 813e678364 [PATCH] xtensa: remove old syscalls
This patch fixes some minor bugs introduced by the previous patch (remove
old syscalls).  Both patches remove the obsolete syscalls.  The changes in
this patch were suggested by Arnd Bergmann.  The vmlinux.lds.S changes are
required for the latest gcc/binutils.

Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-12 16:01:01 -07:00
Paolo 'Blaisorblade' Giarrusso 8b8a9da525 [PATCH] uml:remove user_constants.h on clean
make clean ARCH=um does not remove the generated file
arch/um/include/user_constants.h, fix this.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-12 16:01:00 -07:00
Andrew Morton d312ceda56 [PATCH] x86_64: section alignment fix
This is the second time this has happened: inserting a new section requires
that we adjust the arithmetic which is used to calculate the vsyscall page's
offset.

Cc: Christoph Lameter <christoph@lameter.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-12 16:00:59 -07:00
Linus Torvalds 22a4427972 Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/i2c-2.6 2005-07-12 15:54:36 -07:00
Linus Torvalds 9f02d6b7b4 Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6 2005-07-12 13:17:42 -07:00
Linus Torvalds 9ffc7a0ebf Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2005-07-12 13:16:40 -07:00
Andrew Morton c12a828982 [SPARC64]: Fix SMP build failure.
arch/sparc64/kernel/smp.c:48: error: parse error before "__attribute__"
arch/sparc64/kernel/smp.c:49: error: parse error before "__attribute__"

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-12 12:09:43 -07:00
Sam Ravnborg d5950b4355 [NET]: add a top-level Networking menu to *config
Create a new top-level menu named "Networking" thus moving
net related options and protocol selection way from the drivers
menu and up on the top-level where they belong.

To implement this all architectures has to source "net/Kconfig" before
drivers/*/Kconfig in their Kconfig file. This change has been
implemented for all architectures.

Device drivers for ordinary NIC's are still to be found
in the Device Drivers section, but Bluetooth, IrDA and ax25
are located with their corresponding menu entries under the new
networking menu item.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-11 21:03:49 -07:00
Jean Delvare ad2f931dcb [PATCH] I2C: Move hwmon drivers (1/3)
Part 1: Configuration files and Makefiles.

From: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-07-11 14:14:31 -07:00
Linus Torvalds 1604d9c8f8 Merge master.kernel.org:/pub/scm/linux/kernel/git/aegl/linux-2.6 2005-07-11 14:08:08 -07:00
Kenji Kaneshige 3b5cc09033 [IA64] assign_irq_vector() should not panic
Current assign_irq_vector() will panic if interrupt vectors is running
out. But I think how to handle the case of lack of interrupt vectors
should be handled by the caller of this function. For example, some
PCI devices can raise the interrupt signal via both MSI and I/O
APIC. So even if the driver for these device fails to allocate a
vector for MSI, the driver still has a chance to use I/O APIC based
interrupt. But currently there is no chance for these driver to use
I/O APIC based interrupt because kernel will panic when
assign_irq_vector() fails to allocate interrupt vector.

The following patch changes assign_irq_vector() for ia64 to return
-ENOSPC on error instead of panic (as i386 and x86_64 versions do).

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2005-07-11 10:30:07 -07:00
Nishanth Aravamudan 699139279d [IA64] use msleep_interruptible() instead of schedule_timeout
Description: Replace schedule_timeout() with msleep_interruptible() to
guarantee the task delays as expected.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Acked-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2005-07-11 10:26:40 -07:00
Miles Bader 623cdf4a04 [PATCH] v850: Update checksum.h to match changed function signatures
Signed-off-by: Miles Bader <miles@gnu.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-11 10:22:39 -07:00
Linus Torvalds f43a64c5e1 Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6 2005-07-11 10:09:59 -07:00
Olaf Hering d0feafbf14 [IA64] remove linux/version.h include from arch/ia64
changing CONFIG_LOCALVERSION rebuilds too much, for no appearent reason.

Signed-off-by: Olaf Hering <olh@suse.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2005-07-11 09:58:52 -07:00
Tony Luck e7578c08a4 Auto merge with /home/aegl/GIT/linus 2005-07-11 09:43:11 -07:00
David S. Miller f7ceba360c [SPARC64]: Add syscall auditing support.
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-10 19:29:45 -07:00
David S. Miller 8d8a64796f [SPARC64]: Pass regs and entry/exit boolean to syscall_trace()
Also fix a bug in 32-bit syscall tracing.  We forgot to update
this code when we moved over to the convention that all 32-bit
syscall arguments are zero extended by default.

Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-10 16:55:48 -07:00
David S. Miller bb49bcda15 [SPARC64]: Add SECCOMP support.
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-10 16:49:28 -07:00
David S. Miller af166d15c3 [SPARC64]: Kill ancient and unused SYSCALL_TRACING debugging code.
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-10 15:56:40 -07:00
David S. Miller d369ddd2fc [SPARC64]: Add __read_mostly support.
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-10 15:45:11 -07:00
David S. Miller 9126dfde9e [SPARC]: Add ioprio system call support.
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-10 15:11:45 -07:00
Linus Torvalds 5c23804a09 Merge master.kernel.org:~rmk/linux-2.6-arm.git 2005-07-10 12:57:49 -07:00
Stephen Rothwell 58c853c6ea [PATCH] remove asm-xtensa/ipc.h
Now that sys_ipc has been removed from xtensa, asm/ipc.h is no longer
needed for that architecture.  Not tested, but obviously correct.  This
file is included only from arch code and this patch also removes the only
inclusion.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-10 12:23:24 -07:00
Tony Lindgren ec6bced6c7 [PATCH] ARM: 2803/1: OMAP update 11/11: Add cpufreq support
Patch from Tony Lindgren

This patch adds minimal cpufreq support for OMAP
taking advantage of the clock framework.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-10 19:58:20 +01:00
Tony Lindgren d3b8341911 [PATCH] ARM: 2805/1: OMAP update 10/11: Update H2 defconfig
Patch from Tony Lindgren

This patch updates H2 defconfig.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-10 19:58:19 +01:00
Tony Lindgren bb13b5fdba [PATCH] ARM: 2804/1: OMAP update 9/11: Update OMAP arch files
Patch from Tony Lindgren

This patch by various OMAP developers syncs the OMAP
specific arch files with the linux-omap tree.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-10 19:58:18 +01:00
Tony Lindgren d48af15ea7 [PATCH] ARM: 2802/1: OMAP update 8/11: Update OMAP arch files
Patch from Tony Lindgren

This patch by various OMAP developers syncs the OMAP
specific arch files with the linux-omap tree.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-10 19:58:17 +01:00
Tony Lindgren 5e1c5ff478 [PATCH] ARM: 2812/1: OMAP update 7c/11: Move arch-omap to plat-omap
Patch from Tony Lindgren

This patch move common OMAP code from arch-omap to plat-omap
directory.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-10 19:58:15 +01:00
Tony Lindgren b91585560b [PATCH] ARM: 2809/1: OMAP update 7b/11: Move arch-omap to plat-omap
Patch from Tony Lindgren

This patch move common OMAP code from arch-omap to plat-omap
directory.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-10 19:58:14 +01:00
Tony Lindgren 60906a8a4e [PATCH] ARM: 2807/1: OMAP update 7a/11: Move arch-omap to plat-omap
Patch from Tony Lindgren

This patch move common OMAP code from arch-omap to plat-omap
directory.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-10 19:58:13 +01:00
Tony Lindgren f577ffd75c [PATCH] ARM: 2801/1: OMAP update 6/11: Split OMAP1 common code into id, io and serial
Patch from Tony Lindgren

This patch by Juha Yrjölä and other OMAP developers splits
OMAP1 specific common code into OMAP1 id, io, and serial
code in mach-omap1 directory.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-10 19:58:12 +01:00
Tony Lindgren dbdf9cedfc [PATCH] ARM: 2806/1: OMAP update 5/11: Move board files into mach-omap1 directory
Patch from Tony Lindgren

This patch by Paul Mundt and other OMAP developers
moves OMAP1 board files into mach-omap1 directory.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-10 19:58:11 +01:00
Tony Lindgren 6f3e14163e [PATCH] ARM: 2799/1: OMAP update 4/11: Move OMAP1 LED code into mach-omap1 directory
Patch from Tony Lindgren

This patch by Paul Mundt and other OMAP developers
moves OMAP1 specific LED code into mach-omap1 directory.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-10 19:58:10 +01:00
Tony Lindgren 3b59b6beb4 [PATCH] ARM: 2800/1: OMAP update 3/11: Move OMAP1 core code into mach-omap1 directory
Patch from Tony Lindgren

This patch by Paul Mundt and other OMAP developers
moves OMAP1 specific IRQ, time, and FPGA code into
mach-omap1 directory.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-10 19:58:09 +01:00
Tony Lindgren b288f75ffa [PATCH] ARM: 2798/1: OMAP update 2/11: Change ARM Kconfig to support omap1 and omap2
Patch from Tony Lindgren

This patch by Paul Mundt and other OMAP developers modifies
ARM specific Kconfig to allow sharing code between OMAP1 and
OMAP2 architectures.
In order to share code between OMAP1 and OMAP2, all OMAP1
specific code is moved into mach-omap1 directory in the
following patch. A new mach-omap2 directory will be added
later on.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-10 19:58:08 +01:00
Deepak Saxena 8107338bf9 [PATCH] ARM: 2796/1: Fix ARMv5[TEJ] check in MMU initalization
Patch from Deepak Saxena

The code in mm-armv.c checks for the condition (cpu_architecture()<= ARMv5)
in a few places but should be checking for ARMv5TEJ as the MMU is shared
across all v5 variations.

Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-10 19:44:55 +01:00
Lennert Buytenhek 4bebdab7eb [PATCH] ARM: 2795/1: update ixp2000 defconfigs
Patch from Lennert Buytenhek

Update the ixp2000 defconfigs from 2.6.12-git6 to 2.6.13-rc2.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-10 19:44:54 +01:00
Lennert Buytenhek 28187f2ce3 [PATCH] ARM: 2793/1: platform serial support for ixp2000
Patch from Lennert Buytenhek

This patch converts the ixp2000 serial port over to a platform
serial device.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-10 19:44:53 +01:00
David S. Miller a6524813e0 [SPARC64]: Support CONFIG_HZ
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-08 15:21:51 -07:00
David S. Miller dcc83a0285 [SPARC64]: Typo in dtlb_backend.S, _PAGE_SZ4M --> _PAGE_SZ4MB
Noticed by Eddie C. Dost

Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-08 13:33:10 -07:00
H. J. Lu 763b3917e7 [IA64] Fix a typo in arch/ia64/kernel/entry.S
Both 2.4 and 2.6 kernels need this patch for the next binutils.

Signed-off-by: Tony Luck <tony.luck@intel.com>
2005-07-08 13:23:49 -07:00
Hirokazu Takata 316240f66a [PATCH] m32r: framebuffer device support
This patch is for supporting Epson s1d13xxx framebuffer device for m32r.  #
Sorry, a little bigger.

The Epson s1d13806 is already supported by 2.6.12 kernel, and its driver is
placed as drivers/video/s1d13xxxfb.c.

For the m32r, a header file include/asm-m32r/s1d13806.h was prepared for
several m32r target platforms.  It was originally generated by an Epson
tool S1D13806CFG.EXE, and modified manually for the m32r platforms.

Signed-off-by: Hayato Fujiwara <fujiwara@linux-m32r.org>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-07 18:24:11 -07:00
Christoph Lameter 6c036527a6 [PATCH] mostly_read data section
Add a new section called ".data.read_mostly" for data items that are read
frequently and rarely written to like cpumaps etc.

If these maps are placed in the .data section then these frequenly read
items may end up in cachelines with data is is frequently updated.  In that
case all processors in an SMP system must needlessly reload the cachelines
again and again containing elements of those frequently used variables.

The ability to share these cachelines will allow each cpu in an SMP system
to keep local copies of those shared cachelines thereby optimizing
performance.

Signed-off-by: Alok N Kataria <alokk@calsoftinc.com>
Signed-off-by: Shobhit Dayal <shobhit@calsoftinc.com>
Signed-off-by: Christoph Lameter <christoph@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-07 18:23:46 -07:00
Arnd Bergmann 8759145114 [PATCH] xtensa: remove old syscalls
xtensa is now in -rc1, with the obsolete syscalls still in there, so I
guess this about the last chance to correct the ABI.  Applying the patch
obviously breaks all sorts of user space binaries and probably also
requires the appropriate changes to be made to libc.

On the other hand, if a decision is made to keep the broken interface, it
should at least be a conscious one instead of an oversight.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-07 18:23:44 -07:00
Paolo 'Blaisorblade' Giarrusso 605a69ac81 [PATCH] uml: remove winch sem
Replace a semaphore (winch_handler_sem) used in atomic code with a
spinlock, and reduces as needed the amount of protected code to the bare
minimum (for instance no kmalloc calls are needed).

This fixes the last problems with spinlocking (in UP mode with DEBUG
options); the semaphore, taken inside spinlocks, caused a "spin_lock was
already locked" warning, without this patch.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-07 18:23:44 -07:00
Paolo 'Blaisorblade' Giarrusso 3f580470ba [PATCH] uml: restore hppfs support
Some time ago a trivial patch broke HPPFS (one var became a pointer, not
all uses were updated).  It wasn't fixed at that time because not very
used, now it's been requested so I've fixed this, and it has been tested
positively (at least partially).

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-07 18:23:44 -07:00
Bodo Stroesser 9786a8f3cb [PATCH] uml: Proper clone support for skas0
This patch implements the clone-stub mechanism, which allows skas0 to run
with proc_mm==0, even if the clib in UML uses modify_ldt.

Note: There is a bug in skas3.v7 host patch, that avoids UML-skas from
running properly on a SMP-box.  In full skas3, I never really saw problems,
but in skas0 they showed up.

More commentary by jdike - What this patch does is makes sure that the host
parent of each new host process matches the UML parent of the corresponding
UML process.  This ensures that any changed LDTs are inherited.  This is
done by having clone actually called by the UML process from its stub,
rather than by the kernel.  We have special syscall stubs that are loaded
onto the stub code page because that code must be completely
self-contained.  These stubs are given C interfaces, and used like normal C
functions, but there are subtleties.  Principally, we have to be careful
about stack variables in stub_clone_handler after the clone.  The code is
written so that there aren't any - everything boils down to a fixed
address.  If there were any locals, references to them after the clone
would be wrong because the stack just changed.

Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-07 18:23:44 -07:00
Jeff Dike d67b569f5f [PATCH] uml: skas0 - separate kernel address space on stock hosts
UML has had two modes of operation - an insecure, slow mode (tt mode) in
which the kernel is mapped into every process address space which requires
no host kernel modifications, and a secure, faster mode (skas mode) in
which the UML kernel is in a separate host address space, which requires a
patch to the host kernel.

This patch implements something very close to skas mode for hosts which
don't support skas - I'm calling this skas0.  It provides the security of
the skas host patch, and some of the performance gains.

The two main things that are provided by the skas patch, /proc/mm and
PTRACE_FAULTINFO, are implemented in a way that require no host patch.

For the remote address space changing stuff (mmap, munmap, and mprotect),
we set aside two pages in the process above its stack, one of which
contains a little bit of code which can call mmap et al.

To update the address space, the system call information (system call
number and arguments) are written to the stub page above the code.  The
%esp is set to the beginning of the data, the %eip is set the the start of
the stub, and it repeatedly pops the information into its registers and
makes the system call until it sees a system call number of zero.  This is
to amortize the cost of the context switch across multiple address space
updates.

When the updates are done, it SIGSTOPs itself, and the kernel process
continues what it was doing.

For a PTRACE_FAULTINFO replacement, we set up a SIGSEGV handler in the
child, and let it handle segfaults rather than nullifying them.  The
handler is in the same page as the mmap stub.  The second page is used as
the stack.  The handler reads cr2 and err from the sigcontext, sticks them
at the base of the stack in a faultinfo struct, and SIGSTOPs itself.  The
kernel then reads the faultinfo and handles the fault.

A complication on x86_64 is that this involves resetting the registers to
the segfault values when the process is inside the kill system call.  This
breaks on x86_64 because %rcx will contain %rip because you tell SYSRET
where to return to by putting the value in %rcx.  So, this corrupts $rcx on
return from the segfault.  To work around this, I added an
arch_finish_segv, which on x86 does nothing, but which on x86_64 ptraces
the child back through the sigreturn.  This causes %rcx to be restored by
sigreturn and avoids the corruption.  Ultimately, I think I will replace
this with the trick of having it send itself a blocked signal which will be
unblocked by the sigreturn.  This will allow it to be stopped just after
the sigreturn, and PTRACE_SYSCALLed without all the back-and-forth of
PTRACE_SYSCALLing it through sigreturn.

This runs on a stock host, so theoretically (and hopefully), tt mode isn't
needed any more.  We need to make sure that this is better in every way
than tt mode, though.  I'm concerned about the speed of address space
updates and page fault handling, since they involve extra round-trips to
the child.  We can amortize the round-trip cost for large address space
updates by writing all of the operations to the data page and having the
child execute them all at the same time.  This will help fork and exec, but
not page faults, since they involve only one page.

I can't think of any way to help page faults, except to add something like
PTRACE_FAULTINFO to the host.  There is PTRACE_SIGINFO, but UML doesn't use
siginfo for SIGSEGV (or anything else) because there isn't enough
information in the siginfo struct to handle page faults (the faulting
operation type is missing).  Adding that would make PTRACE_SIGINFO a usable
equivalent to PTRACE_FAULTINFO.

As for the code itself:

- The system call stub is in arch/um/kernel/sys-$(SUBARCH)/stub.S.  It is
  put in its own section of the binary along with stub_segv_handler in
  arch/um/kernel/skas/process.c.  This is manipulated with run_syscall_stub
  in arch/um/kernel/skas/mem_user.c.  syscall_stub will execute any system
  call at all, but it's only used for mmap, munmap, and mprotect.

- The x86_64 stub calls sigreturn by hand rather than allowing the normal
  sigreturn to happen, because the normal sigreturn is a SA_RESTORER in
  UML's address space provided by libc.  Needless to say, this is not
  available in the child's address space.  Also, it does a couple of odd
  pops before that which restore the stack to the state it was in at the
  time the signal handler was called.

- There is a new field in the arch mmu_context, which is now a union.
  This is the pid to be manipulated rather than the /proc/mm file
  descriptor.  Code which deals with this now checks proc_mm to see whether
  it should use the usual skas code or the new code.

- userspace_tramp is now used to create a new host process for every UML
  process, rather than one per UML processor.  It checks proc_mm and
  ptrace_faultinfo to decide whether to map in the pages above its stack.

- start_userspace now makes CLONE_VM conditional on proc_mm since we need
  separate address spaces now.

- switch_mm_skas now just sets userspace_pid[0] to the new pid rather
  than PTRACE_SWITCH_MM.  There is an addition to userspace which updates
  its idea of the pid being manipulated each time around the loop.  This is
  important on exec, when the pid will change underneath userspace().

- The stub page has a pte, but it can't be mapped in using tlb_flush
  because it is part of tlb_flush.  This is why it's required for it to be
  mapped in by userspace_tramp.

Other random things:

- The stub section in uml.lds.S is page aligned.  This page is written
  out to the backing vm file in setup_physmem because it is mapped from
  there into user processes.

- There's some confusion with TASK_SIZE now that there are a couple of
  extra pages that the process can't use.  TASK_SIZE is considered by the
  elf code to be the usable process memory, which is reasonable, so it is
  decreased by two pages.  This confuses the definition of
  USER_PGDS_IN_LAST_PML4, making it too small because of the rounding down
  of the uneven division.  So we round it to the nearest PGDIR_SIZE rather
  than the lower one.

- I added a missing PT_SYSCALL_ARG6_OFFSET macro.

- um_mmu.h was made into a userspace-usable file.

- proc_mm and ptrace_faultinfo are globals which say whether the host
  supports these features.

- There is a bad interaction between the mm.nr_ptes check at the end of
  exit_mmap, stack randomization, and skas0.  exit_mmap will stop freeing
  pages at the PGDIR_SIZE boundary after the last vma.  If the stack isn't
  on the last page table page, the last pte page won't be freed, as it
  should be since the stub ptes are there, and exit_mmap will BUG because
  there is an unfreed page.  To get around this, TASK_SIZE is set to the
  next lowest PGDIR_SIZE boundary and mm->nr_ptes is decremented after the
  calls to init_stub_pte.  This ensures that we know the process stack (and
  all other process mappings) will be below the top page table page, and
  thus we know that mm->nr_ptes will be one too many, and can be
  decremented.

Things that need fixing:

- We may need better assurrences that the stub code is PIC.

- The stub pte is set up in init_new_context_skas.

- alloc_pgdir is probably the right place.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-07 18:23:44 -07:00