linux-stable.git/arch, branch v3.2.19 Linux kernel stable tree x86, relocs: Add jiffies and jiffies_64 to the relative whitelist 2012-05-30T23:44:10+00:00 H. Peter Anvin hpa@zytor.com 2012-05-24T14:01:38+00:00 a4a79515880b12f91cb95bf216075805e3f876cf commit ea17e7414bc62e8d3bde8d08e3df1d921c518c17 upstream. The symbol jiffies is created in the linker script as an alias to jiffies_64. Unfortunately this is done outside any section, and apparently GNU ld 2.21 doesn't carry the section with it, so we end up with an absolute symbol and therefore a broken kernel. Add jiffies and jiffies_64 to the whitelist. The most disturbing bit with this discovery is that it shows that we have had multiple linker bugs in this area crossing multiple generations, and have been silently building bad kernels for some time. Link: http://lkml.kernel.org/r/20120524171604.0d98284f3affc643e9714470@canb.auug.org.au Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit ea17e7414bc62e8d3bde8d08e3df1d921c518c17 upstream.

The symbol jiffies is created in the linker script as an alias to
jiffies_64.  Unfortunately this is done outside any section, and
apparently GNU ld 2.21 doesn't carry the section with it, so we end up
with an absolute symbol and therefore a broken kernel.

Add jiffies and jiffies_64 to the whitelist.

The most disturbing bit with this discovery is that it shows that we
have had multiple linker bugs in this area crossing multiple
generations, and have been silently building bad kernels for some time.

Link: http://lkml.kernel.org/r/20120524171604.0d98284f3affc643e9714470@canb.auug.org.au
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
x86-32, relocs: Whitelist more symbols for ld bug workaround 2012-05-30T23:44:09+00:00 H. Peter Anvin hpa@zytor.com 2012-05-23T21:02:34+00:00 41799aef7b2cb022b60738b8641eff9ea02c6561 commit fd952815307f0f272bf49fd364a7fd2f9992bc42 upstream. As noted in checkin: a3e854d95 x86, relocs: Workaround for binutils 2.22.52.0.1 section bug ld version 2.22.52.0.[12] can incorrectly promote relative symbols to absolute, if the output section they appear in is otherwise empty. Since checkin: 6520fe55 x86, realmode: 16-bit real-mode code support for relocs tool we actually check for this and error out rather than silently creating a kernel which will malfunction if relocated. Ingo found a configuration in which __start_builtin_fw triggered the warning. Go through the linker script sources and look for more symbols that could plausibly get bogusly promoted to absolute, and add them to the whitelist. In general, if the following error triggers: Invalid absolute R_386_32 relocation: <symbol> ... then we should verify that <symbol> is really meant to be relocated, and add it and any related symbols manually to the S_REL regexp. Please note that 6520fe55 does not introduce the error, only the check for the error -- without 6520fe55 this version of ld will simply produce a corrupt kernel if CONFIG_RELOCATABLE is set on x86-32. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit fd952815307f0f272bf49fd364a7fd2f9992bc42 upstream.

As noted in checkin:

a3e854d95 x86, relocs: Workaround for binutils 2.22.52.0.1 section bug

ld version 2.22.52.0.[12] can incorrectly promote relative symbols to
absolute, if the output section they appear in is otherwise empty.

Since checkin:

6520fe55 x86, realmode: 16-bit real-mode code support for relocs tool

we actually check for this and error out rather than silently creating
a kernel which will malfunction if relocated.

Ingo found a configuration in which __start_builtin_fw triggered the
warning.

Go through the linker script sources and look for more symbols that
could plausibly get bogusly promoted to absolute, and add them to the
whitelist.

In general, if the following error triggers:

	Invalid absolute R_386_32 relocation: <symbol>

... then we should verify that <symbol> is really meant to be
relocated, and add it and any related symbols manually to the S_REL
regexp.

Please note that 6520fe55 does not introduce the error, only the check
for the error -- without 6520fe55 this version of ld will simply
produce a corrupt kernel if CONFIG_RELOCATABLE is set on x86-32.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
x86, relocs: Build clean fix 2012-05-30T23:44:09+00:00 Jarkko Sakkinen jarkko.sakkinen@intel.com 2012-05-21T17:51:24+00:00 53f3be9ee6a1cc93d2332274598e22f66fcb56c3 commit b2d668da9307c4c163dd603d2bb3cadb10f9fd37 upstream. relocs was not cleaned up when "make clean" is issued. This patch fixes the issue. Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com> Link: http://lkml.kernel.org/r/1337622684-6834-1-git-send-email-jarkko.sakkinen@intel.com Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit b2d668da9307c4c163dd603d2bb3cadb10f9fd37 upstream.

relocs was not cleaned up when "make clean" is issued. This
patch fixes the issue.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Link: http://lkml.kernel.org/r/1337622684-6834-1-git-send-email-jarkko.sakkinen@intel.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
x86, relocs: When printing an error, say relative or absolute 2012-05-30T23:44:08+00:00 H. Peter Anvin hpa@linux.intel.com 2012-05-18T16:52:01+00:00 cd88adf8add21ce1c73cbf665e80244c44c05d98 commit 24ab82bd9bf18f3efc69a131d73577940941e1b7 upstream. When the relocs tool throws an error, let the error message say if it is an absolute or relative symbol. This should make it a lot more clear what action the programmer needs to take and should help us find the reason if additional symbol bugs show up. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 24ab82bd9bf18f3efc69a131d73577940941e1b7 upstream.

When the relocs tool throws an error, let the error message say if it
is an absolute or relative symbol.  This should make it a lot more
clear what action the programmer needs to take and should help us find
the reason if additional symbol bugs show up.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
x86, relocs: Workaround for binutils 2.22.52.0.1 section bug 2012-05-30T23:44:08+00:00 H. Peter Anvin hpa@linux.intel.com 2012-05-18T07:24:09+00:00 5a3270a97b38858a41c17a5e40a4a03492976047 commit a3e854d95a76862cd37937e0b0438f540536771a upstream. GNU ld 2.22.52.0.1 has a bug that it blindly changes symbols from section-relative to absolute if they are in a section of zero length. This turns the symbols __init_begin and __init_end into absolute symbols. Let the relocs program know that those should be treated as relative symbols. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: H.J. Lu <hjl.tools@gmail.com> Cc: Jarkko Sakkinen <jarkko.sakkinen@intel.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit a3e854d95a76862cd37937e0b0438f540536771a upstream.

GNU ld 2.22.52.0.1 has a bug that it blindly changes symbols from
section-relative to absolute if they are in a section of zero length.
This turns the symbols __init_begin and __init_end into absolute
symbols.  Let the relocs program know that those should be treated as
relative symbols.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
x86, realmode: 16-bit real-mode code support for relocs tool 2012-05-30T23:44:08+00:00 H. Peter Anvin hpa@linux.intel.com 2012-05-08T18:22:24+00:00 b352fc61e3aaa363ab92560187ee994fb6a3e27d commit 6520fe5564acf07ade7b18a1272db1184835c487 upstream. A new option is added to the relocs tool called '--realmode'. This option causes the generation of 16-bit segment relocations and 32-bit linear relocations for the real-mode code. When the real-mode code is moved to the low-memory during kernel initialization, these relocation entries can be used to relocate the code properly. In the assembly code 16-bit segment relocations must be relative to the 'real_mode_seg' absolute symbol. Linear relocations must be relative to a symbol prefixed with 'pa_'. 16-bit segment relocation is used to load cs:ip in 16-bit code. Linear relocations are used in the 32-bit code for relocatable data references. They are declared in the linker script of the real-mode code. The relocs tool is moved to arch/x86/tools/relocs.c, and added new target archscripts that can be used to build scripts needed building an architecture. be compiled before building the arch/x86 tree. [ hpa: accelerating this because it detects invalid absolute relocations, a serious bug in binutils 2.22.52.0.x which currently produces bad kernels. ] Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/1336501366-28617-2-git-send-email-jarkko.sakkinen@intel.com Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: <stable@vger.kernel.org> [bwh: Backported to 3.2: - Adjust context (no archheaders; no insn_sanity) - Expand put_unaligned_le32()] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 6520fe5564acf07ade7b18a1272db1184835c487 upstream.

A new option is added to the relocs tool called '--realmode'.
This option causes the generation of 16-bit segment relocations
and 32-bit linear relocations for the real-mode code. When
the real-mode code is moved to the low-memory during kernel
initialization, these relocation entries can be used to
relocate the code properly.

In the assembly code 16-bit segment relocations must be relative
to the 'real_mode_seg' absolute symbol. Linear relocations must be
relative to a symbol prefixed with 'pa_'.

16-bit segment relocation is used to load cs:ip in 16-bit code.
Linear relocations are used in the 32-bit code for relocatable
data references. They are declared in the linker script of the
real-mode code.

The relocs tool is moved to arch/x86/tools/relocs.c, and added new
target archscripts that can be used to build scripts needed building
an architecture.  be compiled before building the arch/x86 tree.

[ hpa: accelerating this because it detects invalid absolute
  relocations, a serious bug in binutils 2.22.52.0.x which currently
  produces bad kernels. ]

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-2-git-send-email-jarkko.sakkinen@intel.com
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org>
[bwh: Backported to 3.2:
 - Adjust context (no archheaders; no insn_sanity)
 - Expand put_unaligned_le32()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
tile: fix bug where fls(0) was not returning 0 2012-05-30T23:44:03+00:00 Chris Metcalf cmetcalf@tilera.com 2012-05-25T16:32:09+00:00 10c9eea8f9831180c52bfbb0ddf9af6e51989a41 commit 9f1d62bed7f015d11b9164078b7fea433b474114 upstream. This is because __builtin_clz(0) returns 64 for the "undefined" case of 0, since the builtin just does a right-shift 32 and "clz" instruction. So, use the alpha approach of casting to u32 and using __builtin_clzll(). Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 9f1d62bed7f015d11b9164078b7fea433b474114 upstream.

This is because __builtin_clz(0) returns 64 for the "undefined" case
of 0, since the builtin just does a right-shift 32 and "clz" instruction.
So, use the alpha approach of casting to u32 and using __builtin_clzll().

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
x86/mce: Fix check for processor context when machine check was taken. 2012-05-30T23:44:02+00:00 Tony Luck tony.luck@intel.com 2012-05-23T21:14:22+00:00 ada120d8941283a3e921c9f81cb8748f6924aa40 commit 875e26648cf9b6db9d8dc07b7959d7c61fb3f49c upstream. Linus pointed out that there was no value is checking whether m->ip was zero - because zero is a legimate value. If we have a reliable (or faked in the VM86 case) "m->cs" we can use it to tell whether we were in user mode or kernelwhen the machine check hit. Reported-by: Linus Torvalds <torvalds@linuxfoundation.org> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 875e26648cf9b6db9d8dc07b7959d7c61fb3f49c upstream.

Linus pointed out that there was no value is checking whether m->ip
was zero - because zero is a legimate value.  If we have a reliable
(or faked in the VM86 case) "m->cs" we can use it to tell whether we
were in user mode or kernelwhen the machine check hit.

Reported-by: Linus Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
MCE: Fix vm86 handling for 32bit mce handler 2012-05-30T23:44:02+00:00 Andi Kleen andi@firstfloor.org 2010-11-19T12:16:22+00:00 234887cec47a1916d2bd63f9e05a5005af2f03cc commit a129a7c84582629741e5fa6f40026efcd7a65bd4 upstream. When running on 32bit the mce handler could misinterpret vm86 mode as ring 0. This can affect whether it does recovery or not; it was possible to panic when recovery was actually possible. Fix this by always forcing vm86 to look like ring 3. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit a129a7c84582629741e5fa6f40026efcd7a65bd4 upstream.

When running on 32bit the mce handler could misinterpret
vm86 mode as ring 0. This can affect whether it does recovery
or not; it was possible to panic when recovery was actually
possible.

Fix this by always forcing vm86 to look like ring 3.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
xen: do not map the same GSI twice in PVHVM guests. 2012-05-30T23:44:01+00:00 Stefano Stabellini stefano.stabellini@eu.citrix.com 2012-05-21T15:54:10+00:00 482953eeea949295981474e179d37fd61258d3ca commit 68c2c39a76b094e9b2773e5846424ea674bf2c46 upstream. PV on HVM guests map GSIs into event channels. At restore time the event channels are resumed by restore_pirqs. Device drivers might try to register the same GSI again through ACPI at restore time, but the GSI has already been mapped and bound by restore_pirqs. This patch detects these situations and avoids mapping the same GSI multiple times. Without this patch we get: (XEN) irq.c:2235: dom4: pirq 23 or emuirq 28 already mapped and waste a pirq. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 68c2c39a76b094e9b2773e5846424ea674bf2c46 upstream.

PV on HVM guests map GSIs into event channels. At restore time the
event channels are resumed by restore_pirqs.

Device drivers might try to register the same GSI again through ACPI at
restore time, but the GSI has already been mapped and bound by
restore_pirqs. This patch detects these situations and avoids
 mapping the same GSI multiple times.

Without this patch we get:
(XEN) irq.c:2235: dom4: pirq 23 or emuirq 28 already mapped
and waste a pirq.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>