While the description of the commit that originally introduced
asmlinkage_protect() validly says that this doesn't guarantee
clobbering of the function arguments, using "m" constraints
rather than "g" ones reduces the risk (by making it less
attractive to the compiler to move those variables into
registers) and generally results in better code (because we know
the arguments are in memory anyway, and are frequently - if not
always - used just once, with the second [compiler visible] use
in asmlinkage_protect() itself being a fake one).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: <roland@hack.frob.com>
Cc: <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/50FE84EC02000078000B83B7@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Impact: cleanup
1) .p2align 4 and .align 16 are the same meaning
(until a.out format for i386 is used which is
not our case for CONFIG_X86_ALIGNMENT_16 anyway)
2) having 15 as max allowed bytes to be skipped
does not make sense on modulo 16
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
LKML-Reference: <20090309171951.GE9945@localhost>
[ small cleanup, use __stringify(), etc. ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Stephen Rothwell reported:
|Today's linux-next build (x86_64 allmodconfig) produced this warning:
|
|In file included from drivers/char/epca.c:49:
|drivers/char/digiFep1.h:7:1: warning: "GLOBAL" redefined
|In file included from include/linux/linkage.h:5,
| from include/linux/kernel.h:11,
| from arch/x86/include/asm/system.h:10,
| from arch/x86/include/asm/processor.h:17,
| from include/linux/prefetch.h:14,
| from include/linux/list.h:6,
| from include/linux/module.h:9,
| from drivers/char/epca.c:29:
|arch/x86/include/asm/linkage.h:55:1: warning: this is the location of the previous definition
|
|Probably introduced by commit 95695547a7
|("x86: asm linkage - introduce GLOBAL macro") from the x86 tree.
Any assembler specific snippets being placed in headers
are to be protected by __ASSEMBLY__. Fixed.
Also move __ALIGN definition under the same protection as well.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
LKML-Reference: <20090306160833.GB7420@localhost>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
There was an attempt to bring build-time checking for
missed ENTRY_X86/END_X86 and KPROBE... pairs. Using
them will add messy in code. Get just rid of them.
This commit could be easily restored if the need appear
in future.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If the code is time critical and this entry is called
from other places we use ENTRY to have it globally defined
and especially aligned.
Contrary we have some snippets which are size
critical. So we use plane ".globl name; name:"
directive. Introduce GLOBAL macro for this.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: make ENTRY()/END() macros more capable
It's usefull to catch unbalanced or messed or mixed declarations of ENTRY and
KPROBES. These macros would help a bit.
For example the following code would compile without problems
ENTRY_X86(mcount)
retq
END_X86(mcount)
But if you forget and mess the following form
ENTRY_X86(mcount)
retq
END(mcount)
ENTRY_X86(ftrace_caller)
The assembler will issue the following message:
Error: ENTRY_X86/KPROBE_X86 unbalanced,missed,mixed
Actually the checking is performed at every _X86 macro
so maybe it's good idea to put ENTRY_KPROBE_FINAL_X86
at the end of .S file to be sure you didn't miss anything.
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Alexander van Heukelum <heukelum@mailshack.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:
a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Jan Beulich