14 Mar, 2017
1 commit
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The proper idiom for aligning linker sections in modules is different
than for built-in sections. ". = ALIGN();" followed by a forced
output address of 0 does nothing, as forcing the address changes the
value of ".".Use output section alignment specifier instead.
Fixes: 9ddf82521c86 ("kernel: add support for .init_array.* constructors")
Reviewed-by: Andrey Ryabinin
Signed-off-by: David Daney
Signed-off-by: Jessica Yu
08 Mar, 2017
1 commit
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Pull tracing fixes from Steven Rostedt:
"There was some breakage with the changes for jump labels in the 4.11
merge window:- powerpc broke as jump labels uses the two LSB bits as flags in
initialization.A check was added to make sure that all jump label entries were 4
bytes aligned, but powerpc didn't work that way for modules. Adding
an alignment in the module linker script appeared to be the best
solution.- Jump labels also added an anonymous union to access those LSB bits
as a normal long. But because this structure had static
initialization, it broke older compilers that could not statically
initialize anonymous unions without brackets.- The command line parameter for setting function graph filter broke
the "EMPTY_HASH" descriptor by modifying it instead of creating a
new hash to hold the entries.- The command line parameter ftrace_graph_max_depth was added to
allow its setting at boot time. It uses existing code and only the
command line hook was added.This is not really a fix, but as it uses existing code without
affecting anything else, I added it to this release. It was ready
before the merge window closed, but I wanted to let it sit in
linux-next for a couple of days first"* tag 'trace-v4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace/graph: Add ftrace_graph_max_depth kernel parameter
tracing: Add #undef to fix compile error
jump_label: Add comment about initialization order for anonymous unions
jump_label: Fix anonymous union initialization
module: set __jump_table alignment to 8
ftrace/graph: Do not modify the EMPTY_HASH for the function_graph filter
tracing: Fix code comment for ftrace_ops_get_func()
03 Mar, 2017
1 commit
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For powerpc the __jump_table section in modules is not aligned, this
causes a WARN_ON() splat when loading a module containing a __jump_table.Strict alignment became necessary with commit 3821fd35b58d
("jump_label: Reduce the size of struct static_key"), currently in
linux-next, which uses the two least significant bits of pointers to
__jump_table elements.Fix by forcing __jump_table to 8, which is the same alignment used for
this section in the kernel proper.Link: http://lkml.kernel.org/r/20170301220453.4756-1-david.daney@cavium.com
Reviewed-by: Jason Baron
Acked-by: Jessica Yu
Acked-by: Michael Ellerman (powerpc)
Tested-by: Sachin Sant
Signed-off-by: David Daney
Signed-off-by: Steven Rostedt (VMware)
02 Mar, 2017
1 commit
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The '__unreachable' and '__func_stack_frame_non_standard' sections are
only used at compile time. They're discarded for vmlinux but they
should also be discarded for modules.Since this is a recurring pattern, prefix the section names with
".discard.". It's a nice convention and vmlinux.lds.h already discards
such sections.Also remove the 'a' (allocatable) flag from the __unreachable section
since it doesn't make sense for a discarded section.Suggested-by: Linus Torvalds
Signed-off-by: Josh Poimboeuf
Cc: Jessica Yu
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Fixes: d1091c7fa3d5 ("objtool: Improve detection of BUG() and other dead ends")
Link: http://lkml.kernel.org/r/20170301180444.lhd53c5tibc4ns77@treble
Signed-off-by: Ingo Molnar
14 Feb, 2015
1 commit
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KASan uses constructors for initializing redzones for global variables.
Globals instrumentation in GCC 4.9.2 produces constructors with priority
(.init_array.00099)Currently kernel ignores such constructors. Only constructors with
default priority supported (.init_array)This patch adds support for constructors with priorities. For kernel
image we put pointers to constructors between __ctors_start/__ctors_end
and do_ctors() will call them on start up. For modules we merge
.init_array.* sections into resulting .init_array. Module code properly
handles constructors in .init_array section.Signed-off-by: Andrey Ryabinin
Cc: Dmitry Vyukov
Cc: Konstantin Serebryany
Cc: Dmitry Chernenkov
Signed-off-by: Andrey Konovalov
Cc: Yuri Gribov
Cc: Konstantin Khlebnikov
Cc: Sasha Levin
Cc: Christoph Lameter
Cc: Joonsoo Kim
Cc: Dave Hansen
Cc: Andi Kleen
Cc: Ingo Molnar
Cc: Thomas Gleixner
Cc: "H. Peter Anvin"
Cc: Christoph Lameter
Cc: Pekka Enberg
Cc: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
06 Feb, 2015
1 commit
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These __ksymtab*/__kcrctab* sections currently have non-zero addresses.
Non-zero section addresses in a relocatable ELF confuse GDB and it ends
up not relocating all symbols when add-symbol-file is used on modules
which have exports. The kernel's module loader does not care about
these addresses, so let's just set them to zero.Before:
$ readelf -S lib/notifier-error-inject.ko | grep 'Name\| __ksymtab_gpl'
[Nr] Name Type Addr Off Size ES Flg Lk Inf Al
[ 8] __ksymtab_gpl PROGBITS 0000000c 0001b4 000010 00 A 0 0 4(gdb) add-symbol-file lib/notifier-error-inject.ko 0x500000 -s .bss 0x700000
add symbol table from file "lib/notifier-error-inject.ko" at
.text_addr = 0x500000
.bss_addr = 0x700000
(gdb) p ¬ifier_err_inject_dir
$3 = (struct dentry **) 0x0After:
$ readelf -S lib/notifier-error-inject.ko | grep 'Name\| __ksymtab_gpl'
[Nr] Name Type Addr Off Size ES Flg Lk Inf Al
[ 8] __ksymtab_gpl PROGBITS 00000000 0001b4 000010 00 A 0 0 4(gdb) add-symbol-file lib/notifier-error-inject.ko 0x500000 -s .bss 0x700000
add symbol table from file "lib/notifier-error-inject.ko" at
.text_addr = 0x500000
.bss_addr = 0x700000
(gdb) p ¬ifier_err_inject_dir
$3 = (struct dentry **) 0x700000Signed-off-by: Rabin Vincent
Signed-off-by: Rusty Russell
19 May, 2011
1 commit
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This patch places every exported symbol in its own section
(i.e. "___ksymtab+printk"). Thus the linker will use its SORT() directive
to sort and finally merge all symbol in the right and final section
(i.e. "__ksymtab").The symbol prefixed archs use an underscore as prefix for symbols.
To avoid collision we use a different character to create the temporary
section names.This work was supported by a hardware donation from the CE Linux Forum.
Signed-off-by: Alessio Igor Bogani
Signed-off-by: Rusty Russell (folded in '+' fixup)
Tested-by: Dirk Behme
24 Jun, 2009
1 commit
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x86 throws away .discard section but no other archs do. Also,
.discard is not thrown away while linking modules. Make every arch
and module linking throw it away. This will be used to define dummy
variables for percpu declarations and definitions.This patch is based on Ivan Kokshaysky's alpha percpu patch.
[ Impact: always throw away everything in .discard ]
Signed-off-by: Tejun Heo
Cc: Ivan Kokshaysky
Cc: Richard Henderson
Cc: Russell King
Cc: Haavard Skinnemoen
Cc: Bryan Wu
Cc: Mikael Starvik
Cc: Jesper Nilsson
Cc: David Howells
Cc: Yoshinori Sato
Cc: Tony Luck
Cc: Hirokazu Takata
Cc: Geert Uytterhoeven
Cc: Michal Simek
Cc: Ralf Baechle
Cc: Kyle McMartin
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: Paul Mundt
Cc: David S. Miller
Cc: Jeff Dike
Cc: Chris Zankel
Cc: Rusty Russell
Cc: Ingo Molnar
