On 08/01/2016 07:27 AM, Martin Liška wrote:
On 08/01/2016 01:09 PM, Michal Hocko wrote:
[CC our gcc guy - I guess he has some theory for this]
On Sun 31-07-16 14:11:25, Michal Hocko wrote:
It seems that this has been already reported and Jason has noticed [1] that
the problem is in the disabled optimizations:
$ grep CRYPTO_DEV_UX500_DEBUG .config
CONFIG_CRYPTO_DEV_UX500_DEBUG=y
if I disable this particular option the code compiles just fine. I have
no idea what is wrong about the code but it seems to depend on
optimizations enabled which sounds a bit scrary...
[1] http://www.spinics.net/lists/linux-mm/msg109590.html
Hi.
The difference is that w/o any optimization level, GCC doesn't make %c0 an
intermediate integer operand [1] (see description of "i" constraint).
If I change "i" to "X" (Any operand whatsoever is allowed.) and "%c0" to "%k0" I get following assembly:
hmmm...but the the '__jump_table' section there needs to be known
at build time. For example, the 'r3' field in the table is the
'key' which is used to identify the proper branches when we
go to update the branch directions. So this needs to be fixed
at build time...
Thanks,
-Jason
cryp_enable_irq_src:
@ args = 0, pretend = 0, frame = 48
@ frame_needed = 1, uses_anonymous_args = 0
push {fp, lr}
add fp, sp, #4
sub sp, sp, #48
str r0, [fp, #-48]
str r1, [fp, #-52]
ldr r3, .L6
str r3, [fp, #-20]
mov r3, #1
strb r3, [fp, #-21]
ldrb r3, [fp, #-21] @ zero_extendqisi2
ldr r2, [fp, #-20]
add r3, r2, r3
.syntax divided
@ 1607 "/home/marxin/Programming/testcases/asm.i" 1
1:
nop
.pushsection __jump_table, "aw"
.word 1b, .L2, r3 # The operand is the register r3
.popsection
.arm
.syntax unified
mov r3, #0
b .L3
.L2:
While using -O2 really make %c0 an intermediate operand:
cryp_enable_irq_src:
@ args = 0, pretend = 0, frame = 0
@ frame_needed = 0, uses_anonymous_args = 0
push {r4, r5, r6, lr}
mov r5, r0
mov r4, r1
.syntax divided
@ 1607 "/home/marxin/Programming/testcases/asm.i" 1
1:
nop
.pushsection __jump_table, "aw"
.word 1b, .L2, #.LANCHOR0+21 # The operand is the intermediate operand #.LANCHOR0+21
.popsection
Martin
[1] https://gcc.gnu.org/onlinedocs/gcc/Simple-Constraints.html#Simple-Constraints
On Sat 30-07-16 05:04:07, Wu Fengguang wrote:
tree: https://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git auto-latest
head: a7bf930624bb1d3368b71b79c5e3351b5d03aa9f
commit: 966a2c66863bb2d984b9b49aee271de502cf8747 [238/243] dynamic_debug: add jump label support
config: arm-allmodconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (Debian 5.4.0-6) 5.4.0 20160609
reproduce:
wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
git checkout 966a2c66863bb2d984b9b49aee271de502cf8747
# save the attached .config to linux build tree
make.cross ARCH=arm
All errors (new ones prefixed by >>):
In file included from include/linux/compiler.h:58:0,
from include/linux/linkage.h:4,
from include/linux/kernel.h:6,
from drivers/crypto/ux500/cryp/cryp_irq.c:11:
arch/arm/include/asm/jump_label.h: In function 'cryp_enable_irq_src':
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
include/linux/compiler-gcc.h:243:38: error: impossible constraint in 'asm'
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
arch/arm/include/asm/jump_label.h: In function 'cryp_disable_irq_src':
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
--
In file included from include/linux/compiler.h:58:0,
from include/linux/err.h:4,
from include/linux/clk.h:15,
from drivers/crypto/ux500/cryp/cryp_core.c:12:
arch/arm/include/asm/jump_label.h: In function 'cryp_interrupt_handler':
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
include/linux/compiler-gcc.h:243:38: error: impossible constraint in 'asm'
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
arch/arm/include/asm/jump_label.h: In function 'cfg_iv':
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
arch/arm/include/asm/jump_label.h: In function 'cfg_ivs':
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
arch/arm/include/asm/jump_label.h: In function 'set_key':
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
arch/arm/include/asm/jump_label.h: In function 'cfg_keys':
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
arch/arm/include/asm/jump_label.h: In function 'cryp_get_device_data':
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
arch/arm/include/asm/jump_label.h: In function 'cryp_dma_out_callback':
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
arch/arm/include/asm/jump_label.h: In function 'cryp_set_dma_transfer':
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
arch/arm/include/asm/jump_label.h: In function 'cryp_dma_done':
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
arch/arm/include/asm/jump_label.h: In function 'cryp_dma_write':
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
^
arch/arm/include/asm/jump_label.h:13:2: note: in expansion of macro 'asm_volatile_goto'
asm_volatile_goto("1:\n\t"
^
include/linux/compiler-gcc.h:243:38: warning: asm operand 0 probably doesn't match constraints
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
vim +/asm +243 include/linux/compiler-gcc.h
a744fd17 Rasmus Villemoes 2015-11-05 227 * returning extra information in the low bits (but in that case the
a744fd17 Rasmus Villemoes 2015-11-05 228 * compiler should see some alignment anyway, when the return value is
a744fd17 Rasmus Villemoes 2015-11-05 229 * massaged by 'flags = ptr & 3; ptr &= ~3;').
a744fd17 Rasmus Villemoes 2015-11-05 230 */
a744fd17 Rasmus Villemoes 2015-11-05 231 #define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))
a744fd17 Rasmus Villemoes 2015-11-05 232 #endif
a744fd17 Rasmus Villemoes 2015-11-05 233
cb984d10 Joe Perches 2015-06-25 234 /*
cb984d10 Joe Perches 2015-06-25 235 * GCC 'asm goto' miscompiles certain code sequences:
cb984d10 Joe Perches 2015-06-25 236 *
cb984d10 Joe Perches 2015-06-25 237 * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
cb984d10 Joe Perches 2015-06-25 238 *
cb984d10 Joe Perches 2015-06-25 239 * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
cb984d10 Joe Perches 2015-06-25 240 *
cb984d10 Joe Perches 2015-06-25 241 * (asm goto is automatically volatile - the naming reflects this.)
cb984d10 Joe Perches 2015-06-25 242 */
cb984d10 Joe Perches 2015-06-25 @243 #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
cb984d10 Joe Perches 2015-06-25 244
cb984d10 Joe Perches 2015-06-25 245 #ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
cb984d10 Joe Perches 2015-06-25 246 #if GCC_VERSION >= 40400
cb984d10 Joe Perches 2015-06-25 247 #define __HAVE_BUILTIN_BSWAP32__
cb984d10 Joe Perches 2015-06-25 248 #define __HAVE_BUILTIN_BSWAP64__
cb984d10 Joe Perches 2015-06-25 249 #endif
8634de6d Josh Poimboeuf 2016-05-06 250 #if GCC_VERSION >= 40800
cb984d10 Joe Perches 2015-06-25 251 #define __HAVE_BUILTIN_BSWAP16__
:::::: The code at line 243 was first introduced by commit
:::::: cb984d101b30eb7478d32df56a0023e4603cba7f compiler-gcc: integrate the various compiler-gcc[345].h files
:::::: TO: Joe Perches <joe@xxxxxxxxxxx>
:::::: CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
--
Michal Hocko
SUSE Labs
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