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: 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 > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>