kernel/linux.git/include/math-emu, branch v6.6.131

powerpc/math-emu: Remove -w build flag and fix warnings

2022-09-05T07:28:25+00:00

As reported by Nathan, the module_init() macro was not taken into account because the header was missing. That means spe_mathemu_init() was never called. This should have been detected by gcc at build time, but due to '-w' flag it went undetected. Removing that flag leads to many warnings hence errors. Fix those warnings then remove the -w flag. Reported-by: Nathan Chancellor Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Reviewed-by: Nathan Chancellor Link: https://lore.kernel.org/r/2663961738a46073713786d4efeb53100ca156e7.1662134272.git.christophe.leroy@csgroup.eu

math-emu: Fix fall-through warning

2021-07-13T18:57:44+00:00

Fix the following fallthrough warning (nds32-randconfig with GCC): include/math-emu/op-common.h:332:8: warning: this statement may fall through [-Wimplicit-fallthrough=] Reported-by: kernel test robot Link: https://lore.kernel.org/lkml/60edca25.k00ut905IFBjPyt5%25lkp@intel.com/ Signed-off-by: Gustavo A. R. Silva

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva

nds32: Mark expected switch fall-throughs

2019-08-29T16:06:56+00:00

Mark switch cases where we are expecting to fall through. This patch fixes the following warnings (Building: allmodconfig nds32): include/math-emu/soft-fp.h:124:8: warning: this statement may fall through [-Wimplicit-fallthrough=] arch/nds32/kernel/signal.c:362:20: warning: this statement may fall through [-Wimplicit-fallthrough=] arch/nds32/kernel/signal.c:315:7: warning: this statement may fall through [-Wimplicit-fallthrough=] include/math-emu/op-common.h:417:11: warning: this statement may fall through [-Wimplicit-fallthrough=] include/math-emu/op-common.h:430:11: warning: this statement may fall through [-Wimplicit-fallthrough=] include/math-emu/op-common.h:310:11: warning: this statement may fall through [-Wimplicit-fallthrough=] include/math-emu/op-common.h:320:11: warning: this statement may fall through [-Wimplicit-fallthrough=] include/math-emu/op-common.h:310:11: warning: this statement may fall through [-Wimplicit-fallthrough=] include/math-emu/op-common.h:320:11: warning: this statement may fall through [-Wimplicit-fallthrough=] include/math-emu/soft-fp.h:124:8: warning: this statement may fall through [-Wimplicit-fallthrough=] include/math-emu/op-common.h:417:11: warning: this statement may fall through [-Wimplicit-fallthrough=] include/math-emu/op-common.h:430:11: warning: this statement may fall through [-Wimplicit-fallthrough=] include/math-emu/op-common.h:310:11: warning: this statement may fall through [-Wimplicit-fallthrough=] include/math-emu/op-common.h:320:11: warning: this statement may fall through [-Wimplicit-fallthrough=] include/math-emu/op-common.h:310:11: warning: this statement may fall through [-Wimplicit-fallthrough=] include/math-emu/op-common.h:320:11: warning: this statement may fall through [-Wimplicit-fallthrough=] Reported-by: Michael Ellerman Signed-off-by: Gustavo A. R. Silva

math-emu: Use statement expressions to fix Wshift-count-overflow warning

2019-05-31T07:23:25+00:00

To avoid "shift count >= width of type" warning, using statement expressions to implement the conditional controlling before constant shift The modification in op-2.h is taken from the glibc commit 'sysdeps/unix/sysv/lin ("fe0b1e854ad32")'. Signed-off-by: Vincent Chen Acked-by: Greentime Hu Signed-off-by: Greentime Hu

math-emu/soft-fp.h: (_FP_ROUND_ZERO) cast 0 to void to fix warning

2018-11-22T10:13:42+00:00

_FP_ROUND_ZERO is defined as 0 and used as a statemente in macro _FP_ROUND. This generates "error: statement with no effect [-Werror=unused-value]" from gcc. Defining _FP_ROUND_ZERO as (void)0 to fix it. This modification is quoted from glibc 'commit (8ed1e7d5894000c155acbd06f)' Signed-off-by: Vincent Chen Acked-by: Greentime Hu Signed-off-by: Greentime Hu

math-emu/op-2.h: Use statement expressions to prevent negative constant shift

2018-11-22T10:13:33+00:00

This modification is quoted from glibc 'commit < sysdeps/unix/sysv/linux/sparc/sparc64/dl-procinfo.c: Moved to> (fe0b1e854ad32a69b260)' Signed-off-by: Vincent Chen Acked-by: Greentime Hu Signed-off-by: Greentime Hu

math-emu: fix floating-point to integer overflow detection

2014-01-08T00:36:24+00:00

On overflow, the math-emu macro _FP_TO_INT_ROUND tries to saturate its result (subject to the value of rsigned specifying the desired overflow semantics). However, if the rounding step has the effect of increasing the exponent so as to cause overflow (if the rounded result is 1 larger than the largest positive value with the given number of bits, allowing for signedness), the overflow does not get detected, meaning that for unsigned results 0 is produced instead of the maximum unsigned integer with the give number of bits, without an exception being raised for overflow, and that for signed results the minimum (negative) value is produced instead of the maximum (positive) value, again without an exception. This patch makes the code check for rounding increasing the exponent and adjusts the exponent value as needed for the overflow check. Signed-off-by: Joseph Myers Signed-off-by: Scott Wood

math-emu: fix floating-point to integer unsigned saturation

2014-01-08T00:34:47+00:00

The math-emu macros _FP_TO_INT and _FP_TO_INT_ROUND are supposed to saturate their results for out-of-range arguments, except in the case rsigned == 2 (when instead the low bits of the result are taken). However, in the case rsigned == 0 (converting to unsigned integers), they mistakenly produce 0 for positive results and the maximum unsigned integer for negative results, the opposite of correct unsigned saturation. This patch fixes the logic. Signed-off-by: Joseph Myers Signed-off-by: Scott Wood

math-emu: correct test for downshifting fraction in _FP_FROM_INT()

2010-07-21T01:45:14+00:00

The kernel's math-emu code contains a macro _FP_FROM_INT() which is used to convert an integer to a raw normalized floating-point value. It does this basically in three steps: 1. Compute the exponent from the number of leading zero bits. 2. Downshift large fractions to put the MSB in the right position for normalized fractions. 3. Upshift small fractions to put the MSB in the right position. There is an boundary error in step 2, causing a fraction with its MSB exactly one bit above the normalized MSB position to not be downshifted. This results in a non-normalized raw float, which when packed becomes a massively inaccurate representation for that input. The impact of this depends on a number of arch-specific factors, but it is known to have broken emulation of FXTOD instructions on UltraSPARC III, which was originally reported as GCC bug 44631 . Any arch which uses math-emu to emulate conversions from integers to same-size floats may be affected. The fix is simple: the exponent comparison used to determine if the fraction should be downshifted must be "<=" not "<". I'm sending a kernel module to test this as a reply to this message. There are also SPARC user-space test cases in the GCC bug entry. Signed-off-by: Mikael Pettersson Signed-off-by: David S. Miller