similar to: PROPOSAL: Extend inline asm syntax with size spec

Hi Peter, On Wed, Oct 31, 2018 at 9:58 PM Peter Zijlstra <peterz at infradead.org> wrote: > > On Sat, Oct 13, 2018 at 09:33:35PM +0200, Borislav Petkov wrote: > > Ok, > > > > with Segher's help I've been playing with his patch ontop of bleeding > > edge gcc 9 and here are my observations. Please double-check me for > > booboos so that they can be

Hi. On Wed, Oct 10, 2018 at 1:14 AM Segher Boessenkool <segher at kernel.crashing.org> wrote: > > On Mon, Oct 08, 2018 at 11:07:46AM +0200, Richard Biener wrote: > > On Mon, 8 Oct 2018, Segher Boessenkool wrote: > > > On Sun, Oct 07, 2018 at 03:53:26PM +0000, Michael Matz wrote: > > > > On Sun, 7 Oct 2018, Segher Boessenkool wrote: > > > > >

Hi. On Wed, Oct 10, 2018 at 1:14 AM Segher Boessenkool <segher at kernel.crashing.org> wrote: > > On Mon, Oct 08, 2018 at 11:07:46AM +0200, Richard Biener wrote: > > On Mon, 8 Oct 2018, Segher Boessenkool wrote: > > > On Sun, Oct 07, 2018 at 03:53:26PM +0000, Michael Matz wrote: > > > > On Sun, 7 Oct 2018, Segher Boessenkool wrote: > > > > >

Hi Segher, On Sun, Dec 2, 2018 at 3:48 PM Segher Boessenkool <segher at kernel.crashing.org> wrote: > > On Fri, Nov 30, 2018 at 10:06:02AM +0100, Boris Petkov wrote: > > On November 29, 2018 1:25:02 PM GMT+01:00, Segher Boessenkool <segher at kernel.crashing.org> wrote: > > >This will only be fixed from GCC 9 on, if the compiler adopts it. The > >

On Tue, Jun 19, 2018 at 12:48:45PM -0700, Nadav Amit wrote: > Nadav Amit (9): > Makefile: Prepare for using macros for inline asm > x86: objtool: use asm macro for better compiler decisions > x86: refcount: prevent gcc distortions > x86: alternatives: macrofy locks for better inlining > x86: bug: prevent gcc distortions > x86: prevent inline distortion by paravirt

On Tue, Sep 18, 2018 at 2:28 PM, Nadav Amit <namit at vmware.com> wrote: > This patch-set deals with an interesting yet stupid problem: kernel code > that does not get inlined despite its simplicity. There are several > causes for this behavior: "cold" attribute on __init, different function > optimization levels; conditional constant computations based on >

* Masahiro Yamada <yamada.masahiro at socionext.com> wrote: > This series reverts the in-kernel workarounds for inlining issues. > > The commit description of 77b0bf55bc67 mentioned > "We also hope that GCC will eventually get fixed,..." > > Now, GCC provides a solution. > > https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html > explains the new

On Mon, Jun 04, 2018 at 04:21:22AM -0700, Nadav Amit wrote: > This patch-set deals with an interesting yet stupid problem: kernel code > that does not get inlined despite its simplicity. There are several > causes for this behavior: "cold" attribute on __init, different function > optimization levels; conditional constant computations based on > __builtin_constant_p(); and

On Sun, Dec 16, 2018 at 12:29 PM Nadav Amit <namit at vmware.com> wrote: > > > On Dec 15, 2018, at 6:50 PM, Masahiro Yamada <yamada.masahiro at socionext.com> wrote: > > > > Revert the following 9 commits: > > > > [1] 5bdcd510c2ac ("x86/jump-labels: Macrofy inline assembly code to > > work around GCC inlining bugs") > > >

Revert the following commits: - 5bdcd510c2ac9efaf55c4cbd8d46421d8e2320cd ("x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs") - d5a581d84ae6b8a4a740464b80d8d9cf1e7947b2 ("x86/cpufeature: Macrofy inline assembly code to work around GCC inlining bugs") - 0474d5d9d2f7f3b11262f7bf87d0e7314ead9200. ("x86/extable: Macrofy inline assembly

Revert the following commits: - 5bdcd510c2ac9efaf55c4cbd8d46421d8e2320cd ("x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs") - d5a581d84ae6b8a4a740464b80d8d9cf1e7947b2 ("x86/cpufeature: Macrofy inline assembly code to work around GCC inlining bugs") - 0474d5d9d2f7f3b11262f7bf87d0e7314ead9200. ("x86/extable: Macrofy inline assembly

On Wed, Oct 10, 2018 at 01:54:33PM -0500, Segher Boessenkool wrote: > It would be great to hear from kernel people if it works adequately for > what you guys want it for :-) Sure, ping me when you have the final version and I'll try to build gcc with it and do some size comparisons. Thx. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the

On Wed, Oct 10, 2018 at 01:54:33PM -0500, Segher Boessenkool wrote: > It would be great to hear from kernel people if it works adequately for > what you guys want it for :-) Sure, ping me when you have the final version and I'll try to build gcc with it and do some size comparisons. Thx. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the

Revert the following 9 commits: [1] 5bdcd510c2ac ("x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs") This was partially reverted because it made good cleanups irrespective of the inlining issue; the error message is still unneeded, and the conversion to STATIC_BRANCH_{NOP,JUMP} should be kept. [2] d5a581d84ae6 ("x86/cpufeature:

This series reverts the in-kernel workarounds for inlining issues. The commit description of 77b0bf55bc67 mentioned "We also hope that GCC will eventually get fixed,..." Now, GCC provides a solution. https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html explains the new "asm inline" syntax. The performance issue will be eventually solved. [About Code cleanups] I know Nadam

This series reverts the in-kernel workarounds for inlining issues. The commit description of 77b0bf55bc67 mentioned "We also hope that GCC will eventually get fixed,..." Now, GCC provides a solution. https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html explains the new "asm inline" syntax. The performance issue will be eventually solved. [About Code cleanups] I know Nadam

On Sun, Oct 07, 2018 at 08:22:28AM -0500, Segher Boessenkool wrote: > GCC already estimates the *size* of inline asm, and this is required > *for correctness*. I didn't say it didn't - but the heuristic could use improving. > So I guess the real issue is that the inline asm size estimate for x86 > isn't very good (since it has to be pessimistic, and x86 insns can be >

* Segher Boessenkool <segher at kernel.crashing.org> wrote: > > > More precise *size* estimates, yes. And if the user lies he should not > > > be surprised to get assembler errors, etc. > > > > Yes. > > > > Another option would be if gcc parses the inline asm directly and > > does a more precise size estimation. Which is a lot more involved

* Michael Matz <matz at suse.de> wrote: > (without an built-in assembler which hopefully noone proposes). There are disadvantages (the main one is having to implement it), but a built-in assembler has numerous advantages as well: - Better optimizations: for example -Os could more accurately estimate true instruction size. - Better inlining: as the examples in this thread are

From: Michael Matz > Sent: 07 October 2018 16:53 ... > I think the examples I saw from Boris were all indirect inlines: > > static inline void foo() { asm("large-looking-but-small-asm"); } > static void bar1() { ... foo() ... } > static void bar2() { ... foo() ... } > void goo (void) { bar1(); } // bar1 should have been inlined > > So, while the