[valgrind] [Bug 434840] PPC64 darn instruction not supported
https://bugs.kde.org/show_bug.cgi?id=434840 Will Schmidt changed: What|Removed |Added CC||will_schm...@vnet.ibm.com -- You are receiving this mail because: You are watching all bug changes.
[valgrind] [Bug 434840] PPC64 darn instruction not supported
https://bugs.kde.org/show_bug.cgi?id=434840 Carl Love changed: What|Removed |Added Status|RESOLVED|CLOSED -- You are receiving this mail because: You are watching all bug changes.
[valgrind] [Bug 434840] PPC64 darn instruction not supported
https://bugs.kde.org/show_bug.cgi?id=434840 Carl Love changed: What|Removed |Added Resolution|--- |FIXED Status|REPORTED|RESOLVED --- Comment #10 from Carl Love --- Closing issue -- You are receiving this mail because: You are watching all bug changes.
[valgrind] [Bug 434840] PPC64 darn instruction not supported
https://bugs.kde.org/show_bug.cgi?id=434840 --- Comment #9 from Carl Love --- Patch committed. commit 8afb49abe04a341d60b441c1f09a956aeccf0bbb (HEAD -> master, origin/master, origin/HEAD) Author: Carl Love Date: Mon Mar 22 17:55:05 2021 -0500 PPC64: Add support for the darn instruction -- You are receiving this mail because: You are watching all bug changes.
[valgrind] [Bug 434840] PPC64 darn instruction not supported
https://bugs.kde.org/show_bug.cgi?id=434840 Carl Love changed: What|Removed |Added Attachment #137204|0 |1 is obsolete|| --- Comment #8 from Carl Love --- Created attachment 138144 --> https://bugs.kde.org/attachment.cgi?id=138144=edit patch to add darn instruction support Updated the patch. Added a comment to thedis_darn() function in guest_ppc_toIR.c and darn_dirty_helper in guest_ppc_helpers stating the dirty helper does not change the guest state or guest memory. It simply returns the value from running the darn instruction on the host. -- You are receiving this mail because: You are watching all bug changes.
[valgrind] [Bug 434840] PPC64 darn instruction not supported
https://bugs.kde.org/show_bug.cgi?id=434840 --- Comment #7 from Julian Seward --- (In reply to Carl Love from comment #6) > Created attachment 137204 [details] > patch to add darn instruction support +static Int dis_darn ( UInt prefix, UInt theInstr, + + IRExpr** args = mkIRExprVec_1( mkU32( L ) ); + + d = unsafeIRDirty_1_N ( + rD, + 0/*regparms*/, + "darn_dirty_helper", + fnptr_to_fnentry( vbi, _dirty_helper ), + args ); This wants a comment saying that there are no effects on memory or guest state, since it is unusual for a dirty helper to have no such effects. Otherwise looks fine to me. -- You are receiving this mail because: You are watching all bug changes.
[valgrind] [Bug 434840] PPC64 darn instruction not supported
https://bugs.kde.org/show_bug.cgi?id=434840 Carl Love changed: What|Removed |Added Attachment #136999|0 |1 is obsolete|| --- Comment #6 from Carl Love --- Created attachment 137204 --> https://bugs.kde.org/attachment.cgi?id=137204=edit patch to add darn instruction support Updated patch Fixed: Return false on L=3 to generate SIGILL on illegal instruction. Removed #else clause in dirty helper as the return value, val, is already set to the error value. -- You are receiving this mail because: You are watching all bug changes.
[valgrind] [Bug 434840] PPC64 darn instruction not supported
https://bugs.kde.org/show_bug.cgi?id=434840
--- Comment #5 from Julian Seward ---
(In reply to Carl Love from comment #4)
> Created attachment 136999 [details]
> patch to add darn instruction support
+ULong darn_dirty_helper ( UInt L )
+{
+
...
+# else
+ val = 0xULL; /* error */
+# endif
Given that you initialise `val` to the error value outside of any ifdef,
this #else clause is redundant. You could remove it.
+static Int dis_darn ( UInt prefix, UInt theInstr,
+ const VexAbiInfo* vbi )
..
+ if (L == 3)
+ /* Hardware reports illegal instruction if L = 3. */
+ vpanic("ERROR: darn instruction L=3 is not valid\n");
Generate SIGILL for an unrecognised instruction, don't assert.
Please always do this -- I've asked multiple times before.
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[valgrind] [Bug 434840] PPC64 darn instruction not supported
https://bugs.kde.org/show_bug.cgi?id=434840 Carl Love changed: What|Removed |Added Attachment #136990|0 |1 is obsolete|| --- Comment #4 from Carl Love --- Created attachment 136999 --> https://bugs.kde.org/attachment.cgi?id=136999=edit patch to add darn instruction support Updated the patch. - Removed the C code random number generator code. Was not supposed to be included in previous patch. - Reworked the helper to make it a dirty helper that returns the random value. Patch tested on Power 8, Power 9 and on ISA 3.1 prototype hardware. Please let me know if the updated patch is good to go. Thanks. -- You are receiving this mail because: You are watching all bug changes.
[valgrind] [Bug 434840] PPC64 darn instruction not supported
https://bugs.kde.org/show_bug.cgi?id=434840 --- Comment #3 from Carl Love --- Argh, I inadvertently added the alternate C code solution. That was for playing. I thought I had removed that. I will change to a dirty helper and get rid of the C code solution. Thanks -- You are receiving this mail because: You are watching all bug changes.
[valgrind] [Bug 434840] PPC64 darn instruction not supported
https://bugs.kde.org/show_bug.cgi?id=434840 --- Comment #2 from Julian Seward --- (In reply to Carl Love from comment #1) Handing it off to the hardware via a helper function is the right thing to do. But you can't use a clean helper for this; that breaks the rules for clean helpers. A clean helper * must produce a value which depends only on its arguments * given the same argument, always produces the same result. and the IR optimiser relies (or may rely) on the above being true. You need to use a dirty helper. Also I'm not happy about the replacement C implementations; I'm not sure when they would ever get used. I'd prefer if they were removed. -- You are receiving this mail because: You are watching all bug changes.
[valgrind] [Bug 434840] PPC64 darn instruction not supported
https://bugs.kde.org/show_bug.cgi?id=434840 --- Comment #1 from Carl Love --- Created attachment 136990 --> https://bugs.kde.org/attachment.cgi?id=136990=edit patch to add darn instruction support The attached patch to add support for the darn instruction uses a clean helper to add the support. The clean helper uses an inline assembly statement to call the darn (Deliver a Random Number) instruction. This is not the normal or preferred way to support an instruction. AMD 64 used a dirty helper to support its random number generator. I looked at C code random number generators but did not a good solution. Julian, please let me know if you are ok with this non-standard implementation for supporting the random number generation instruction. -- You are receiving this mail because: You are watching all bug changes.
