Thread (26 messages) 26 messages, 2 authors, 2025-06-11

Re: [PATCH v6 5/9] kselftest/arm64/mte: check MTE_FAR feature is supported

From: Yeo Reum Yun <hidden>
Date: 2025-06-11 12:24:05
Also in: linux-doc, lkml

Hi Mark,
quoted
 #include <unistd.h>
Not sure why we'd be including time.h here?
As you mention, This is my bad for wrong plcae .. Sorry
quoted
+bool mtefar_support;
This is a non-static variable so won't have a defined default value...
Right, at the first write, I declare this with static.
But forgetting when changing more....
quoted
+
       if (mode == MTE_SYNC_ERR)
               cur_mte_cxt.trig_si_code = SEGV_MTESERR;
     else if (mode == MTE_ASYNC_ERR)
Unrelated whitespace change.
Thanks.
...this will only set mtefar_support if the hwcap is present, leaving it

undefined if not.  If you just make this

     mtefar_support = hwcap3 & HWCAP3_MTE_FAR
that should avoid the issue.
Thanks for catching this.
I'll change.

--  
Sincerely,
Yeoreum Yun




________________________________________
From: Mark Brown
Sent: Wednesday, June 11, 2025 12:52
To: Yeo Reum Yun
Cc: Catalin Marinas; pcc@google.com; will@kernel.org; Anshuman Khandual; Joey Gouly; Yury Khrustalev; maz@kernel.org; oliver.upton@linux.dev; frederic@kernel.org; akpm@linux-foundation.org; surenb@google.com; linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; linux-doc@vger.kernel.org
Subject: Re: [PATCH v6 5/9] kselftest/arm64/mte: check MTE_FAR feature is supported


On Wed, Jun 11, 2025 at 10:41:03AM +0100, Yeoreum Yun wrote:
quoted hunk ↗ jump to hunk
--- a/tools/testing/selftests/arm64/mte/mte_common_util.c
quoted hunk ↗ jump to hunk
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
quoted hunk ↗ jump to hunk
@@ -6,6 +6,7 @@
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <time.h>
 #include <unistd.h>


Not sure why we'd be including time.h here?


 #include <linux/auxvec.h>
quoted hunk ↗ jump to hunk
@@ -26,6 +27,7 @@
 #define INIT_BUFFER_SIZE       256
 struct mte_fault_cxt cur_mte_cxt;
+bool mtefar_support;


This is a non-static variable so won't have a defined default value...


quoted hunk ↗ jump to hunk
@@ -273,6 +275,7 @@ void mte_initialize_current_context(int mode, uintptr_t ptr, ssize_t range)
       cur_mte_cxt.fault_valid = false;
       cur_mte_cxt.trig_addr = ptr;
       cur_mte_cxt.trig_range = range;
+
       if (mode == MTE_SYNC_ERR)
               cur_mte_cxt.trig_si_code = SEGV_MTESERR;
       else if (mode == MTE_ASYNC_ERR)


Unrelated whitespace change.


       if (!(hwcaps2 & HWCAP2_MTE))
               ksft_exit_skip("MTE features unavailable\n");
+     if (hwcaps3 & HWCAP3_MTE_FAR)
+             mtefar_support = true;
+


...this will only set mtefar_support if the hwcap is present, leaving it

undefined if not.  If you just make this



        mtefar_support = hwcap3 & HWCAP3_MTE_FAR



that should avoid the issue.

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