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Date:      Mon, 11 May 2020 21:24:22 +0000 (UTC)
From:      John Baldwin <jhb@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org
Subject:   svn commit: r360932 - stable/12/lib/libc/riscv/gen
Message-ID:  <202005112124.04BLOMMR041197@repo.freebsd.org>

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Author: jhb
Date: Mon May 11 21:24:22 2020
New Revision: 360932
URL: https://svnweb.freebsd.org/changeset/base/360932

Log:
  MFC 357643: Tidy the _set_tp function for RISC-V.
  
  - Use a constant for the offset instead of a magic number.
  - Use an addi instruction that writes to tp directly instead of a mv
    that writes the result of a compiler-generated addi.

Modified:
  stable/12/lib/libc/riscv/gen/_set_tp.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/lib/libc/riscv/gen/_set_tp.c
==============================================================================
--- stable/12/lib/libc/riscv/gen/_set_tp.c	Mon May 11 21:24:05 2020	(r360931)
+++ stable/12/lib/libc/riscv/gen/_set_tp.c	Mon May 11 21:24:22 2020	(r360932)
@@ -38,13 +38,14 @@ __FBSDID("$FreeBSD$");
 #include <string.h>
 #include <sys/types.h>
 
-#include <machine/sysarch.h>
-
 #include <stdlib.h>
 
+/* NB: size of 'struct tcb'. */
+#define	TP_OFFSET	(sizeof(void *) * 2)
+
 void
 _set_tp(void *tp)
 {
 
-	__asm __volatile("mv  tp, %0" :: "r"((char*)tp + 0x10));
+	__asm __volatile("addi  tp, %0, %1" :: "r" (tp), "I" (TP_OFFSET));
 }



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