[src/trunk]: src/sys/arch/arc/arc Make sure to preserve MIPS_CURLWP (t8) regi...

[tsutsui <tsutsui%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/ff81c0e2742d
branches:  trunk
changeset: 972547:ff81c0e2742d
user:      tsutsui <tsutsui%NetBSD.org@localhost>
date:      Fri May 29 23:02:51 2020 +0000

description:
Make sure to preserve MIPS_CURLWP (t8) register from ARC BIOS calls.

Fixes silent hangup right after starting a kernel on my
Express5800/230 R4400 PCI (finally I've repaired its PSU and RTC).
Reviewed by soda@.  Maybe other ARC machines are also affected.

Note GXemul was not affected by this problem because it doesn't
have actual ARC BIOS ROM and emulates ARC functions internally.

Should be pulled up to at least netbsd-9.

diffstat:

 sys/arch/arc/arc/arcbios.c |  65 +++++++++++++++++++++++++++++++++++----------
 1 files changed, 50 insertions(+), 15 deletions(-)

diffs (98 lines):

diff -r 351b8c0c65da -r ff81c0e2742d sys/arch/arc/arc/arcbios.c
--- a/sys/arch/arc/arc/arcbios.c        Fri May 29 22:40:15 2020 +0000
+++ b/sys/arch/arc/arc/arcbios.c        Fri May 29 23:02:51 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: arcbios.c,v 1.17 2009/11/27 03:23:04 rmind Exp $       */
+/*     $NetBSD: arcbios.c,v 1.18 2020/05/29 23:02:51 tsutsui Exp $     */
 /*     $OpenBSD: arcbios.c,v 1.3 1998/06/06 06:33:33 mickey Exp $      */
 
 /*-
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: arcbios.c,v 1.17 2009/11/27 03:23:04 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: arcbios.c,v 1.18 2020/05/29 23:02:51 tsutsui Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -39,7 +39,9 @@
 #include <sys/kcore.h>
 #include <uvm/uvm_extern.h>
 #include <dev/cons.h>
+#include <machine/asm.h>
 #include <machine/cpu.h>
+#include <machine/regdef.h>
 #include <arc/arc/arcbios.h>
 
 int Bios_Read(int, char *, int, int *);
@@ -68,23 +70,56 @@
 
 /*
  *     ARC Bios trampoline code.
+ *     Note we have to save/restore reserved MIPS_CURLWP register.
  */
-#define ARC_Call(Name,Offset)  \
-__asm("\n"                     \
-"      .text\n"                \
-"      .ent    " #Name "\n"    \
-"      .align  3\n"            \
-"      .set    noreorder\n"    \
-"      .globl  " #Name "\n"    \
-#Name":\n"                     \
-"      lw      $2, 0x80001020\n"\
-"      lw      $2," #Offset "($2)\n"\
-"      jr      $2\n"           \
-"      nop\n"                  \
+#define ARC_Call(Name,Offset)                                  \
+__asm("\n"                                                     \
+"      .text\n"                                                \
+"      .ent    " #Name "\n"                                    \
+"      .align  3\n"                                            \
+"      .set    noreorder\n"                                    \
+"      .globl  " #Name "\n"                                    \
+#Name":\n"                                                     \
+"      subu    $29, " ___STRING(CALLFRAME_SIZ) "\n"            \
+"      sw      $31, " ___STRING(CALLFRAME_RA) "($29)\n"        \
+"      sw      $16, " ___STRING(CALLFRAME_SP) "($29)\n"        \
+"      lw      $2, 0x80001020\n"                               \
+"      lw      $2," #Offset "($2)\n"                           \
+"      jalr    $2\n"                                           \
+"       move   $16, " ___STRING(MIPS_CURLWP) "\n"              \
+"      move    " ___STRING(MIPS_CURLWP) ", $16\n"              \
+"      lw      $31, " ___STRING(CALLFRAME_RA) "($29)\n"        \
+"      lw      $16, " ___STRING(CALLFRAME_SP) "($29)\n"        \
+"      j       $31\n"                                          \
+"       addu   $29, " ___STRING(CALLFRAME_SIZ) "\n"            \
+"      .end    " #Name "\n"    );
+
+#define ARC_Call5(Name,Offset)                                 \
+__asm("\n"                                                     \
+"      .text\n"                                                \
+"      .ent    " #Name "\n"                                    \
+"      .align  3\n"                                            \
+"      .set    noreorder\n"                                    \
+"      .globl  " #Name "\n"                                    \
+#Name":\n"                                                     \
+"      subu    $29, " ___STRING(CALLFRAME_SIZ + 4) "\n"        \
+"      sw      $31, " ___STRING(CALLFRAME_RA + 4) "($29)\n"    \
+"      sw      $16, " ___STRING(CALLFRAME_SP + 4) "($29)\n"    \
+"      lw      $12, " ___STRING(CALLFRAME_SIZ + 4 + 16) "($29)\n" \
+"      sw      $12, 16($29)\n"                                 \
+"      lw      $2, 0x80001020\n"                               \
+"      lw      $2," #Offset "($2)\n"                           \
+"      jalr    $2\n"                                           \
+"       move   $16, " ___STRING(MIPS_CURLWP) "\n"              \
+"      move    " ___STRING(MIPS_CURLWP) ", $16\n"              \
+"      lw      $31, " ___STRING(CALLFRAME_RA + 4) "($29)\n"    \
+"      lw      $16, " ___STRING(CALLFRAME_SP + 4) "($29)\n"    \
+"      j       $31\n"                                          \
+"       addu   $29, " ___STRING(CALLFRAME_SIZ + 4) "\n"        \
 "      .end    " #Name "\n"    );
 
 ARC_Call(Bios_Load,                    0x00);
-ARC_Call(Bios_Invoke,                  0x04);
+ARC_Call5(Bios_Invoke,                 0x04);
 ARC_Call(Bios_Execute,                 0x08);
 ARC_Call(Bios_Halt,                    0x0c);
 ARC_Call(Bios_PowerDown,               0x10);