From: Petar Jovanovic <mips32r2@gmail.com>
Date: Wed, 3 Apr 2019 17:38:08 +0000 (+0000)
Subject: mips32: pass correct syscall value to kernel in case of __NR_syscall
X-Git-Tag: VALGRIND_3_15_0~27
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=37f09ed248387ed3f4c7ba712fbc90e7468f6f4d;p=thirdparty%2Fvalgrind.git

mips32: pass correct syscall value to kernel in case of __NR_syscall

The syscall number has to be put in register v0 before call into the kernel.
This was omitted when system call is __NR_syscall (and when the syscall
argument is the system call number of interest).

Patch by Nikola Milutinovic.
---

diff --git a/coregrind/m_syswrap/syscall-mips32-linux.S b/coregrind/m_syswrap/syscall-mips32-linux.S
index 0bbfb2b5cd..51f6518ebc 100644
--- a/coregrind/m_syswrap/syscall-mips32-linux.S
+++ b/coregrind/m_syswrap/syscall-mips32-linux.S
@@ -112,7 +112,7 @@ ML_(do_syscall_for_client_WRK):
 
     lw $8, 48($29)    /* t0 == ThreadState */
 
-    lw $2, 52($29) /* v0 == syscallno */
+    lw $2, OFFSET_mips32_r2($8) /* v0 == guest_v0 */
     lw $4, OFFSET_mips32_r4($8)
     lw $5, OFFSET_mips32_r5($8)
     lw $6, OFFSET_mips32_r6($8)