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[Qemu-devel] [PULL 19/38] linux-user: Set r14 on exit from microblaze sy
From: |
riku . voipio |
Subject: |
[Qemu-devel] [PULL 19/38] linux-user: Set r14 on exit from microblaze syscall |
Date: |
Wed, 25 May 2016 13:31:51 +0300 |
From: Peter Maydell <address@hidden>
All syscall exits on microblaze result in r14 being equal to the
PC we return to, because the kernel syscall exit instruction "rtbd"
does this. (This is true even for sigreturn(); note that r14 is
not a userspace-usable register as the kernel may clobber it at
any point.)
Emulate the setting of r14 on exit; this isn't really a guest
visible change for valid guest code because r14 isn't reliably
observable anyway. However having the code and the comment helps
to explain why it's ok for the ERESTARTSYS handling not to undo
the changes to r14 that happen on syscall entry.
Signed-off-by: Peter Maydell <address@hidden>
Signed-off-by: Riku Voipio <address@hidden>
---
linux-user/main.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/linux-user/main.c b/linux-user/main.c
index 1f604a7..aa6b414 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -2983,6 +2983,13 @@ void cpu_loop(CPUMBState *env)
env->regs[10],
0, 0);
env->regs[3] = ret;
+ /* All syscall exits result in guest r14 being equal to the
+ * PC we return to, because the kernel syscall exit "rtbd" does
+ * this. (This is true even for sigreturn(); note that r14 is
+ * not a userspace-usable register, as the kernel may clobber it
+ * at any point.)
+ */
+ env->regs[14] = env->sregs[SR_PC];
break;
case EXCP_HW_EXCP:
env->regs[17] = env->sregs[SR_PC] + 4;
--
2.1.4
- [Qemu-devel] [PULL 08/38] linux-user: Support for restarting system calls for MIPS targets, (continued)
- [Qemu-devel] [PULL 08/38] linux-user: Support for restarting system calls for MIPS targets, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 10/38] linux-user: Support for restarting system calls for SPARC targets, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 11/38] linux-user: Support for restarting system calls for SH4 targets, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 13/38] linux-user: Support for restarting system calls for UniCore32 targets, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 12/38] linux-user: Support for restarting system calls for Alpha targets, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 14/38] linux-user: Support for restarting system calls for OpenRISC targets, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 17/38] linux-user: Support for restarting system calls for CRIS targets, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 09/38] linux-user: Support for restarting system calls for PPC targets, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 15/38] linux-user: Support for restarting system calls for M68K targets, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 20/38] linux-user: Support for restarting system calls for Microblaze targets, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 19/38] linux-user: Set r14 on exit from microblaze syscall,
riku . voipio <=
- [Qemu-devel] [PULL 16/38] linux-user: Support for restarting system calls for S390 targets, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 21/38] linux-user: Add debug code to exercise restarting system calls, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 18/38] linux-user: Support for restarting system calls for tilegx targets, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 23/38] linux-user: Use safe_syscall for read and write system calls, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 22/38] linux-user: Provide safe_syscall for fixing races between signals and syscalls, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 25/38] linux-user: Use safe_syscall for wait system calls, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 24/38] linux-user: Use safe_syscall for open and openat system calls, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 28/38] linux-user: Use safe_syscall for futex syscall, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 26/38] linux-user: Use safe_syscall for execve syscall, riku . voipio, 2016/05/25
- [Qemu-devel] [PULL 27/38] linux-user: Use safe_syscall for pselect, select syscalls, riku . voipio, 2016/05/25