commit 8904976e8ca45be3ec75acc71f5d855ef671a079
author John A. Williams <john.williams@petalogix.com> Tue May 24 18:57:11 2011 +1000
committer Michal Simek <monstr@monstr.eu> Mon Jul 25 09:13:42 2011 +0200
tree 9c76c35266329312ace36ab009d686d5e2cd77f8
parent 5db34eb92f5699361de355dcd7958fdd2a9fb98a

microblaze: Unprivileged stream instruction awareness

Add cpuinfo support for the new MicroBlaze option permitting userspace
(unprivileged) access to the streaming instructions (FSL / AXI-stream).

Emit a noisy warning at bootup if this is enabled, because bad user code
can potentially lockup the CPU.

Signed-off-by: John A. Williams <john.williams@petalogix.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>

arch/microblaze/kernel/cpu/cpuinfo-pvr-full.c

diff --git a/arch/microblaze/kernel/cpu/cpuinfo-pvr-full.c b/arch/microblaze/kernel/cpu/cpuinfo-pvr-full.c
index f70a604..916aaed 100644
--- a/arch/microblaze/kernel/cpu/cpuinfo-pvr-full.c
+++ b/arch/microblaze/kernel/cpu/cpuinfo-pvr-full.c
@@ -72,6 +72,7 @@
 	CI(pvr_user2, USER2);
 
 	CI(mmu, USE_MMU);
+	CI(mmu_privins, MMU_PRIVINS);
 	CI(endian, ENDIAN);
 
 	CI(use_icache, USE_ICACHE);

arch/microblaze/kernel/cpu/cpuinfo-static.c

diff --git a/arch/microblaze/kernel/cpu/cpuinfo-static.c b/arch/microblaze/kernel/cpu/cpuinfo-static.c
index b16b994..592bb2e 100644
--- a/arch/microblaze/kernel/cpu/cpuinfo-static.c
+++ b/arch/microblaze/kernel/cpu/cpuinfo-static.c
@@ -119,6 +119,7 @@
 	ci->pvr_user2 = fcpu(cpu, "xlnx,pvr-user2");
 
 	ci->mmu = fcpu(cpu, "xlnx,use-mmu");
+	ci->mmu_privins = fcpu(cpu, "xlnx,mmu-privileged-instr");
 	ci->endian = fcpu(cpu, "xlnx,endianness");
 
 	ci->ver_code = 0;

arch/microblaze/kernel/cpu/cpuinfo.c

diff --git a/arch/microblaze/kernel/cpu/cpuinfo.c b/arch/microblaze/kernel/cpu/cpuinfo.c
index c1640c5..44394d8 100644
--- a/arch/microblaze/kernel/cpu/cpuinfo.c
+++ b/arch/microblaze/kernel/cpu/cpuinfo.c
@@ -88,4 +88,8 @@
 		printk(KERN_WARNING "%s: Unsupported PVR setting\n", __func__);
 		set_cpuinfo_static(&cpuinfo, cpu);
 	}
+
+	if (cpuinfo.mmu_privins)
+		printk(KERN_WARNING "%s: Stream instructions enabled"
+			" - USERSPACE CAN LOCK THIS KERNEL!\n", __func__);
 }

arch/microblaze/kernel/cpu/mb.c

diff --git a/arch/microblaze/kernel/cpu/mb.c b/arch/microblaze/kernel/cpu/mb.c
index b4048af..0afebae 100644
--- a/arch/microblaze/kernel/cpu/mb.c
+++ b/arch/microblaze/kernel/cpu/mb.c
@@ -97,6 +97,10 @@
 		(cpuinfo.use_exc & PVR2_FPU_EXC_MASK) ? "fpu " : "",
 		(cpuinfo.use_exc & PVR2_USE_FSL_EXC) ? "fsl " : "");
 
+	count += seq_printf(m,
+			"Stream-insns:\t%sprivileged\n",
+			cpuinfo.mmu_privins ? "un" : "");
+
 	if (cpuinfo.use_icache)
 		count += seq_printf(m,
 				"Icache:\t\t%ukB\tline length:\t%dB\n",