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microblaze: Unprivileged stream instruction awareness

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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>
This commit is contained in:
John A. Williams
2011-05-24 18:57:11 +10:00
committed by Michal Simek
parent 5db34eb92f
commit 8904976e8c
6 changed files with 13 additions and 1 deletions
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1
arch/microblaze/kernel/cpu/cpuinfo-pvr-full.c
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@@ -72,6 +72,7 @@ void set_cpuinfo_pvr_full(struct cpuinfo *ci, struct device_node *cpu)
CI(pvr_user2, USER2);
CI(mmu, USE_MMU);
CI(mmu_privins, MMU_PRIVINS);
CI(endian, ENDIAN);
CI(use_icache, USE_ICACHE);

1
arch/microblaze/kernel/cpu/cpuinfo-static.c
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@@ -119,6 +119,7 @@ void __init set_cpuinfo_static(struct cpuinfo *ci, struct device_node *cpu)
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;

4
arch/microblaze/kernel/cpu/cpuinfo.c
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@@ -88,4 +88,8 @@ void __init setup_cpuinfo(void)
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__);
}

4
arch/microblaze/kernel/cpu/mb.c
View File

@@ -97,6 +97,10 @@ static int show_cpuinfo(struct seq_file *m, void *v)
(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",