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authorRussell King <rmk+kernel@arm.linux.org.uk>2012-09-30 09:03:44 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2012-09-30 09:03:44 +0100
commit648f3b69986b4d0ade57e59504a431b973ce2875 (patch)
tree6d0b6ccc6f243c1c582d52b88ab917eaffa022ba /arch/arm/kernel
parent8ee777fd915b0e36f35a430225729007a1df6441 (diff)
parent8ec58be9f3ff2ad4a4d7bde8f48b4a4c406768e7 (diff)
downloadop-kernel-dev-648f3b69986b4d0ade57e59504a431b973ce2875.zip
op-kernel-dev-648f3b69986b4d0ade57e59504a431b973ce2875.tar.gz
Merge branch 'hyp-boot-mode-rmk' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into devel-stable
Diffstat (limited to 'arch/arm/kernel')
-rw-r--r--arch/arm/kernel/Makefile2
-rw-r--r--arch/arm/kernel/head.S14
-rw-r--r--arch/arm/kernel/hyp-stub.S223
-rw-r--r--arch/arm/kernel/setup.c20
-rw-r--r--arch/arm/kernel/smp.c3
5 files changed, 259 insertions, 3 deletions
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 7ad2d5c..49b61a3 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -82,4 +82,6 @@ head-y := head$(MMUEXT).o
obj-$(CONFIG_DEBUG_LL) += debug.o
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
+obj-$(CONFIG_ARM_VIRT_EXT) += hyp-stub.o
+
extra-y := $(head-y) vmlinux.lds
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 3db960e..27093e4 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -83,8 +83,12 @@ ENTRY(stext)
THUMB( .thumb ) @ switch to Thumb now.
THUMB(1: )
- setmode PSR_F_BIT | PSR_I_BIT | SVC_MODE, r9 @ ensure svc mode
- @ and irqs disabled
+#ifdef CONFIG_ARM_VIRT_EXT
+ bl __hyp_stub_install
+#endif
+ @ ensure svc mode and all interrupts masked
+ safe_svcmode_maskall r9
+
mrc p15, 0, r9, c0, c0 @ get processor id
bl __lookup_processor_type @ r5=procinfo r9=cpuid
movs r10, r5 @ invalid processor (r5=0)?
@@ -326,7 +330,11 @@ ENTRY(secondary_startup)
* the processor type - there is no need to check the machine type
* as it has already been validated by the primary processor.
*/
- setmode PSR_F_BIT | PSR_I_BIT | SVC_MODE, r9
+#ifdef CONFIG_ARM_VIRT_EXT
+ bl __hyp_stub_install
+#endif
+ safe_svcmode_maskall r9
+
mrc p15, 0, r9, c0, c0 @ get processor id
bl __lookup_processor_type
movs r10, r5 @ invalid processor?
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
new file mode 100644
index 0000000..65b2417
--- /dev/null
+++ b/arch/arm/kernel/hyp-stub.S
@@ -0,0 +1,223 @@
+/*
+ * Copyright (c) 2012 Linaro Limited.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <linux/init.h>
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <asm/virt.h>
+
+#ifndef ZIMAGE
+/*
+ * For the kernel proper, we need to find out the CPU boot mode long after
+ * boot, so we need to store it in a writable variable.
+ *
+ * This is not in .bss, because we set it sufficiently early that the boot-time
+ * zeroing of .bss would clobber it.
+ */
+.data
+ENTRY(__boot_cpu_mode)
+ .long 0
+.text
+
+ /*
+ * Save the primary CPU boot mode. Requires 3 scratch registers.
+ */
+ .macro store_primary_cpu_mode reg1, reg2, reg3
+ mrs \reg1, cpsr
+ and \reg1, \reg1, #MODE_MASK
+ adr \reg2, .L__boot_cpu_mode_offset
+ ldr \reg3, [\reg2]
+ str \reg1, [\reg2, \reg3]
+ .endm
+
+ /*
+ * Compare the current mode with the one saved on the primary CPU.
+ * If they don't match, record that fact. The Z bit indicates
+ * if there's a match or not.
+ * Requires 3 additionnal scratch registers.
+ */
+ .macro compare_cpu_mode_with_primary mode, reg1, reg2, reg3
+ adr \reg2, .L__boot_cpu_mode_offset
+ ldr \reg3, [\reg2]
+ ldr \reg1, [\reg2, \reg3]
+ cmp \mode, \reg1 @ matches primary CPU boot mode?
+ orrne r7, r7, #BOOT_CPU_MODE_MISMATCH
+ strne r7, [r5, r6] @ record what happened and give up
+ .endm
+
+#else /* ZIMAGE */
+
+ .macro store_primary_cpu_mode reg1:req, reg2:req, reg3:req
+ .endm
+
+/*
+ * The zImage loader only runs on one CPU, so we don't bother with mult-CPU
+ * consistency checking:
+ */
+ .macro compare_cpu_mode_with_primary mode, reg1, reg2, reg3
+ cmp \mode, \mode
+ .endm
+
+#endif /* ZIMAGE */
+
+/*
+ * Hypervisor stub installation functions.
+ *
+ * These must be called with the MMU and D-cache off.
+ * They are not ABI compliant and are only intended to be called from the kernel
+ * entry points in head.S.
+ */
+@ Call this from the primary CPU
+ENTRY(__hyp_stub_install)
+ store_primary_cpu_mode r4, r5, r6
+ENDPROC(__hyp_stub_install)
+
+ @ fall through...
+
+@ Secondary CPUs should call here
+ENTRY(__hyp_stub_install_secondary)
+ mrs r4, cpsr
+ and r4, r4, #MODE_MASK
+
+ /*
+ * If the secondary has booted with a different mode, give up
+ * immediately.
+ */
+ compare_cpu_mode_with_primary r4, r5, r6, r7
+ bxne lr
+
+ /*
+ * Once we have given up on one CPU, we do not try to install the
+ * stub hypervisor on the remaining ones: because the saved boot mode
+ * is modified, it can't compare equal to the CPSR mode field any
+ * more.
+ *
+ * Otherwise...
+ */
+
+ cmp r4, #HYP_MODE
+ bxne lr @ give up if the CPU is not in HYP mode
+
+/*
+ * Configure HSCTLR to set correct exception endianness/instruction set
+ * state etc.
+ * Turn off all traps
+ * Eventually, CPU-specific code might be needed -- assume not for now
+ *
+ * This code relies on the "eret" instruction to synchronize the
+ * various coprocessor accesses.
+ */
+ @ Now install the hypervisor stub:
+ adr r7, __hyp_stub_vectors
+ mcr p15, 4, r7, c12, c0, 0 @ set hypervisor vector base (HVBAR)
+
+ @ Disable all traps, so we don't get any nasty surprise
+ mov r7, #0
+ mcr p15, 4, r7, c1, c1, 0 @ HCR
+ mcr p15, 4, r7, c1, c1, 2 @ HCPTR
+ mcr p15, 4, r7, c1, c1, 3 @ HSTR
+
+THUMB( orr r7, #(1 << 30) ) @ HSCTLR.TE
+#ifdef CONFIG_CPU_BIG_ENDIAN
+ orr r7, #(1 << 9) @ HSCTLR.EE
+#endif
+ mcr p15, 4, r7, c1, c0, 0 @ HSCTLR
+
+ mrc p15, 4, r7, c1, c1, 1 @ HDCR
+ and r7, #0x1f @ Preserve HPMN
+ mcr p15, 4, r7, c1, c1, 1 @ HDCR
+
+#if !defined(ZIMAGE) && defined(CONFIG_ARM_ARCH_TIMER)
+ @ make CNTP_* and CNTPCT accessible from PL1
+ mrc p15, 0, r7, c0, c1, 1 @ ID_PFR1
+ lsr r7, #16
+ and r7, #0xf
+ cmp r7, #1
+ bne 1f
+ mrc p15, 4, r7, c14, c1, 0 @ CNTHCTL
+ orr r7, r7, #3 @ PL1PCEN | PL1PCTEN
+ mcr p15, 4, r7, c14, c1, 0 @ CNTHCTL
+1:
+#endif
+
+ bic r7, r4, #MODE_MASK
+ orr r7, r7, #SVC_MODE
+THUMB( orr r7, r7, #PSR_T_BIT )
+ msr spsr_cxsf, r7 @ This is SPSR_hyp.
+
+ __MSR_ELR_HYP(14) @ msr elr_hyp, lr
+ __ERET @ return, switching to SVC mode
+ @ The boot CPU mode is left in r4.
+ENDPROC(__hyp_stub_install_secondary)
+
+__hyp_stub_do_trap:
+ cmp r0, #-1
+ mrceq p15, 4, r0, c12, c0, 0 @ get HVBAR
+ mcrne p15, 4, r0, c12, c0, 0 @ set HVBAR
+ __ERET
+ENDPROC(__hyp_stub_do_trap)
+
+/*
+ * __hyp_set_vectors: Call this after boot to set the initial hypervisor
+ * vectors as part of hypervisor installation. On an SMP system, this should
+ * be called on each CPU.
+ *
+ * r0 must be the physical address of the new vector table (which must lie in
+ * the bottom 4GB of physical address space.
+ *
+ * r0 must be 32-byte aligned.
+ *
+ * Before calling this, you must check that the stub hypervisor is installed
+ * everywhere, by waiting for any secondary CPUs to be brought up and then
+ * checking that BOOT_CPU_MODE_HAVE_HYP(__boot_cpu_mode) is true.
+ *
+ * If not, there is a pre-existing hypervisor, some CPUs failed to boot, or
+ * something else went wrong... in such cases, trying to install a new
+ * hypervisor is unlikely to work as desired.
+ *
+ * When you call into your shiny new hypervisor, sp_hyp will contain junk,
+ * so you will need to set that to something sensible at the new hypervisor's
+ * initialisation entry point.
+ */
+ENTRY(__hyp_get_vectors)
+ mov r0, #-1
+ENDPROC(__hyp_get_vectors)
+ @ fall through
+ENTRY(__hyp_set_vectors)
+ __HVC(0)
+ bx lr
+ENDPROC(__hyp_set_vectors)
+
+#ifndef ZIMAGE
+.align 2
+.L__boot_cpu_mode_offset:
+ .long __boot_cpu_mode - .
+#endif
+
+.align 5
+__hyp_stub_vectors:
+__hyp_stub_reset: W(b) .
+__hyp_stub_und: W(b) .
+__hyp_stub_svc: W(b) .
+__hyp_stub_pabort: W(b) .
+__hyp_stub_dabort: W(b) .
+__hyp_stub_trap: W(b) __hyp_stub_do_trap
+__hyp_stub_irq: W(b) .
+__hyp_stub_fiq: W(b) .
+ENDPROC(__hyp_stub_vectors)
+
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index a81dcec..04fd01f 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -55,6 +55,7 @@
#include <asm/traps.h>
#include <asm/unwind.h>
#include <asm/memblock.h>
+#include <asm/virt.h>
#if defined(CONFIG_DEPRECATED_PARAM_STRUCT)
#include "compat.h"
@@ -937,6 +938,21 @@ static int __init meminfo_cmp(const void *_a, const void *_b)
return cmp < 0 ? -1 : cmp > 0 ? 1 : 0;
}
+void __init hyp_mode_check(void)
+{
+#ifdef CONFIG_ARM_VIRT_EXT
+ if (is_hyp_mode_available()) {
+ pr_info("CPU: All CPU(s) started in HYP mode.\n");
+ pr_info("CPU: Virtualization extensions available.\n");
+ } else if (is_hyp_mode_mismatched()) {
+ pr_warn("CPU: WARNING: CPU(s) started in wrong/inconsistent modes (primary CPU mode 0x%x)\n",
+ __boot_cpu_mode & MODE_MASK);
+ pr_warn("CPU: This may indicate a broken bootloader or firmware.\n");
+ } else
+ pr_info("CPU: All CPU(s) started in SVC mode.\n");
+#endif
+}
+
void __init setup_arch(char **cmdline_p)
{
struct machine_desc *mdesc;
@@ -980,6 +996,10 @@ void __init setup_arch(char **cmdline_p)
if (is_smp())
smp_init_cpus();
#endif
+
+ if (!is_smp())
+ hyp_mode_check();
+
reserve_crashkernel();
tcm_init();
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 199558b..f34514a 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -42,6 +42,7 @@
#include <asm/ptrace.h>
#include <asm/localtimer.h>
#include <asm/smp_plat.h>
+#include <asm/virt.h>
/*
* as from 2.5, kernels no longer have an init_tasks structure
@@ -290,6 +291,8 @@ void __init smp_cpus_done(unsigned int max_cpus)
num_online_cpus(),
bogosum / (500000/HZ),
(bogosum / (5000/HZ)) % 100);
+
+ hyp_mode_check();
}
void __init smp_prepare_boot_cpu(void)
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