forked from Minki/linux
6849b5eba1
Updates to the Generic Timer architecture allow ID_PFR1.GenTimer to
have values other than 0 or 1 while still preserving backward
compatibility. At the moment, Linux is quite strict in the way it
handles this field at early boot and will not configure arch timer if
it doesn't find the value 1.
Since here use ubfx for arch timer version extraction (hyb-stub build
with -march=armv7-a, so it is safe)
To help backports (even though the code was correct at the time of writing)
Fixes: 8ec58be9f3 ("ARM: virt: arch_timers: enable access to physical timers")
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
272 lines
6.8 KiB
ArmAsm
272 lines
6.8 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Copyright (c) 2012 Linaro Limited.
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*/
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#include <linux/init.h>
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#include <linux/irqchip/arm-gic-v3.h>
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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#include <asm/virt.h>
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#ifndef ZIMAGE
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/*
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* For the kernel proper, we need to find out the CPU boot mode long after
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* boot, so we need to store it in a writable variable.
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*
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* This is not in .bss, because we set it sufficiently early that the boot-time
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* zeroing of .bss would clobber it.
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*/
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.data
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.align 2
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ENTRY(__boot_cpu_mode)
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.long 0
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.text
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/*
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* Save the primary CPU boot mode. Requires 3 scratch registers.
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*/
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.macro store_primary_cpu_mode reg1, reg2, reg3
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mrs \reg1, cpsr
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and \reg1, \reg1, #MODE_MASK
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adr \reg2, .L__boot_cpu_mode_offset
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ldr \reg3, [\reg2]
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str \reg1, [\reg2, \reg3]
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.endm
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/*
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* Compare the current mode with the one saved on the primary CPU.
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* If they don't match, record that fact. The Z bit indicates
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* if there's a match or not.
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* Requires 3 additionnal scratch registers.
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*/
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.macro compare_cpu_mode_with_primary mode, reg1, reg2, reg3
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adr \reg2, .L__boot_cpu_mode_offset
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ldr \reg3, [\reg2]
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ldr \reg1, [\reg2, \reg3]
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cmp \mode, \reg1 @ matches primary CPU boot mode?
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orrne \reg1, \reg1, #BOOT_CPU_MODE_MISMATCH
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strne \reg1, [\reg2, \reg3] @ record what happened and give up
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.endm
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#else /* ZIMAGE */
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.macro store_primary_cpu_mode reg1:req, reg2:req, reg3:req
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.endm
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/*
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* The zImage loader only runs on one CPU, so we don't bother with mult-CPU
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* consistency checking:
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*/
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.macro compare_cpu_mode_with_primary mode, reg1, reg2, reg3
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cmp \mode, \mode
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.endm
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#endif /* ZIMAGE */
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/*
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* Hypervisor stub installation functions.
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*
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* These must be called with the MMU and D-cache off.
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* They are not ABI compliant and are only intended to be called from the kernel
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* entry points in head.S.
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*/
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@ Call this from the primary CPU
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ENTRY(__hyp_stub_install)
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store_primary_cpu_mode r4, r5, r6
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ENDPROC(__hyp_stub_install)
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@ fall through...
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@ Secondary CPUs should call here
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ENTRY(__hyp_stub_install_secondary)
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mrs r4, cpsr
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and r4, r4, #MODE_MASK
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/*
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* If the secondary has booted with a different mode, give up
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* immediately.
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*/
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compare_cpu_mode_with_primary r4, r5, r6, r7
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retne lr
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/*
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* Once we have given up on one CPU, we do not try to install the
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* stub hypervisor on the remaining ones: because the saved boot mode
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* is modified, it can't compare equal to the CPSR mode field any
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* more.
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*
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* Otherwise...
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*/
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cmp r4, #HYP_MODE
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retne lr @ give up if the CPU is not in HYP mode
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/*
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* Configure HSCTLR to set correct exception endianness/instruction set
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* state etc.
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* Turn off all traps
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* Eventually, CPU-specific code might be needed -- assume not for now
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*
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* This code relies on the "eret" instruction to synchronize the
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* various coprocessor accesses. This is done when we switch to SVC
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* (see safe_svcmode_maskall).
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*/
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@ Now install the hypervisor stub:
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W(adr) r7, __hyp_stub_vectors
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mcr p15, 4, r7, c12, c0, 0 @ set hypervisor vector base (HVBAR)
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@ Disable all traps, so we don't get any nasty surprise
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mov r7, #0
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mcr p15, 4, r7, c1, c1, 0 @ HCR
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mcr p15, 4, r7, c1, c1, 2 @ HCPTR
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mcr p15, 4, r7, c1, c1, 3 @ HSTR
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THUMB( orr r7, #(1 << 30) ) @ HSCTLR.TE
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ARM_BE8(orr r7, r7, #(1 << 25)) @ HSCTLR.EE
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mcr p15, 4, r7, c1, c0, 0 @ HSCTLR
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mrc p15, 4, r7, c1, c1, 1 @ HDCR
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and r7, #0x1f @ Preserve HPMN
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mcr p15, 4, r7, c1, c1, 1 @ HDCR
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@ Make sure NS-SVC is initialised appropriately
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mrc p15, 0, r7, c1, c0, 0 @ SCTLR
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orr r7, #(1 << 5) @ CP15 barriers enabled
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bic r7, #(3 << 7) @ Clear SED/ITD for v8 (RES0 for v7)
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bic r7, #(3 << 19) @ WXN and UWXN disabled
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mcr p15, 0, r7, c1, c0, 0 @ SCTLR
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mrc p15, 0, r7, c0, c0, 0 @ MIDR
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mcr p15, 4, r7, c0, c0, 0 @ VPIDR
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mrc p15, 0, r7, c0, c0, 5 @ MPIDR
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mcr p15, 4, r7, c0, c0, 5 @ VMPIDR
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#if !defined(ZIMAGE) && defined(CONFIG_ARM_ARCH_TIMER)
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@ make CNTP_* and CNTPCT accessible from PL1
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mrc p15, 0, r7, c0, c1, 1 @ ID_PFR1
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ubfx r7, r7, #16, #4
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teq r7, #0
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beq 1f
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mrc p15, 4, r7, c14, c1, 0 @ CNTHCTL
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orr r7, r7, #3 @ PL1PCEN | PL1PCTEN
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mcr p15, 4, r7, c14, c1, 0 @ CNTHCTL
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mov r7, #0
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mcrr p15, 4, r7, r7, c14 @ CNTVOFF
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@ Disable virtual timer in case it was counting
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mrc p15, 0, r7, c14, c3, 1 @ CNTV_CTL
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bic r7, #1 @ Clear ENABLE
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mcr p15, 0, r7, c14, c3, 1 @ CNTV_CTL
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1:
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#endif
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#ifdef CONFIG_ARM_GIC_V3
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@ Check whether GICv3 system registers are available
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mrc p15, 0, r7, c0, c1, 1 @ ID_PFR1
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ubfx r7, r7, #28, #4
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teq r7, #0
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beq 2f
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@ Enable system register accesses
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mrc p15, 4, r7, c12, c9, 5 @ ICC_HSRE
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orr r7, r7, #(ICC_SRE_EL2_ENABLE | ICC_SRE_EL2_SRE)
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mcr p15, 4, r7, c12, c9, 5 @ ICC_HSRE
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isb
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@ SRE bit could be forced to 0 by firmware.
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@ Check whether it sticks before accessing any other sysreg
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mrc p15, 4, r7, c12, c9, 5 @ ICC_HSRE
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tst r7, #ICC_SRE_EL2_SRE
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beq 2f
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mov r7, #0
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mcr p15, 4, r7, c12, c11, 0 @ ICH_HCR
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2:
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#endif
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bx lr @ The boot CPU mode is left in r4.
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ENDPROC(__hyp_stub_install_secondary)
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__hyp_stub_do_trap:
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teq r0, #HVC_SET_VECTORS
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bne 1f
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mcr p15, 4, r1, c12, c0, 0 @ set HVBAR
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b __hyp_stub_exit
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1: teq r0, #HVC_SOFT_RESTART
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bne 1f
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bx r1
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1: teq r0, #HVC_RESET_VECTORS
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beq __hyp_stub_exit
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ldr r0, =HVC_STUB_ERR
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__ERET
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__hyp_stub_exit:
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mov r0, #0
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__ERET
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ENDPROC(__hyp_stub_do_trap)
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/*
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* __hyp_set_vectors: Call this after boot to set the initial hypervisor
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* vectors as part of hypervisor installation. On an SMP system, this should
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* be called on each CPU.
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*
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* r0 must be the physical address of the new vector table (which must lie in
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* the bottom 4GB of physical address space.
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*
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* r0 must be 32-byte aligned.
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*
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* Before calling this, you must check that the stub hypervisor is installed
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* everywhere, by waiting for any secondary CPUs to be brought up and then
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* checking that BOOT_CPU_MODE_HAVE_HYP(__boot_cpu_mode) is true.
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*
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* If not, there is a pre-existing hypervisor, some CPUs failed to boot, or
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* something else went wrong... in such cases, trying to install a new
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* hypervisor is unlikely to work as desired.
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*
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* When you call into your shiny new hypervisor, sp_hyp will contain junk,
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* so you will need to set that to something sensible at the new hypervisor's
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* initialisation entry point.
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*/
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ENTRY(__hyp_set_vectors)
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mov r1, r0
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mov r0, #HVC_SET_VECTORS
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__HVC(0)
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ret lr
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ENDPROC(__hyp_set_vectors)
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ENTRY(__hyp_soft_restart)
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mov r1, r0
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mov r0, #HVC_SOFT_RESTART
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__HVC(0)
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ret lr
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ENDPROC(__hyp_soft_restart)
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ENTRY(__hyp_reset_vectors)
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mov r0, #HVC_RESET_VECTORS
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__HVC(0)
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ret lr
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ENDPROC(__hyp_reset_vectors)
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#ifndef ZIMAGE
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.align 2
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.L__boot_cpu_mode_offset:
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.long __boot_cpu_mode - .
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#endif
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.align 5
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ENTRY(__hyp_stub_vectors)
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__hyp_stub_reset: W(b) .
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__hyp_stub_und: W(b) .
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__hyp_stub_svc: W(b) .
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__hyp_stub_pabort: W(b) .
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__hyp_stub_dabort: W(b) .
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__hyp_stub_trap: W(b) __hyp_stub_do_trap
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__hyp_stub_irq: W(b) .
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__hyp_stub_fiq: W(b) .
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ENDPROC(__hyp_stub_vectors)
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