linux_dsm_epyc7002/arch/arm/kernel/hyp-stub.S
Marc Zyngier 15ff9a39cd arm: Remove the ability to set HYP vectors outside of the decompressor
Although we have to bounce between HYP and SVC to decompress and
relocate the kernel, we don't need to be able to use it in the
kernel itself. So let's drop the functionnality.

Since the vectors are never changed, there is no need to reset them
either, and nobody calls that stub anyway. The last function
(SOFT_RESTART) is still present in order to support kexec.

Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-24 10:56:05 +00:00

249 lines
6.0 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (c) 2012 Linaro Limited.
*/
#include <linux/init.h>
#include <linux/irqchip/arm-gic-v3.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
.align 2
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 \reg1, \reg1, #BOOT_CPU_MODE_MISMATCH
strne \reg1, [\reg2, \reg3] @ 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
retne 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
retne 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. This is done when we switch to SVC
* (see safe_svcmode_maskall).
*/
@ Now install the hypervisor stub:
W(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
ARM_BE8(orr r7, r7, #(1 << 25)) @ HSCTLR.EE
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
@ Make sure NS-SVC is initialised appropriately
mrc p15, 0, r7, c1, c0, 0 @ SCTLR
orr r7, #(1 << 5) @ CP15 barriers enabled
bic r7, #(3 << 7) @ Clear SED/ITD for v8 (RES0 for v7)
bic r7, #(3 << 19) @ WXN and UWXN disabled
mcr p15, 0, r7, c1, c0, 0 @ SCTLR
mrc p15, 0, r7, c0, c0, 0 @ MIDR
mcr p15, 4, r7, c0, c0, 0 @ VPIDR
mrc p15, 0, r7, c0, c0, 5 @ MPIDR
mcr p15, 4, r7, c0, c0, 5 @ VMPIDR
#if !defined(ZIMAGE) && defined(CONFIG_ARM_ARCH_TIMER)
@ make CNTP_* and CNTPCT accessible from PL1
mrc p15, 0, r7, c0, c1, 1 @ ID_PFR1
ubfx r7, r7, #16, #4
teq r7, #0
beq 1f
mrc p15, 4, r7, c14, c1, 0 @ CNTHCTL
orr r7, r7, #3 @ PL1PCEN | PL1PCTEN
mcr p15, 4, r7, c14, c1, 0 @ CNTHCTL
mov r7, #0
mcrr p15, 4, r7, r7, c14 @ CNTVOFF
@ Disable virtual timer in case it was counting
mrc p15, 0, r7, c14, c3, 1 @ CNTV_CTL
bic r7, #1 @ Clear ENABLE
mcr p15, 0, r7, c14, c3, 1 @ CNTV_CTL
1:
#endif
#ifdef CONFIG_ARM_GIC_V3
@ Check whether GICv3 system registers are available
mrc p15, 0, r7, c0, c1, 1 @ ID_PFR1
ubfx r7, r7, #28, #4
teq r7, #0
beq 2f
@ Enable system register accesses
mrc p15, 4, r7, c12, c9, 5 @ ICC_HSRE
orr r7, r7, #(ICC_SRE_EL2_ENABLE | ICC_SRE_EL2_SRE)
mcr p15, 4, r7, c12, c9, 5 @ ICC_HSRE
isb
@ SRE bit could be forced to 0 by firmware.
@ Check whether it sticks before accessing any other sysreg
mrc p15, 4, r7, c12, c9, 5 @ ICC_HSRE
tst r7, #ICC_SRE_EL2_SRE
beq 2f
mov r7, #0
mcr p15, 4, r7, c12, c11, 0 @ ICH_HCR
2:
#endif
bx lr @ The boot CPU mode is left in r4.
ENDPROC(__hyp_stub_install_secondary)
__hyp_stub_do_trap:
#ifdef ZIMAGE
teq r0, #HVC_SET_VECTORS
bne 1f
/* Only the ZIMAGE stubs can change the HYP vectors */
mcr p15, 4, r1, c12, c0, 0 @ set HVBAR
b __hyp_stub_exit
#endif
1: teq r0, #HVC_SOFT_RESTART
bne 2f
bx r1
2: ldr r0, =HVC_STUB_ERR
__ERET
__hyp_stub_exit:
mov r0, #0
__ERET
ENDPROC(__hyp_stub_do_trap)
/*
* __hyp_set_vectors is only used when ZIMAGE must bounce between HYP
* and SVC. For the kernel itself, the vectors are set once and for
* all by the stubs.
*/
ENTRY(__hyp_set_vectors)
mov r1, r0
mov r0, #HVC_SET_VECTORS
__HVC(0)
ret lr
ENDPROC(__hyp_set_vectors)
ENTRY(__hyp_soft_restart)
mov r1, r0
mov r0, #HVC_SOFT_RESTART
__HVC(0)
ret lr
ENDPROC(__hyp_soft_restart)
#ifndef ZIMAGE
.align 2
.L__boot_cpu_mode_offset:
.long __boot_cpu_mode - .
#endif
.align 5
ENTRY(__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)