Peter Hoyes 53b40e8d54 armv8: Disable pointer authentication traps for EL1
The use of ARMv8.3 pointer authentication (PAuth) is governed by fields
in HCR_EL2, which trigger a 'trap to EL2' if not enabled. The reset
value of these fields is 'architecturally unknown' so we must ensure
that the fields are enabled (to disable the traps) if we are entering
the kernel at EL1.

The APK field disables PAuth instruction traps and the API field
disables PAuth register traps

Add code to disable the traps in armv8_switch_to_el1_m. Prior to doing
so, it checks fields in the ID_AA64ISAR1_EL1 register to ensure pointer
authentication is supported by the hardware.

The runtime checks require a second temporary register, so add this to
the EL1 transition macro signature and update 2 call sites.

Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
2021-09-02 10:17:45 -04:00

363 lines
9.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0+ */
/*
* include/asm-arm/macro.h
*
* Copyright (C) 2009 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
*/
#ifndef __ASM_ARM_MACRO_H__
#define __ASM_ARM_MACRO_H__
#ifdef CONFIG_ARM64
#include <asm/system.h>
#endif
#ifdef __ASSEMBLY__
/*
* These macros provide a convenient way to write 8, 16 and 32 bit data
* to any address.
* Registers r4 and r5 are used, any data in these registers are
* overwritten by the macros.
* The macros are valid for any ARM architecture, they do not implement
* any memory barriers so caution is recommended when using these when the
* caches are enabled or on a multi-core system.
*/
.macro write32, addr, data
ldr r4, =\addr
ldr r5, =\data
str r5, [r4]
.endm
.macro write16, addr, data
ldr r4, =\addr
ldrh r5, =\data
strh r5, [r4]
.endm
.macro write8, addr, data
ldr r4, =\addr
ldrb r5, =\data
strb r5, [r4]
.endm
/*
* This macro generates a loop that can be used for delays in the code.
* Register r4 is used, any data in this register is overwritten by the
* macro.
* The macro is valid for any ARM architeture. The actual time spent in the
* loop will vary from CPU to CPU though.
*/
.macro wait_timer, time
ldr r4, =\time
1:
nop
subs r4, r4, #1
bcs 1b
.endm
#ifdef CONFIG_ARM64
/*
* Register aliases.
*/
lr .req x30
/*
* Branch according to exception level
*/
.macro switch_el, xreg, el3_label, el2_label, el1_label
mrs \xreg, CurrentEL
cmp \xreg, 0xc
b.eq \el3_label
cmp \xreg, 0x8
b.eq \el2_label
cmp \xreg, 0x4
b.eq \el1_label
.endm
/*
* Branch if we are not in the highest exception level
*/
.macro branch_if_not_highest_el, xreg, label
switch_el \xreg, 3f, 2f, 1f
2: mrs \xreg, ID_AA64PFR0_EL1
and \xreg, \xreg, #(ID_AA64PFR0_EL1_EL3)
cbnz \xreg, \label
b 3f
1: mrs \xreg, ID_AA64PFR0_EL1
and \xreg, \xreg, #(ID_AA64PFR0_EL1_EL3 | ID_AA64PFR0_EL1_EL2)
cbnz \xreg, \label
3:
.endm
/*
* Branch if current processor is a Cortex-A57 core.
*/
.macro branch_if_a57_core, xreg, a57_label
mrs \xreg, midr_el1
lsr \xreg, \xreg, #4
and \xreg, \xreg, #0x00000FFF
cmp \xreg, #0xD07 /* Cortex-A57 MPCore processor. */
b.eq \a57_label
.endm
/*
* Branch if current processor is a Cortex-A53 core.
*/
.macro branch_if_a53_core, xreg, a53_label
mrs \xreg, midr_el1
lsr \xreg, \xreg, #4
and \xreg, \xreg, #0x00000FFF
cmp \xreg, #0xD03 /* Cortex-A53 MPCore processor. */
b.eq \a53_label
.endm
/*
* Branch if current processor is a slave,
* choose processor with all zero affinity value as the master.
*/
.macro branch_if_slave, xreg, slave_label
#ifdef CONFIG_ARMV8_MULTIENTRY
/* NOTE: MPIDR handling will be erroneous on multi-cluster machines */
mrs \xreg, mpidr_el1
tst \xreg, #0xff /* Test Affinity 0 */
b.ne \slave_label
lsr \xreg, \xreg, #8
tst \xreg, #0xff /* Test Affinity 1 */
b.ne \slave_label
lsr \xreg, \xreg, #8
tst \xreg, #0xff /* Test Affinity 2 */
b.ne \slave_label
lsr \xreg, \xreg, #16
tst \xreg, #0xff /* Test Affinity 3 */
b.ne \slave_label
#endif
.endm
/*
* Branch if current processor is a master,
* choose processor with all zero affinity value as the master.
*/
.macro branch_if_master, xreg1, xreg2, master_label
#ifdef CONFIG_ARMV8_MULTIENTRY
/* NOTE: MPIDR handling will be erroneous on multi-cluster machines */
mrs \xreg1, mpidr_el1
lsr \xreg2, \xreg1, #32
lsl \xreg2, \xreg2, #32
lsl \xreg1, \xreg1, #40
lsr \xreg1, \xreg1, #40
orr \xreg1, \xreg1, \xreg2
cbz \xreg1, \master_label
#else
b \master_label
#endif
.endm
/*
* Switch from EL3 to EL2 for ARMv8
* @ep: kernel entry point
* @flag: The execution state flag for lower exception
* level, ES_TO_AARCH64 or ES_TO_AARCH32
* @tmp: temporary register
*
* For loading 32-bit OS, x1 is machine nr and x2 is ftaddr.
* For loading 64-bit OS, x0 is physical address to the FDT blob.
* They will be passed to the guest.
*/
.macro armv8_switch_to_el2_m, ep, flag, tmp
msr cptr_el3, xzr /* Disable coprocessor traps to EL3 */
mov \tmp, #CPTR_EL2_RES1
msr cptr_el2, \tmp /* Disable coprocessor traps to EL2 */
/* Initialize Generic Timers */
msr cntvoff_el2, xzr
/* Initialize SCTLR_EL2
*
* setting RES1 bits (29,28,23,22,18,16,11,5,4) to 1
* and RES0 bits (31,30,27,26,24,21,20,17,15-13,10-6) +
* EE,WXN,I,SA,C,A,M to 0
*/
ldr \tmp, =(SCTLR_EL2_RES1 | SCTLR_EL2_EE_LE |\
SCTLR_EL2_WXN_DIS | SCTLR_EL2_ICACHE_DIS |\
SCTLR_EL2_SA_DIS | SCTLR_EL2_DCACHE_DIS |\
SCTLR_EL2_ALIGN_DIS | SCTLR_EL2_MMU_DIS)
msr sctlr_el2, \tmp
mov \tmp, sp
msr sp_el2, \tmp /* Migrate SP */
mrs \tmp, vbar_el3
msr vbar_el2, \tmp /* Migrate VBAR */
/* Check switch to AArch64 EL2 or AArch32 Hypervisor mode */
cmp \flag, #ES_TO_AARCH32
b.eq 1f
/*
* The next lower exception level is AArch64, 64bit EL2 | HCE |
* RES1 (Bits[5:4]) | Non-secure EL0/EL1.
* and the SMD depends on requirements.
*/
#ifdef CONFIG_ARMV8_PSCI
ldr \tmp, =(SCR_EL3_RW_AARCH64 | SCR_EL3_HCE_EN |\
SCR_EL3_RES1 | SCR_EL3_NS_EN)
#else
ldr \tmp, =(SCR_EL3_RW_AARCH64 | SCR_EL3_HCE_EN |\
SCR_EL3_SMD_DIS | SCR_EL3_RES1 |\
SCR_EL3_NS_EN)
#endif
#ifdef CONFIG_ARMV8_EA_EL3_FIRST
orr \tmp, \tmp, #SCR_EL3_EA_EN
#endif
msr scr_el3, \tmp
/* Return to the EL2_SP2 mode from EL3 */
ldr \tmp, =(SPSR_EL_DEBUG_MASK | SPSR_EL_SERR_MASK |\
SPSR_EL_IRQ_MASK | SPSR_EL_FIQ_MASK |\
SPSR_EL_M_AARCH64 | SPSR_EL_M_EL2H)
msr spsr_el3, \tmp
msr elr_el3, \ep
eret
1:
/*
* The next lower exception level is AArch32, 32bit EL2 | HCE |
* SMD | RES1 (Bits[5:4]) | Non-secure EL0/EL1.
*/
ldr \tmp, =(SCR_EL3_RW_AARCH32 | SCR_EL3_HCE_EN |\
SCR_EL3_SMD_DIS | SCR_EL3_RES1 |\
SCR_EL3_NS_EN)
msr scr_el3, \tmp
/* Return to AArch32 Hypervisor mode */
ldr \tmp, =(SPSR_EL_END_LE | SPSR_EL_ASYN_MASK |\
SPSR_EL_IRQ_MASK | SPSR_EL_FIQ_MASK |\
SPSR_EL_T_A32 | SPSR_EL_M_AARCH32 |\
SPSR_EL_M_HYP)
msr spsr_el3, \tmp
msr elr_el3, \ep
eret
.endm
/*
* Switch from EL2 to EL1 for ARMv8
* @ep: kernel entry point
* @flag: The execution state flag for lower exception
* level, ES_TO_AARCH64 or ES_TO_AARCH32
* @tmp: temporary register
*
* For loading 32-bit OS, x1 is machine nr and x2 is ftaddr.
* For loading 64-bit OS, x0 is physical address to the FDT blob.
* They will be passed to the guest.
*/
.macro armv8_switch_to_el1_m, ep, flag, tmp, tmp2
/* Initialize Generic Timers */
mrs \tmp, cnthctl_el2
/* Enable EL1 access to timers */
orr \tmp, \tmp, #(CNTHCTL_EL2_EL1PCEN_EN |\
CNTHCTL_EL2_EL1PCTEN_EN)
msr cnthctl_el2, \tmp
msr cntvoff_el2, xzr
/* Initilize MPID/MPIDR registers */
mrs \tmp, midr_el1
msr vpidr_el2, \tmp
mrs \tmp, mpidr_el1
msr vmpidr_el2, \tmp
/* Disable coprocessor traps */
mov \tmp, #CPTR_EL2_RES1
msr cptr_el2, \tmp /* Disable coprocessor traps to EL2 */
msr hstr_el2, xzr /* Disable coprocessor traps to EL2 */
mov \tmp, #CPACR_EL1_FPEN_EN
msr cpacr_el1, \tmp /* Enable FP/SIMD at EL1 */
/* SCTLR_EL1 initialization
*
* setting RES1 bits (29,28,23,22,20,11) to 1
* and RES0 bits (31,30,27,21,17,13,10,6) +
* UCI,EE,EOE,WXN,nTWE,nTWI,UCT,DZE,I,UMA,SED,ITD,
* CP15BEN,SA0,SA,C,A,M to 0
*/
ldr \tmp, =(SCTLR_EL1_RES1 | SCTLR_EL1_UCI_DIS |\
SCTLR_EL1_EE_LE | SCTLR_EL1_WXN_DIS |\
SCTLR_EL1_NTWE_DIS | SCTLR_EL1_NTWI_DIS |\
SCTLR_EL1_UCT_DIS | SCTLR_EL1_DZE_DIS |\
SCTLR_EL1_ICACHE_DIS | SCTLR_EL1_UMA_DIS |\
SCTLR_EL1_SED_EN | SCTLR_EL1_ITD_EN |\
SCTLR_EL1_CP15BEN_DIS | SCTLR_EL1_SA0_DIS |\
SCTLR_EL1_SA_DIS | SCTLR_EL1_DCACHE_DIS |\
SCTLR_EL1_ALIGN_DIS | SCTLR_EL1_MMU_DIS)
msr sctlr_el1, \tmp
mov \tmp, sp
msr sp_el1, \tmp /* Migrate SP */
mrs \tmp, vbar_el2
msr vbar_el1, \tmp /* Migrate VBAR */
/* Check switch to AArch64 EL1 or AArch32 Supervisor mode */
cmp \flag, #ES_TO_AARCH32
b.eq 1f
/* Initialize HCR_EL2 */
/* Only disable PAuth traps if PAuth is supported */
mrs \tmp, id_aa64isar1_el1
ldr \tmp2, =(ID_AA64ISAR1_EL1_GPI | ID_AA64ISAR1_EL1_GPA | \
ID_AA64ISAR1_EL1_API | ID_AA64ISAR1_EL1_APA)
tst \tmp, \tmp2
mov \tmp2, #(HCR_EL2_RW_AARCH64 | HCR_EL2_HCD_DIS)
orr \tmp, \tmp2, #(HCR_EL2_APK | HCR_EL2_API)
csel \tmp, \tmp2, \tmp, eq
msr hcr_el2, \tmp
/* Return to the EL1_SP1 mode from EL2 */
ldr \tmp, =(SPSR_EL_DEBUG_MASK | SPSR_EL_SERR_MASK |\
SPSR_EL_IRQ_MASK | SPSR_EL_FIQ_MASK |\
SPSR_EL_M_AARCH64 | SPSR_EL_M_EL1H)
msr spsr_el2, \tmp
msr elr_el2, \ep
eret
1:
/* Initialize HCR_EL2 */
ldr \tmp, =(HCR_EL2_RW_AARCH32 | HCR_EL2_HCD_DIS)
msr hcr_el2, \tmp
/* Return to AArch32 Supervisor mode from EL2 */
ldr \tmp, =(SPSR_EL_END_LE | SPSR_EL_ASYN_MASK |\
SPSR_EL_IRQ_MASK | SPSR_EL_FIQ_MASK |\
SPSR_EL_T_A32 | SPSR_EL_M_AARCH32 |\
SPSR_EL_M_SVC)
msr spsr_el2, \tmp
msr elr_el2, \ep
eret
.endm
#if defined(CONFIG_GICV3)
.macro gic_wait_for_interrupt_m xreg1
0 : wfi
mrs \xreg1, ICC_IAR1_EL1
msr ICC_EOIR1_EL1, \xreg1
cbnz \xreg1, 0b
.endm
#elif defined(CONFIG_GICV2)
.macro gic_wait_for_interrupt_m xreg1, wreg2
0 : wfi
ldr \wreg2, [\xreg1, GICC_AIAR]
str \wreg2, [\xreg1, GICC_AEOIR]
and \wreg2, \wreg2, #0x3ff
cbnz \wreg2, 0b
.endm
#endif
#endif /* CONFIG_ARM64 */
#endif /* __ASSEMBLY__ */
#endif /* __ASM_ARM_MACRO_H__ */