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-rw-r--r--arch/arm64/include/asm/assembler.h470
1 files changed, 275 insertions, 195 deletions
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 54d181177656..f0ca7196f6fa 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -5,15 +5,18 @@
* Copyright (C) 1996-2000 Russell King
* Copyright (C) 2012 ARM Ltd.
*/
-#ifndef __ASSEMBLY__
+#ifndef __ASSEMBLER__
#error "Only include this from assembly code"
#endif
#ifndef __ASM_ASSEMBLER_H
#define __ASM_ASSEMBLER_H
-#include <asm-generic/export.h>
+#include <linux/export.h>
+#include <asm/alternative.h>
+#include <asm/asm-bug.h>
+#include <asm/asm-extable.h>
#include <asm/asm-offsets.h>
#include <asm/cpufeature.h>
#include <asm/cputype.h>
@@ -23,50 +26,41 @@
#include <asm/ptrace.h>
#include <asm/thread_info.h>
- .macro save_and_disable_daif, flags
- mrs \flags, daif
- msr daifset, #0xf
- .endm
+ /*
+ * Provide a wxN alias for each wN register so what we can paste a xN
+ * reference after a 'w' to obtain the 32-bit version.
+ */
+ .irp n,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30
+ wx\n .req w\n
+ .endr
.macro disable_daif
msr daifset, #0xf
.endm
- .macro enable_daif
- msr daifclr, #0xf
- .endm
-
- .macro restore_daif, flags:req
- msr daif, \flags
- .endm
-
- /* IRQ is the lowest priority flag, unconditionally unmask the rest. */
- .macro enable_da_f
- msr daifclr, #(8 | 4 | 1)
- .endm
-
/*
* Save/restore interrupts.
*/
+ .macro save_and_disable_daif, flags
+ mrs \flags, daif
+ msr daifset, #0xf
+ .endm
+
.macro save_and_disable_irq, flags
mrs \flags, daif
- msr daifset, #2
+ msr daifset, #3
.endm
.macro restore_irq, flags
msr daif, \flags
.endm
- .macro enable_dbg
- msr daifclr, #8
- .endm
-
.macro disable_step_tsk, flgs, tmp
tbz \flgs, #TIF_SINGLESTEP, 9990f
mrs \tmp, mdscr_el1
- bic \tmp, \tmp, #DBG_MDSCR_SS
+ bic \tmp, \tmp, #MDSCR_EL1_SS
msr mdscr_el1, \tmp
- isb // Synchronise with enable_dbg
+ isb // Take effect before a subsequent clear of DAIF.D
9990:
.endm
@@ -74,7 +68,7 @@
.macro enable_step_tsk, flgs, tmp
tbz \flgs, #TIF_SINGLESTEP, 9990f
mrs \tmp, mdscr_el1
- orr \tmp, \tmp, #DBG_MDSCR_SS
+ orr \tmp, \tmp, #MDSCR_EL1_SS
msr mdscr_el1, \tmp
9990:
.endm
@@ -98,6 +92,13 @@
.endm
/*
+ * Clear Branch History instruction
+ */
+ .macro clearbhb
+ hint #22
+ .endm
+
+/*
* Speculation barrier
*/
.macro sb
@@ -120,20 +121,6 @@ alternative_endif
.endm
/*
- * Emit an entry into the exception table
- */
- .macro _asm_extable, from, to
- .pushsection __ex_table, "a"
- .align 3
- .long (\from - .), (\to - .)
- .popsection
- .endm
-
-#define USER(l, x...) \
-9999: x; \
- _asm_extable 9999b, l
-
-/*
* Register aliases.
*/
lr .req x30 // link register
@@ -219,6 +206,31 @@ lr .req x30 // link register
.endm
/*
+ * @dst: destination register
+ */
+#if defined(__KVM_NVHE_HYPERVISOR__) || defined(__KVM_VHE_HYPERVISOR__)
+ .macro get_this_cpu_offset, dst
+ mrs \dst, tpidr_el2
+ .endm
+#else
+ .macro get_this_cpu_offset, dst
+alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
+ mrs \dst, tpidr_el1
+alternative_else
+ mrs \dst, tpidr_el2
+alternative_endif
+ .endm
+
+ .macro set_this_cpu_offset, src
+alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
+ msr tpidr_el1, \src
+alternative_else
+ msr tpidr_el2, \src
+alternative_endif
+ .endm
+#endif
+
+ /*
* @dst: Result of per_cpu(sym, smp_processor_id()) (can be SP)
* @sym: The name of the per-cpu variable
* @tmp: scratch register
@@ -226,11 +238,7 @@ lr .req x30 // link register
.macro adr_this_cpu, dst, sym, tmp
adrp \tmp, \sym
add \dst, \tmp, #:lo12:\sym
-alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
- mrs \tmp, tpidr_el1
-alternative_else
- mrs \tmp, tpidr_el2
-alternative_endif
+ get_this_cpu_offset \tmp
add \dst, \dst, \tmp
.endm
@@ -241,32 +249,33 @@ alternative_endif
*/
.macro ldr_this_cpu dst, sym, tmp
adr_l \dst, \sym
-alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
- mrs \tmp, tpidr_el1
-alternative_else
- mrs \tmp, tpidr_el2
-alternative_endif
+ get_this_cpu_offset \tmp
ldr \dst, [\dst, \tmp]
.endm
/*
- * vma_vm_mm - get mm pointer from vma pointer (vma->vm_mm)
- */
- .macro vma_vm_mm, rd, rn
- ldr \rd, [\rn, #VMA_VM_MM]
- .endm
-
-/*
* read_ctr - read CTR_EL0. If the system has mismatched register fields,
* provide the system wide safe value from arm64_ftr_reg_ctrel0.sys_val
*/
.macro read_ctr, reg
+#ifndef __KVM_NVHE_HYPERVISOR__
alternative_if_not ARM64_MISMATCHED_CACHE_TYPE
mrs \reg, ctr_el0 // read CTR
nop
alternative_else
ldr_l \reg, arm64_ftr_reg_ctrel0 + ARM64_FTR_SYSVAL
alternative_endif
+#else
+alternative_if_not ARM64_KVM_PROTECTED_MODE
+ ASM_BUG()
+alternative_else_nop_endif
+alternative_cb ARM64_ALWAYS_SYSTEM, kvm_compute_final_ctr_el0
+ movz \reg, #0
+ movk \reg, #0, lsl #16
+ movk \reg, #0, lsl #32
+ movk \reg, #0, lsl #48
+alternative_cb_end
+#endif
.endm
@@ -316,14 +325,14 @@ alternative_endif
* tcr_set_t0sz - update TCR.T0SZ so that we can load the ID map
*/
.macro tcr_set_t0sz, valreg, t0sz
- bfi \valreg, \t0sz, #TCR_T0SZ_OFFSET, #TCR_TxSZ_WIDTH
+ bfi \valreg, \t0sz, #TCR_EL1_T0SZ_SHIFT, #TCR_EL1_T0SZ_WIDTH
.endm
/*
* tcr_set_t1sz - update TCR.T1SZ
*/
.macro tcr_set_t1sz, valreg, t1sz
- bfi \valreg, \t1sz, #TCR_T1SZ_OFFSET, #TCR_TxSZ_WIDTH
+ bfi \valreg, \t1sz, #TCR_EL1_T1SZ_SHIFT, #TCR_EL1_T1SZ_WIDTH
.endm
/*
@@ -337,58 +346,81 @@ alternative_endif
.macro tcr_compute_pa_size, tcr, pos, tmp0, tmp1
mrs \tmp0, ID_AA64MMFR0_EL1
// Narrow PARange to fit the PS field in TCR_ELx
- ubfx \tmp0, \tmp0, #ID_AA64MMFR0_PARANGE_SHIFT, #3
- mov \tmp1, #ID_AA64MMFR0_PARANGE_MAX
+ ubfx \tmp0, \tmp0, #ID_AA64MMFR0_EL1_PARANGE_SHIFT, #3
+ mov \tmp1, #ID_AA64MMFR0_EL1_PARANGE_MAX
+#ifdef CONFIG_ARM64_LPA2
+alternative_if_not ARM64_HAS_VA52
+ mov \tmp1, #ID_AA64MMFR0_EL1_PARANGE_48
+alternative_else_nop_endif
+#endif
cmp \tmp0, \tmp1
csel \tmp0, \tmp1, \tmp0, hi
bfi \tcr, \tmp0, \pos, #3
.endm
-/*
- * Macro to perform a data cache maintenance for the interval
- * [kaddr, kaddr + size)
- *
- * op: operation passed to dc instruction
- * domain: domain used in dsb instruciton
- * kaddr: starting virtual address of the region
- * size: size of the region
- * Corrupts: kaddr, size, tmp1, tmp2
- */
- .macro __dcache_op_workaround_clean_cache, op, kaddr
+ .macro __dcache_op_workaround_clean_cache, op, addr
alternative_if_not ARM64_WORKAROUND_CLEAN_CACHE
- dc \op, \kaddr
+ dc \op, \addr
alternative_else
- dc civac, \kaddr
+ dc civac, \addr
alternative_endif
.endm
- .macro dcache_by_line_op op, domain, kaddr, size, tmp1, tmp2
- dcache_line_size \tmp1, \tmp2
- add \size, \kaddr, \size
- sub \tmp2, \tmp1, #1
- bic \kaddr, \kaddr, \tmp2
-9998:
+/*
+ * Macro to perform a data cache maintenance for the interval
+ * [start, end) with dcache line size explicitly provided.
+ *
+ * op: operation passed to dc instruction
+ * domain: domain used in dsb instruction
+ * start: starting virtual address of the region
+ * end: end virtual address of the region
+ * linesz: dcache line size
+ * fixup: optional label to branch to on user fault
+ * Corrupts: start, end, tmp
+ */
+ .macro dcache_by_myline_op op, domain, start, end, linesz, tmp, fixup
+ sub \tmp, \linesz, #1
+ bic \start, \start, \tmp
+.Ldcache_op\@:
.ifc \op, cvau
- __dcache_op_workaround_clean_cache \op, \kaddr
+ __dcache_op_workaround_clean_cache \op, \start
.else
.ifc \op, cvac
- __dcache_op_workaround_clean_cache \op, \kaddr
+ __dcache_op_workaround_clean_cache \op, \start
.else
.ifc \op, cvap
- sys 3, c7, c12, 1, \kaddr // dc cvap
+ sys 3, c7, c12, 1, \start // dc cvap
.else
.ifc \op, cvadp
- sys 3, c7, c13, 1, \kaddr // dc cvadp
+ sys 3, c7, c13, 1, \start // dc cvadp
.else
- dc \op, \kaddr
+ dc \op, \start
.endif
.endif
.endif
.endif
- add \kaddr, \kaddr, \tmp1
- cmp \kaddr, \size
- b.lo 9998b
+ add \start, \start, \linesz
+ cmp \start, \end
+ b.lo .Ldcache_op\@
dsb \domain
+
+ _cond_uaccess_extable .Ldcache_op\@, \fixup
+ .endm
+
+/*
+ * Macro to perform a data cache maintenance for the interval
+ * [start, end)
+ *
+ * op: operation passed to dc instruction
+ * domain: domain used in dsb instruction
+ * start: starting virtual address of the region
+ * end: end virtual address of the region
+ * fixup: optional label to branch to on user fault
+ * Corrupts: start, end, tmp1, tmp2
+ */
+ .macro dcache_by_line_op op, domain, start, end, tmp1, tmp2, fixup
+ dcache_line_size \tmp1, \tmp2
+ dcache_by_myline_op \op, \domain, \start, \end, \tmp1, \tmp2, \fixup
.endm
/*
@@ -396,20 +428,50 @@ alternative_endif
* [start, end)
*
* start, end: virtual addresses describing the region
- * label: A label to branch to on user fault.
+ * fixup: optional label to branch to on user fault
* Corrupts: tmp1, tmp2
*/
- .macro invalidate_icache_by_line start, end, tmp1, tmp2, label
+ .macro invalidate_icache_by_line start, end, tmp1, tmp2, fixup
icache_line_size \tmp1, \tmp2
sub \tmp2, \tmp1, #1
bic \tmp2, \start, \tmp2
-9997:
-USER(\label, ic ivau, \tmp2) // invalidate I line PoU
+.Licache_op\@:
+ ic ivau, \tmp2 // invalidate I line PoU
add \tmp2, \tmp2, \tmp1
cmp \tmp2, \end
- b.lo 9997b
+ b.lo .Licache_op\@
dsb ish
isb
+
+ _cond_uaccess_extable .Licache_op\@, \fixup
+ .endm
+
+/*
+ * load_ttbr1 - install @pgtbl as a TTBR1 page table
+ * pgtbl preserved
+ * tmp1/tmp2 clobbered, either may overlap with pgtbl
+ */
+ .macro load_ttbr1, pgtbl, tmp1, tmp2
+ phys_to_ttbr \tmp1, \pgtbl
+ offset_ttbr1 \tmp1, \tmp2
+ msr ttbr1_el1, \tmp1
+ isb
+ .endm
+
+/*
+ * To prevent the possibility of old and new partial table walks being visible
+ * in the tlb, switch the ttbr to a zero page when we invalidate the old
+ * records. D4.7.1 'General TLB maintenance requirements' in ARM DDI 0487A.i
+ * Even switching to our copied tables will cause a changed output address at
+ * each stage of the walk.
+ */
+ .macro break_before_make_ttbr_switch zero_page, page_table, tmp, tmp2
+ phys_to_ttbr \tmp, \zero_page
+ msr ttbr1_el1, \tmp
+ isb
+ tlbi vmalle1
+ dsb nsh
+ load_ttbr1 \page_table, \tmp, \tmp2
.endm
/*
@@ -417,9 +479,10 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU
*/
.macro reset_pmuserenr_el0, tmpreg
mrs \tmpreg, id_aa64dfr0_el1
- sbfx \tmpreg, \tmpreg, #ID_AA64DFR0_PMUVER_SHIFT, #4
- cmp \tmpreg, #1 // Skip if no PMU present
- b.lt 9000f
+ ubfx \tmpreg, \tmpreg, #ID_AA64DFR0_EL1_PMUVer_SHIFT, #4
+ cmp \tmpreg, #ID_AA64DFR0_EL1_PMUVer_NI
+ ccmp \tmpreg, #ID_AA64DFR0_EL1_PMUVer_IMP_DEF, #4, ne
+ b.eq 9000f // Skip if no PMU present or IMP_DEF
msr pmuserenr_el0, xzr // Disable PMU access from EL0
9000:
.endm
@@ -429,7 +492,7 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU
*/
.macro reset_amuserenr_el0, tmpreg
mrs \tmpreg, id_aa64pfr0_el1 // Check ID_AA64PFR0_EL1
- ubfx \tmpreg, \tmpreg, #ID_AA64PFR0_AMU_SHIFT, #4
+ ubfx \tmpreg, \tmpreg, #ID_AA64PFR0_EL1_AMU_SHIFT, #4
cbz \tmpreg, .Lskip_\@ // Skip if no AMU present
msr_s SYS_AMUSERENR_EL0, xzr // Disable AMU access from EL0
.Lskip_\@:
@@ -464,7 +527,7 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU
#define NOKPROBE(x)
#endif
-#ifdef CONFIG_KASAN
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
#define EXPORT_SYMBOL_NOKASAN(name)
#else
#define EXPORT_SYMBOL_NOKASAN(name) EXPORT_SYMBOL(name)
@@ -509,29 +572,27 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU
.endm
/*
- * Offset ttbr1 to allow for 48-bit kernel VAs set with 52-bit PTRS_PER_PGD.
+ * If the kernel is built for 52-bit virtual addressing but the hardware only
+ * supports 48 bits, we cannot program the pgdir address into TTBR1 directly,
+ * but we have to add an offset so that the TTBR1 address corresponds with the
+ * pgdir entry that covers the lowest 48-bit addressable VA.
+ *
+ * Note that this trick is only used for LVA/64k pages - LPA2/4k pages uses an
+ * additional paging level, and on LPA2/16k pages, we would end up with a root
+ * level table with only 2 entries, which is suboptimal in terms of TLB
+ * utilization, so there we fall back to 47 bits of translation if LPA2 is not
+ * supported.
+ *
* orr is used as it can cover the immediate value (and is idempotent).
- * In future this may be nop'ed out when dealing with 52-bit kernel VAs.
* ttbr: Value of ttbr to set, modified.
*/
.macro offset_ttbr1, ttbr, tmp
-#ifdef CONFIG_ARM64_VA_BITS_52
- mrs_s \tmp, SYS_ID_AA64MMFR2_EL1
- and \tmp, \tmp, #(0xf << ID_AA64MMFR2_LVA_SHIFT)
- cbnz \tmp, .Lskipoffs_\@
- orr \ttbr, \ttbr, #TTBR1_BADDR_4852_OFFSET
-.Lskipoffs_\@ :
-#endif
- .endm
-
-/*
- * Perform the reverse of offset_ttbr1.
- * bic is used as it can cover the immediate value and, in future, won't need
- * to be nop'ed out when dealing with 52-bit kernel VAs.
- */
- .macro restore_ttbr1, ttbr
-#ifdef CONFIG_ARM64_VA_BITS_52
- bic \ttbr, \ttbr, #TTBR1_BADDR_4852_OFFSET
+#if defined(CONFIG_ARM64_VA_BITS_52) && !defined(CONFIG_ARM64_LPA2)
+ mrs \tmp, tcr_el1
+ and \tmp, \tmp, #TCR_EL1_T1SZ_MASK
+ cmp \tmp, #TCR_T1SZ(VA_BITS_MIN)
+ orr \tmp, \ttbr, #TTBR1_BADDR_4852_OFFSET
+ csel \ttbr, \tmp, \ttbr, eq
#endif
.endm
@@ -553,27 +614,13 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU
.macro phys_to_pte, pte, phys
#ifdef CONFIG_ARM64_PA_BITS_52
- /*
- * We assume \phys is 64K aligned and this is guaranteed by only
- * supporting this configuration with 64K pages.
- */
- orr \pte, \phys, \phys, lsr #36
- and \pte, \pte, #PTE_ADDR_MASK
+ orr \pte, \phys, \phys, lsr #PTE_ADDR_HIGH_SHIFT
+ and \pte, \pte, #PHYS_TO_PTE_ADDR_MASK
#else
mov \pte, \phys
#endif
.endm
- .macro pte_to_phys, phys, pte
-#ifdef CONFIG_ARM64_PA_BITS_52
- ubfiz \phys, \pte, #(48 - 16 - 12), #16
- bfxil \phys, \pte, #16, #32
- lsl \phys, \phys, #16
-#else
- and \phys, \pte, #PTE_ADDR_MASK
-#endif
- .endm
-
/*
* tcr_clear_errata_bits - Clear TCR bits that trigger an errata on this CPU.
*/
@@ -667,73 +714,60 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU
.endm
/*
- * Check whether to yield to another runnable task from kernel mode NEON code
- * (which runs with preemption disabled).
- *
- * if_will_cond_yield_neon
- * // pre-yield patchup code
- * do_cond_yield_neon
- * // post-yield patchup code
- * endif_yield_neon <label>
- *
- * where <label> is optional, and marks the point where execution will resume
- * after a yield has been performed. If omitted, execution resumes right after
- * the endif_yield_neon invocation. Note that the entire sequence, including
- * the provided patchup code, will be omitted from the image if
- * CONFIG_PREEMPTION is not defined.
- *
- * As a convenience, in the case where no patchup code is required, the above
- * sequence may be abbreviated to
- *
- * cond_yield_neon <label>
- *
- * Note that the patchup code does not support assembler directives that change
- * the output section, any use of such directives is undefined.
- *
- * The yield itself consists of the following:
- * - Check whether the preempt count is exactly 1 and a reschedule is also
- * needed. If so, calling of preempt_enable() in kernel_neon_end() will
- * trigger a reschedule. If it is not the case, yielding is pointless.
- * - Disable and re-enable kernel mode NEON, and branch to the yield fixup
- * code.
- *
- * This macro sequence may clobber all CPU state that is not guaranteed by the
- * AAPCS to be preserved across an ordinary function call.
+ * Set SCTLR_ELx to the @reg value, and invalidate the local icache
+ * in the process. This is called when setting the MMU on.
*/
+.macro set_sctlr, sreg, reg
+ msr \sreg, \reg
+ isb
+ /*
+ * Invalidate the local I-cache so that any instructions fetched
+ * speculatively from the PoC are discarded, since they may have
+ * been dynamically patched at the PoU.
+ */
+ ic iallu
+ dsb nsh
+ isb
+.endm
- .macro cond_yield_neon, lbl
- if_will_cond_yield_neon
- do_cond_yield_neon
- endif_yield_neon \lbl
- .endm
+.macro set_sctlr_el1, reg
+ set_sctlr sctlr_el1, \reg
+.endm
- .macro if_will_cond_yield_neon
-#ifdef CONFIG_PREEMPTION
- get_current_task x0
- ldr x0, [x0, #TSK_TI_PREEMPT]
- sub x0, x0, #PREEMPT_DISABLE_OFFSET
- cbz x0, .Lyield_\@
- /* fall through to endif_yield_neon */
- .subsection 1
-.Lyield_\@ :
-#else
- .section ".discard.cond_yield_neon", "ax"
-#endif
- .endm
+.macro set_sctlr_el2, reg
+ set_sctlr sctlr_el2, \reg
+.endm
- .macro do_cond_yield_neon
- bl kernel_neon_end
- bl kernel_neon_begin
+ /*
+ * Check whether asm code should yield as soon as it is able. This is
+ * the case if we are currently running in task context, and the
+ * TIF_NEED_RESCHED flag is set. (Note that the TIF_NEED_RESCHED flag
+ * is stored negated in the top word of the thread_info::preempt_count
+ * field)
+ */
+ .macro cond_yield, lbl:req, tmp:req, tmp2
+#ifdef CONFIG_PREEMPT_VOLUNTARY
+ get_current_task \tmp
+ ldr \tmp, [\tmp, #TSK_TI_PREEMPT]
+ /*
+ * If we are serving a softirq, there is no point in yielding: the
+ * softirq will not be preempted no matter what we do, so we should
+ * run to completion as quickly as we can. The preempt_count field will
+ * have BIT(SOFTIRQ_SHIFT) set in this case, so the zero check will
+ * catch this case too.
+ */
+ cbz \tmp, \lbl
+#endif
.endm
- .macro endif_yield_neon, lbl
- .ifnb \lbl
- b \lbl
- .else
- b .Lyield_out_\@
- .endif
- .previous
-.Lyield_out_\@ :
+/*
+ * Branch Target Identifier (BTI)
+ */
+ .macro bti, targets
+ .equ .L__bti_targets_c, 34
+ .equ .L__bti_targets_j, 36
+ .equ .L__bti_targets_jc,38
+ hint #.L__bti_targets_\targets
.endm
/*
@@ -786,4 +820,50 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU
#endif /* GNU_PROPERTY_AARCH64_FEATURE_1_DEFAULT */
+ .macro __mitigate_spectre_bhb_loop tmp
+#ifdef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY
+alternative_cb ARM64_ALWAYS_SYSTEM, spectre_bhb_patch_loop_iter
+ mov \tmp, #32 // Patched to correct the immediate
+alternative_cb_end
+.Lspectre_bhb_loop\@:
+ b . + 4
+ subs \tmp, \tmp, #1
+ b.ne .Lspectre_bhb_loop\@
+ sb
+#endif /* CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY */
+ .endm
+
+ .macro mitigate_spectre_bhb_loop tmp
+#ifdef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY
+alternative_cb ARM64_ALWAYS_SYSTEM, spectre_bhb_patch_loop_mitigation_enable
+ b .L_spectre_bhb_loop_done\@ // Patched to NOP
+alternative_cb_end
+ __mitigate_spectre_bhb_loop \tmp
+.L_spectre_bhb_loop_done\@:
+#endif /* CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY */
+ .endm
+
+ /* Save/restores x0-x3 to the stack */
+ .macro __mitigate_spectre_bhb_fw
+#ifdef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY
+ stp x0, x1, [sp, #-16]!
+ stp x2, x3, [sp, #-16]!
+ mov w0, #ARM_SMCCC_ARCH_WORKAROUND_3
+alternative_cb ARM64_ALWAYS_SYSTEM, smccc_patch_fw_mitigation_conduit
+ nop // Patched to SMC/HVC #0
+alternative_cb_end
+ ldp x2, x3, [sp], #16
+ ldp x0, x1, [sp], #16
+#endif /* CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY */
+ .endm
+
+ .macro mitigate_spectre_bhb_clear_insn
+#ifdef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY
+alternative_cb ARM64_ALWAYS_SYSTEM, spectre_bhb_patch_clearbhb
+ /* Patched to NOP when not supported */
+ clearbhb
+ isb
+alternative_cb_end
+#endif /* CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY */
+ .endm
#endif /* __ASM_ASSEMBLER_H */