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Diffstat (limited to 'arch/arm64/include/asm/assembler.h')
| -rw-r--r-- | arch/arm64/include/asm/assembler.h | 924 |
1 files changed, 924 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h new file mode 100644 index 000000000..e5957a53b --- /dev/null +++ b/arch/arm64/include/asm/assembler.h @@ -0,0 +1,924 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Based on arch/arm/include/asm/assembler.h, arch/arm/mm/proc-macros.S + * + * Copyright (C) 1996-2000 Russell King + * Copyright (C) 2012 ARM Ltd. + */ +#ifndef __ASSEMBLY__ +#error "Only include this from assembly code" +#endif + +#ifndef __ASM_ASSEMBLER_H +#define __ASM_ASSEMBLER_H + +#include <asm-generic/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> +#include <asm/debug-monitors.h> +#include <asm/page.h> +#include <asm/pgtable-hwdef.h> +#include <asm/ptrace.h> +#include <asm/thread_info.h> + + /* + * 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 save_and_disable_daif, flags + mrs \flags, daif + msr daifset, #0xf + .endm + + .macro disable_daif + msr daifset, #0xf + .endm + + .macro enable_daif + msr daifclr, #0xf + .endm + + .macro restore_daif, flags:req + msr daif, \flags + .endm + + /* IRQ/FIQ are the lowest priority flags, unconditionally unmask the rest. */ + .macro enable_da + msr daifclr, #(8 | 4) + .endm + +/* + * Save/restore interrupts. + */ + .macro save_and_disable_irq, flags + mrs \flags, daif + 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 + msr mdscr_el1, \tmp + isb // Synchronise with enable_dbg +9990: + .endm + + /* call with daif masked */ + .macro enable_step_tsk, flgs, tmp + tbz \flgs, #TIF_SINGLESTEP, 9990f + mrs \tmp, mdscr_el1 + orr \tmp, \tmp, #DBG_MDSCR_SS + msr mdscr_el1, \tmp +9990: + .endm + +/* + * RAS Error Synchronization barrier + */ + .macro esb +#ifdef CONFIG_ARM64_RAS_EXTN + hint #16 +#else + nop +#endif + .endm + +/* + * Value prediction barrier + */ + .macro csdb + hint #20 + .endm + +/* + * Clear Branch History instruction + */ + .macro clearbhb + hint #22 + .endm + +/* + * Speculation barrier + */ + .macro sb +alternative_if_not ARM64_HAS_SB + dsb nsh + isb +alternative_else + SB_BARRIER_INSN + nop +alternative_endif + .endm + +/* + * NOP sequence + */ + .macro nops, num + .rept \num + nop + .endr + .endm + +/* + * Register aliases. + */ +lr .req x30 // link register + +/* + * Vector entry + */ + .macro ventry label + .align 7 + b \label + .endm + +/* + * Select code when configured for BE. + */ +#ifdef CONFIG_CPU_BIG_ENDIAN +#define CPU_BE(code...) code +#else +#define CPU_BE(code...) +#endif + +/* + * Select code when configured for LE. + */ +#ifdef CONFIG_CPU_BIG_ENDIAN +#define CPU_LE(code...) +#else +#define CPU_LE(code...) code +#endif + +/* + * Define a macro that constructs a 64-bit value by concatenating two + * 32-bit registers. Note that on big endian systems the order of the + * registers is swapped. + */ +#ifndef CONFIG_CPU_BIG_ENDIAN + .macro regs_to_64, rd, lbits, hbits +#else + .macro regs_to_64, rd, hbits, lbits +#endif + orr \rd, \lbits, \hbits, lsl #32 + .endm + +/* + * Pseudo-ops for PC-relative adr/ldr/str <reg>, <symbol> where + * <symbol> is within the range +/- 4 GB of the PC. + */ + /* + * @dst: destination register (64 bit wide) + * @sym: name of the symbol + */ + .macro adr_l, dst, sym + adrp \dst, \sym + add \dst, \dst, :lo12:\sym + .endm + + /* + * @dst: destination register (32 or 64 bit wide) + * @sym: name of the symbol + * @tmp: optional 64-bit scratch register to be used if <dst> is a + * 32-bit wide register, in which case it cannot be used to hold + * the address + */ + .macro ldr_l, dst, sym, tmp= + .ifb \tmp + adrp \dst, \sym + ldr \dst, [\dst, :lo12:\sym] + .else + adrp \tmp, \sym + ldr \dst, [\tmp, :lo12:\sym] + .endif + .endm + + /* + * @src: source register (32 or 64 bit wide) + * @sym: name of the symbol + * @tmp: mandatory 64-bit scratch register to calculate the address + * while <src> needs to be preserved. + */ + .macro str_l, src, sym, tmp + adrp \tmp, \sym + str \src, [\tmp, :lo12:\sym] + .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 + */ + .macro adr_this_cpu, dst, sym, tmp + adrp \tmp, \sym + add \dst, \tmp, #:lo12:\sym + get_this_cpu_offset \tmp + add \dst, \dst, \tmp + .endm + + /* + * @dst: Result of READ_ONCE(per_cpu(sym, smp_processor_id())) + * @sym: The name of the per-cpu variable + * @tmp: scratch register + */ + .macro ldr_this_cpu dst, sym, tmp + adr_l \dst, \sym + 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 + + +/* + * raw_dcache_line_size - get the minimum D-cache line size on this CPU + * from the CTR register. + */ + .macro raw_dcache_line_size, reg, tmp + mrs \tmp, ctr_el0 // read CTR + ubfm \tmp, \tmp, #16, #19 // cache line size encoding + mov \reg, #4 // bytes per word + lsl \reg, \reg, \tmp // actual cache line size + .endm + +/* + * dcache_line_size - get the safe D-cache line size across all CPUs + */ + .macro dcache_line_size, reg, tmp + read_ctr \tmp + ubfm \tmp, \tmp, #16, #19 // cache line size encoding + mov \reg, #4 // bytes per word + lsl \reg, \reg, \tmp // actual cache line size + .endm + +/* + * raw_icache_line_size - get the minimum I-cache line size on this CPU + * from the CTR register. + */ + .macro raw_icache_line_size, reg, tmp + mrs \tmp, ctr_el0 // read CTR + and \tmp, \tmp, #0xf // cache line size encoding + mov \reg, #4 // bytes per word + lsl \reg, \reg, \tmp // actual cache line size + .endm + +/* + * icache_line_size - get the safe I-cache line size across all CPUs + */ + .macro icache_line_size, reg, tmp + read_ctr \tmp + and \tmp, \tmp, #0xf // cache line size encoding + mov \reg, #4 // bytes per word + lsl \reg, \reg, \tmp // actual cache line size + .endm + +/* + * 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 + .endm + +/* + * tcr_set_t1sz - update TCR.T1SZ + */ + .macro tcr_set_t1sz, valreg, t1sz + bfi \valreg, \t1sz, #TCR_T1SZ_OFFSET, #TCR_TxSZ_WIDTH + .endm + +/* + * idmap_get_t0sz - get the T0SZ value needed to cover the ID map + * + * Calculate the maximum allowed value for TCR_EL1.T0SZ so that the + * entire ID map region can be mapped. As T0SZ == (64 - #bits used), + * this number conveniently equals the number of leading zeroes in + * the physical address of _end. + */ + .macro idmap_get_t0sz, reg + adrp \reg, _end + orr \reg, \reg, #(1 << VA_BITS_MIN) - 1 + clz \reg, \reg + .endm + +/* + * tcr_compute_pa_size - set TCR.(I)PS to the highest supported + * ID_AA64MMFR0_EL1.PARange value + * + * tcr: register with the TCR_ELx value to be updated + * pos: IPS or PS bitfield position + * tmp{0,1}: temporary registers + */ + .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_EL1_PARANGE_SHIFT, #3 + mov \tmp1, #ID_AA64MMFR0_EL1_PARANGE_MAX + cmp \tmp0, \tmp1 + csel \tmp0, \tmp1, \tmp0, hi + bfi \tcr, \tmp0, \pos, #3 + .endm + + .macro __dcache_op_workaround_clean_cache, op, addr +alternative_if_not ARM64_WORKAROUND_CLEAN_CACHE + dc \op, \addr +alternative_else + dc civac, \addr +alternative_endif + .endm + +/* + * 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 instruciton + * 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, \start + .else + .ifc \op, cvac + __dcache_op_workaround_clean_cache \op, \start + .else + .ifc \op, cvap + sys 3, c7, c12, 1, \start // dc cvap + .else + .ifc \op, cvadp + sys 3, c7, c13, 1, \start // dc cvadp + .else + dc \op, \start + .endif + .endif + .endif + .endif + 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 instruciton + * 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 + +/* + * Macro to perform an instruction cache maintenance for the interval + * [start, end) + * + * start, end: virtual addresses describing the region + * fixup: optional label to branch to on user fault + * Corrupts: tmp1, tmp2 + */ + .macro invalidate_icache_by_line start, end, tmp1, tmp2, fixup + icache_line_size \tmp1, \tmp2 + sub \tmp2, \tmp1, #1 + bic \tmp2, \start, \tmp2 +.Licache_op\@: + ic ivau, \tmp2 // invalidate I line PoU + add \tmp2, \tmp2, \tmp1 + cmp \tmp2, \end + 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 + +/* + * reset_pmuserenr_el0 - reset PMUSERENR_EL0 if PMUv3 present + */ + .macro reset_pmuserenr_el0, tmpreg + mrs \tmpreg, id_aa64dfr0_el1 + sbfx \tmpreg, \tmpreg, #ID_AA64DFR0_EL1_PMUVer_SHIFT, #4 + cmp \tmpreg, #1 // Skip if no PMU present + b.lt 9000f + msr pmuserenr_el0, xzr // Disable PMU access from EL0 +9000: + .endm + +/* + * reset_amuserenr_el0 - reset AMUSERENR_EL0 if AMUv1 present + */ + .macro reset_amuserenr_el0, tmpreg + mrs \tmpreg, id_aa64pfr0_el1 // Check ID_AA64PFR0_EL1 + 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_\@: + .endm +/* + * copy_page - copy src to dest using temp registers t1-t8 + */ + .macro copy_page dest:req src:req t1:req t2:req t3:req t4:req t5:req t6:req t7:req t8:req +9998: ldp \t1, \t2, [\src] + ldp \t3, \t4, [\src, #16] + ldp \t5, \t6, [\src, #32] + ldp \t7, \t8, [\src, #48] + add \src, \src, #64 + stnp \t1, \t2, [\dest] + stnp \t3, \t4, [\dest, #16] + stnp \t5, \t6, [\dest, #32] + stnp \t7, \t8, [\dest, #48] + add \dest, \dest, #64 + tst \src, #(PAGE_SIZE - 1) + b.ne 9998b + .endm + +/* + * Annotate a function as being unsuitable for kprobes. + */ +#ifdef CONFIG_KPROBES +#define NOKPROBE(x) \ + .pushsection "_kprobe_blacklist", "aw"; \ + .quad x; \ + .popsection; +#else +#define NOKPROBE(x) +#endif + +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) +#define EXPORT_SYMBOL_NOKASAN(name) +#else +#define EXPORT_SYMBOL_NOKASAN(name) EXPORT_SYMBOL(name) +#endif + + /* + * Emit a 64-bit absolute little endian symbol reference in a way that + * ensures that it will be resolved at build time, even when building a + * PIE binary. This requires cooperation from the linker script, which + * must emit the lo32/hi32 halves individually. + */ + .macro le64sym, sym + .long \sym\()_lo32 + .long \sym\()_hi32 + .endm + + /* + * mov_q - move an immediate constant into a 64-bit register using + * between 2 and 4 movz/movk instructions (depending on the + * magnitude and sign of the operand) + */ + .macro mov_q, reg, val + .if (((\val) >> 31) == 0 || ((\val) >> 31) == 0x1ffffffff) + movz \reg, :abs_g1_s:\val + .else + .if (((\val) >> 47) == 0 || ((\val) >> 47) == 0x1ffff) + movz \reg, :abs_g2_s:\val + .else + movz \reg, :abs_g3:\val + movk \reg, :abs_g2_nc:\val + .endif + movk \reg, :abs_g1_nc:\val + .endif + movk \reg, :abs_g0_nc:\val + .endm + +/* + * Return the current task_struct. + */ + .macro get_current_task, rd + mrs \rd, sp_el0 + .endm + +/* + * Offset ttbr1 to allow for 48-bit kernel VAs set with 52-bit PTRS_PER_PGD. + * 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_EL1_VARange_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 +#endif + .endm + +/* + * Arrange a physical address in a TTBR register, taking care of 52-bit + * addresses. + * + * phys: physical address, preserved + * ttbr: returns the TTBR value + */ + .macro phys_to_ttbr, ttbr, phys +#ifdef CONFIG_ARM64_PA_BITS_52 + orr \ttbr, \phys, \phys, lsr #46 + and \ttbr, \ttbr, #TTBR_BADDR_MASK_52 +#else + mov \ttbr, \phys +#endif + .endm + + .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 +#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. + */ + .macro tcr_clear_errata_bits, tcr, tmp1, tmp2 +#ifdef CONFIG_FUJITSU_ERRATUM_010001 + mrs \tmp1, midr_el1 + + mov_q \tmp2, MIDR_FUJITSU_ERRATUM_010001_MASK + and \tmp1, \tmp1, \tmp2 + mov_q \tmp2, MIDR_FUJITSU_ERRATUM_010001 + cmp \tmp1, \tmp2 + b.ne 10f + + mov_q \tmp2, TCR_CLEAR_FUJITSU_ERRATUM_010001 + bic \tcr, \tcr, \tmp2 +10: +#endif /* CONFIG_FUJITSU_ERRATUM_010001 */ + .endm + +/** + * Errata workaround prior to disable MMU. Insert an ISB immediately prior + * to executing the MSR that will change SCTLR_ELn[M] from a value of 1 to 0. + */ + .macro pre_disable_mmu_workaround +#ifdef CONFIG_QCOM_FALKOR_ERRATUM_E1041 + isb +#endif + .endm + + /* + * frame_push - Push @regcount callee saved registers to the stack, + * starting at x19, as well as x29/x30, and set x29 to + * the new value of sp. Add @extra bytes of stack space + * for locals. + */ + .macro frame_push, regcount:req, extra + __frame st, \regcount, \extra + .endm + + /* + * frame_pop - Pop the callee saved registers from the stack that were + * pushed in the most recent call to frame_push, as well + * as x29/x30 and any extra stack space that may have been + * allocated. + */ + .macro frame_pop + __frame ld + .endm + + .macro __frame_regs, reg1, reg2, op, num + .if .Lframe_regcount == \num + \op\()r \reg1, [sp, #(\num + 1) * 8] + .elseif .Lframe_regcount > \num + \op\()p \reg1, \reg2, [sp, #(\num + 1) * 8] + .endif + .endm + + .macro __frame, op, regcount, extra=0 + .ifc \op, st + .if (\regcount) < 0 || (\regcount) > 10 + .error "regcount should be in the range [0 ... 10]" + .endif + .if ((\extra) % 16) != 0 + .error "extra should be a multiple of 16 bytes" + .endif + .ifdef .Lframe_regcount + .if .Lframe_regcount != -1 + .error "frame_push/frame_pop may not be nested" + .endif + .endif + .set .Lframe_regcount, \regcount + .set .Lframe_extra, \extra + .set .Lframe_local_offset, ((\regcount + 3) / 2) * 16 + stp x29, x30, [sp, #-.Lframe_local_offset - .Lframe_extra]! + mov x29, sp + .endif + + __frame_regs x19, x20, \op, 1 + __frame_regs x21, x22, \op, 3 + __frame_regs x23, x24, \op, 5 + __frame_regs x25, x26, \op, 7 + __frame_regs x27, x28, \op, 9 + + .ifc \op, ld + .if .Lframe_regcount == -1 + .error "frame_push/frame_pop may not be nested" + .endif + ldp x29, x30, [sp], #.Lframe_local_offset + .Lframe_extra + .set .Lframe_regcount, -1 + .endif + .endm + +/* + * 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 set_sctlr_el1, reg + set_sctlr sctlr_el1, \reg +.endm + +.macro set_sctlr_el2, reg + set_sctlr sctlr_el2, \reg +.endm + + /* + * Check whether preempt/bh-disabled asm code should yield as soon as + * it is able. This is the case if we are currently running in task + * context, and either a softirq is pending, or the TIF_NEED_RESCHED + * flag is set and re-enabling preemption a single time would result in + * a preempt count of zero. (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:req + 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. + */ + tbnz \tmp, #SOFTIRQ_SHIFT, .Lnoyield_\@ +#ifdef CONFIG_PREEMPTION + sub \tmp, \tmp, #PREEMPT_DISABLE_OFFSET + cbz \tmp, \lbl +#endif + adr_l \tmp, irq_stat + IRQ_CPUSTAT_SOFTIRQ_PENDING + get_this_cpu_offset \tmp2 + ldr w\tmp, [\tmp, \tmp2] + cbnz w\tmp, \lbl // yield on pending softirq in task context +.Lnoyield_\@: + .endm + +/* + * 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 + +/* + * This macro emits a program property note section identifying + * architecture features which require special handling, mainly for + * use in assembly files included in the VDSO. + */ + +#define NT_GNU_PROPERTY_TYPE_0 5 +#define GNU_PROPERTY_AARCH64_FEATURE_1_AND 0xc0000000 + +#define GNU_PROPERTY_AARCH64_FEATURE_1_BTI (1U << 0) +#define GNU_PROPERTY_AARCH64_FEATURE_1_PAC (1U << 1) + +#ifdef CONFIG_ARM64_BTI_KERNEL +#define GNU_PROPERTY_AARCH64_FEATURE_1_DEFAULT \ + ((GNU_PROPERTY_AARCH64_FEATURE_1_BTI | \ + GNU_PROPERTY_AARCH64_FEATURE_1_PAC)) +#endif + +#ifdef GNU_PROPERTY_AARCH64_FEATURE_1_DEFAULT +.macro emit_aarch64_feature_1_and, feat=GNU_PROPERTY_AARCH64_FEATURE_1_DEFAULT + .pushsection .note.gnu.property, "a" + .align 3 + .long 2f - 1f + .long 6f - 3f + .long NT_GNU_PROPERTY_TYPE_0 +1: .string "GNU" +2: + .align 3 +3: .long GNU_PROPERTY_AARCH64_FEATURE_1_AND + .long 5f - 4f +4: + /* + * This is described with an array of char in the Linux API + * spec but the text and all other usage (including binutils, + * clang and GCC) treat this as a 32 bit value so no swizzling + * is required for big endian. + */ + .long \feat +5: + .align 3 +6: + .popsection +.endm + +#else +.macro emit_aarch64_feature_1_and, feat=0 +.endm + +#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 */ |