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987 lines
25 KiB
987 lines
25 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
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/* |
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* Low-level exception handling code |
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* |
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* Copyright (C) 2012 ARM Ltd. |
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* Authors: Catalin Marinas <catalin.marinas@arm.com> |
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* Will Deacon <will.deacon@arm.com> |
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*/ |
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#include <linux/arm-smccc.h> |
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#include <linux/init.h> |
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#include <linux/linkage.h> |
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#include <asm/alternative.h> |
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#include <asm/assembler.h> |
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#include <asm/asm-offsets.h> |
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#include <asm/asm_pointer_auth.h> |
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#include <asm/bug.h> |
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#include <asm/cpufeature.h> |
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#include <asm/errno.h> |
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#include <asm/esr.h> |
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#include <asm/irq.h> |
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#include <asm/memory.h> |
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#include <asm/mmu.h> |
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#include <asm/processor.h> |
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#include <asm/ptrace.h> |
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#include <asm/scs.h> |
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#include <asm/thread_info.h> |
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#include <asm/asm-uaccess.h> |
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#include <asm/unistd.h> |
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.macro clear_gp_regs |
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.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 |
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mov x\n, xzr |
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.endr |
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.endm |
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.macro kernel_ventry, el:req, ht:req, regsize:req, label:req |
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.align 7 |
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#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 |
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.if \el == 0 |
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alternative_if ARM64_UNMAP_KERNEL_AT_EL0 |
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.if \regsize == 64 |
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mrs x30, tpidrro_el0 |
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msr tpidrro_el0, xzr |
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.else |
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mov x30, xzr |
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.endif |
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alternative_else_nop_endif |
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.endif |
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#endif |
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sub sp, sp, #PT_REGS_SIZE |
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#ifdef CONFIG_VMAP_STACK |
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/* |
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* Test whether the SP has overflowed, without corrupting a GPR. |
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* Task and IRQ stacks are aligned so that SP & (1 << THREAD_SHIFT) |
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* should always be zero. |
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*/ |
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add sp, sp, x0 // sp' = sp + x0 |
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sub x0, sp, x0 // x0' = sp' - x0 = (sp + x0) - x0 = sp |
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tbnz x0, #THREAD_SHIFT, 0f |
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sub x0, sp, x0 // x0'' = sp' - x0' = (sp + x0) - sp = x0 |
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sub sp, sp, x0 // sp'' = sp' - x0 = (sp + x0) - x0 = sp |
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b el\el\ht\()_\regsize\()_\label |
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0: |
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/* |
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* Either we've just detected an overflow, or we've taken an exception |
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* while on the overflow stack. Either way, we won't return to |
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* userspace, and can clobber EL0 registers to free up GPRs. |
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*/ |
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/* Stash the original SP (minus PT_REGS_SIZE) in tpidr_el0. */ |
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msr tpidr_el0, x0 |
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/* Recover the original x0 value and stash it in tpidrro_el0 */ |
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sub x0, sp, x0 |
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msr tpidrro_el0, x0 |
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/* Switch to the overflow stack */ |
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adr_this_cpu sp, overflow_stack + OVERFLOW_STACK_SIZE, x0 |
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/* |
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* Check whether we were already on the overflow stack. This may happen |
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* after panic() re-enables interrupts. |
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*/ |
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mrs x0, tpidr_el0 // sp of interrupted context |
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sub x0, sp, x0 // delta with top of overflow stack |
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tst x0, #~(OVERFLOW_STACK_SIZE - 1) // within range? |
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b.ne __bad_stack // no? -> bad stack pointer |
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/* We were already on the overflow stack. Restore sp/x0 and carry on. */ |
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sub sp, sp, x0 |
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mrs x0, tpidrro_el0 |
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#endif |
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b el\el\ht\()_\regsize\()_\label |
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.endm |
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.macro tramp_alias, dst, sym |
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mov_q \dst, TRAMP_VALIAS |
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add \dst, \dst, #(\sym - .entry.tramp.text) |
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.endm |
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/* |
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* This macro corrupts x0-x3. It is the caller's duty to save/restore |
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* them if required. |
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*/ |
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.macro apply_ssbd, state, tmp1, tmp2 |
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alternative_cb spectre_v4_patch_fw_mitigation_enable |
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b .L__asm_ssbd_skip\@ // Patched to NOP |
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alternative_cb_end |
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ldr_this_cpu \tmp2, arm64_ssbd_callback_required, \tmp1 |
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cbz \tmp2, .L__asm_ssbd_skip\@ |
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ldr \tmp2, [tsk, #TSK_TI_FLAGS] |
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tbnz \tmp2, #TIF_SSBD, .L__asm_ssbd_skip\@ |
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mov w0, #ARM_SMCCC_ARCH_WORKAROUND_2 |
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mov w1, #\state |
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alternative_cb spectre_v4_patch_fw_mitigation_conduit |
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nop // Patched to SMC/HVC #0 |
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alternative_cb_end |
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.L__asm_ssbd_skip\@: |
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.endm |
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/* Check for MTE asynchronous tag check faults */ |
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.macro check_mte_async_tcf, tmp, ti_flags, thread_sctlr |
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#ifdef CONFIG_ARM64_MTE |
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.arch_extension lse |
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alternative_if_not ARM64_MTE |
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b 1f |
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alternative_else_nop_endif |
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/* |
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* Asynchronous tag check faults are only possible in ASYNC (2) or |
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* ASYM (3) modes. In each of these modes bit 1 of SCTLR_EL1.TCF0 is |
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* set, so skip the check if it is unset. |
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*/ |
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tbz \thread_sctlr, #(SCTLR_EL1_TCF0_SHIFT + 1), 1f |
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mrs_s \tmp, SYS_TFSRE0_EL1 |
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tbz \tmp, #SYS_TFSR_EL1_TF0_SHIFT, 1f |
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/* Asynchronous TCF occurred for TTBR0 access, set the TI flag */ |
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mov \tmp, #_TIF_MTE_ASYNC_FAULT |
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add \ti_flags, tsk, #TSK_TI_FLAGS |
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stset \tmp, [\ti_flags] |
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1: |
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#endif |
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.endm |
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/* Clear the MTE asynchronous tag check faults */ |
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.macro clear_mte_async_tcf thread_sctlr |
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#ifdef CONFIG_ARM64_MTE |
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alternative_if ARM64_MTE |
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/* See comment in check_mte_async_tcf above. */ |
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tbz \thread_sctlr, #(SCTLR_EL1_TCF0_SHIFT + 1), 1f |
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dsb ish |
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msr_s SYS_TFSRE0_EL1, xzr |
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1: |
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alternative_else_nop_endif |
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#endif |
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.endm |
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.macro mte_set_gcr, mte_ctrl, tmp |
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#ifdef CONFIG_ARM64_MTE |
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ubfx \tmp, \mte_ctrl, #MTE_CTRL_GCR_USER_EXCL_SHIFT, #16 |
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orr \tmp, \tmp, #SYS_GCR_EL1_RRND |
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msr_s SYS_GCR_EL1, \tmp |
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#endif |
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.endm |
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.macro mte_set_kernel_gcr, tmp, tmp2 |
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#ifdef CONFIG_KASAN_HW_TAGS |
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alternative_if_not ARM64_MTE |
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b 1f |
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alternative_else_nop_endif |
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mov \tmp, KERNEL_GCR_EL1 |
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msr_s SYS_GCR_EL1, \tmp |
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1: |
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#endif |
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.endm |
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.macro mte_set_user_gcr, tsk, tmp, tmp2 |
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#ifdef CONFIG_ARM64_MTE |
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alternative_if_not ARM64_MTE |
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b 1f |
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alternative_else_nop_endif |
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ldr \tmp, [\tsk, #THREAD_MTE_CTRL] |
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mte_set_gcr \tmp, \tmp2 |
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1: |
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#endif |
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.endm |
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.macro kernel_entry, el, regsize = 64 |
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.if \regsize == 32 |
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mov w0, w0 // zero upper 32 bits of x0 |
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.endif |
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stp x0, x1, [sp, #16 * 0] |
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stp x2, x3, [sp, #16 * 1] |
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stp x4, x5, [sp, #16 * 2] |
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stp x6, x7, [sp, #16 * 3] |
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stp x8, x9, [sp, #16 * 4] |
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stp x10, x11, [sp, #16 * 5] |
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stp x12, x13, [sp, #16 * 6] |
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stp x14, x15, [sp, #16 * 7] |
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stp x16, x17, [sp, #16 * 8] |
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stp x18, x19, [sp, #16 * 9] |
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stp x20, x21, [sp, #16 * 10] |
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stp x22, x23, [sp, #16 * 11] |
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stp x24, x25, [sp, #16 * 12] |
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stp x26, x27, [sp, #16 * 13] |
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stp x28, x29, [sp, #16 * 14] |
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.if \el == 0 |
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clear_gp_regs |
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mrs x21, sp_el0 |
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ldr_this_cpu tsk, __entry_task, x20 |
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msr sp_el0, tsk |
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/* |
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* Ensure MDSCR_EL1.SS is clear, since we can unmask debug exceptions |
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* when scheduling. |
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*/ |
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ldr x19, [tsk, #TSK_TI_FLAGS] |
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disable_step_tsk x19, x20 |
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/* Check for asynchronous tag check faults in user space */ |
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ldr x0, [tsk, THREAD_SCTLR_USER] |
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check_mte_async_tcf x22, x23, x0 |
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#ifdef CONFIG_ARM64_PTR_AUTH |
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alternative_if ARM64_HAS_ADDRESS_AUTH |
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/* |
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* Enable IA for in-kernel PAC if the task had it disabled. Although |
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* this could be implemented with an unconditional MRS which would avoid |
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* a load, this was measured to be slower on Cortex-A75 and Cortex-A76. |
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* |
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* Install the kernel IA key only if IA was enabled in the task. If IA |
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* was disabled on kernel exit then we would have left the kernel IA |
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* installed so there is no need to install it again. |
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*/ |
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tbz x0, SCTLR_ELx_ENIA_SHIFT, 1f |
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__ptrauth_keys_install_kernel_nosync tsk, x20, x22, x23 |
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b 2f |
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1: |
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mrs x0, sctlr_el1 |
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orr x0, x0, SCTLR_ELx_ENIA |
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msr sctlr_el1, x0 |
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2: |
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alternative_else_nop_endif |
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#endif |
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apply_ssbd 1, x22, x23 |
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mte_set_kernel_gcr x22, x23 |
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/* |
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* Any non-self-synchronizing system register updates required for |
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* kernel entry should be placed before this point. |
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*/ |
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alternative_if ARM64_MTE |
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isb |
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b 1f |
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alternative_else_nop_endif |
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alternative_if ARM64_HAS_ADDRESS_AUTH |
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isb |
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alternative_else_nop_endif |
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1: |
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scs_load tsk |
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.else |
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add x21, sp, #PT_REGS_SIZE |
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get_current_task tsk |
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.endif /* \el == 0 */ |
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mrs x22, elr_el1 |
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mrs x23, spsr_el1 |
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stp lr, x21, [sp, #S_LR] |
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/* |
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* For exceptions from EL0, create a final frame record. |
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* For exceptions from EL1, create a synthetic frame record so the |
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* interrupted code shows up in the backtrace. |
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*/ |
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.if \el == 0 |
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stp xzr, xzr, [sp, #S_STACKFRAME] |
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.else |
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stp x29, x22, [sp, #S_STACKFRAME] |
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.endif |
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add x29, sp, #S_STACKFRAME |
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#ifdef CONFIG_ARM64_SW_TTBR0_PAN |
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alternative_if_not ARM64_HAS_PAN |
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bl __swpan_entry_el\el |
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alternative_else_nop_endif |
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#endif |
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stp x22, x23, [sp, #S_PC] |
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/* Not in a syscall by default (el0_svc overwrites for real syscall) */ |
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.if \el == 0 |
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mov w21, #NO_SYSCALL |
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str w21, [sp, #S_SYSCALLNO] |
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.endif |
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/* Save pmr */ |
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alternative_if ARM64_HAS_IRQ_PRIO_MASKING |
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mrs_s x20, SYS_ICC_PMR_EL1 |
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str x20, [sp, #S_PMR_SAVE] |
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mov x20, #GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET |
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msr_s SYS_ICC_PMR_EL1, x20 |
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alternative_else_nop_endif |
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/* Re-enable tag checking (TCO set on exception entry) */ |
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#ifdef CONFIG_ARM64_MTE |
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alternative_if ARM64_MTE |
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SET_PSTATE_TCO(0) |
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alternative_else_nop_endif |
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#endif |
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/* |
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* Registers that may be useful after this macro is invoked: |
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* |
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* x20 - ICC_PMR_EL1 |
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* x21 - aborted SP |
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* x22 - aborted PC |
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* x23 - aborted PSTATE |
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*/ |
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.endm |
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.macro kernel_exit, el |
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.if \el != 0 |
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disable_daif |
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.endif |
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/* Restore pmr */ |
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alternative_if ARM64_HAS_IRQ_PRIO_MASKING |
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ldr x20, [sp, #S_PMR_SAVE] |
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msr_s SYS_ICC_PMR_EL1, x20 |
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mrs_s x21, SYS_ICC_CTLR_EL1 |
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tbz x21, #6, .L__skip_pmr_sync\@ // Check for ICC_CTLR_EL1.PMHE |
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dsb sy // Ensure priority change is seen by redistributor |
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.L__skip_pmr_sync\@: |
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alternative_else_nop_endif |
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ldp x21, x22, [sp, #S_PC] // load ELR, SPSR |
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#ifdef CONFIG_ARM64_SW_TTBR0_PAN |
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alternative_if_not ARM64_HAS_PAN |
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bl __swpan_exit_el\el |
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alternative_else_nop_endif |
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#endif |
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.if \el == 0 |
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ldr x23, [sp, #S_SP] // load return stack pointer |
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msr sp_el0, x23 |
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tst x22, #PSR_MODE32_BIT // native task? |
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b.eq 3f |
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#ifdef CONFIG_ARM64_ERRATUM_845719 |
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alternative_if ARM64_WORKAROUND_845719 |
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#ifdef CONFIG_PID_IN_CONTEXTIDR |
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mrs x29, contextidr_el1 |
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msr contextidr_el1, x29 |
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#else |
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msr contextidr_el1, xzr |
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#endif |
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alternative_else_nop_endif |
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#endif |
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3: |
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scs_save tsk |
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/* Ignore asynchronous tag check faults in the uaccess routines */ |
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ldr x0, [tsk, THREAD_SCTLR_USER] |
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clear_mte_async_tcf x0 |
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#ifdef CONFIG_ARM64_PTR_AUTH |
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alternative_if ARM64_HAS_ADDRESS_AUTH |
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/* |
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* IA was enabled for in-kernel PAC. Disable it now if needed, or |
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* alternatively install the user's IA. All other per-task keys and |
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* SCTLR bits were updated on task switch. |
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* |
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* No kernel C function calls after this. |
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*/ |
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tbz x0, SCTLR_ELx_ENIA_SHIFT, 1f |
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__ptrauth_keys_install_user tsk, x0, x1, x2 |
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b 2f |
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1: |
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mrs x0, sctlr_el1 |
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bic x0, x0, SCTLR_ELx_ENIA |
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msr sctlr_el1, x0 |
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2: |
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alternative_else_nop_endif |
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#endif |
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mte_set_user_gcr tsk, x0, x1 |
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apply_ssbd 0, x0, x1 |
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.endif |
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msr elr_el1, x21 // set up the return data |
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msr spsr_el1, x22 |
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ldp x0, x1, [sp, #16 * 0] |
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ldp x2, x3, [sp, #16 * 1] |
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ldp x4, x5, [sp, #16 * 2] |
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ldp x6, x7, [sp, #16 * 3] |
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ldp x8, x9, [sp, #16 * 4] |
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ldp x10, x11, [sp, #16 * 5] |
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ldp x12, x13, [sp, #16 * 6] |
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ldp x14, x15, [sp, #16 * 7] |
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ldp x16, x17, [sp, #16 * 8] |
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ldp x18, x19, [sp, #16 * 9] |
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ldp x20, x21, [sp, #16 * 10] |
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ldp x22, x23, [sp, #16 * 11] |
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ldp x24, x25, [sp, #16 * 12] |
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ldp x26, x27, [sp, #16 * 13] |
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ldp x28, x29, [sp, #16 * 14] |
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ldr lr, [sp, #S_LR] |
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add sp, sp, #PT_REGS_SIZE // restore sp |
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.if \el == 0 |
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alternative_insn eret, nop, ARM64_UNMAP_KERNEL_AT_EL0 |
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#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 |
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bne 4f |
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msr far_el1, x30 |
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tramp_alias x30, tramp_exit_native |
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br x30 |
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4: |
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tramp_alias x30, tramp_exit_compat |
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br x30 |
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#endif |
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.else |
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/* Ensure any device/NC reads complete */ |
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alternative_insn nop, "dmb sy", ARM64_WORKAROUND_1508412 |
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eret |
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.endif |
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sb |
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.endm |
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#ifdef CONFIG_ARM64_SW_TTBR0_PAN |
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/* |
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* Set the TTBR0 PAN bit in SPSR. When the exception is taken from |
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* EL0, there is no need to check the state of TTBR0_EL1 since |
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* accesses are always enabled. |
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* Note that the meaning of this bit differs from the ARMv8.1 PAN |
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* feature as all TTBR0_EL1 accesses are disabled, not just those to |
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* user mappings. |
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*/ |
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SYM_CODE_START_LOCAL(__swpan_entry_el1) |
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mrs x21, ttbr0_el1 |
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tst x21, #TTBR_ASID_MASK // Check for the reserved ASID |
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orr x23, x23, #PSR_PAN_BIT // Set the emulated PAN in the saved SPSR |
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b.eq 1f // TTBR0 access already disabled |
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and x23, x23, #~PSR_PAN_BIT // Clear the emulated PAN in the saved SPSR |
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SYM_INNER_LABEL(__swpan_entry_el0, SYM_L_LOCAL) |
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__uaccess_ttbr0_disable x21 |
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1: ret |
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SYM_CODE_END(__swpan_entry_el1) |
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/* |
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* Restore access to TTBR0_EL1. If returning to EL0, no need for SPSR |
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* PAN bit checking. |
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*/ |
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SYM_CODE_START_LOCAL(__swpan_exit_el1) |
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tbnz x22, #22, 1f // Skip re-enabling TTBR0 access if the PSR_PAN_BIT is set |
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__uaccess_ttbr0_enable x0, x1 |
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1: and x22, x22, #~PSR_PAN_BIT // ARMv8.0 CPUs do not understand this bit |
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ret |
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SYM_CODE_END(__swpan_exit_el1) |
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SYM_CODE_START_LOCAL(__swpan_exit_el0) |
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__uaccess_ttbr0_enable x0, x1 |
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/* |
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* Enable errata workarounds only if returning to user. The only |
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* workaround currently required for TTBR0_EL1 changes are for the |
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* Cavium erratum 27456 (broadcast TLBI instructions may cause I-cache |
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* corruption). |
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*/ |
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b post_ttbr_update_workaround |
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SYM_CODE_END(__swpan_exit_el0) |
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#endif |
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/* GPRs used by entry code */ |
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tsk .req x28 // current thread_info |
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.text |
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/* |
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* Exception vectors. |
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*/ |
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.pushsection ".entry.text", "ax" |
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.align 11 |
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SYM_CODE_START(vectors) |
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kernel_ventry 1, t, 64, sync // Synchronous EL1t |
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kernel_ventry 1, t, 64, irq // IRQ EL1t |
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kernel_ventry 1, t, 64, fiq // FIQ EL1h |
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kernel_ventry 1, t, 64, error // Error EL1t |
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kernel_ventry 1, h, 64, sync // Synchronous EL1h |
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kernel_ventry 1, h, 64, irq // IRQ EL1h |
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kernel_ventry 1, h, 64, fiq // FIQ EL1h |
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kernel_ventry 1, h, 64, error // Error EL1h |
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kernel_ventry 0, t, 64, sync // Synchronous 64-bit EL0 |
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kernel_ventry 0, t, 64, irq // IRQ 64-bit EL0 |
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kernel_ventry 0, t, 64, fiq // FIQ 64-bit EL0 |
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kernel_ventry 0, t, 64, error // Error 64-bit EL0 |
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kernel_ventry 0, t, 32, sync // Synchronous 32-bit EL0 |
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kernel_ventry 0, t, 32, irq // IRQ 32-bit EL0 |
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kernel_ventry 0, t, 32, fiq // FIQ 32-bit EL0 |
|
kernel_ventry 0, t, 32, error // Error 32-bit EL0 |
|
SYM_CODE_END(vectors) |
|
|
|
#ifdef CONFIG_VMAP_STACK |
|
SYM_CODE_START_LOCAL(__bad_stack) |
|
/* |
|
* We detected an overflow in kernel_ventry, which switched to the |
|
* overflow stack. Stash the exception regs, and head to our overflow |
|
* handler. |
|
*/ |
|
|
|
/* Restore the original x0 value */ |
|
mrs x0, tpidrro_el0 |
|
|
|
/* |
|
* Store the original GPRs to the new stack. The orginal SP (minus |
|
* PT_REGS_SIZE) was stashed in tpidr_el0 by kernel_ventry. |
|
*/ |
|
sub sp, sp, #PT_REGS_SIZE |
|
kernel_entry 1 |
|
mrs x0, tpidr_el0 |
|
add x0, x0, #PT_REGS_SIZE |
|
str x0, [sp, #S_SP] |
|
|
|
/* Stash the regs for handle_bad_stack */ |
|
mov x0, sp |
|
|
|
/* Time to die */ |
|
bl handle_bad_stack |
|
ASM_BUG() |
|
SYM_CODE_END(__bad_stack) |
|
#endif /* CONFIG_VMAP_STACK */ |
|
|
|
|
|
.macro entry_handler el:req, ht:req, regsize:req, label:req |
|
SYM_CODE_START_LOCAL(el\el\ht\()_\regsize\()_\label) |
|
kernel_entry \el, \regsize |
|
mov x0, sp |
|
bl el\el\ht\()_\regsize\()_\label\()_handler |
|
.if \el == 0 |
|
b ret_to_user |
|
.else |
|
b ret_to_kernel |
|
.endif |
|
SYM_CODE_END(el\el\ht\()_\regsize\()_\label) |
|
.endm |
|
|
|
/* |
|
* Early exception handlers |
|
*/ |
|
entry_handler 1, t, 64, sync |
|
entry_handler 1, t, 64, irq |
|
entry_handler 1, t, 64, fiq |
|
entry_handler 1, t, 64, error |
|
|
|
entry_handler 1, h, 64, sync |
|
entry_handler 1, h, 64, irq |
|
entry_handler 1, h, 64, fiq |
|
entry_handler 1, h, 64, error |
|
|
|
entry_handler 0, t, 64, sync |
|
entry_handler 0, t, 64, irq |
|
entry_handler 0, t, 64, fiq |
|
entry_handler 0, t, 64, error |
|
|
|
entry_handler 0, t, 32, sync |
|
entry_handler 0, t, 32, irq |
|
entry_handler 0, t, 32, fiq |
|
entry_handler 0, t, 32, error |
|
|
|
SYM_CODE_START_LOCAL(ret_to_kernel) |
|
kernel_exit 1 |
|
SYM_CODE_END(ret_to_kernel) |
|
|
|
SYM_CODE_START_LOCAL(ret_to_user) |
|
ldr x19, [tsk, #TSK_TI_FLAGS] // re-check for single-step |
|
enable_step_tsk x19, x2 |
|
#ifdef CONFIG_GCC_PLUGIN_STACKLEAK |
|
bl stackleak_erase |
|
#endif |
|
kernel_exit 0 |
|
SYM_CODE_END(ret_to_user) |
|
|
|
.popsection // .entry.text |
|
|
|
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 |
|
/* |
|
* Exception vectors trampoline. |
|
*/ |
|
.pushsection ".entry.tramp.text", "ax" |
|
|
|
// Move from tramp_pg_dir to swapper_pg_dir |
|
.macro tramp_map_kernel, tmp |
|
mrs \tmp, ttbr1_el1 |
|
add \tmp, \tmp, #TRAMP_SWAPPER_OFFSET |
|
bic \tmp, \tmp, #USER_ASID_FLAG |
|
msr ttbr1_el1, \tmp |
|
#ifdef CONFIG_QCOM_FALKOR_ERRATUM_1003 |
|
alternative_if ARM64_WORKAROUND_QCOM_FALKOR_E1003 |
|
/* ASID already in \tmp[63:48] */ |
|
movk \tmp, #:abs_g2_nc:(TRAMP_VALIAS >> 12) |
|
movk \tmp, #:abs_g1_nc:(TRAMP_VALIAS >> 12) |
|
/* 2MB boundary containing the vectors, so we nobble the walk cache */ |
|
movk \tmp, #:abs_g0_nc:((TRAMP_VALIAS & ~(SZ_2M - 1)) >> 12) |
|
isb |
|
tlbi vae1, \tmp |
|
dsb nsh |
|
alternative_else_nop_endif |
|
#endif /* CONFIG_QCOM_FALKOR_ERRATUM_1003 */ |
|
.endm |
|
|
|
// Move from swapper_pg_dir to tramp_pg_dir |
|
.macro tramp_unmap_kernel, tmp |
|
mrs \tmp, ttbr1_el1 |
|
sub \tmp, \tmp, #TRAMP_SWAPPER_OFFSET |
|
orr \tmp, \tmp, #USER_ASID_FLAG |
|
msr ttbr1_el1, \tmp |
|
/* |
|
* We avoid running the post_ttbr_update_workaround here because |
|
* it's only needed by Cavium ThunderX, which requires KPTI to be |
|
* disabled. |
|
*/ |
|
.endm |
|
|
|
.macro tramp_ventry, regsize = 64 |
|
.align 7 |
|
1: |
|
.if \regsize == 64 |
|
msr tpidrro_el0, x30 // Restored in kernel_ventry |
|
.endif |
|
/* |
|
* Defend against branch aliasing attacks by pushing a dummy |
|
* entry onto the return stack and using a RET instruction to |
|
* enter the full-fat kernel vectors. |
|
*/ |
|
bl 2f |
|
b . |
|
2: |
|
tramp_map_kernel x30 |
|
#ifdef CONFIG_RANDOMIZE_BASE |
|
adr x30, tramp_vectors + PAGE_SIZE |
|
alternative_insn isb, nop, ARM64_WORKAROUND_QCOM_FALKOR_E1003 |
|
ldr x30, [x30] |
|
#else |
|
ldr x30, =vectors |
|
#endif |
|
alternative_if_not ARM64_WORKAROUND_CAVIUM_TX2_219_PRFM |
|
prfm plil1strm, [x30, #(1b - tramp_vectors)] |
|
alternative_else_nop_endif |
|
msr vbar_el1, x30 |
|
add x30, x30, #(1b - tramp_vectors) |
|
isb |
|
ret |
|
.endm |
|
|
|
.macro tramp_exit, regsize = 64 |
|
adr x30, tramp_vectors |
|
msr vbar_el1, x30 |
|
tramp_unmap_kernel x30 |
|
.if \regsize == 64 |
|
mrs x30, far_el1 |
|
.endif |
|
eret |
|
sb |
|
.endm |
|
|
|
.align 11 |
|
SYM_CODE_START_NOALIGN(tramp_vectors) |
|
.space 0x400 |
|
|
|
tramp_ventry |
|
tramp_ventry |
|
tramp_ventry |
|
tramp_ventry |
|
|
|
tramp_ventry 32 |
|
tramp_ventry 32 |
|
tramp_ventry 32 |
|
tramp_ventry 32 |
|
SYM_CODE_END(tramp_vectors) |
|
|
|
SYM_CODE_START(tramp_exit_native) |
|
tramp_exit |
|
SYM_CODE_END(tramp_exit_native) |
|
|
|
SYM_CODE_START(tramp_exit_compat) |
|
tramp_exit 32 |
|
SYM_CODE_END(tramp_exit_compat) |
|
|
|
.ltorg |
|
.popsection // .entry.tramp.text |
|
#ifdef CONFIG_RANDOMIZE_BASE |
|
.pushsection ".rodata", "a" |
|
.align PAGE_SHIFT |
|
SYM_DATA_START(__entry_tramp_data_start) |
|
.quad vectors |
|
SYM_DATA_END(__entry_tramp_data_start) |
|
.popsection // .rodata |
|
#endif /* CONFIG_RANDOMIZE_BASE */ |
|
#endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */ |
|
|
|
/* |
|
* Register switch for AArch64. The callee-saved registers need to be saved |
|
* and restored. On entry: |
|
* x0 = previous task_struct (must be preserved across the switch) |
|
* x1 = next task_struct |
|
* Previous and next are guaranteed not to be the same. |
|
* |
|
*/ |
|
SYM_FUNC_START(cpu_switch_to) |
|
mov x10, #THREAD_CPU_CONTEXT |
|
add x8, x0, x10 |
|
mov x9, sp |
|
stp x19, x20, [x8], #16 // store callee-saved registers |
|
stp x21, x22, [x8], #16 |
|
stp x23, x24, [x8], #16 |
|
stp x25, x26, [x8], #16 |
|
stp x27, x28, [x8], #16 |
|
stp x29, x9, [x8], #16 |
|
str lr, [x8] |
|
add x8, x1, x10 |
|
ldp x19, x20, [x8], #16 // restore callee-saved registers |
|
ldp x21, x22, [x8], #16 |
|
ldp x23, x24, [x8], #16 |
|
ldp x25, x26, [x8], #16 |
|
ldp x27, x28, [x8], #16 |
|
ldp x29, x9, [x8], #16 |
|
ldr lr, [x8] |
|
mov sp, x9 |
|
msr sp_el0, x1 |
|
ptrauth_keys_install_kernel x1, x8, x9, x10 |
|
scs_save x0 |
|
scs_load x1 |
|
ret |
|
SYM_FUNC_END(cpu_switch_to) |
|
NOKPROBE(cpu_switch_to) |
|
|
|
/* |
|
* This is how we return from a fork. |
|
*/ |
|
SYM_CODE_START(ret_from_fork) |
|
bl schedule_tail |
|
cbz x19, 1f // not a kernel thread |
|
mov x0, x20 |
|
blr x19 |
|
1: get_current_task tsk |
|
mov x0, sp |
|
bl asm_exit_to_user_mode |
|
b ret_to_user |
|
SYM_CODE_END(ret_from_fork) |
|
NOKPROBE(ret_from_fork) |
|
|
|
/* |
|
* void call_on_irq_stack(struct pt_regs *regs, |
|
* void (*func)(struct pt_regs *)); |
|
* |
|
* Calls func(regs) using this CPU's irq stack and shadow irq stack. |
|
*/ |
|
SYM_FUNC_START(call_on_irq_stack) |
|
#ifdef CONFIG_SHADOW_CALL_STACK |
|
stp scs_sp, xzr, [sp, #-16]! |
|
ldr_this_cpu scs_sp, irq_shadow_call_stack_ptr, x17 |
|
#endif |
|
/* Create a frame record to save our LR and SP (implicit in FP) */ |
|
stp x29, x30, [sp, #-16]! |
|
mov x29, sp |
|
|
|
ldr_this_cpu x16, irq_stack_ptr, x17 |
|
mov x15, #IRQ_STACK_SIZE |
|
add x16, x16, x15 |
|
|
|
/* Move to the new stack and call the function there */ |
|
mov sp, x16 |
|
blr x1 |
|
|
|
/* |
|
* Restore the SP from the FP, and restore the FP and LR from the frame |
|
* record. |
|
*/ |
|
mov sp, x29 |
|
ldp x29, x30, [sp], #16 |
|
#ifdef CONFIG_SHADOW_CALL_STACK |
|
ldp scs_sp, xzr, [sp], #16 |
|
#endif |
|
ret |
|
SYM_FUNC_END(call_on_irq_stack) |
|
NOKPROBE(call_on_irq_stack) |
|
|
|
#ifdef CONFIG_ARM_SDE_INTERFACE |
|
|
|
#include <asm/sdei.h> |
|
#include <uapi/linux/arm_sdei.h> |
|
|
|
.macro sdei_handler_exit exit_mode |
|
/* On success, this call never returns... */ |
|
cmp \exit_mode, #SDEI_EXIT_SMC |
|
b.ne 99f |
|
smc #0 |
|
b . |
|
99: hvc #0 |
|
b . |
|
.endm |
|
|
|
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 |
|
/* |
|
* The regular SDEI entry point may have been unmapped along with the rest of |
|
* the kernel. This trampoline restores the kernel mapping to make the x1 memory |
|
* argument accessible. |
|
* |
|
* This clobbers x4, __sdei_handler() will restore this from firmware's |
|
* copy. |
|
*/ |
|
.ltorg |
|
.pushsection ".entry.tramp.text", "ax" |
|
SYM_CODE_START(__sdei_asm_entry_trampoline) |
|
mrs x4, ttbr1_el1 |
|
tbz x4, #USER_ASID_BIT, 1f |
|
|
|
tramp_map_kernel tmp=x4 |
|
isb |
|
mov x4, xzr |
|
|
|
/* |
|
* Remember whether to unmap the kernel on exit. |
|
*/ |
|
1: str x4, [x1, #(SDEI_EVENT_INTREGS + S_SDEI_TTBR1)] |
|
|
|
#ifdef CONFIG_RANDOMIZE_BASE |
|
adr x4, tramp_vectors + PAGE_SIZE |
|
add x4, x4, #:lo12:__sdei_asm_trampoline_next_handler |
|
ldr x4, [x4] |
|
#else |
|
ldr x4, =__sdei_asm_handler |
|
#endif |
|
br x4 |
|
SYM_CODE_END(__sdei_asm_entry_trampoline) |
|
NOKPROBE(__sdei_asm_entry_trampoline) |
|
|
|
/* |
|
* Make the exit call and restore the original ttbr1_el1 |
|
* |
|
* x0 & x1: setup for the exit API call |
|
* x2: exit_mode |
|
* x4: struct sdei_registered_event argument from registration time. |
|
*/ |
|
SYM_CODE_START(__sdei_asm_exit_trampoline) |
|
ldr x4, [x4, #(SDEI_EVENT_INTREGS + S_SDEI_TTBR1)] |
|
cbnz x4, 1f |
|
|
|
tramp_unmap_kernel tmp=x4 |
|
|
|
1: sdei_handler_exit exit_mode=x2 |
|
SYM_CODE_END(__sdei_asm_exit_trampoline) |
|
NOKPROBE(__sdei_asm_exit_trampoline) |
|
.ltorg |
|
.popsection // .entry.tramp.text |
|
#ifdef CONFIG_RANDOMIZE_BASE |
|
.pushsection ".rodata", "a" |
|
SYM_DATA_START(__sdei_asm_trampoline_next_handler) |
|
.quad __sdei_asm_handler |
|
SYM_DATA_END(__sdei_asm_trampoline_next_handler) |
|
.popsection // .rodata |
|
#endif /* CONFIG_RANDOMIZE_BASE */ |
|
#endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */ |
|
|
|
/* |
|
* Software Delegated Exception entry point. |
|
* |
|
* x0: Event number |
|
* x1: struct sdei_registered_event argument from registration time. |
|
* x2: interrupted PC |
|
* x3: interrupted PSTATE |
|
* x4: maybe clobbered by the trampoline |
|
* |
|
* Firmware has preserved x0->x17 for us, we must save/restore the rest to |
|
* follow SMC-CC. We save (or retrieve) all the registers as the handler may |
|
* want them. |
|
*/ |
|
SYM_CODE_START(__sdei_asm_handler) |
|
stp x2, x3, [x1, #SDEI_EVENT_INTREGS + S_PC] |
|
stp x4, x5, [x1, #SDEI_EVENT_INTREGS + 16 * 2] |
|
stp x6, x7, [x1, #SDEI_EVENT_INTREGS + 16 * 3] |
|
stp x8, x9, [x1, #SDEI_EVENT_INTREGS + 16 * 4] |
|
stp x10, x11, [x1, #SDEI_EVENT_INTREGS + 16 * 5] |
|
stp x12, x13, [x1, #SDEI_EVENT_INTREGS + 16 * 6] |
|
stp x14, x15, [x1, #SDEI_EVENT_INTREGS + 16 * 7] |
|
stp x16, x17, [x1, #SDEI_EVENT_INTREGS + 16 * 8] |
|
stp x18, x19, [x1, #SDEI_EVENT_INTREGS + 16 * 9] |
|
stp x20, x21, [x1, #SDEI_EVENT_INTREGS + 16 * 10] |
|
stp x22, x23, [x1, #SDEI_EVENT_INTREGS + 16 * 11] |
|
stp x24, x25, [x1, #SDEI_EVENT_INTREGS + 16 * 12] |
|
stp x26, x27, [x1, #SDEI_EVENT_INTREGS + 16 * 13] |
|
stp x28, x29, [x1, #SDEI_EVENT_INTREGS + 16 * 14] |
|
mov x4, sp |
|
stp lr, x4, [x1, #SDEI_EVENT_INTREGS + S_LR] |
|
|
|
mov x19, x1 |
|
|
|
#if defined(CONFIG_VMAP_STACK) || defined(CONFIG_SHADOW_CALL_STACK) |
|
ldrb w4, [x19, #SDEI_EVENT_PRIORITY] |
|
#endif |
|
|
|
#ifdef CONFIG_VMAP_STACK |
|
/* |
|
* entry.S may have been using sp as a scratch register, find whether |
|
* this is a normal or critical event and switch to the appropriate |
|
* stack for this CPU. |
|
*/ |
|
cbnz w4, 1f |
|
ldr_this_cpu dst=x5, sym=sdei_stack_normal_ptr, tmp=x6 |
|
b 2f |
|
1: ldr_this_cpu dst=x5, sym=sdei_stack_critical_ptr, tmp=x6 |
|
2: mov x6, #SDEI_STACK_SIZE |
|
add x5, x5, x6 |
|
mov sp, x5 |
|
#endif |
|
|
|
#ifdef CONFIG_SHADOW_CALL_STACK |
|
/* Use a separate shadow call stack for normal and critical events */ |
|
cbnz w4, 3f |
|
ldr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_normal_ptr, tmp=x6 |
|
b 4f |
|
3: ldr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_critical_ptr, tmp=x6 |
|
4: |
|
#endif |
|
|
|
/* |
|
* We may have interrupted userspace, or a guest, or exit-from or |
|
* return-to either of these. We can't trust sp_el0, restore it. |
|
*/ |
|
mrs x28, sp_el0 |
|
ldr_this_cpu dst=x0, sym=__entry_task, tmp=x1 |
|
msr sp_el0, x0 |
|
|
|
/* If we interrupted the kernel point to the previous stack/frame. */ |
|
and x0, x3, #0xc |
|
mrs x1, CurrentEL |
|
cmp x0, x1 |
|
csel x29, x29, xzr, eq // fp, or zero |
|
csel x4, x2, xzr, eq // elr, or zero |
|
|
|
stp x29, x4, [sp, #-16]! |
|
mov x29, sp |
|
|
|
add x0, x19, #SDEI_EVENT_INTREGS |
|
mov x1, x19 |
|
bl __sdei_handler |
|
|
|
msr sp_el0, x28 |
|
/* restore regs >x17 that we clobbered */ |
|
mov x4, x19 // keep x4 for __sdei_asm_exit_trampoline |
|
ldp x28, x29, [x4, #SDEI_EVENT_INTREGS + 16 * 14] |
|
ldp x18, x19, [x4, #SDEI_EVENT_INTREGS + 16 * 9] |
|
ldp lr, x1, [x4, #SDEI_EVENT_INTREGS + S_LR] |
|
mov sp, x1 |
|
|
|
mov x1, x0 // address to complete_and_resume |
|
/* x0 = (x0 <= 1) ? EVENT_COMPLETE:EVENT_COMPLETE_AND_RESUME */ |
|
cmp x0, #1 |
|
mov_q x2, SDEI_1_0_FN_SDEI_EVENT_COMPLETE |
|
mov_q x3, SDEI_1_0_FN_SDEI_EVENT_COMPLETE_AND_RESUME |
|
csel x0, x2, x3, ls |
|
|
|
ldr_l x2, sdei_exit_mode |
|
|
|
alternative_if_not ARM64_UNMAP_KERNEL_AT_EL0 |
|
sdei_handler_exit exit_mode=x2 |
|
alternative_else_nop_endif |
|
|
|
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 |
|
tramp_alias dst=x5, sym=__sdei_asm_exit_trampoline |
|
br x5 |
|
#endif |
|
SYM_CODE_END(__sdei_asm_handler) |
|
NOKPROBE(__sdei_asm_handler) |
|
#endif /* CONFIG_ARM_SDE_INTERFACE */
|
|
|