diff options
Diffstat (limited to 'arch/arm64/kernel/entry.S')
| -rw-r--r-- | arch/arm64/kernel/entry.S | 415 |
1 files changed, 369 insertions, 46 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 3028d9b028c7..4ed652aa62fd 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -27,8 +27,12 @@ #include <asm/cpufeature.h> #include <asm/errno.h> #include <asm/esr.h> +#include <asm/irq.h> #include <asm/memory.h> +#include <asm/mmu.h> +#include <asm/ptrace.h> #include <asm/thread_info.h> +#include <asm/uaccess.h> #include <asm/asm-uaccess.h> #include <asm/unistd.h> @@ -67,8 +71,31 @@ #define BAD_FIQ 2 #define BAD_ERROR 3 - .macro kernel_entry, el, regsize = 64 + .macro kernel_ventry, el, label, regsize = 64 + .align 7 +#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 +alternative_if ARM64_UNMAP_KERNEL_AT_EL0 + .if \el == 0 + .if \regsize == 64 + mrs x30, tpidrro_el0 + msr tpidrro_el0, xzr + .else + mov x30, xzr + .endif + .endif +alternative_else_nop_endif +#endif + sub sp, sp, #S_FRAME_SIZE + b el\()\el\()_\label + .endm + + .macro tramp_alias, dst, sym + mov_q \dst, TRAMP_VALIAS + add \dst, \dst, #(\sym - .entry.tramp.text) + .endm + + .macro kernel_entry, el, regsize = 64 .if \regsize == 32 mov w0, w0 // zero upper 32 bits of x0 .endif @@ -90,21 +117,64 @@ .if \el == 0 mrs x21, sp_el0 - get_thread_info tsk // Ensure MDSCR_EL1.SS is clear, +#ifdef CONFIG_THREAD_INFO_IN_TASK + ldr_this_cpu tsk, __entry_task, x20 // Ensure MDSCR_EL1.SS is clear, + ldr x19, [tsk, #TSK_TI_FLAGS] // since we can unmask debug +#else + mov tsk, sp + and tsk, tsk, #~(THREAD_SIZE - 1) // Ensure MDSCR_EL1.SS is clear, ldr x19, [tsk, #TI_FLAGS] // since we can unmask debug +#endif disable_step_tsk x19, x20 // exceptions when scheduling. + + mov x29, xzr // fp pointed to user-space .else add x21, sp, #S_FRAME_SIZE get_thread_info tsk /* Save the task's original addr_limit and set USER_DS (TASK_SIZE_64) */ +#ifdef CONFIG_THREAD_INFO_IN_TASK + ldr x20, [tsk, #TSK_TI_ADDR_LIMIT] +#else ldr x20, [tsk, #TI_ADDR_LIMIT] +#endif str x20, [sp, #S_ORIG_ADDR_LIMIT] mov x20, #TASK_SIZE_64 +#ifdef CONFIG_THREAD_INFO_IN_TASK + str x20, [tsk, #TSK_TI_ADDR_LIMIT] +#else str x20, [tsk, #TI_ADDR_LIMIT] +#endif + ALTERNATIVE(nop, SET_PSTATE_UAO(0), ARM64_HAS_UAO, CONFIG_ARM64_UAO) .endif /* \el == 0 */ mrs x22, elr_el1 mrs x23, spsr_el1 stp lr, x21, [sp, #S_LR] + +#ifdef CONFIG_ARM64_SW_TTBR0_PAN + /* + * Set the TTBR0 PAN bit in SPSR. When the exception is taken from + * EL0, there is no need to check the state of TTBR0_EL1 since + * accesses are always enabled. + * Note that the meaning of this bit differs from the ARMv8.1 PAN + * feature as all TTBR0_EL1 accesses are disabled, not just those to + * user mappings. + */ +alternative_if ARM64_HAS_PAN + b 1f // skip TTBR0 PAN +alternative_else_nop_endif + + .if \el != 0 + mrs x21, ttbr0_el1 + tst x21, #TTBR_ASID_MASK // Check for the reserved ASID + orr x23, x23, #PSR_PAN_BIT // Set the emulated PAN in the saved SPSR + b.eq 1f // TTBR0 access already disabled + and x23, x23, #~PSR_PAN_BIT // Clear the emulated PAN in the saved SPSR + .endif + + __uaccess_ttbr0_disable x21 +1: +#endif + stp x22, x23, [sp, #S_PC] /* @@ -116,6 +186,13 @@ .endif /* + * Set sp_el0 to current thread_info. + */ + .if \el == 0 + msr sp_el0, tsk + .endif + + /* * Registers that may be useful after this macro is invoked: * * x21 - aborted SP @@ -128,33 +205,70 @@ .if \el != 0 /* Restore the task's original addr_limit. */ ldr x20, [sp, #S_ORIG_ADDR_LIMIT] +#ifdef CONFIG_THREAD_INFO_IN_TASK + str x20, [tsk, #TSK_TI_ADDR_LIMIT] +#else str x20, [tsk, #TI_ADDR_LIMIT] +#endif + + /* No need to restore UAO, it will be restored from SPSR_EL1 */ .endif ldp x21, x22, [sp, #S_PC] // load ELR, SPSR .if \el == 0 ct_user_enter + .endif + +#ifdef CONFIG_ARM64_SW_TTBR0_PAN + /* + * Restore access to TTBR0_EL1. If returning to EL0, no need for SPSR + * PAN bit checking. + */ +alternative_if ARM64_HAS_PAN + b 2f // skip TTBR0 PAN +alternative_else_nop_endif + + .if \el != 0 + tbnz x22, #22, 1f // Skip re-enabling TTBR0 access if the PSR_PAN_BIT is set + .endif + + __uaccess_ttbr0_enable x0, x1 + + .if \el == 0 + /* + * Enable errata workarounds only if returning to user. The only + * workaround currently required for TTBR0_EL1 changes are for the + * Cavium erratum 27456 (broadcast TLBI instructions may cause I-cache + * corruption). + */ + bl post_ttbr_update_workaround + .endif +1: + .if \el != 0 + and x22, x22, #~PSR_PAN_BIT // ARMv8.0 CPUs do not understand this bit + .endif +2: +#endif + + .if \el == 0 ldr x23, [sp, #S_SP] // load return stack pointer msr sp_el0, x23 + tst x22, #PSR_MODE32_BIT // native task? + b.eq 3f + #ifdef CONFIG_ARM64_ERRATUM_845719 -alternative_if_not ARM64_WORKAROUND_845719 - nop - nop -#ifdef CONFIG_PID_IN_CONTEXTIDR - nop -#endif -alternative_else - tbz x22, #4, 1f +alternative_if ARM64_WORKAROUND_845719 #ifdef CONFIG_PID_IN_CONTEXTIDR mrs x29, contextidr_el1 msr contextidr_el1, x29 #else msr contextidr_el1, xzr #endif -1: -alternative_endif +alternative_else_nop_endif #endif +3: .endif + msr elr_el1, x21 // set up the return data msr spsr_el1, x22 ldp x0, x1, [sp, #16 * 0] @@ -174,12 +288,65 @@ alternative_endif ldp x28, x29, [sp, #16 * 14] ldr lr, [sp, #S_LR] add sp, sp, #S_FRAME_SIZE // restore sp - eret // return to kernel + + .if \el == 0 +alternative_insn eret, nop, ARM64_UNMAP_KERNEL_AT_EL0 +#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 + bne 4f + msr far_el1, x30 + tramp_alias x30, tramp_exit_native + br x30 +4: + tramp_alias x30, tramp_exit_compat + br x30 +#endif + .else + eret + .endif .endm - .macro get_thread_info, rd - mov \rd, sp - and \rd, \rd, #~(THREAD_SIZE - 1) // top of stack + .macro irq_stack_entry + mov x19, sp // preserve the original sp + + /* + * Compare sp with the base of the task stack. + * If the top ~(THREAD_SIZE - 1) bits match, we are on a task stack, + * and should switch to the irq stack. + */ +#ifdef CONFIG_THREAD_INFO_IN_TASK + ldr x25, [tsk, TSK_STACK] + eor x25, x25, x19 + and x25, x25, #~(THREAD_SIZE - 1) + cbnz x25, 9998f +#else + and x25, x19, #~(THREAD_SIZE - 1) + cmp x25, tsk + b.ne 9998f +#endif + + adr_this_cpu x25, irq_stack, x26 + mov x26, #IRQ_STACK_START_SP + add x26, x25, x26 + + /* switch to the irq stack */ + mov sp, x26 + + /* + * Add a dummy stack frame, this non-standard format is fixed up + * by unwind_frame() + */ + stp x29, x19, [sp, #-16]! + mov x29, sp + +9998: + .endm + + /* + * x19 should be preserved between irq_stack_entry and + * irq_stack_exit. + */ + .macro irq_stack_exit + mov sp, x19 .endm /* @@ -197,10 +364,11 @@ tsk .req x28 // current thread_info * Interrupt handling. */ .macro irq_handler - adrp x1, handle_arch_irq - ldr x1, [x1, #:lo12:handle_arch_irq] + ldr_l x1, handle_arch_irq mov x0, sp + irq_stack_entry blr x1 + irq_stack_exit .endm .text @@ -211,31 +379,31 @@ tsk .req x28 // current thread_info .align 11 ENTRY(vectors) - ventry el1_sync_invalid // Synchronous EL1t - ventry el1_irq_invalid // IRQ EL1t - ventry el1_fiq_invalid // FIQ EL1t - ventry el1_error_invalid // Error EL1t + kernel_ventry 1, sync_invalid // Synchronous EL1t + kernel_ventry 1, irq_invalid // IRQ EL1t + kernel_ventry 1, fiq_invalid // FIQ EL1t + kernel_ventry 1, error_invalid // Error EL1t - ventry el1_sync // Synchronous EL1h - ventry el1_irq // IRQ EL1h - ventry el1_fiq_invalid // FIQ EL1h - ventry el1_error_invalid // Error EL1h + kernel_ventry 1, sync // Synchronous EL1h + kernel_ventry 1, irq // IRQ EL1h + kernel_ventry 1, fiq_invalid // FIQ EL1h + kernel_ventry 1, error_invalid // Error EL1h - ventry el0_sync // Synchronous 64-bit EL0 - ventry el0_irq // IRQ 64-bit EL0 - ventry el0_fiq_invalid // FIQ 64-bit EL0 - ventry el0_error_invalid // Error 64-bit EL0 + kernel_ventry 0, sync // Synchronous 64-bit EL0 + kernel_ventry 0, irq // IRQ 64-bit EL0 + kernel_ventry 0, fiq_invalid // FIQ 64-bit EL0 + kernel_ventry 0, error_invalid // Error 64-bit EL0 #ifdef CONFIG_COMPAT - ventry el0_sync_compat // Synchronous 32-bit EL0 - ventry el0_irq_compat // IRQ 32-bit EL0 - ventry el0_fiq_invalid_compat // FIQ 32-bit EL0 - ventry el0_error_invalid_compat // Error 32-bit EL0 + kernel_ventry 0, sync_compat, 32 // Synchronous 32-bit EL0 + kernel_ventry 0, irq_compat, 32 // IRQ 32-bit EL0 + kernel_ventry 0, fiq_invalid_compat, 32 // FIQ 32-bit EL0 + kernel_ventry 0, error_invalid_compat, 32 // Error 32-bit EL0 #else - ventry el0_sync_invalid // Synchronous 32-bit EL0 - ventry el0_irq_invalid // IRQ 32-bit EL0 - ventry el0_fiq_invalid // FIQ 32-bit EL0 - ventry el0_error_invalid // Error 32-bit EL0 + kernel_ventry 0, sync_invalid, 32 // Synchronous 32-bit EL0 + kernel_ventry 0, irq_invalid, 32 // IRQ 32-bit EL0 + kernel_ventry 0, fiq_invalid, 32 // FIQ 32-bit EL0 + kernel_ventry 0, error_invalid, 32 // Error 32-bit EL0 #endif END(vectors) @@ -243,7 +411,7 @@ END(vectors) * Invalid mode handlers */ .macro inv_entry, el, reason, regsize = 64 - kernel_entry el, \regsize + kernel_entry \el, \regsize mov x0, sp mov x1, #\reason mrs x2, esr_el1 @@ -302,6 +470,8 @@ el1_sync: lsr x24, x1, #ESR_ELx_EC_SHIFT // exception class cmp x24, #ESR_ELx_EC_DABT_CUR // data abort in EL1 b.eq el1_da + cmp x24, #ESR_ELx_EC_IABT_CUR // instruction abort in EL1 + b.eq el1_ia cmp x24, #ESR_ELx_EC_SYS64 // configurable trap b.eq el1_undef cmp x24, #ESR_ELx_EC_SP_ALIGN // stack alignment exception @@ -313,6 +483,11 @@ el1_sync: cmp x24, #ESR_ELx_EC_BREAKPT_CUR // debug exception in EL1 b.ge el1_dbg b el1_inv + +el1_ia: + /* + * Fall through to the Data abort case + */ el1_da: /* * Data abort handling @@ -376,10 +551,17 @@ el1_irq: irq_handler #ifdef CONFIG_PREEMPT - get_thread_info tsk +#ifdef CONFIG_THREAD_INFO_IN_TASK + ldr w24, [tsk, #TSK_TI_PREEMPT] // get preempt count +#else ldr w24, [tsk, #TI_PREEMPT] // get preempt count +#endif cbnz w24, 1f // preempt count != 0 +#ifdef CONFIG_THREAD_INFO_IN_TASK + ldr x0, [tsk, #TSK_TI_FLAGS] // get flags +#else ldr x0, [tsk, #TI_FLAGS] // get flags +#endif tbz x0, #TIF_NEED_RESCHED, 1f // needs rescheduling? bl el1_preempt 1: @@ -394,7 +576,11 @@ ENDPROC(el1_irq) el1_preempt: mov x24, lr 1: bl preempt_schedule_irq // irq en/disable is done inside +#ifdef CONFIG_THREAD_INFO_IN_TASK + ldr x0, [tsk, #TSK_TI_FLAGS] // get new tasks TI_FLAGS +#else ldr x0, [tsk, #TI_FLAGS] // get new tasks TI_FLAGS +#endif tbnz x0, #TIF_NEED_RESCHED, 1b // needs rescheduling? ret x24 #endif @@ -418,7 +604,7 @@ el0_sync: cmp x24, #ESR_ELx_EC_FP_EXC64 // FP/ASIMD exception b.eq el0_fpsimd_exc cmp x24, #ESR_ELx_EC_SYS64 // configurable trap - b.eq el0_undef + b.eq el0_sys cmp x24, #ESR_ELx_EC_SP_ALIGN // stack alignment exception b.eq el0_sp_pc cmp x24, #ESR_ELx_EC_PC_ALIGN // pc alignment exception @@ -499,7 +685,7 @@ el0_ia: enable_dbg_and_irq ct_user_exit mov x0, x26 - orr x1, x25, #1 << 24 // use reserved ISS bit for instruction aborts + mov x1, x25 mov x2, sp bl do_mem_abort b ret_to_user @@ -546,6 +732,16 @@ el0_undef: mov x0, sp bl do_undefinstr b ret_to_user +el0_sys: + /* + * System instructions, for trapped cache maintenance instructions + */ + enable_dbg_and_irq + ct_user_exit + mov x0, x25 + mov x1, sp + bl do_sysinstr + b ret_to_user el0_dbg: /* * Debug exception handling @@ -614,6 +810,12 @@ ENTRY(cpu_switch_to) ldp x29, x9, [x8], #16 ldr lr, [x8] mov sp, x9 +#ifdef CONFIG_THREAD_INFO_IN_TASK + msr sp_el0, x1 +#else + and x9, x9, #~(THREAD_SIZE - 1) + msr sp_el0, x9 +#endif ret ENDPROC(cpu_switch_to) @@ -624,7 +826,11 @@ ENDPROC(cpu_switch_to) ret_fast_syscall: disable_irq // disable interrupts str x0, [sp, #S_X0] // returned x0 +#ifdef CONFIG_THREAD_INFO_IN_TASK + ldr x1, [tsk, #TSK_TI_FLAGS] // re-check for syscall tracing +#else ldr x1, [tsk, #TI_FLAGS] // re-check for syscall tracing +#endif and x2, x1, #_TIF_SYSCALL_WORK cbnz x2, ret_fast_syscall_trace and x2, x1, #_TIF_WORK_MASK @@ -641,10 +847,7 @@ ret_fast_syscall_trace: work_pending: tbnz x1, #TIF_NEED_RESCHED, work_resched /* TIF_SIGPENDING, TIF_NOTIFY_RESUME or TIF_FOREIGN_FPSTATE case */ - ldr x2, [sp, #S_PSTATE] mov x0, sp // 'regs' - tst x2, #PSR_MODE_MASK // user mode regs? - b.ne no_work_pending // returning to kernel enable_irq // enable interrupts for do_notify_resume() bl do_notify_resume b ret_to_user @@ -659,11 +862,14 @@ work_resched: */ ret_to_user: disable_irq // disable interrupts +#ifdef CONFIG_THREAD_INFO_IN_TASK + ldr x1, [tsk, #TSK_TI_FLAGS] +#else ldr x1, [tsk, #TI_FLAGS] +#endif and x2, x1, #_TIF_WORK_MASK cbnz x2, work_pending enable_step_tsk x1, x2 -no_work_pending: kernel_exit 0 ENDPROC(ret_to_user) @@ -692,7 +898,11 @@ el0_svc_naked: // compat entry point enable_dbg_and_irq ct_user_exit 1 +#ifdef CONFIG_THREAD_INFO_IN_TASK + ldr x16, [tsk, #TSK_TI_FLAGS] // check for syscall hooks +#else ldr x16, [tsk, #TI_FLAGS] // check for syscall hooks +#endif tst x16, #_TIF_SYSCALL_WORK b.ne __sys_trace cmp scno, sc_nr // check upper syscall limit @@ -743,6 +953,119 @@ __ni_sys_trace: bl do_ni_syscall b __sys_trace_return +#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 +/* + * Exception vectors trampoline. + */ + .pushsection ".entry.tramp.text", "ax" + + .macro tramp_map_kernel, tmp + mrs \tmp, ttbr1_el1 + sub \tmp, \tmp, #(SWAPPER_DIR_SIZE + RESERVED_TTBR0_SIZE) + bic \tmp, \tmp, #USER_ASID_FLAG + msr ttbr1_el1, \tmp +#ifdef CONFIG_ARCH_MSM8996 + /* 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 +#endif /* CONFIG_ARCH_MSM8996 */ + .endm + + .macro tramp_unmap_kernel, tmp + mrs \tmp, ttbr1_el1 + add \tmp, \tmp, #(SWAPPER_DIR_SIZE + RESERVED_TTBR0_SIZE) + orr \tmp, \tmp, #USER_ASID_FLAG + msr ttbr1_el1, \tmp + /* + * We avoid running the post_ttbr_update_workaround here because the + * user and kernel ASIDs don't have conflicting mappings, so any + * "blessing" as described in: + * + * http://lkml.kernel.org/r/56BB848A.6060603@caviumnetworks.com + * + * will not hurt correctness. Whilst this may partially defeat the + * point of using split ASIDs in the first place, it avoids + * the hit of invalidating the entire I-cache on every return to + * userspace. + */ + .endm + + .macro tramp_ventry, regsize = 64 + .align 7 +1: + .if \regsize == 64 + msr tpidrro_el0, x30 // Restored in kernel_ventry + .endif + bl 2f + b . +2: + tramp_map_kernel x30 +#ifdef CONFIG_RANDOMIZE_BASE + adr x30, tramp_vectors + PAGE_SIZE +#ifndef CONFIG_ARCH_MSM8996 + isb +#endif + ldr x30, [x30] +#else + ldr x30, =vectors +#endif + prfm plil1strm, [x30, #(1b - tramp_vectors)] + 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 + .endm + + .align 11 +ENTRY(tramp_vectors) + .space 0x400 + + tramp_ventry + tramp_ventry + tramp_ventry + tramp_ventry + + tramp_ventry 32 + tramp_ventry 32 + tramp_ventry 32 + tramp_ventry 32 +END(tramp_vectors) + +ENTRY(tramp_exit_native) + tramp_exit +END(tramp_exit_native) + +ENTRY(tramp_exit_compat) + tramp_exit 32 +END(tramp_exit_compat) + + .ltorg + .popsection // .entry.tramp.text +#ifdef CONFIG_RANDOMIZE_BASE + .pushsection ".rodata", "a" + .align PAGE_SHIFT + .globl __entry_tramp_data_start +__entry_tramp_data_start: + .quad vectors + .popsection // .rodata +#endif /* CONFIG_RANDOMIZE_BASE */ +#endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */ + /* * Special system call wrappers. */ |