diff options
Diffstat (limited to 'arch/arm64/kernel/entry.S')
| -rw-r--r-- | arch/arm64/kernel/entry.S | 112 |
1 files changed, 85 insertions, 27 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 223d54a4d66b..43512d4d7df2 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -29,7 +29,9 @@ #include <asm/esr.h> #include <asm/irq.h> #include <asm/memory.h> +#include <asm/ptrace.h> #include <asm/thread_info.h> +#include <asm/asm-uaccess.h> #include <asm/unistd.h> /* @@ -90,9 +92,8 @@ .if \el == 0 mrs x21, sp_el0 - 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 + ldr_this_cpu tsk, __entry_task, x20 // Ensure MDSCR_EL1.SS is clear, + ldr x19, [tsk, #TSK_TI_FLAGS] // since we can unmask debug disable_step_tsk x19, x20 // exceptions when scheduling. mov x29, xzr // fp pointed to user-space @@ -100,15 +101,41 @@ add x21, sp, #S_FRAME_SIZE get_thread_info tsk /* Save the task's original addr_limit and set USER_DS (TASK_SIZE_64) */ - ldr x20, [tsk, #TI_ADDR_LIMIT] + ldr x20, [tsk, #TSK_TI_ADDR_LIMIT] str x20, [sp, #S_ORIG_ADDR_LIMIT] mov x20, #TASK_SIZE_64 - str x20, [tsk, #TI_ADDR_LIMIT] + str x20, [tsk, #TSK_TI_ADDR_LIMIT] /* No need to reset PSTATE.UAO, hardware's already set it to 0 for us */ .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, #0xffff << 48 // 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] /* @@ -139,7 +166,7 @@ .if \el != 0 /* Restore the task's original addr_limit. */ ldr x20, [sp, #S_ORIG_ADDR_LIMIT] - str x20, [tsk, #TI_ADDR_LIMIT] + str x20, [tsk, #TSK_TI_ADDR_LIMIT] /* No need to restore UAO, it will be restored from SPSR_EL1 */ .endif @@ -147,6 +174,40 @@ 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 + + .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). + */ + post_ttbr0_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 #ifdef CONFIG_ARM64_ERRATUM_845719 @@ -162,6 +223,7 @@ alternative_if ARM64_WORKAROUND_845719 alternative_else_nop_endif #endif .endif + msr elr_el1, x21 // set up the return data msr spsr_el1, x22 ldp x0, x1, [sp, #16 * 0] @@ -184,23 +246,20 @@ alternative_else_nop_endif eret // return to kernel .endm - .macro get_thread_info, rd - mrs \rd, sp_el0 - .endm - .macro irq_stack_entry mov x19, sp // preserve the original sp /* - * Compare sp with the current thread_info, if the top - * ~(THREAD_SIZE - 1) bits match, we are on a task stack, and - * should switch to the irq stack. + * 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. */ - and x25, x19, #~(THREAD_SIZE - 1) - cmp x25, tsk - b.ne 9998f + ldr x25, [tsk, TSK_STACK] + eor x25, x25, x19 + and x25, x25, #~(THREAD_SIZE - 1) + cbnz x25, 9998f - this_cpu_ptr irq_stack, x25, x26 + adr_this_cpu x25, irq_stack, x26 mov x26, #IRQ_STACK_START_SP add x26, x25, x26 @@ -427,9 +486,9 @@ el1_irq: irq_handler #ifdef CONFIG_PREEMPT - ldr w24, [tsk, #TI_PREEMPT] // get preempt count + ldr w24, [tsk, #TSK_TI_PREEMPT] // get preempt count cbnz w24, 1f // preempt count != 0 - ldr x0, [tsk, #TI_FLAGS] // get flags + ldr x0, [tsk, #TSK_TI_FLAGS] // get flags tbz x0, #TIF_NEED_RESCHED, 1f // needs rescheduling? bl el1_preempt 1: @@ -444,7 +503,7 @@ ENDPROC(el1_irq) el1_preempt: mov x24, lr 1: bl preempt_schedule_irq // irq en/disable is done inside - ldr x0, [tsk, #TI_FLAGS] // get new tasks TI_FLAGS + ldr x0, [tsk, #TSK_TI_FLAGS] // get new tasks TI_FLAGS tbnz x0, #TIF_NEED_RESCHED, 1b // needs rescheduling? ret x24 #endif @@ -624,7 +683,7 @@ el0_inv: mov x0, sp mov x1, #BAD_SYNC mov x2, x25 - bl bad_mode + bl bad_el0_sync b ret_to_user ENDPROC(el0_sync) @@ -674,8 +733,7 @@ ENTRY(cpu_switch_to) ldp x29, x9, [x8], #16 ldr lr, [x8] mov sp, x9 - and x9, x9, #~(THREAD_SIZE - 1) - msr sp_el0, x9 + msr sp_el0, x1 ret ENDPROC(cpu_switch_to) @@ -686,7 +744,7 @@ ENDPROC(cpu_switch_to) ret_fast_syscall: disable_irq // disable interrupts str x0, [sp, #S_X0] // returned x0 - ldr x1, [tsk, #TI_FLAGS] // re-check for syscall tracing + ldr x1, [tsk, #TSK_TI_FLAGS] // re-check for syscall tracing and x2, x1, #_TIF_SYSCALL_WORK cbnz x2, ret_fast_syscall_trace and x2, x1, #_TIF_WORK_MASK @@ -706,14 +764,14 @@ work_pending: #ifdef CONFIG_TRACE_IRQFLAGS bl trace_hardirqs_on // enabled while in userspace #endif - ldr x1, [tsk, #TI_FLAGS] // re-check for single-step + ldr x1, [tsk, #TSK_TI_FLAGS] // re-check for single-step b finish_ret_to_user /* * "slow" syscall return path. */ ret_to_user: disable_irq // disable interrupts - ldr x1, [tsk, #TI_FLAGS] + ldr x1, [tsk, #TSK_TI_FLAGS] and x2, x1, #_TIF_WORK_MASK cbnz x2, work_pending finish_ret_to_user: @@ -746,7 +804,7 @@ el0_svc_naked: // compat entry point enable_dbg_and_irq ct_user_exit 1 - ldr x16, [tsk, #TI_FLAGS] // check for syscall hooks + ldr x16, [tsk, #TSK_TI_FLAGS] // check for syscall hooks tst x16, #_TIF_SYSCALL_WORK b.ne __sys_trace cmp scno, sc_nr // check upper syscall limit |