diff options
| -rw-r--r-- | arch/arm64/kernel/entry.S | 34 |
1 files changed, 19 insertions, 15 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 5304d193c79d..9757a8d5fd94 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -167,6 +167,17 @@ alternative_cb_end stp x28, x29, [sp, #16 * 14] .if \el == 0 + .if \regsize == 32 + // If we're returning from a 32-bit task on a system affected by + // 1418040 then re-enable userspace access to the virtual counter. +#ifdef CONFIG_ARM64_ERRATUM_1418040 +alternative_if ARM64_WORKAROUND_1418040 + mrs x0, cntkctl_el1 + orr x0, x0, #2 // ARCH_TIMER_USR_VCT_ACCESS_EN + msr cntkctl_el1, x0 +alternative_else_nop_endif +#endif + .endif clear_gp_regs mrs x21, sp_el0 ldr_this_cpu tsk, __entry_task, x20 @@ -320,6 +331,14 @@ alternative_else_nop_endif tst x22, #PSR_MODE32_BIT // native task? b.eq 3f +#ifdef CONFIG_ARM64_ERRATUM_1418040 +alternative_if ARM64_WORKAROUND_1418040 + mrs x0, cntkctl_el1 + bic x0, x0, #2 // ARCH_TIMER_USR_VCT_ACCESS_EN + msr cntkctl_el1, x0 +alternative_else_nop_endif +#endif + #ifdef CONFIG_ARM64_ERRATUM_845719 alternative_if ARM64_WORKAROUND_845719 #ifdef CONFIG_PID_IN_CONTEXTIDR @@ -331,21 +350,6 @@ alternative_if ARM64_WORKAROUND_845719 alternative_else_nop_endif #endif 3: -#ifdef CONFIG_ARM64_ERRATUM_1418040 -alternative_if_not ARM64_WORKAROUND_1418040 - b 4f -alternative_else_nop_endif - /* - * if (x22.mode32 == cntkctl_el1.el0vcten) - * cntkctl_el1.el0vcten = ~cntkctl_el1.el0vcten - */ - mrs x1, cntkctl_el1 - eon x0, x1, x22, lsr #3 - tbz x0, #1, 4f - eor x1, x1, #2 // ARCH_TIMER_USR_VCT_ACCESS_EN - msr cntkctl_el1, x1 -4: -#endif scs_save tsk, x0 /* No kernel C function calls after this as user keys are set. */ |