Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64...

[linux-2.6-microblaze.git] / arch / arm64 / kernel / entry.S

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 945b46a..2646178 100644 (file)
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -127,8 +127,10 @@ alternative_else_nop_endif
        add     \dst, \dst, #(\sym - .entry.tramp.text)
        .endm
 
-       // This macro corrupts x0-x3. It is the caller's duty
-       // to save/restore them if required.
+       /*
+        * This macro corrupts x0-x3. It is the caller's duty  to save/restore
+        * them if required.
+        */
        .macro  apply_ssbd, state, tmp1, tmp2
 #ifdef CONFIG_ARM64_SSBD
 alternative_cb arm64_enable_wa2_handling
@@ -168,13 +170,28 @@ 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
        msr     sp_el0, tsk
 
-       // Ensure MDSCR_EL1.SS is clear, since we can unmask debug exceptions
-       // when scheduling.
+       /*
+        * Ensure MDSCR_EL1.SS is clear, since we can unmask debug exceptions
+        * when scheduling.
+        */
        ldr     x19, [tsk, #TSK_TI_FLAGS]
        disable_step_tsk x19, x20
 
@@ -277,6 +294,14 @@ 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
@@ -288,21 +313,6 @@ 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. */
@@ -334,11 +344,11 @@ alternative_else_nop_endif
        .if     \el == 0
 alternative_insn eret, nop, ARM64_UNMAP_KERNEL_AT_EL0
 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
-       bne     5f
+       bne     4f
        msr     far_el1, x30
        tramp_alias     x30, tramp_exit_native
        br      x30
-5:
+4:
        tramp_alias     x30, tramp_exit_compat
        br      x30
 #endif