xnu-4570.51.1.tar.gz

[apple/xnu.git] / osfmk / arm64 / locore.s

diff --git a/osfmk/arm64/locore.s b/osfmk/arm64/locore.s
index ea33d6b42c6a4d64e2cf9b282702dbfa1370bc81..4430d3b5ce0593bbfdaea9ea49d280cdc5a0b3f7 100644 (file)
--- a/osfmk/arm64/locore.s
+++ b/osfmk/arm64/locore.s
@@ -199,7 +199,7 @@
 .endmacro
 
 #if __ARM_KERNEL_PROTECT__
-       .data
+       .text
        .align 3
        .globl EXT(exc_vectors_table)
 LEXT(exc_vectors_table)
@@ -564,12 +564,38 @@ fleh_dispatch64:
        /* Save arm_saved_state64 */
        SPILL_REGISTERS
 
-       /* If exception is from userspace, zero lr */
-       ldr             w21, [x0, SS64_CPSR]
-       and             x21, x21, #(PSR64_MODE_EL_MASK)
-       cmp             x21, #(PSR64_MODE_EL0)
+       /* If exception is from userspace, zero unused registers */
+       and             x23, x23, #(PSR64_MODE_EL_MASK)
+       cmp             x23, #(PSR64_MODE_EL0)
        bne             1f
-       mov             lr, #0
+
+       mov             x2, xzr
+       mov             x3, xzr
+       mov             x4, xzr
+       mov             x5, xzr
+       mov             x6, xzr
+       mov             x7, xzr
+       mov             x8, xzr
+       mov             x9, xzr
+       mov             x10, xzr
+       mov             x11, xzr
+       mov             x12, xzr
+       mov             x13, xzr
+       mov             x14, xzr
+       mov             x15, xzr
+       mov             x16, xzr
+       mov             x17, xzr
+       mov             x18, xzr
+       mov             x19, xzr
+       mov             x20, xzr
+       /* x21, x22 cleared in common case below */
+       mov             x23, xzr
+       mov             x24, xzr
+       mov             x25, xzr
+       mov             x26, xzr
+       mov             x27, xzr
+       mov             x28, xzr
+       /* fp/lr already cleared by EL0_64_VECTOR */
 1:
 
        mov             x21, x0                                                         // Copy arm_context_t pointer to x21
@@ -885,9 +911,9 @@ check_user_asts:
 
 
 exception_return:
-       msr             DAIFSet, #(DAIFSC_IRQF | DAIFSC_FIQF)   // Disable interrupts
-       mrs             x3, TPIDR_EL1                                           // Load thread pointer
-       mov             sp, x21                                                         // Reload the pcb pointer
+       msr             DAIFSet, #DAIFSC_ALL                            // Disable exceptions
+       mrs             x3, TPIDR_EL1                                   // Load thread pointer
+       mov             sp, x21                                         // Reload the pcb pointer
 
        /* ARM64_TODO Reserve x18 until we decide what to do with it */
        ldr             x0, [x3, TH_CTH_DATA]                           // Load cthread data pointer