arm64: entry: refine comment of stack overflow check

[linux.git] / arch / arm64 / kernel / entry.S

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 583f71abbe98d7b130a38ffd4915a95110169fcc..7c6a0a41676f83ce0f40cfc1e3197a03e6ca3570 100644 (file)
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -76,7 +76,8 @@ alternative_else_nop_endif
 #ifdef CONFIG_VMAP_STACK
        /*
         * Test whether the SP has overflowed, without corrupting a GPR.
-        * Task and IRQ stacks are aligned to (1 << THREAD_SHIFT).
+        * Task and IRQ stacks are aligned so that SP & (1 << THREAD_SHIFT)
+        * should always be zero.
         */
        add     sp, sp, x0                      // sp' = sp + x0
        sub     x0, sp, x0                      // x0' = sp' - x0 = (sp + x0) - x0 = sp