Commit 0909c719 authored Jul 07, 2025 by Breno Leitao Committed by Will Deacon Jul 08, 2025

arm64: Remove CONFIG_VMAP_STACK conditionals from THREAD_SHIFT and THREAD_ALIGN



Now that VMAP_STACK is always enabled on arm64, remove the
CONFIG_VMAP_STACK conditional logic from the definitions of THREAD_SHIFT
and THREAD_ALIGN in arch/arm64/include/asm/memory.h. This simplifies the
code by unconditionally setting THREAD_ALIGN to (2 * THREAD_SIZE) and
adjusting the THREAD_SHIFT definition to only depend on MIN_THREAD_SHIFT
and PAGE_SHIFT.

This change reflects the updated arm64 stack model, where all kernel
threads use virtually mapped stacks with guard pages, and ensures
alignment and stack sizing are consistently handled.

Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20250707-arm64_vmap-v1-3-8de98ca0f91c@debian.org


Signed-off-by: Will Deacon <will@kernel.org>

parent 63829521

arch/arm64/include/asm/memory.h

+1 −5

Original line number	Diff line number	Diff line
		@@ -118,7 +118,7 @@
		* VMAP'd stacks are allocated at page granularity, so we must ensure that such
		* stacks are a multiple of page size.
		*/
		#if defined(CONFIG_VMAP_STACK) && (MIN_THREAD_SHIFT < PAGE_SHIFT)
		#if (MIN_THREAD_SHIFT < PAGE_SHIFT)
		#define THREAD_SHIFT PAGE_SHIFT
		#else
		#define THREAD_SHIFT MIN_THREAD_SHIFT
		@@ -135,11 +135,7 @@
		* checking sp & (1 << THREAD_SHIFT), which we can do cheaply in the entry
		* assembly.
		*/
		#ifdef CONFIG_VMAP_STACK
		#define THREAD_ALIGN (2 * THREAD_SIZE)
		#else
		#define THREAD_ALIGN THREAD_SIZE
		#endif

		#define IRQ_STACK_SIZE THREAD_SIZE