From: Breno Leitao <leitao@debian.org>
Date: Mon, 7 Jul 2025 16:01:08 +0000 (-0700)
Subject: arm64: remove CONFIG_VMAP_STACK checks from entry code
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9d1869f0f537d26005a521a141dde759fc3303f5;p=thirdparty%2Flinux.git

arm64: remove CONFIG_VMAP_STACK checks from entry code

With VMAP_STACK now always enabled on arm64, remove all CONFIG_VMAP_STACK
conditionals from entry handling in arch/arm64/kernel/entry-common.c and
arch/arm64/kernel/entry.S.

This change unconditionally includes the bad stack handling and overflow
detection logic, simplifying the code and reflecting the mandatory use of
VMAP_STACK for all arm64 kernel builds.

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-v1-8-8de98ca0f91c@debian.org
Signed-off-by: Will Deacon <will@kernel.org>
---

diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
index 7c1970b341b8c..99a341ee71313 100644
--- a/arch/arm64/kernel/entry-common.c
+++ b/arch/arm64/kernel/entry-common.c
@@ -977,7 +977,6 @@ UNHANDLED(el0t, 32, fiq)
 UNHANDLED(el0t, 32, error)
 #endif /* CONFIG_COMPAT */
 
-#ifdef CONFIG_VMAP_STACK
 asmlinkage void noinstr __noreturn handle_bad_stack(struct pt_regs *regs)
 {
 	unsigned long esr = read_sysreg(esr_el1);
@@ -986,7 +985,6 @@ asmlinkage void noinstr __noreturn handle_bad_stack(struct pt_regs *regs)
 	arm64_enter_nmi(regs);
 	panic_bad_stack(regs, esr, far);
 }
-#endif /* CONFIG_VMAP_STACK */
 
 #ifdef CONFIG_ARM_SDE_INTERFACE
 asmlinkage noinstr unsigned long
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 5ae2a34b50bda..ea74cb7aac5b8 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -55,7 +55,6 @@
 	.endif
 
 	sub	sp, sp, #PT_REGS_SIZE
-#ifdef CONFIG_VMAP_STACK
 	/*
 	 * Test whether the SP has overflowed, without corrupting a GPR.
 	 * Task and IRQ stacks are aligned so that SP & (1 << THREAD_SHIFT)
@@ -97,7 +96,6 @@
 	/* We were already on the overflow stack. Restore sp/x0 and carry on. */
 	sub	sp, sp, x0
 	mrs	x0, tpidrro_el0
-#endif
 	b	el\el\ht\()_\regsize\()_\label
 .org .Lventry_start\@ + 128	// Did we overflow the ventry slot?
 	.endm
@@ -540,7 +538,6 @@ SYM_CODE_START(vectors)
 	kernel_ventry	0, t, 32, error		// Error 32-bit EL0
 SYM_CODE_END(vectors)
 
-#ifdef CONFIG_VMAP_STACK
 SYM_CODE_START_LOCAL(__bad_stack)
 	/*
 	 * We detected an overflow in kernel_ventry, which switched to the
@@ -568,7 +565,6 @@ SYM_CODE_START_LOCAL(__bad_stack)
 	bl	handle_bad_stack
 	ASM_BUG()
 SYM_CODE_END(__bad_stack)
-#endif /* CONFIG_VMAP_STACK */
 
 
 	.macro entry_handler el:req, ht:req, regsize:req, label:req
@@ -1003,7 +999,6 @@ SYM_CODE_START(__sdei_asm_handler)
 1:	adr_this_cpu dst=x5, sym=sdei_active_critical_event, tmp=x6
 2:	str	x19, [x5]
 
-#ifdef CONFIG_VMAP_STACK
 	/*
 	 * entry.S may have been using sp as a scratch register, find whether
 	 * this is a normal or critical event and switch to the appropriate
@@ -1016,7 +1011,6 @@ SYM_CODE_START(__sdei_asm_handler)
 2:	mov	x6, #SDEI_STACK_SIZE
 	add	x5, x5, x6
 	mov	sp, x5
-#endif
 
 #ifdef CONFIG_SHADOW_CALL_STACK
 	/* Use a separate shadow call stack for normal and critical events */