linux-kernel - [PATCH v1 2/6] powerpc/vdso: Don't reference vdso32 static functions/vars without CONFIG

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Date:   Thu, 27 Aug 2020 15:49:25 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v1 2/6] powerpc/vdso: Don't reference vdso32 static
 functions/vars without CONFIG_VDSO32

When CONFIG_VDSO32 is not selected, just don't reference the static
vdso32 variables and functions.

This allows the compiler to optimise them out, and allows to
drop an #ifdef CONFIG_VDSO32.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/powerpc/kernel/vdso.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index a44e8e6a4692..465150253c31 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -159,11 +159,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	if (!vdso_ready)
 		return 0;
 
-	if (is_32bit_task()) {
-		vdso_spec = &vdso32_spec;
-		vdso_pages = vdso32_pages;
-		vdso_base = VDSO32_MBASE;
-	} else {
+	if (!is_32bit_task()) {
 		vdso_spec = &vdso64_spec;
 		vdso_pages = vdso64_pages;
 		/*
@@ -172,6 +168,12 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 		 * and most likely share a SLB entry.
 		 */
 		vdso_base = 0;
+	} else if (IS_ENABLED(CONFIG_VDSO32)) {
+		vdso_spec = &vdso32_spec;
+		vdso_pages = vdso32_pages;
+		vdso_base = VDSO32_MBASE;
+	} else {
+		return 0;
 	}
 
 	current->mm->context.vdso_base = 0;
@@ -696,12 +698,10 @@ static int __init vdso_init(void)
 
 	vdso32_kbase = &vdso32_start;
 
-#ifdef CONFIG_VDSO32
 	/*
 	 * Calculate the size of the 32 bits vDSO
 	 */
 	vdso32_pages = (&vdso32_end - &vdso32_start) >> PAGE_SHIFT;
-#endif
 
 	/*
 	 * Setup the syscall map in the vDOS
-- 
2.25.0