linux-kernel - [PATCH v2 2/5] powerpc/vdso: Don't rely on vdso

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Message-Id: <1a065ae3042e3b47cc9418162cd8003dff35b5f7.1598594308.git.christophe.leroy@csgroup.eu>
Date:   Fri, 28 Aug 2020 05:58:47 +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 v2 2/5] powerpc/vdso: Don't rely on vdso_pages being 0 for
 failure

If vdso initialisation failed, vdso_ready is not set.
Otherwise, vdso_pages is only 0 when it is a 32 bits task
and CONFIG_VDSO32 is not selected.

As arch_setup_additional_pages() now bails out directly in
that case, we don't need to set vdso_pages to 0.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/powerpc/kernel/vdso.c | 23 ++++++-----------------
 1 file changed, 6 insertions(+), 17 deletions(-)

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 3ef3fc546ac8..8f245e988a8a 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -176,11 +176,6 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 
 	current->mm->context.vdso_base = 0;
 
-	/* vDSO has a problem and was disabled, just don't "enable" it for the
-	 * process
-	 */
-	if (vdso_pages == 0)
-		return 0;
 	/* Add a page to the vdso size for the data page */
 	vdso_pages ++;
 
@@ -710,14 +705,16 @@ static int __init vdso_init(void)
 	 * Initialize the vDSO images in memory, that is do necessary
 	 * fixups of vDSO symbols, locate trampolines, etc...
 	 */
-	if (vdso_setup())
-		goto setup_failed;
+	if (vdso_setup()) {
+		pr_err("vDSO setup failure, not enabled !\n");
+		return 0;
+	}
 
 	if (IS_ENABLED(CONFIG_VDSO32)) {
 		/* Make sure pages are in the correct state */
 		pagelist = kcalloc(vdso32_pages + 1, sizeof(struct page *), GFP_KERNEL);
 		if (!pagelist)
-			goto alloc_failed;
+			return 0;
 
 		pagelist[0] = virt_to_page(vdso_data);
 
@@ -730,7 +727,7 @@ static int __init vdso_init(void)
 	if (IS_ENABLED(CONFIG_PPC64)) {
 		pagelist = kcalloc(vdso64_pages + 1, sizeof(struct page *), GFP_KERNEL);
 		if (!pagelist)
-			goto alloc_failed;
+			return 0;
 
 		pagelist[0] = virt_to_page(vdso_data);
 
@@ -743,14 +740,6 @@ static int __init vdso_init(void)
 	smp_wmb();
 	vdso_ready = 1;
 
-	return 0;
-
-setup_failed:
-	pr_err("vDSO setup failure, not enabled !\n");
-alloc_failed:
-	vdso32_pages = 0;
-	vdso64_pages = 0;
-
 	return 0;
 }
 arch_initcall(vdso_init);
-- 
2.25.0