linux-kernel - [PATCH] x86/vdso: Move VDSO image init to vdso2c generated code

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Message-Id: <20230124184019.26850-1-brgerst@gmail.com>
Date:   Tue, 24 Jan 2023 13:40:19 -0500
From:   Brian Gerst <brgerst@...il.com>
To:     linux-kernel@...r.kernel.org, x86@...nel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>,
        Ingo Molnar <mingo@...nel.org>, Brian Gerst <brgerst@...il.com>
Subject: [PATCH] x86/vdso: Move VDSO image init to vdso2c generated code

Generate an init function for each VDSO image, replacing init_vdso() and
sysenter_setup().

Signed-off-by: Brian Gerst <brgerst@...il.com>
---
 arch/x86/entry/vdso/vdso2c.h       |  6 ++++++
 arch/x86/entry/vdso/vdso32-setup.c |  9 ---------
 arch/x86/entry/vdso/vma.c          | 19 ++++---------------
 arch/x86/include/asm/processor.h   |  1 -
 arch/x86/include/asm/vdso.h        |  2 +-
 arch/x86/kernel/cpu/common.c       |  1 -
 6 files changed, 11 insertions(+), 27 deletions(-)

diff --git a/arch/x86/entry/vdso/vdso2c.h b/arch/x86/entry/vdso/vdso2c.h
index 5264daa8859f..67b3e37576a6 100644
--- a/arch/x86/entry/vdso/vdso2c.h
+++ b/arch/x86/entry/vdso/vdso2c.h
@@ -179,6 +179,7 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
 
 	fprintf(outfile, "/* AUTOMATICALLY GENERATED -- DO NOT EDIT */\n\n");
 	fprintf(outfile, "#include <linux/linkage.h>\n");
+	fprintf(outfile, "#include <linux/init.h>\n");
 	fprintf(outfile, "#include <asm/page_types.h>\n");
 	fprintf(outfile, "#include <asm/vdso.h>\n");
 	fprintf(outfile, "\n");
@@ -218,5 +219,10 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
 			fprintf(outfile, "\t.sym_%s = %" PRIi64 ",\n",
 				required_syms[i].name, (int64_t)syms[i]);
 	}
+	fprintf(outfile, "};\n\n");
+	fprintf(outfile, "static __init int init_%s(void) {\n", image_name);
+	fprintf(outfile, "\treturn init_vdso_image(&%s);\n", image_name);
 	fprintf(outfile, "};\n");
+	fprintf(outfile, "subsys_initcall(init_%s);\n", image_name);
+
 }
diff --git a/arch/x86/entry/vdso/vdso32-setup.c b/arch/x86/entry/vdso/vdso32-setup.c
index 43842fade8fa..3b300a773c7e 100644
--- a/arch/x86/entry/vdso/vdso32-setup.c
+++ b/arch/x86/entry/vdso/vdso32-setup.c
@@ -51,17 +51,8 @@ __setup("vdso32=", vdso32_setup);
 __setup_param("vdso=", vdso_setup, vdso32_setup, 0);
 #endif
 
-int __init sysenter_setup(void)
-{
-	init_vdso_image(&vdso_image_32);
-
-	return 0;
-}
-
 #ifdef CONFIG_X86_64
 
-subsys_initcall(sysenter_setup);
-
 #ifdef CONFIG_SYSCTL
 /* Register vsyscall32 into the ABI table */
 #include <linux/sysctl.h>
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index b8f3f9b9e53c..2738eb28cb2e 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -44,13 +44,16 @@ unsigned int vclocks_used __read_mostly;
 unsigned int __read_mostly vdso64_enabled = 1;
 #endif
 
-void __init init_vdso_image(const struct vdso_image *image)
+int __init init_vdso_image(const struct vdso_image *image)
 {
+	BUILD_BUG_ON(VDSO_CLOCKMODE_MAX >= 32);
 	BUG_ON(image->size % PAGE_SIZE != 0);
 
 	apply_alternatives((struct alt_instr *)(image->data + image->alt),
 			   (struct alt_instr *)(image->data + image->alt +
 						image->alt_len));
+
+	return 0;
 }
 
 static const struct vm_special_mapping vvar_mapping;
@@ -418,18 +421,4 @@ static __init int vdso_setup(char *s)
 	return 1;
 }
 __setup("vdso=", vdso_setup);
-
-static int __init init_vdso(void)
-{
-	BUILD_BUG_ON(VDSO_CLOCKMODE_MAX >= 32);
-
-	init_vdso_image(&vdso_image_64);
-
-#ifdef CONFIG_X86_X32_ABI
-	init_vdso_image(&vdso_image_x32);
-#endif
-
-	return 0;
-}
-subsys_initcall(init_vdso);
 #endif /* CONFIG_X86_64 */
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index a77dee6a2bf2..8d73004e4cac 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -542,7 +542,6 @@ enum idle_boot_override {IDLE_NO_OVERRIDE=0, IDLE_HALT, IDLE_NOMWAIT,
 			 IDLE_POLL};
 
 extern void enable_sep_cpu(void);
-extern int sysenter_setup(void);
 
 
 /* Defined in head.S */
diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
index 2963a2f5dbc4..d7f6592b74a9 100644
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -45,7 +45,7 @@ extern const struct vdso_image vdso_image_x32;
 extern const struct vdso_image vdso_image_32;
 #endif
 
-extern void __init init_vdso_image(const struct vdso_image *image);
+extern int __init init_vdso_image(const struct vdso_image *image);
 
 extern int map_vdso_once(const struct vdso_image *image, unsigned long addr);
 
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 5fe56f0ec9d7..6aac42902ee0 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1953,7 +1953,6 @@ void __init identify_boot_cpu(void)
 	if (HAS_KERNEL_IBT && cpu_feature_enabled(X86_FEATURE_IBT))
 		pr_info("CET detected: Indirect Branch Tracking enabled\n");
 #ifdef CONFIG_X86_32
-	sysenter_setup();
 	enable_sep_cpu();
 #endif
 	cpu_detect_tlb(&boot_cpu_data);
-- 
2.39.1