[PATCH v2 1/5] powerpc/vdso: Remove DBG()

[PATCH v2 1/5] powerpc/vdso: Remove DBG()

[Christophe Leroy]

DBG() is defined as void when DEBUG is not defined,
and DEBUG is explicitly undefined.

It means there is no other way than modifying source code
to get the messages printed.

It was most likely useful in the first days of VDSO, but
today the only 3 DBG() calls don't deserve a special
handling.

Just remove them. If one day someone need such messages back,
use a standard pr_debug() or equivalent.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
This is a follow up series, applying on top of the series that
switches powerpc VDSO to _install_special_mapping(),
rebased on today's powerpc/next-test (dd419a93bd99)

v2 removes the modification to arch_setup_additional_pages() to
consider when is_32bit_task() returning true when CONFIG_VDSO32
not set, as this should never happen.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/kernel/vdso.c | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index e2568d9ecdff..3ef3fc546ac8 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -31,14 +31,6 @@
 #include <asm/vdso_datapage.h>
 #include <asm/setup.h>
 
-#undef DEBUG
-
-#ifdef DEBUG
-#define DBG(fmt...) printk(fmt)
-#else
-#define DBG(fmt...)
-#endif
-
 /* Max supported size for symbol names */
 #define MAX_SYMNAME	64
 
@@ -567,9 +559,6 @@ static __init int vdso_fixup_alt_funcs(struct lib32_elfinfo *v32,
 		if (!match)
 			continue;
 
-		DBG("replacing %s with %s...\n", patch->gen_name,
-		    patch->fix_name ? "NONE" : patch->fix_name);
-
 		/*
 		 * Patch the 32 bits and 64 bits symbols. Note that we do not
 		 * patch the "." symbol on 64 bits.
@@ -704,7 +693,6 @@ static int __init vdso_init(void)
 	 * Calculate the size of the 64 bits vDSO
 	 */
 	vdso64_pages = (&vdso64_end - &vdso64_start) >> PAGE_SHIFT;
-	DBG("vdso64_kbase: %p, 0x%x pages\n", vdso64_kbase, vdso64_pages);
 
 	vdso32_kbase = &vdso32_start;
 
@@ -712,7 +700,6 @@ static int __init vdso_init(void)
 	 * Calculate the size of the 32 bits vDSO
 	 */
 	vdso32_pages = (&vdso32_end - &vdso32_start) >> PAGE_SHIFT;
-	DBG("vdso32_kbase: %p, 0x%x pages\n", vdso32_kbase, vdso32_pages);
 
 	/*
 	 * Setup the syscall map in the vDOS
-- 
2.25.0

[PATCH v2 2/5] powerpc/vdso: Don't rely on vdso_pages being 0 for failure

[Christophe Leroy]

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@csgroup.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

[PATCH v2 3/5] powerpc/vdso: Initialise vdso32_kbase at compile time

[Christophe Leroy]

Initialise vdso32_kbase at compile time like vdso64_kbase.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/kernel/vdso.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 8f245e988a8a..fb393266b9cb 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -37,13 +37,12 @@
 /* The alignment of the vDSO */
 #define VDSO_ALIGNMENT	(1 << 16)
 
+extern char vdso32_start, vdso32_end;
 static unsigned int vdso32_pages;
-static void *vdso32_kbase;
+static void *vdso32_kbase = &vdso32_start;
 unsigned long vdso32_sigtramp;
 unsigned long vdso32_rt_sigtramp;
 
-extern char vdso32_start, vdso32_end;
-
 extern char vdso64_start, vdso64_end;
 static void *vdso64_kbase = &vdso64_start;
 static unsigned int vdso64_pages;
@@ -689,8 +688,6 @@ static int __init vdso_init(void)
 	 */
 	vdso64_pages = (&vdso64_end - &vdso64_start) >> PAGE_SHIFT;
 
-	vdso32_kbase = &vdso32_start;
-
 	/*
 	 * Calculate the size of the 32 bits vDSO
 	 */
-- 
2.25.0

[PATCH v2 4/5] powerpc/vdso: Declare constant vars as __ro_after_init

[Christophe Leroy]

To avoid any risk of modification of vital VDSO variables,
declare them __ro_after_init.

vdso32_kbase and vdso64_kbase could be made 'const', but it would
have high impact on all functions using them as the compiler doesn't
expect const property to be discarded.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/kernel/vdso.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index fb393266b9cb..4ad042995ccc 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -38,19 +38,19 @@
 #define VDSO_ALIGNMENT	(1 << 16)
 
 extern char vdso32_start, vdso32_end;
-static unsigned int vdso32_pages;
-static void *vdso32_kbase = &vdso32_start;
-unsigned long vdso32_sigtramp;
-unsigned long vdso32_rt_sigtramp;
+static unsigned int vdso32_pages __ro_after_init;
+static void *vdso32_kbase __ro_after_init = &vdso32_start;
+unsigned long vdso32_sigtramp __ro_after_init;
+unsigned long vdso32_rt_sigtramp __ro_after_init;
 
 extern char vdso64_start, vdso64_end;
-static void *vdso64_kbase = &vdso64_start;
-static unsigned int vdso64_pages;
+static void *vdso64_kbase __ro_after_init = &vdso64_start;
+static unsigned int vdso64_pages __ro_after_init;
 #ifdef CONFIG_PPC64
-unsigned long vdso64_rt_sigtramp;
+unsigned long vdso64_rt_sigtramp __ro_after_init;
 #endif /* CONFIG_PPC64 */
 
-static int vdso_ready;
+static int vdso_ready __ro_after_init;
 
 /*
  * The vdso data page (aka. systemcfg for old ppc64 fans) is here.
-- 
2.25.0

[PATCH v2 5/5] powerpc/vdso: Declare vdso_patches[] as __initdata

[Christophe Leroy]

vdso_patches[] table is used only at init time.

Mark it __initdata.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/kernel/vdso.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 4ad042995ccc..dfa08a7b4e7c 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -76,7 +76,7 @@ struct vdso_patch_def
  * Currently, we only change sync_dicache to do nothing on processors
  * with a coherent icache
  */
-static struct vdso_patch_def vdso_patches[] = {
+static struct vdso_patch_def vdso_patches[] __initdata = {
 	{
 		CPU_FTR_COHERENT_ICACHE, CPU_FTR_COHERENT_ICACHE,
 		"__kernel_sync_dicache", "__kernel_sync_dicache_p5"
-- 
2.25.0