[PATCH 1/3] powerpc/vdso: Remove unused debug code

[PATCH 1/3] powerpc/vdso: Remove unused debug code

[Michael Ellerman]

It's in the git history if we ever need it back.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/kernel/vdso.c | 44 --------------------------------------------
 1 file changed, 44 deletions(-)

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 305eb0d9b768..869fd0c53280 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -140,50 +140,6 @@ struct lib64_elfinfo
 };
 
 
-#ifdef __DEBUG
-static void dump_one_vdso_page(struct page *pg, struct page *upg)
-{
-	printk("kpg: %p (c:%d,f:%08lx)", __va(page_to_pfn(pg) << PAGE_SHIFT),
-	       page_count(pg),
-	       pg->flags);
-	if (upg && !IS_ERR(upg) /* && pg != upg*/) {
-		printk(" upg: %p (c:%d,f:%08lx)", __va(page_to_pfn(upg)
-						       << PAGE_SHIFT),
-		       page_count(upg),
-		       upg->flags);
-	}
-	printk("\n");
-}
-
-static void dump_vdso_pages(struct vm_area_struct * vma)
-{
-	int i;
-
-	if (!vma || is_32bit_task()) {
-		printk("vDSO32 @ %016lx:\n", (unsigned long)vdso32_kbase);
-		for (i=0; i<vdso32_pages; i++) {
-			struct page *pg = virt_to_page(vdso32_kbase +
-						       i*PAGE_SIZE);
-			struct page *upg = (vma && vma->vm_mm) ?
-				follow_page(vma, vma->vm_start + i*PAGE_SIZE, 0)
-				: NULL;
-			dump_one_vdso_page(pg, upg);
-		}
-	}
-	if (!vma || !is_32bit_task()) {
-		printk("vDSO64 @ %016lx:\n", (unsigned long)vdso64_kbase);
-		for (i=0; i<vdso64_pages; i++) {
-			struct page *pg = virt_to_page(vdso64_kbase +
-						       i*PAGE_SIZE);
-			struct page *upg = (vma && vma->vm_mm) ?
-				follow_page(vma, vma->vm_start + i*PAGE_SIZE, 0)
-				: NULL;
-			dump_one_vdso_page(pg, upg);
-		}
-	}
-}
-#endif /* DEBUG */
-
 /*
  * This is called from binfmt_elf, we create the special vma for the
  * vDSO and insert it into the mm struct tree
-- 
2.1.0

[PATCH 2/3] powerpc/vdso: Combine start/size variables

[Michael Ellerman]

In vdso_fixup_features() we have start64/start32 and size64/size32, but
they have the same types, ie. void * and unsigned long.

They're only used to save the return value from find_sectionXX() for the
subsequent call to do_feature_fixups(), so there's no overlap in their
usage either.

So we can just consolidate them into start/size and avoid the
duplication.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/kernel/vdso.c | 55 ++++++++++++++++++++++------------------------
 1 file changed, 26 insertions(+), 29 deletions(-)

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 869fd0c53280..8331d0bef0fb 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -525,55 +525,52 @@ static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
 static __init int vdso_fixup_features(struct lib32_elfinfo *v32,
 				      struct lib64_elfinfo *v64)
 {
-	void *start32;
-	unsigned long size32;
+	unsigned long size;
+	void *start;
 
 #ifdef CONFIG_PPC64
-	void *start64;
-	unsigned long size64;
-
-	start64 = find_section64(v64->hdr, "__ftr_fixup", &size64);
-	if (start64)
+	start = find_section64(v64->hdr, "__ftr_fixup", &size);
+	if (start)
 		do_feature_fixups(cur_cpu_spec->cpu_features,
-				  start64, start64 + size64);
+				  start, start + size);
 
-	start64 = find_section64(v64->hdr, "__mmu_ftr_fixup", &size64);
-	if (start64)
+	start = find_section64(v64->hdr, "__mmu_ftr_fixup", &size);
+	if (start)
 		do_feature_fixups(cur_cpu_spec->mmu_features,
-				  start64, start64 + size64);
+				  start, start + size);
 
-	start64 = find_section64(v64->hdr, "__fw_ftr_fixup", &size64);
-	if (start64)
+	start = find_section64(v64->hdr, "__fw_ftr_fixup", &size);
+	if (start)
 		do_feature_fixups(powerpc_firmware_features,
-				  start64, start64 + size64);
+				  start, start + size);
 
-	start64 = find_section64(v64->hdr, "__lwsync_fixup", &size64);
-	if (start64)
+	start = find_section64(v64->hdr, "__lwsync_fixup", &size);
+	if (start)
 		do_lwsync_fixups(cur_cpu_spec->cpu_features,
-				 start64, start64 + size64);
+				 start, start + size);
 #endif /* CONFIG_PPC64 */
 
-	start32 = find_section32(v32->hdr, "__ftr_fixup", &size32);
-	if (start32)
+	start = find_section32(v32->hdr, "__ftr_fixup", &size);
+	if (start)
 		do_feature_fixups(cur_cpu_spec->cpu_features,
-				  start32, start32 + size32);
+				  start, start + size);
 
-	start32 = find_section32(v32->hdr, "__mmu_ftr_fixup", &size32);
-	if (start32)
+	start = find_section32(v32->hdr, "__mmu_ftr_fixup", &size);
+	if (start)
 		do_feature_fixups(cur_cpu_spec->mmu_features,
-				  start32, start32 + size32);
+				  start, start + size);
 
 #ifdef CONFIG_PPC64
-	start32 = find_section32(v32->hdr, "__fw_ftr_fixup", &size32);
-	if (start32)
+	start = find_section32(v32->hdr, "__fw_ftr_fixup", &size);
+	if (start)
 		do_feature_fixups(powerpc_firmware_features,
-				  start32, start32 + size32);
+				  start, start + size);
 #endif /* CONFIG_PPC64 */
 
-	start32 = find_section32(v32->hdr, "__lwsync_fixup", &size32);
-	if (start32)
+	start = find_section32(v32->hdr, "__lwsync_fixup", &size);
+	if (start)
 		do_lwsync_fixups(cur_cpu_spec->cpu_features,
-				 start32, start32 + size32);
+				 start, start + size);
 
 	return 0;
 }
-- 
2.1.0

[PATCH 3/3] powerpc/vdso: Disable building the 32-bit VDSO on little endian

[Michael Ellerman]

The only little endian configuration we support is ppc64le. As such if
we're building little endian we don't need a 32-bit VDSO, because there
is no 32-bit userspace.

This patch is a fairly ugly mess of #ifdefs, but is the minimal logic
required to disable the 32-bit VDSO. We can hopefully clean up the
result in future with some further refactoring.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/include/asm/vdso.h        |  1 +
 arch/powerpc/kernel/Makefile           |  3 ++-
 arch/powerpc/kernel/vdso.c             | 40 ++++++++++++++++++++++++++++++----
 arch/powerpc/platforms/Kconfig.cputype | 10 +++++++++
 4 files changed, 49 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/include/asm/vdso.h b/arch/powerpc/include/asm/vdso.h
index c53f5f6d1761..f455adb471e7 100644
--- a/arch/powerpc/include/asm/vdso.h
+++ b/arch/powerpc/include/asm/vdso.h
@@ -19,6 +19,7 @@
 
 /* Offsets relative to thread->vdso_base */
 extern unsigned long vdso64_rt_sigtramp;
+
 extern unsigned long vdso32_sigtramp;
 extern unsigned long vdso32_rt_sigtramp;
 
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index c1ebbdaac28f..87c7d1473488 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -33,11 +33,12 @@ obj-y				:= cputable.o ptrace.o syscalls.o \
 				   signal.o sysfs.o cacheinfo.o time.o \
 				   prom.o traps.o setup-common.o \
 				   udbg.o misc.o io.o dma.o \
-				   misc_$(CONFIG_WORD_SIZE).o vdso32/ \
+				   misc_$(CONFIG_WORD_SIZE).o \
 				   of_platform.o prom_parse.o
 obj-$(CONFIG_PPC64)		+= setup_64.o sys_ppc32.o \
 				   signal_64.o ptrace32.o \
 				   paca.o nvram_64.o firmware.o
+obj-$(CONFIG_VDSO32)		+= vdso32/
 obj-$(CONFIG_HAVE_HW_BREAKPOINT)	+= hw_breakpoint.o
 obj-$(CONFIG_PPC_BOOK3S_64)	+= cpu_setup_ppc970.o cpu_setup_pa6t.o
 obj-$(CONFIG_PPC_BOOK3S_64)	+= cpu_setup_power.o
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 8331d0bef0fb..c2bd45187315 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -49,12 +49,15 @@
 /* The alignment of the vDSO */
 #define VDSO_ALIGNMENT	(1 << 16)
 
-extern char vdso32_start, vdso32_end;
-static void *vdso32_kbase = &vdso32_start;
 static unsigned int vdso32_pages;
+static void *vdso32_kbase;
 static struct page **vdso32_pagelist;
-unsigned long vdso32_sigtramp;
-unsigned long vdso32_rt_sigtramp;
+unsigned long vdso32_sigtramp = 0;
+unsigned long vdso32_rt_sigtramp = 0;
+
+#ifdef CONFIG_VDSO32
+extern char vdso32_start, vdso32_end;
+#endif
 
 #ifdef CONFIG_PPC64
 extern char vdso64_start, vdso64_end;
@@ -248,6 +251,7 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 
 
 
+#ifdef CONFIG_VDSO32
 static void * __init find_section32(Elf32_Ehdr *ehdr, const char *secname,
 				  unsigned long *size)
 {
@@ -335,6 +339,20 @@ static int __init vdso_do_func_patch32(struct lib32_elfinfo *v32,
 
 	return 0;
 }
+#else /* !CONFIG_VDSO32 */
+static unsigned long __init find_function32(struct lib32_elfinfo *lib,
+					    const char *symname)
+{
+	return 0;
+}
+
+static int __init vdso_do_func_patch32(struct lib32_elfinfo *v32,
+				       struct lib64_elfinfo *v64,
+				       const char *orig, const char *fix)
+{
+	return 0;
+}
+#endif /* CONFIG_VDSO32 */
 
 
 #ifdef CONFIG_PPC64
@@ -445,6 +463,7 @@ static __init int vdso_do_find_sections(struct lib32_elfinfo *v32,
 	 * Locate symbol tables & text section
 	 */
 
+#ifdef CONFIG_VDSO32
 	v32->dynsym = find_section32(v32->hdr, ".dynsym", &v32->dynsymsize);
 	v32->dynstr = find_section32(v32->hdr, ".dynstr", NULL);
 	if (v32->dynsym == NULL || v32->dynstr == NULL) {
@@ -457,6 +476,7 @@ static __init int vdso_do_find_sections(struct lib32_elfinfo *v32,
 		return -1;
 	}
 	v32->text = sect - vdso32_kbase;
+#endif
 
 #ifdef CONFIG_PPC64
 	v64->dynsym = find_section64(v64->hdr, ".dynsym", &v64->dynsymsize);
@@ -493,7 +513,9 @@ static __init void vdso_setup_trampolines(struct lib32_elfinfo *v32,
 static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
 				       struct lib64_elfinfo *v64)
 {
+#ifdef CONFIG_VDSO32
 	Elf32_Sym *sym32;
+#endif
 #ifdef CONFIG_PPC64
 	Elf64_Sym *sym64;
 
@@ -508,6 +530,7 @@ static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
 		(sym64->st_value - VDSO64_LBASE);
 #endif /* CONFIG_PPC64 */
 
+#ifdef CONFIG_VDSO32
 	sym32 = find_symbol32(v32, "__kernel_datapage_offset");
 	if (sym32 == NULL) {
 		printk(KERN_ERR "vDSO32: Can't find symbol "
@@ -517,6 +540,7 @@ static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
 	*((int *)(vdso32_kbase + (sym32->st_value - VDSO32_LBASE))) =
 		(vdso32_pages << PAGE_SHIFT) -
 		(sym32->st_value - VDSO32_LBASE);
+#endif
 
 	return 0;
 }
@@ -550,6 +574,7 @@ static __init int vdso_fixup_features(struct lib32_elfinfo *v32,
 				 start, start + size);
 #endif /* CONFIG_PPC64 */
 
+#ifdef CONFIG_VDSO32
 	start = find_section32(v32->hdr, "__ftr_fixup", &size);
 	if (start)
 		do_feature_fixups(cur_cpu_spec->cpu_features,
@@ -571,6 +596,7 @@ static __init int vdso_fixup_features(struct lib32_elfinfo *v32,
 	if (start)
 		do_lwsync_fixups(cur_cpu_spec->cpu_features,
 				 start, start + size);
+#endif
 
 	return 0;
 }
@@ -732,11 +758,15 @@ static int __init vdso_init(void)
 #endif /* CONFIG_PPC64 */
 
 
+#ifdef CONFIG_VDSO32
+	vdso32_kbase = &vdso32_start;
+
 	/*
 	 * 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);
+#endif
 
 
 	/*
@@ -757,6 +787,7 @@ static int __init vdso_init(void)
 		return 0;
 	}
 
+#ifdef CONFIG_VDSO32
 	/* Make sure pages are in the correct state */
 	vdso32_pagelist = kzalloc(sizeof(struct page *) * (vdso32_pages + 2),
 				  GFP_KERNEL);
@@ -769,6 +800,7 @@ static int __init vdso_init(void)
 	}
 	vdso32_pagelist[i++] = virt_to_page(vdso_data);
 	vdso32_pagelist[i] = NULL;
+#endif
 
 #ifdef CONFIG_PPC64
 	vdso64_pagelist = kzalloc(sizeof(struct page *) * (vdso64_pages + 2),
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index c8ae35f564fd..c140e94c7c72 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -405,6 +405,16 @@ config PPC_DOORBELL
 
 endmenu
 
+config VDSO32
+	def_bool y
+	depends on PPC32 || CPU_BIG_ENDIAN
+	help
+	  This symbol controls whether we build the 32-bit VDSO. We obviously
+	  want to do that if we're building a 32-bit kernel. If we're building
+	  a 64-bit kernel then we only want a 32-bit VDSO if we're building for
+	  big endian. That is because the only little endian configuration we
+	  support is ppc64le which is 64-bit only.
+
 choice
 	prompt "Endianness selection"
 	default CPU_BIG_ENDIAN
-- 
2.1.0

Re: [PATCH 3/3] powerpc/vdso: Disable building the 32-bit VDSO on little endian

[Stephen Rothwell]

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Hi Michael,

On Wed, 22 Apr 2015 15:40:36 +1000 Michael Ellerman <mpe@ellerman.id.au> wrote:
>
> diff --git a/arch/powerpc/include/asm/vdso.h b/arch/powerpc/include/asm/vdso.h
> index c53f5f6d1761..f455adb471e7 100644
> --- a/arch/powerpc/include/asm/vdso.h
> +++ b/arch/powerpc/include/asm/vdso.h
> @@ -19,6 +19,7 @@
>  
>  /* Offsets relative to thread->vdso_base */
>  extern unsigned long vdso64_rt_sigtramp;
> +
>  extern unsigned long vdso32_sigtramp;
>  extern unsigned long vdso32_rt_sigtramp;

You could drop this hunk :-)

> diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
> index 8331d0bef0fb..c2bd45187315 100644
> --- a/arch/powerpc/kernel/vdso.c
> +++ b/arch/powerpc/kernel/vdso.c
> @@ -49,12 +49,15 @@
>  /* The alignment of the vDSO */
>  #define VDSO_ALIGNMENT	(1 << 16)
>  
> -extern char vdso32_start, vdso32_end;
> -static void *vdso32_kbase = &vdso32_start;
>  static unsigned int vdso32_pages;
> +static void *vdso32_kbase;
>  static struct page **vdso32_pagelist;
> -unsigned long vdso32_sigtramp;
> -unsigned long vdso32_rt_sigtramp;
> +unsigned long vdso32_sigtramp = 0;
> +unsigned long vdso32_rt_sigtramp = 0;

And they should be zero anyway, right?

-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au

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Re: [PATCH 3/3] powerpc/vdso: Disable building the 32-bit VDSO on little endian

[Michael Ellerman]

On Thu, 2015-04-23 at 13:06 +1000, Stephen Rothwell wrote:
> Hi Michael,
> 
> On Wed, 22 Apr 2015 15:40:36 +1000 Michael Ellerman <mpe@ellerman.id.au> wrote:
> >
> > diff --git a/arch/powerpc/include/asm/vdso.h b/arch/powerpc/include/asm/vdso.h
> > index c53f5f6d1761..f455adb471e7 100644
> > --- a/arch/powerpc/include/asm/vdso.h
> > +++ b/arch/powerpc/include/asm/vdso.h
> > @@ -19,6 +19,7 @@
> >  
> >  /* Offsets relative to thread->vdso_base */
> >  extern unsigned long vdso64_rt_sigtramp;
> > +
> >  extern unsigned long vdso32_sigtramp;
> >  extern unsigned long vdso32_rt_sigtramp;
> 
> You could drop this hunk :-)

Darn it.

> > diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
> > index 8331d0bef0fb..c2bd45187315 100644
> > --- a/arch/powerpc/kernel/vdso.c
> > +++ b/arch/powerpc/kernel/vdso.c
> > @@ -49,12 +49,15 @@
> >  /* The alignment of the vDSO */
> >  #define VDSO_ALIGNMENT	(1 << 16)
> >  
> > -extern char vdso32_start, vdso32_end;
> > -static void *vdso32_kbase = &vdso32_start;
> >  static unsigned int vdso32_pages;
> > +static void *vdso32_kbase;
> >  static struct page **vdso32_pagelist;
> > -unsigned long vdso32_sigtramp;
> > -unsigned long vdso32_rt_sigtramp;
> > +unsigned long vdso32_sigtramp = 0;
> > +unsigned long vdso32_rt_sigtramp = 0;
> 
> And they should be zero anyway, right?

Yeah I guess, I wanted to be sure :)

cheers