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* [PATCH 0/6] arm64: compat: Add COMPAT_VDSO
@ 2017-11-15 22:05 Mark Salyzyn
  2017-11-15 22:05 ` [PATCH 1/6] arm64: compat: Use vDSO sigreturn trampolines if available Mark Salyzyn
                   ` (5 more replies)
  0 siblings, 6 replies; 7+ messages in thread
From: Mark Salyzyn @ 2017-11-15 22:05 UTC (permalink / raw)
  To: linux-kernel
  Cc: Mark Salyzyn, Kevin Brodsky, Catalin Marinas, Will Deacon,
	Dave Martin, Eric W. Biederman, linux-arm-kernel

Add compatible vDSO32 support to arm64, provide the files necessary
for building a compat (AArch32) vDSO in arch/arm64/kernel/vdso32.

Leverages effort to unify the vgettimeofday.c file as outlined below.

To be applied over top the following pending patches:

[PATCH] arm64: compat: Remove leftover variable declaration
NB: approved, in arch64/for-next/core
[PATCH v3 1/3] arm64: compat: Split the sigreturn trampolines and kuser helpers (C sources)
[PATCH v3 2/3] arm64: compat: Split the sigreturn trampolines and kuser helpers (assembler sources)
[PATCH v3 3/3] arm64: compat: Add CONFIG_KUSER_HELPERS
[PATCH] arm64: compat: Expose offset to registers in sigframes
[PATCH v5 01/12] arm: vdso: rename vdso_datapage variables
[PATCH v5 02/12] arm: vdso: add include file defining __get_datapage()
[PATCH v5 03/12] arm: vdso: inline assembler operations to compiler.h
[PATCH v5 04/12] arm: vdso: do calculations outside reader loops
[PATCH v6 05/12] arm: vdso: Add support for CLOCK_MONOTONIC_RAW
[PATCH v5 06/12] arm: vdso: add support for clock_getres
[PATCH v5 07/12] arm: vdso: disable profiling
[PATCH v5 08/12] arm: vdso: Add ARCH_CLOCK_FIXED_MASK
[PATCH v5 09/12] arm: vdso: move vgettimeofday.c to lib/vdso/
[PATCH v5 10/12] arm64: vdso: replace gettimeofday.S with global vgettimeofday.C
[PATCH v5 11/12] lib: vdso: Add support for CLOCK_BOOTTIME
[PATCH v5 12/12] lib: vdso: do not expose gettimeofday, if no arch supported timer
[PATCH] lib: vdso: add support for time

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org

^ permalink raw reply	[flat|nested] 7+ messages in thread
* [PATCH 1/6] arm64: compat: Use vDSO sigreturn trampolines if available
  2017-11-15 22:05 [PATCH 0/6] arm64: compat: Add COMPAT_VDSO Mark Salyzyn
@ 2017-11-15 22:05 ` Mark Salyzyn
  2017-11-15 22:05 ` [PATCH 2/6] arm64: elf: Set AT_SYSINFO_EHDR in compat processes Mark Salyzyn
                   ` (4 subsequent siblings)
  5 siblings, 0 replies; 7+ messages in thread
From: Mark Salyzyn @ 2017-11-15 22:05 UTC (permalink / raw)
  To: linux-kernel
  Cc: Kevin Brodsky, Mark Salyzyn, Catalin Marinas, Will Deacon,
	Dave Martin, Eric W. Biederman, linux-arm-kernel

From: Kevin Brodsky <kevin.brodsky@arm.com>

If the compat vDSO is enabled, it replaces the sigreturn page.
Therefore, we use the sigreturn trampolines the vDSO provides instead.

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
 arch/arm64/include/asm/vdso.h |  3 +++
 arch/arm64/kernel/signal32.c  | 15 +++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/arch/arm64/include/asm/vdso.h b/arch/arm64/include/asm/vdso.h
index 839ce0031bd5..f2a952338f1e 100644
--- a/arch/arm64/include/asm/vdso.h
+++ b/arch/arm64/include/asm/vdso.h
@@ -28,6 +28,9 @@
 #ifndef __ASSEMBLY__
 
 #include <generated/vdso-offsets.h>
+#ifdef CONFIG_VDSO32
+#include <generated/vdso32-offsets.h>
+#endif
 
 #define VDSO_SYMBOL(base, name)						   \
 ({									   \
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c
index 4f0c0aa14cba..37095782622d 100644
--- a/arch/arm64/kernel/signal32.c
+++ b/arch/arm64/kernel/signal32.c
@@ -28,6 +28,7 @@
 #include <asm/signal32.h>
 #include <linux/uaccess.h>
 #include <asm/unistd.h>
+#include <asm/vdso.h>
 
 struct compat_vfp_sigframe {
 	compat_ulong_t	magic;
@@ -433,6 +434,19 @@ static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka,
 		retcode = ptr_to_compat(ka->sa.sa_restorer);
 	} else {
 		/* Set up sigreturn pointer */
+#ifdef CONFIG_VDSO32
+		void *vdso_base = current->mm->context.vdso;
+		void *trampoline =
+			(ka->sa.sa_flags & SA_SIGINFO
+			 ? (thumb
+			    ? VDSO_SYMBOL(vdso_base, compat_rt_sigreturn_thumb)
+			    : VDSO_SYMBOL(vdso_base, compat_rt_sigreturn_arm))
+			 : (thumb
+			    ? VDSO_SYMBOL(vdso_base, compat_sigreturn_thumb)
+			    : VDSO_SYMBOL(vdso_base, compat_sigreturn_arm)));
+
+		retcode = ptr_to_compat(trampoline) + thumb;
+#else
 		void *sigreturn_base = current->mm->context.vdso;
 		unsigned int idx = thumb << 1;
 
@@ -440,6 +454,7 @@ static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka,
 			idx += 3;
 
 		retcode = ptr_to_compat(sigreturn_base) + (idx << 2) + thumb;
+#endif
 	}
 
 	regs->regs[0]	= usig;
-- 
2.15.0.448.gf294e3d99a-goog

^ permalink raw reply related	[flat|nested] 7+ messages in thread
* [PATCH 2/6] arm64: elf: Set AT_SYSINFO_EHDR in compat processes
  2017-11-15 22:05 [PATCH 0/6] arm64: compat: Add COMPAT_VDSO Mark Salyzyn
  2017-11-15 22:05 ` [PATCH 1/6] arm64: compat: Use vDSO sigreturn trampolines if available Mark Salyzyn
@ 2017-11-15 22:05 ` Mark Salyzyn
  2017-11-15 22:05 ` [PATCH 3/6] arm64: Refactor vDSO init/setup Mark Salyzyn
                   ` (3 subsequent siblings)
  5 siblings, 0 replies; 7+ messages in thread
From: Mark Salyzyn @ 2017-11-15 22:05 UTC (permalink / raw)
  To: linux-kernel
  Cc: Kevin Brodsky, Mark Salyzyn, Catalin Marinas, Will Deacon,
	Dave Martin, Eric W. Biederman, linux-arm-kernel, Andrew Morton,
	Yury Norov, Kees Cook, Dong Bo

From: Kevin Brodsky <kevin.brodsky@arm.com>

If the compat vDSO is enabled, we need to set AT_SYSINFO_EHDR in the
auxiliary vector of compat processes to the address of the vDSO code
page, so that the dynamic linker can find it (just like the regular vDSO).

Note that we cast context.vdso to Elf64_Off, instead of elf_addr_t,
because elf_addr_t is Elf32_Off in compat_binfmt_elf.c, and casting
context.vdso to u32 would trigger a pointer narrowing warning.

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
 arch/arm64/include/asm/elf.h | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index 33be513ef24c..675fa096d4a4 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -144,11 +144,12 @@ typedef struct user_fpsimd_state elf_fpregset_t;
 })
 
 /* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT entries changes */
-#define ARCH_DLINFO							\
+#define _SET_AUX_ENT_VDSO						\
 do {									\
 	NEW_AUX_ENT(AT_SYSINFO_EHDR,					\
-		    (elf_addr_t)current->mm->context.vdso);		\
+		    (Elf64_Off)current->mm->context.vdso);		\
 } while (0)
+#define ARCH_DLINFO _SET_AUX_ENT_VDSO
 
 #define ARCH_HAS_SETUP_ADDITIONAL_PAGES
 struct linux_binprm;
@@ -196,7 +197,11 @@ typedef compat_elf_greg_t		compat_elf_gregset_t[COMPAT_ELF_NGREG];
 ({									\
 	set_thread_flag(TIF_32BIT);					\
  })
+#ifdef CONFIG_VDSO32
+#define COMPAT_ARCH_DLINFO	_SET_AUX_ENT_VDSO
+#else
 #define COMPAT_ARCH_DLINFO
+#endif
 extern int aarch32_setup_vectors_page(struct linux_binprm *bprm,
 				      int uses_interp);
 #define compat_arch_setup_additional_pages \
-- 
2.15.0.448.gf294e3d99a-goog

^ permalink raw reply related	[flat|nested] 7+ messages in thread
* [PATCH 3/6] arm64: Refactor vDSO init/setup
  2017-11-15 22:05 [PATCH 0/6] arm64: compat: Add COMPAT_VDSO Mark Salyzyn
  2017-11-15 22:05 ` [PATCH 1/6] arm64: compat: Use vDSO sigreturn trampolines if available Mark Salyzyn
  2017-11-15 22:05 ` [PATCH 2/6] arm64: elf: Set AT_SYSINFO_EHDR in compat processes Mark Salyzyn
@ 2017-11-15 22:05 ` Mark Salyzyn
  2017-11-15 22:05 ` [PATCH 4/6] arm64: compat: Add a 32-bit vDSO Mark Salyzyn
                   ` (2 subsequent siblings)
  5 siblings, 0 replies; 7+ messages in thread
From: Mark Salyzyn @ 2017-11-15 22:05 UTC (permalink / raw)
  To: linux-kernel
  Cc: Kevin Brodsky, Mark Salyzyn, Catalin Marinas, Will Deacon,
	Dave Martin, Eric W. Biederman, linux-arm-kernel, John Stultz,
	Dmitry Safonov, Kees Cook

From: Kevin Brodsky <kevin.brodsky@arm.com>

Move the logic for setting up mappings and pages for the vDSO into
static functions. This makes the vDSO setup code more consistent with
the compat side and will allow to reuse it for the future compat vDSO.

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
 arch/arm64/kernel/vdso.c | 118 ++++++++++++++++++++++++++++-------------------
 1 file changed, 70 insertions(+), 48 deletions(-)

diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 26d510474ffa..48b4111a933f 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -39,8 +39,11 @@
 #include <asm/vdso.h>
 #include <asm/vdso_datapage.h>
 
-extern char vdso_start[], vdso_end[];
-static unsigned long vdso_pages __ro_after_init;
+struct vdso_mappings {
+	unsigned long num_code_pages;
+	struct vm_special_mapping data_mapping;
+	struct vm_special_mapping code_mapping;
+};
 
 /*
  * The vDSO data page.
@@ -164,95 +167,114 @@ static int vdso_mremap(const struct vm_special_mapping *sm,
 	return 0;
 }
 
-static struct vm_special_mapping vdso_spec[2] __ro_after_init = {
-	{
-		.name	= "[vvar]",
-	},
-	{
-		.name	= "[vdso]",
-		.mremap = vdso_mremap,
-	},
-};
-
-static int __init vdso_init(void)
+static int __init vdso_mappings_init(const char *name,
+				     const char *code_start,
+				     const char *code_end,
+				     struct vdso_mappings *mappings)
 {
-	int i;
+	unsigned long i, vdso_page;
 	struct page **vdso_pagelist;
 	unsigned long pfn;
 
-	if (memcmp(vdso_start, "\177ELF", 4)) {
-		pr_err("vDSO is not a valid ELF object!\n");
+	if (memcmp(code_start, "\177ELF", 4)) {
+		pr_err("%s is not a valid ELF object!\n", name);
 		return -EINVAL;
 	}
 
-	vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
-	pr_info("vdso: %ld pages (%ld code @ %p, %ld data @ %p)\n",
-		vdso_pages + 1, vdso_pages, vdso_start, 1L, vdso_data);
-
-	/* Allocate the vDSO pagelist, plus a page for the data. */
-	vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *),
-				GFP_KERNEL);
+	vdso_pages = (code_end - code_start) >> PAGE_SHIFT;
+	pr_info("%s: %ld pages (%ld code @ %p, %ld data @ %p)\n",
+		name, vdso_pages + 1, vdso_pages, code_start, 1L,
+		vdso_data);
+
+	/*
+	 * Allocate space for storing pointers to the vDSO code pages + the
+	 * data page. The pointers must have the same lifetime as the mappings,
+	 * which are static, so there is no need to keep track of the pointer
+	 * array to free it.
+	 */
+	vdso_pagelist = kmalloc_array(vdso_pages + 1, sizeof(struct page *),
+				      GFP_KERNEL);
 	if (vdso_pagelist == NULL)
 		return -ENOMEM;
 
 	/* Grab the vDSO data page. */
 	vdso_pagelist[0] = phys_to_page(__pa_symbol(vdso_data));
 
-
 	/* Grab the vDSO code pages. */
-	pfn = sym_to_pfn(vdso_start);
+	pfn = sym_to_pfn(code_start);
 
 	for (i = 0; i < vdso_pages; i++)
 		vdso_pagelist[i + 1] = pfn_to_page(pfn + i);
 
-	vdso_spec[0].pages = &vdso_pagelist[0];
-	vdso_spec[1].pages = &vdso_pagelist[1];
+	/* Populate the special mapping structures */
+	mappings->data_mapping = (struct vm_special_mapping) {
+		.name	= "[vvar]",
+		.pages	= &vdso_pagelist[0],
+	};
+
+	mappings->code_mapping = (struct vm_special_mapping) {
+		.name	= "[vdso]",
+		.pages	= &vdso_pagelist[1],
+	};
 
+	mappings->num_code_pages = vdso_pages;
 	return 0;
 }
+
+static struct vdso_mappings vdso_mappings __ro_after_init;
+
+static int __init vdso_init(void)
+{
+	extern char vdso_start[], vdso_end[];
+
+	return vdso_mappings_init("vdso", vdso_start, vdso_end,
+				  &vdso_mappings);
+}
 arch_initcall(vdso_init);
 
-int arch_setup_additional_pages(struct linux_binprm *bprm,
-				int uses_interp)
+static int vdso_setup(struct mm_struct *mm,
+		      const struct vdso_mappings *mappings)
 {
-	struct mm_struct *mm = current->mm;
 	unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
 	void *ret;
 
-	vdso_text_len = vdso_pages << PAGE_SHIFT;
+	vdso_text_len = mappings->num_code_pages << PAGE_SHIFT;
 	/* Be sure to map the data page */
 	vdso_mapping_len = vdso_text_len + PAGE_SIZE;
 
-	if (down_write_killable(&mm->mmap_sem))
-		return -EINTR;
 	vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0);
-	if (IS_ERR_VALUE(vdso_base)) {
-		ret = ERR_PTR(vdso_base);
-		goto up_fail;
-	}
+	if (IS_ERR_VALUE(vdso_base))
+		ret = PTR_ERR_OR_ZERO(ERR_PTR(vdso_base));
+
 	ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE,
 				       VM_READ|VM_MAYREAD,
-				       &vdso_spec[0]);
+				       &mappings->data_mapping);
 	if (IS_ERR(ret))
-		goto up_fail;
+		return PTR_ERR_OR_ZERO(ret);
 
 	vdso_base += PAGE_SIZE;
-	mm->context.vdso = (void *)vdso_base;
 	ret = _install_special_mapping(mm, vdso_base, vdso_text_len,
 				       VM_READ|VM_EXEC|
 				       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
-				       &vdso_spec[1]);
-	if (IS_ERR(ret))
-		goto up_fail;
+				       &mappings->code_mapping);
+	if (!IS_ERR(ret))
+		mm->context.vdso = (void *)vdso_base;
+
+	return PTR_ERR_OR_ZERO(ret);
+}
 
+int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+{
+	struct mm_struct *mm = current->mm;
+	int ret;
 
-	up_write(&mm->mmap_sem);
-	return 0;
+	if (down_write_killable(&mm->mmap_sem))
+		return -EINTR;
+
+	ret = vdso_setup(mm, &vdso_mappings);
 
-up_fail:
-	mm->context.vdso = NULL;
 	up_write(&mm->mmap_sem);
-	return PTR_ERR(ret);
+	return ret;
 }
 
 /*
-- 
2.15.0.448.gf294e3d99a-goog

^ permalink raw reply related	[flat|nested] 7+ messages in thread
* [PATCH 4/6] arm64: compat: Add a 32-bit vDSO
  2017-11-15 22:05 [PATCH 0/6] arm64: compat: Add COMPAT_VDSO Mark Salyzyn
                   ` (2 preceding siblings ...)
  2017-11-15 22:05 ` [PATCH 3/6] arm64: Refactor vDSO init/setup Mark Salyzyn
@ 2017-11-15 22:05 ` Mark Salyzyn
  2017-11-15 22:05 ` [PATCH 5/6] arm64: compat: 32-bit vDSO setup Mark Salyzyn
  2017-11-15 22:05 ` [PATCH 6/6] arm64: Wire up and expose the new compat vDSO Mark Salyzyn
  5 siblings, 0 replies; 7+ messages in thread
From: Mark Salyzyn @ 2017-11-15 22:05 UTC (permalink / raw)
  To: linux-kernel
  Cc: Kevin Brodsky, Mark Salyzyn, Catalin Marinas, Will Deacon,
	Dave Martin, Eric W. Biederman, linux-arm-kernel

From: Kevin Brodsky <kevin.brodsky@arm.com>

Provide the files necessary for building a compat (AArch32) vDSO in
kernel/vdso32.

This is mostly an adaptation of the arm vDSO. The most significant
change in vgettimeofday.c is the use of the arm64 vdso_data struct,
allowing the vDSO data page to be shared between the 32 and 64-bit
vDSOs. Additionally, a different set of barrier macros is used (see
aarch32-barrier.h), as we want to support old 32-bit compilers that
may not support ARMv8 and its new barrier arguments (*ld).

In addition to the time functions, sigreturn trampolines are also
provided, aiming at replacing those in the sigreturn page as the
latter don't provide any unwinding information (and it's easier to
have just one "user code" page). arm-specific unwinding directives are
used, based on glibc's implementation. Symbol offsets are made
available to the kernel using the same method as the 64-bit vDSO.

There is unfortunately an important caveat: we cannot get away with
hand-coding 32-bit instructions like in kernel/kuser32.S, this time we
really need a 32-bit compiler. The compat vDSO Makefile relies on
CROSS_COMPILE_ARM32 to provide a 32-bit compiler, appropriate logic
will be added to the arm64 Makefile later on to ensure that an attempt
to build the compat vDSO is made only if this variable has been set
properly.

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>

Take an effort to recode the arm64 vdso code from assembler to C
previously submitted by Andrew Pinski <apinski@cavium.com>, rework
it for use in both arm and arm64, overlapping any optimizations
for each architecture.

Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
 arch/arm64/kernel/vdso32/.gitignore      |   2 +
 arch/arm64/kernel/vdso32/Makefile        | 172 +++++++++++++++++++++++++++++++
 arch/arm64/kernel/vdso32/compiler.h      | 120 +++++++++++++++++++++
 arch/arm64/kernel/vdso32/datapage.h      |   1 +
 arch/arm64/kernel/vdso32/sigreturn.S     |  76 ++++++++++++++
 arch/arm64/kernel/vdso32/vdso.S          |  32 ++++++
 arch/arm64/kernel/vdso32/vdso.lds.S      |  95 +++++++++++++++++
 arch/arm64/kernel/vdso32/vgettimeofday.c |   3 +
 8 files changed, 501 insertions(+)
 create mode 100644 arch/arm64/kernel/vdso32/.gitignore
 create mode 100644 arch/arm64/kernel/vdso32/Makefile
 create mode 100644 arch/arm64/kernel/vdso32/compiler.h
 create mode 100644 arch/arm64/kernel/vdso32/datapage.h
 create mode 100644 arch/arm64/kernel/vdso32/sigreturn.S
 create mode 100644 arch/arm64/kernel/vdso32/vdso.S
 create mode 100644 arch/arm64/kernel/vdso32/vdso.lds.S
 create mode 100644 arch/arm64/kernel/vdso32/vgettimeofday.c

diff --git a/arch/arm64/kernel/vdso32/.gitignore b/arch/arm64/kernel/vdso32/.gitignore
new file mode 100644
index 000000000000..4fea950fa5ed
--- /dev/null
+++ b/arch/arm64/kernel/vdso32/.gitignore
@@ -0,0 +1,2 @@
+vdso.lds
+vdso.so.raw
diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile
new file mode 100644
index 000000000000..6d44d972e89d
--- /dev/null
+++ b/arch/arm64/kernel/vdso32/Makefile
@@ -0,0 +1,172 @@
+#
+# Building a vDSO image for AArch32.
+#
+# Author: Kevin Brodsky <kevin.brodsky@arm.com>
+# A mix between the arm64 and arm vDSO Makefiles.
+
+ifeq ($(cc-name),clang)
+  CC_ARM32 := $(cc-name) $(CLANG_TARGET_ARM32) -no-integrated-as
+else
+  CC_ARM32 := $(CROSS_COMPILE_ARM32)$(cc-name)
+endif
+
+# Same as cc-*option, but using CC_ARM32 instead of CC
+cc32-option = $(call try-run,\
+        $(CC_ARM32) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
+cc32-disable-warning = $(call try-run,\
+	$(CC_ARM32) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
+cc32-ldoption = $(call try-run,\
+        $(CC_ARM32) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2))
+
+# We cannot use the global flags to compile the vDSO files, the main reason
+# being that the 32-bit compiler may be older than the main (64-bit) compiler
+# and therefore may not understand flags set using $(cc-option ...). Besides,
+# arch-specific options should be taken from the arm Makefile instead of the
+# arm64 one.
+# As a result we set our own flags here.
+
+# From top-level Makefile
+# NOSTDINC_FLAGS
+VDSO_CPPFLAGS := -nostdinc -isystem $(shell $(CC_ARM32) -print-file-name=include)
+VDSO_CPPFLAGS += $(LINUXINCLUDE)
+VDSO_CPPFLAGS += $(KBUILD_CPPFLAGS)
+
+# Common C and assembly flags
+# From top-level Makefile
+VDSO_CAFLAGS := $(VDSO_CPPFLAGS)
+VDSO_CAFLAGS += $(call cc32-option,-fno-PIE)
+ifdef CONFIG_DEBUG_INFO
+VDSO_CAFLAGS += -g
+endif
+ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC_ARM32)), y)
+VDSO_CAFLAGS += -DCC_HAVE_ASM_GOTO
+endif
+
+# From arm Makefile
+VDSO_CAFLAGS += $(call cc32-option,-fno-dwarf2-cfi-asm)
+VDSO_CAFLAGS += -mabi=aapcs-linux -mfloat-abi=soft
+ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)
+VDSO_CAFLAGS += -mbig-endian
+else
+VDSO_CAFLAGS += -mlittle-endian
+endif
+
+# From arm vDSO Makefile
+VDSO_CAFLAGS += -fPIC -fno-builtin -fno-stack-protector
+VDSO_CAFLAGS += -DDISABLE_BRANCH_PROFILING
+
+# Try to compile for ARMv8. If the compiler is too old and doesn't support it,
+# fall back to v7. There is no easy way to check for what architecture the code
+# is being compiled, so define a macro specifying that (see arch/arm/Makefile).
+VDSO_CAFLAGS += $(call cc32-option,-march=armv8-a -D__LINUX_ARM_ARCH__=8,\
+                                   -march=armv7-a -D__LINUX_ARM_ARCH__=7)
+
+VDSO_CFLAGS := $(VDSO_CAFLAGS)
+# KBUILD_CFLAGS from top-level Makefile
+VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
+               -fno-strict-aliasing -fno-common \
+               -Werror-implicit-function-declaration \
+               -Wno-format-security \
+               -std=gnu89
+VDSO_CFLAGS  += -O2
+# Some useful compiler-dependent flags from top-level Makefile
+VDSO_CFLAGS += $(call cc32-option,-Wdeclaration-after-statement,)
+VDSO_CFLAGS += $(call cc32-option,-Wno-pointer-sign)
+VDSO_CFLAGS += $(call cc32-option,-fno-strict-overflow)
+VDSO_CFLAGS += $(call cc32-option,-Werror=strict-prototypes)
+VDSO_CFLAGS += $(call cc32-option,-Werror=date-time)
+VDSO_CFLAGS += $(call cc32-option,-Werror=incompatible-pointer-types)
+
+# The 32-bit compiler does not provide 128-bit integers, which are used in
+# some headers that are indirectly included from the vDSO code.
+# This hack makes the compiler happy and should trigger a warning/error if
+# variables of such type are referenced.
+VDSO_CFLAGS += -D__uint128_t='void*'
+# Silence some warnings coming from headers that operate on long's
+# (on GCC 4.8 or older, there is unfortunately no way to silence this warning)
+VDSO_CFLAGS += $(call cc32-disable-warning,shift-count-overflow)
+VDSO_CFLAGS += -Wno-int-to-pointer-cast
+
+VDSO_AFLAGS := $(VDSO_CAFLAGS)
+VDSO_AFLAGS += -D__ASSEMBLY__
+
+VDSO_LDFLAGS := $(VDSO_CPPFLAGS)
+# From arm vDSO Makefile
+VDSO_LDFLAGS += -Wl,-Bsymbolic -Wl,--no-undefined -Wl,-soname=linux-vdso.so.1
+VDSO_LDFLAGS += -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096
+VDSO_LDFLAGS += -nostdlib -shared -mfloat-abi=soft
+VDSO_LDFLAGS += $(call cc32-ldoption,-Wl$(comma)--hash-style=sysv)
+VDSO_LDFLAGS += $(call cc32-ldoption,-Wl$(comma)--build-id)
+VDSO_LDFLAGS += $(call cc32-ldoption,-fuse-ld=bfd)
+
+
+# Borrow vdsomunge.c from the arm vDSO
+# We have to use a relative path because scripts/Makefile.host prefixes
+# $(hostprogs-y) with $(obj)
+munge := ../../../arm/vdso/vdsomunge
+hostprogs-y := $(munge)
+
+c-obj-vdso := vgettimeofday.o
+asm-obj-vdso := sigreturn.o
+
+# Build rules
+targets := $(c-obj-vdso) $(asm-obj-vdso) vdso.so vdso.so.dbg vdso.so.raw
+c-obj-vdso := $(addprefix $(obj)/, $(c-obj-vdso))
+asm-obj-vdso := $(addprefix $(obj)/, $(asm-obj-vdso))
+obj-vdso := $(c-obj-vdso) $(asm-obj-vdso)
+
+obj-y += vdso.o
+extra-y += vdso.lds
+CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
+
+# Force dependency (vdso.s includes vdso.so through incbin)
+$(obj)/vdso.o: $(obj)/vdso.so
+
+include/generated/vdso32-offsets.h: $(obj)/vdso.so.dbg FORCE
+	$(call if_changed,vdsosym)
+
+# Strip rule for vdso.so
+$(obj)/vdso.so: OBJCOPYFLAGS := -S
+$(obj)/vdso.so: $(obj)/vdso.so.dbg FORCE
+	$(call if_changed,objcopy)
+
+$(obj)/vdso.so.dbg: $(obj)/vdso.so.raw $(obj)/$(munge) FORCE
+	$(call if_changed,vdsomunge)
+
+# Link rule for the .so file, .lds has to be first
+$(obj)/vdso.so.raw: $(src)/vdso.lds $(obj-vdso) FORCE
+	$(call if_changed,vdsold)
+
+# Compilation rules for the vDSO sources
+$(filter-out vgettimeofday.o, $(c-obj-vdso)): %.o: %.c FORCE
+	$(call if_changed_dep,vdsocc)
+$(asm-obj-vdso): %.o: %.S FORCE
+	$(call if_changed_dep,vdsoas)
+
+# Actual build commands
+quiet_cmd_vdsold = VDSOL32   $@
+      cmd_vdsold = $(CC_ARM32) -Wp,-MD,$(depfile) $(VDSO_LDFLAGS) \
+                   -Wl,-T $(filter %.lds,$^) $(filter %.o,$^) -o $@
+quiet_cmd_vdsocc = VDSOC32   $@
+      cmd_vdsocc = $(CC_ARM32) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) -c -o $@ $<
+quiet_cmd_vdsoas = VDSOA32   $@
+      cmd_vdsoas = $(CC_ARM32) -Wp,-MD,$(depfile) $(VDSO_AFLAGS) -c -o $@ $<
+
+quiet_cmd_vdsomunge = MUNGE   $@
+      cmd_vdsomunge = $(obj)/$(munge) $< $@
+
+# Generate vDSO offsets using helper script (borrowed from the 64-bit vDSO)
+gen-vdsosym := $(srctree)/$(src)/../vdso/gen_vdso_offsets.sh
+quiet_cmd_vdsosym = VDSOSYM $@
+# The AArch64 nm should be able to read an AArch32 binary
+      cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
+
+# Install commands for the unstripped file
+quiet_cmd_vdso_install = INSTALL $@
+      cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/vdso32.so
+
+vdso.so: $(obj)/vdso.so.dbg
+	@mkdir -p $(MODLIB)/vdso
+	$(call cmd,vdso_install)
+
+vdso_install: vdso.so
diff --git a/arch/arm64/kernel/vdso32/compiler.h b/arch/arm64/kernel/vdso32/compiler.h
new file mode 100644
index 000000000000..a2ac3959518a
--- /dev/null
+++ b/arch/arm64/kernel/vdso32/compiler.h
@@ -0,0 +1,120 @@
+/*
+ * Userspace implementations of fallback calls
+ *
+ * Copyright (C) 2017 Cavium, Inc.
+ * Copyright (C) 2012 ARM Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Will Deacon <will.deacon@arm.com>
+ * Rewriten into C by: Andrew Pinski <apinski@cavium.com>
+ */
+
+#ifndef __VDSO_COMPILER_H
+#define __VDSO_COMPILER_H
+
+#include <asm/barrier.h>	/* for isb() & dmb()	*/
+#include <asm/param.h>		/* for HZ		*/
+#include <asm/unistd32.h>
+#include <linux/compiler.h>
+
+#ifdef CONFIG_ARM_ARCH_TIMER
+#define ARCH_PROVIDES_TIMER
+#endif
+
+/* can not include linux/time.h because of too much architectural cruft */
+#ifndef NSEC_PER_SEC
+#define NSEC_PER_SEC    1000000000L
+#endif
+
+/* can not include linux/jiffies.h because of too much architectural cruft */
+#ifndef TICK_NSEC
+#define TICK_NSEC ((NSEC_PER_SEC+HZ/2)/HZ)
+#endif
+
+/* can not include linux/hrtimer.h because of too much architectural cruft */
+#ifndef LOW_RES_NSEC
+#define LOW_RES_NSEC        TICK_NSEC
+#ifdef ARCH_PROVIDES_TIMER
+#ifdef CONFIG_HIGH_RES_TIMERS
+# define HIGH_RES_NSEC        1
+# define MONOTONIC_RES_NSEC    HIGH_RES_NSEC
+#else
+# define MONOTONIC_RES_NSEC    LOW_RES_NSEC
+#endif
+#endif
+#endif
+
+#define DEFINE_FALLBACK(name, type_arg1, name_arg1, type_arg2, name_arg2) \
+static notrace long name##_fallback(type_arg1 _##name_arg1,		  \
+				    type_arg2 _##name_arg2)		  \
+{									  \
+	register type_arg1 name_arg1 asm("r0") = _##name_arg1;		  \
+	register type_arg2 name_arg2 asm("r1") = _##name_arg2;		  \
+	register long ret asm ("r0");					  \
+	register long nr asm("r7") = __NR_##name;			  \
+									  \
+	asm volatile(							  \
+	"	swi #0\n"						  \
+	: "=r" (ret)							  \
+	: "r" (name_arg1), "r" (name_arg2), "r" (nr)			  \
+	: "memory");							  \
+									  \
+	return ret;							  \
+}
+
+/*
+ * AArch32 implementation of arch_counter_get_cntvct() suitable for vdso
+ */
+static __always_inline notrace u64 arch_vdso_read_counter(void)
+{
+	u64 res;
+
+	/* Read the virtual counter. */
+	isb();
+	asm volatile("mrrc p15, 1, %Q0, %R0, c14" : "=r" (res));
+
+	return res;
+}
+
+/*
+ * Can not include asm/processor.h to pick this up because of all the
+ * architectural components also included, so we open code a copy.
+ */
+static inline void cpu_relax(void)
+{
+	asm volatile("yield" ::: "memory");
+}
+
+#undef smp_rmb
+#if __LINUX_ARM_ARCH__ >= 8
+#define	smp_rmb()	dmb(ishld) /* ok on ARMv8 */
+#else
+#define	smp_rmb()	dmb(ish) /* ishld does not exist on ARMv7 */
+#endif
+
+/* Avoid unresolved references emitted by GCC */
+
+void __aeabi_unwind_cpp_pr0(void)
+{
+}
+
+void __aeabi_unwind_cpp_pr1(void)
+{
+}
+
+void __aeabi_unwind_cpp_pr2(void)
+{
+}
+
+#endif /* __VDSO_COMPILER_H */
diff --git a/arch/arm64/kernel/vdso32/datapage.h b/arch/arm64/kernel/vdso32/datapage.h
new file mode 100644
index 000000000000..fe3e216d94d1
--- /dev/null
+++ b/arch/arm64/kernel/vdso32/datapage.h
@@ -0,0 +1 @@
+#include "../vdso/datapage.h"
diff --git a/arch/arm64/kernel/vdso32/sigreturn.S b/arch/arm64/kernel/vdso32/sigreturn.S
new file mode 100644
index 000000000000..14e5f9ca34f9
--- /dev/null
+++ b/arch/arm64/kernel/vdso32/sigreturn.S
@@ -0,0 +1,76 @@
+/*
+ * Sigreturn trampolines for returning from a signal when the SA_RESTORER
+ * flag is not set.
+ *
+ * Copyright (C) 2016 ARM Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Based on glibc's arm sa_restorer. While this is not strictly necessary, we
+ * provide both A32 and T32 versions, in accordance with the arm sigreturn
+ * code.
+ */
+
+#include <linux/linkage.h>
+#include <asm/asm-offsets.h>
+#include <asm/unistd32.h>
+
+.macro sigreturn_trampoline name, syscall, regs_offset
+	/*
+	 * We provide directives for enabling stack unwinding through the
+	 * trampoline. On arm, CFI directives are only used for debugging (and
+	 * the vDSO is stripped of debug information), so only the arm-specific
+	 * unwinding directives are useful here.
+	 */
+	.fnstart
+	.save {r0-r15}
+	.pad #\regs_offset
+	/*
+	 * It is necessary to start the unwind tables at least one instruction
+	 * before the trampoline, as the unwinder will assume that the signal
+	 * handler has been called from the trampoline, that is just before
+	 * where the signal handler returns (mov r7, ...).
+	 */
+	nop
+ENTRY(\name)
+	mov	r7, #\syscall
+	svc	#0
+	.fnend
+	/*
+	 * We would like to use ENDPROC, but the macro uses @ which is a
+	 * comment symbol for arm assemblers, so directly use .type with %
+	 * instead.
+	 */
+	.type \name, %function
+END(\name)
+.endm
+
+	.text
+
+	.arm
+	sigreturn_trampoline __kernel_sigreturn_arm, \
+			     __NR_sigreturn, \
+			     COMPAT_SIGFRAME_REGS_OFFSET
+
+	sigreturn_trampoline __kernel_rt_sigreturn_arm, \
+			     __NR_rt_sigreturn, \
+			     COMPAT_RT_SIGFRAME_REGS_OFFSET
+
+	.thumb
+	sigreturn_trampoline __kernel_sigreturn_thumb, \
+			     __NR_sigreturn, \
+			     COMPAT_SIGFRAME_REGS_OFFSET
+
+	sigreturn_trampoline __kernel_rt_sigreturn_thumb, \
+			     __NR_rt_sigreturn, \
+			     COMPAT_RT_SIGFRAME_REGS_OFFSET
diff --git a/arch/arm64/kernel/vdso32/vdso.S b/arch/arm64/kernel/vdso32/vdso.S
new file mode 100644
index 000000000000..fe19ff70eb76
--- /dev/null
+++ b/arch/arm64/kernel/vdso32/vdso.S
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2012 ARM Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Will Deacon <will.deacon@arm.com>
+ */
+
+#include <linux/init.h>
+#include <linux/linkage.h>
+#include <linux/const.h>
+#include <asm/page.h>
+
+	.globl vdso32_start, vdso32_end
+	.section .rodata
+	.balign PAGE_SIZE
+vdso32_start:
+	.incbin "arch/arm64/kernel/vdso32/vdso.so"
+	.balign PAGE_SIZE
+vdso32_end:
+
+	.previous
diff --git a/arch/arm64/kernel/vdso32/vdso.lds.S b/arch/arm64/kernel/vdso32/vdso.lds.S
new file mode 100644
index 000000000000..f95cb1c431fb
--- /dev/null
+++ b/arch/arm64/kernel/vdso32/vdso.lds.S
@@ -0,0 +1,95 @@
+/*
+ * Adapted from arm64 version.
+ *
+ * GNU linker script for the VDSO library.
+ *
+ * Copyright (C) 2012 ARM Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Will Deacon <will.deacon@arm.com>
+ * Heavily based on the vDSO linker scripts for other archs.
+ */
+
+#include <linux/const.h>
+#include <asm/page.h>
+#include <asm/vdso.h>
+
+OUTPUT_FORMAT("elf32-littlearm", "elf32-bigarm", "elf32-littlearm")
+OUTPUT_ARCH(arm)
+
+SECTIONS
+{
+	PROVIDE_HIDDEN(_vdso_data = . - PAGE_SIZE);
+	. = VDSO_LBASE + SIZEOF_HEADERS;
+
+	.hash		: { *(.hash) }			:text
+	.gnu.hash	: { *(.gnu.hash) }
+	.dynsym		: { *(.dynsym) }
+	.dynstr		: { *(.dynstr) }
+	.gnu.version	: { *(.gnu.version) }
+	.gnu.version_d	: { *(.gnu.version_d) }
+	.gnu.version_r	: { *(.gnu.version_r) }
+
+	.note		: { *(.note.*) }		:text	:note
+
+	.dynamic	: { *(.dynamic) }		:text	:dynamic
+
+	.rodata		: { *(.rodata*) }		:text
+
+	.text		: { *(.text*) }			:text	=0xe7f001f2
+
+	.got		: { *(.got) }
+	.rel.plt	: { *(.rel.plt) }
+
+	/DISCARD/	: {
+		*(.note.GNU-stack)
+		*(.data .data.* .gnu.linkonce.d.* .sdata*)
+		*(.bss .sbss .dynbss .dynsbss)
+	}
+}
+
+/*
+ * We must supply the ELF program headers explicitly to get just one
+ * PT_LOAD segment, and set the flags explicitly to make segments read-only.
+ */
+PHDRS
+{
+	text		PT_LOAD		FLAGS(5) FILEHDR PHDRS; /* PF_R|PF_X */
+	dynamic		PT_DYNAMIC	FLAGS(4);		/* PF_R */
+	note		PT_NOTE		FLAGS(4);		/* PF_R */
+}
+
+VERSION
+{
+	LINUX_2.6 {
+	global:
+		__vdso_clock_gettime;
+		__vdso_gettimeofday;
+		__vdso_clock_getres;
+		__vdso_time;
+		__kernel_sigreturn_arm;
+		__kernel_sigreturn_thumb;
+		__kernel_rt_sigreturn_arm;
+		__kernel_rt_sigreturn_thumb;
+	local: *;
+	};
+}
+
+/*
+ * Make the sigreturn code visible to the kernel.
+ */
+VDSO_compat_sigreturn_arm	= __kernel_sigreturn_arm;
+VDSO_compat_sigreturn_thumb	= __kernel_sigreturn_thumb;
+VDSO_compat_rt_sigreturn_arm	= __kernel_rt_sigreturn_arm;
+VDSO_compat_rt_sigreturn_thumb	= __kernel_rt_sigreturn_thumb;
diff --git a/arch/arm64/kernel/vdso32/vgettimeofday.c b/arch/arm64/kernel/vdso32/vgettimeofday.c
new file mode 100644
index 000000000000..b73d4011993d
--- /dev/null
+++ b/arch/arm64/kernel/vdso32/vgettimeofday.c
@@ -0,0 +1,3 @@
+#include "compiler.h"
+#include "datapage.h"
+#include "../../../../lib/vdso/vgettimeofday.c"
-- 
2.15.0.448.gf294e3d99a-goog

^ permalink raw reply related	[flat|nested] 7+ messages in thread
* [PATCH 5/6] arm64: compat: 32-bit vDSO setup
  2017-11-15 22:05 [PATCH 0/6] arm64: compat: Add COMPAT_VDSO Mark Salyzyn
                   ` (3 preceding siblings ...)
  2017-11-15 22:05 ` [PATCH 4/6] arm64: compat: Add a 32-bit vDSO Mark Salyzyn
@ 2017-11-15 22:05 ` Mark Salyzyn
  2017-11-15 22:05 ` [PATCH 6/6] arm64: Wire up and expose the new compat vDSO Mark Salyzyn
  5 siblings, 0 replies; 7+ messages in thread
From: Mark Salyzyn @ 2017-11-15 22:05 UTC (permalink / raw)
  To: linux-kernel
  Cc: Kevin Brodsky, Mark Salyzyn, Catalin Marinas, Will Deacon,
	Dave Martin, Eric W. Biederman, linux-arm-kernel, John Stultz,
	Dmitry Safonov, Kees Cook

From: Kevin Brodsky <kevin.brodsky@arm.com>

If the compat vDSO is enabled, install it in compat processes. In this
case, the compat vDSO replaces the sigreturn page (it provides its own
sigreturn trampolines).

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
 arch/arm64/kernel/vdso.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 48b4111a933f..9d44ce962538 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -58,6 +58,7 @@ struct vdso_data *vdso_data = &vdso_data_store.data;
 /*
  * Create and map the vectors page for AArch32 tasks.
  */
+#if !defined(CONFIG_VDSO32) || defined(CONFIG_KUSER_HELPERS)
 static struct page *vectors_page[] __ro_after_init;
 static const struct vm_special_mapping compat_vdso_spec[] = {
 	{
@@ -73,6 +74,7 @@ static const struct vm_special_mapping compat_vdso_spec[] = {
 #endif
 };
 static struct page *vectors_page[ARRAY_SIZE(compat_vdso_spec)] __ro_after_init;
+#endif
 
 static int __init alloc_vectors_page(void)
 {
@@ -82,6 +84,7 @@ static int __init alloc_vectors_page(void)
 	unsigned long kuser_vpage;
 #endif
 
+#ifndef CONFIG_VDSO32
 	extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[];
 	size_t sigret_sz =
 		__aarch32_sigret_code_end - __aarch32_sigret_code_start;
@@ -90,19 +93,24 @@ static int __init alloc_vectors_page(void)
 	sigret_vpage = get_zeroed_page(GFP_ATOMIC);
 	if (!sigret_vpage)
 		return -ENOMEM;
+#endif
 
 #ifdef CONFIG_KUSER_HELPERS
 	kuser_vpage = get_zeroed_page(GFP_ATOMIC);
 	if (!kuser_vpage) {
+#ifndef CONFIG_VDSO32
 		free_page(sigret_vpage);
+#endif
 		return -ENOMEM;
 	}
 #endif
 
+#ifndef CONFIG_VDSO32
 	/* sigreturn code */
 	memcpy((void *)sigret_vpage, __aarch32_sigret_code_start, sigret_sz);
 	flush_icache_range(sigret_vpage, sigret_vpage + PAGE_SIZE);
 	vectors_page[0] = virt_to_page(sigret_vpage);
+#endif
 
 #ifdef CONFIG_KUSER_HELPERS
 	/* kuser helpers */
@@ -116,6 +124,7 @@ static int __init alloc_vectors_page(void)
 }
 arch_initcall(alloc_vectors_page);
 
+#ifndef CONFIG_VDSO32
 int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
 {
 	struct mm_struct *mm = current->mm;
@@ -151,6 +160,7 @@ int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
 
 	return PTR_ERR_OR_ZERO(ret);
 }
+#endif /* !CONFIG_VDSO32 */
 #endif /* CONFIG_COMPAT */
 
 static int vdso_mremap(const struct vm_special_mapping *sm,
@@ -221,6 +231,23 @@ static int __init vdso_mappings_init(const char *name,
 	return 0;
 }
 
+#ifdef CONFIG_COMPAT
+#ifdef CONFIG_VDSO32
+
+static struct vdso_mappings vdso32_mappings __ro_after_init;
+
+static int __init vdso32_init(void)
+{
+	extern char vdso32_start[], vdso32_end[];
+
+	return vdso_mappings_init("vdso32", vdso32_start, vdso32_end,
+				  &vdso32_mappings);
+}
+arch_initcall(vdso32_init);
+
+#endif /* CONFIG_VDSO32 */
+#endif /* CONFIG_COMPAT */
+
 static struct vdso_mappings vdso_mappings __ro_after_init;
 
 static int __init vdso_init(void)
@@ -263,6 +290,34 @@ static int vdso_setup(struct mm_struct *mm,
 	return PTR_ERR_OR_ZERO(ret);
 }
 
+#ifdef CONFIG_COMPAT
+#ifdef CONFIG_VDSO32
+int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
+{
+	struct mm_struct *mm = current->mm;
+	void *ret;
+
+	if (down_write_killable(&mm->mmap_sem))
+		return -EINTR;
+
+	ret = ERR_PTR(vdso_setup(mm, &vdso32_mappings));
+#ifdef CONFIG_KUSER_HELPERS
+	if (!IS_ERR(ret))
+		/* Map the kuser helpers at the ABI-defined high address. */
+		ret = _install_special_mapping(mm, AARCH32_KUSER_HELPERS_BASE,
+					       PAGE_SIZE,
+					       VM_READ|VM_EXEC|
+					       VM_MAYREAD|VM_MAYEXEC,
+					       &compat_vdso_spec[1]);
+#endif
+
+	up_write(&mm->mmap_sem);
+
+	return PTR_ERR_OR_ZERO(ret);
+}
+#endif /* CONFIG_VDSO32 */
+#endif /* CONFIG_COMPAT */
+
 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 {
 	struct mm_struct *mm = current->mm;
-- 
2.15.0.448.gf294e3d99a-goog

^ permalink raw reply related	[flat|nested] 7+ messages in thread
* [PATCH 6/6] arm64: Wire up and expose the new compat vDSO
  2017-11-15 22:05 [PATCH 0/6] arm64: compat: Add COMPAT_VDSO Mark Salyzyn
                   ` (4 preceding siblings ...)
  2017-11-15 22:05 ` [PATCH 5/6] arm64: compat: 32-bit vDSO setup Mark Salyzyn
@ 2017-11-15 22:05 ` Mark Salyzyn
  5 siblings, 0 replies; 7+ messages in thread
From: Mark Salyzyn @ 2017-11-15 22:05 UTC (permalink / raw)
  To: linux-kernel
  Cc: Kevin Brodsky, Mark Salyzyn, Catalin Marinas, Will Deacon,
	Dave Martin, Eric W. Biederman, linux-arm-kernel, Ard Biesheuvel,
	Greg Kroah-Hartman, AKASHI Takahiro

From: Kevin Brodsky <kevin.brodsky@arm.com>

Expose the new compat vDSO via the COMPAT_VDSO config option.

The option is not enabled in defconfig because we really need a 32-bit
compiler this time, and we rely on the user to provide it themselves
by setting CROSS_COMPILE_ARM32. Therefore enabling the option by
default would make little sense, since the user must explicitly set a
non-standard environment variable anyway.

CONFIG_COMPAT_VDSO is not directly used in the code, because we want
to ignore it (build as if it were not set) if the user didn't set
CROSS_COMPILE_ARM32. If the variable has been set to a valid prefix,
CONFIG_VDSO32 will be set; this is the option that the code and
Makefiles test.

For more flexibility, like CROSS_COMPILE, CROSS_COMPILE_ARM32 can also
be set via CONFIG_CROSS_COMPILE_ARM32 (the environment variable
overrides the config option, as expected).

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
 arch/arm64/Kconfig         | 24 ++++++++++++++++++++++++
 arch/arm64/Makefile        | 35 +++++++++++++++++++++++++++++++++--
 arch/arm64/kernel/Makefile |  3 +++
 3 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index d8a4fda50477..379d0154b363 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1183,6 +1183,30 @@ config SYSVIPC_COMPAT
 	def_bool y
 	depends on COMPAT && SYSVIPC
 
+config COMPAT_VDSO
+	bool "32-bit vDSO"
+	depends on COMPAT
+	default n
+	help
+	  Warning: a 32-bit toolchain is necessary to build the vDSO. You
+	  must explicitly define which toolchain should be used by setting
+	  CROSS_COMPILE_ARM32 to the prefix of the 32-bit toolchain (same format
+	  as CROSS_COMPILE). If CROSS_COMPILE_ARM32 is empty, a warning will be
+	  printed and the kernel will be built as if COMPAT_VDSO had not been
+	  set. If CROSS_COMPILE_ARM32 is set to an invalid prefix, compilation
+	  will be aborted.
+
+	  Provide a vDSO to 32-bit processes. It includes the symbols provided
+	  by the vDSO from the 32-bit kernel, so that a 32-bit libc can use
+	  the compat vDSO without modification. It also provides sigreturn
+	  trampolines, replacing the sigreturn page.
+
+config CROSS_COMPILE_ARM32
+	string "32-bit toolchain prefix"
+	help
+	  Same as setting CROSS_COMPILE_ARM32 in the environment, but saved for
+	  future builds. The environment variable overrides this config option.
+
 endmenu
 
 menu "Power management options"
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 939b310913cf..baf36f0a992d 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -45,10 +45,39 @@ $(warning Detected assembler with broken .inst; disassembly will be unreliable)
   endif
 endif
 
-KBUILD_CFLAGS	+= -mgeneral-regs-only $(lseinstr) $(brokengasinst)
+ifeq ($(CONFIG_COMPAT_VDSO), y)
+  CROSS_COMPILE_ARM32 ?= $(CONFIG_CROSS_COMPILE_ARM32:"%"=%)
+
+  # Check that the user has provided a valid prefix for the 32-bit toolchain.
+  # To prevent selecting the system $(cc-name) by default, the prefix is not
+  # allowed to be empty, unlike CROSS_COMPILE. In the unlikely event that the
+  # system $(cc-name) is actually the 32-bit ARM compiler to be used, the
+  # variable can be set to the dirname (e.g. CROSS_COMPILE_ARM32=/usr/bin/).
+  # Note: this Makefile is read both before and after regenerating the config
+  # (if needed). Any warning appearing before the config has been regenerated
+  # should be ignored. If the error is triggered and you set
+  # CONFIG_CROSS_COMPILE_ARM32, set CROSS_COMPILE_ARM32 to an appropriate value
+  # when invoking make and fix CONFIG_CROSS_COMPILE_ARM32.
+  ifeq ($(CROSS_COMPILE_ARM32),)
+    $(error CROSS_COMPILE_ARM32 not defined or empty, the compat vDSO will not be built)
+  else ifeq ($(cc-name),clang)
+    export CLANG_TRIPLE_ARM32 ?= $(CROSS_COMPILE_ARM32)
+    export CLANG_TARGET_ARM32 := --target=$(notdir $(CLANG_TRIPLE_ARM32:%-=%))
+    export CONFIG_VDSO32 := y
+    vdso32 := -DCONFIG_VDSO32=1
+  else ifeq ($(shell which $(CROSS_COMPILE_ARM32)$(cc-name) 2> /dev/null),)
+    $(error $(CROSS_COMPILE_ARM32)$(cc-name) not found, check CROSS_COMPILE_ARM32)
+  else
+    export CROSS_COMPILE_ARM32
+    export CONFIG_VDSO32 := y
+    vdso32 := -DCONFIG_VDSO32=1
+  endif
+endif
+
+KBUILD_CFLAGS	+= -mgeneral-regs-only $(lseinstr) $(brokengasinst) $(vdso32)
 KBUILD_CFLAGS	+= -fno-asynchronous-unwind-tables
 KBUILD_CFLAGS	+= $(call cc-option, -mpc-relative-literal-loads)
-KBUILD_AFLAGS	+= $(lseinstr) $(brokengasinst)
+KBUILD_AFLAGS	+= $(lseinstr) $(brokengasinst) $(vdso32)
 
 KBUILD_CFLAGS	+= $(call cc-option,-mabi=lp64)
 KBUILD_AFLAGS	+= $(call cc-option,-mabi=lp64)
@@ -157,6 +186,8 @@ archclean:
 prepare: vdso_prepare
 vdso_prepare: prepare0
 	$(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso include/generated/vdso-offsets.h
+	$(if $(CONFIG_VDSO32),$(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso32 \
+					  include/generated/vdso32-offsets.h)
 
 define archhelp
   echo  '* Image.gz      - Compressed kernel image (arch/$(ARCH)/boot/Image.gz)'
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 6e969f3cde6c..5db2b239cd68 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -30,7 +30,9 @@ $(obj)/%.stub.o: $(obj)/%.o FORCE
 
 arm64-obj-$(CONFIG_COMPAT)		+= sys32.o signal32.o	\
 					   sys_compat.o entry32.o
+ifneq ($(CONFIG_VDSO32),y)
 arm64-obj-$(CONFIG_COMPAT)		+= sigreturn32.o
+endif
 arm64-obj-$(CONFIG_KUSER_HELPERS)	+= kuser32.o
 arm64-obj-$(CONFIG_FUNCTION_TRACER)	+= ftrace.o entry-ftrace.o
 arm64-obj-$(CONFIG_MODULES)		+= arm64ksyms.o module.o
@@ -58,6 +60,7 @@ arm64-reloc-test-y := reloc_test_core.o reloc_test_syms.o
 arm64-obj-$(CONFIG_CRASH_DUMP)		+= crash_dump.o
 
 obj-y					+= $(arm64-obj-y) vdso/ probes/
+obj-$(CONFIG_VDSO32)			+= vdso32/
 obj-m					+= $(arm64-obj-m)
 head-y					:= head.o
 extra-y					+= $(head-y) vmlinux.lds
-- 
2.15.0.448.gf294e3d99a-goog

^ permalink raw reply related	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2017-11-15 22:08 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-11-15 22:05 [PATCH 0/6] arm64: compat: Add COMPAT_VDSO Mark Salyzyn
2017-11-15 22:05 ` [PATCH 1/6] arm64: compat: Use vDSO sigreturn trampolines if available Mark Salyzyn
2017-11-15 22:05 ` [PATCH 2/6] arm64: elf: Set AT_SYSINFO_EHDR in compat processes Mark Salyzyn
2017-11-15 22:05 ` [PATCH 3/6] arm64: Refactor vDSO init/setup Mark Salyzyn
2017-11-15 22:05 ` [PATCH 4/6] arm64: compat: Add a 32-bit vDSO Mark Salyzyn
2017-11-15 22:05 ` [PATCH 5/6] arm64: compat: 32-bit vDSO setup Mark Salyzyn
2017-11-15 22:05 ` [PATCH 6/6] arm64: Wire up and expose the new compat vDSO Mark Salyzyn

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