arm64:ilp32: add vdso-ilp32 and use for signal return

ILP32 VDSO exports following symbols: __kernel_rt_sigreturn; __kernel_gettimeofday; __kernel_clock_gettime; __kernel_clock_getres. What shared object to use, kernel selects depending on result of is_ilp32_compat_task() in arch/arm64/kernel/vdso.c, so it substitutes correct pages and spec. Adjusted to move the data page before code pages in sync with commit 601255a ("arm64: vdso: move data page before code pages") Signed-off-by: Philipp Tomsich <[email protected]> Signed-off-by: Christoph Muellner <[email protected]> Signed-off-by: Yury Norov <[email protected]> Signed-off-by: Bamvor Jian Zhang <[email protected]> Signed-off-by: Yury Norov <[email protected]>
norov · viordash · May 16, 2018 · May 16, 2018 · May 16, 2018 · May 16, 2018
commit e613acc4d45aea9f0cfb620a06f112cc726ba1b3
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
@@ -164,6 +164,9 @@ ifeq ($(KBUILD_EXTMOD),)
 prepare: vdso_prepare
 vdso_prepare: prepare0
 	$(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso include/generated/vdso-offsets.h
+ifeq ($(CONFIG_ARM64_ILP32), y)
+	$(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso-ilp32 include/generated/vdso-ilp32-offsets.h
+endif
 endif
 
 define archhelp

diff --git a/arch/arm64/include/asm/vdso.h b/arch/arm64/include/asm/vdso.h
@@ -18,6 +18,12 @@
 
 #include <generated/vdso-offsets.h>
 
+#ifdef CONFIG_ARM64_ILP32
+#include <generated/vdso-ilp32-offsets.h>
+#else
+#define vdso_offset_sigtramp_ilp32	({ BUILD_BUG(); 0; })
+#endif
+
 #define VDSO_SYMBOL(base, name)						   \
 ({									   \
 	(void *)(vdso_offset_##name - VDSO_LBASE + (unsigned long)(base)); \

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
@@ -65,6 +65,7 @@ obj-$(CONFIG_ARM64_SSBD)		+= ssbd.o
 obj-$(CONFIG_ARM64_PTR_AUTH)		+= pointer_auth.o
 
 obj-y					+= vdso/ probes/
+obj-$(CONFIG_ARM64_ILP32)		+= vdso-ilp32/
 head-y					:= head.o
 extra-y					+= $(head-y) vmlinux.lds
 

diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
@@ -104,6 +104,13 @@ int main(void)
   DEFINE(TVAL_TV_SEC,		offsetof(struct timeval, tv_sec));
   DEFINE(TSPEC_TV_SEC,		offsetof(struct timespec, tv_sec));
   BLANK();
+#ifdef CONFIG_COMPAT
+  DEFINE(COMPAT_TVAL_TV_SEC,	offsetof(struct compat_timeval, tv_sec));
+  DEFINE(COMPAT_TVAL_TV_USEC,	offsetof(struct compat_timeval, tv_usec));
+  DEFINE(COMPAT_TSPEC_TV_SEC,	offsetof(struct compat_timespec, tv_sec));
+  DEFINE(COMPAT_TSPEC_TV_NSEC,	offsetof(struct compat_timespec, tv_nsec));
+  BLANK();
+#endif
   DEFINE(TZ_MINWEST,		offsetof(struct timezone, tz_minuteswest));
   DEFINE(TZ_DSTTIME,		offsetof(struct timezone, tz_dsttime));
   BLANK();

diff --git a/arch/arm64/kernel/vdso-ilp32/.gitignore b/arch/arm64/kernel/vdso-ilp32/.gitignore
@@ -0,0 +1,2 @@
+vdso-ilp32.lds
+vdso-ilp32-offsets.h
diff --git a/arch/arm64/kernel/vdso-ilp32/Makefile b/arch/arm64/kernel/vdso-ilp32/Makefile
@@ -0,0 +1,82 @@
+# SPDX-License-Identifier: GPL-2.0
+
+#
+# Building a vDSO image for AArch64.
+#
+# Author: Will Deacon <[email protected]>
+# Heavily based on the vDSO Makefiles for other archs.
+#
+
+obj-ilp32-vdso := gettimeofday-ilp32.o note-ilp32.o sigreturn-ilp32.o
+
+# Build rules
+targets := $(obj-ilp32-vdso) vdso-ilp32.so vdso-ilp32.so.dbg
+obj-ilp32-vdso := $(addprefix $(obj)/, $(obj-ilp32-vdso))
+
+ccflags-y := -shared -fno-common -fno-builtin
+ccflags-y += -nostdlib -Wl,-soname=linux-ilp32-vdso.so.1 \
+		$(call cc-ldoption, -Wl$(comma)--hash-style=sysv)
+
+# Disable gcov profiling for VDSO code
+GCOV_PROFILE := n
+
+# Workaround for bare-metal (ELF) toolchains that neglect to pass -shared
+# down to collect2, resulting in silent corruption of the vDSO image.
+ccflags-y += -Wl,-shared
+
+obj-y += vdso-ilp32.o
+extra-y += vdso-ilp32.lds
+CPPFLAGS_vdso-ilp32.lds += -P -C -U$(ARCH) -mabi=ilp32
+
+# Force dependency (incbin is bad)
+$(obj)/vdso-ilp32.o : $(obj)/vdso-ilp32.so
+
+# Link rule for the .so file, .lds has to be first
+$(obj)/vdso-ilp32.so.dbg: $(src)/vdso-ilp32.lds $(obj-ilp32-vdso)
+	$(call if_changed,vdso-ilp32ld)
+
+# Strip rule for the .so file
+$(obj)/%.so: OBJCOPYFLAGS := -S
+$(obj)/%.so: $(obj)/%.so.dbg FORCE
+	$(call if_changed,objcopy)
+
+# Generate VDSO offsets using helper script
+gen-vdsosym := $(srctree)/$(src)/../vdso/gen_vdso_offsets.sh
+quiet_cmd_vdsosym = VDSOSYM $@
+define cmd_vdsosym
+	$(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
+endef
+
+include/generated/vdso-ilp32-offsets.h: $(obj)/vdso-ilp32.so.dbg FORCE
+	$(call if_changed,vdsosym)
+
+# Assembly rules for the .S files
+#$(obj-ilp32-vdso): %.o: $(src)/../vdso/$(subst -ilp32,,%.S)
+#	$(call if_changed_dep,vdso-ilp32as)
+
+$(obj)/gettimeofday-ilp32.o: $(src)/../vdso/gettimeofday.S
+	$(call if_changed_dep,vdso-ilp32as)
+
+$(obj)/note-ilp32.o: $(src)/../vdso/note.S
+	$(call if_changed_dep,vdso-ilp32as)
+
+# This one should be fine because ILP32 uses the same generic
+# __NR_rt_sigreturn syscall number.
+$(obj)/sigreturn-ilp32.o: $(src)/../vdso/sigreturn.S
+	$(call if_changed_dep,vdso-ilp32as)
+
+# Actual build commands
+quiet_cmd_vdso-ilp32ld = VDSOILP32L $@
+      cmd_vdso-ilp32ld = $(CC) $(c_flags) -mabi=ilp32  -Wl,-n -Wl,-T $^ -o $@
+quiet_cmd_vdso-ilp32as = VDSOILP32A $@
+      cmd_vdso-ilp32as = $(CC) $(a_flags) -mabi=ilp32 -c -o $@ $<
+
+# Install commands for the unstripped file
+quiet_cmd_vdso_install = INSTALL $@
+      cmd_vdso_install = cp $(obj)/[email protected] $(MODLIB)/vdso/$@
+
+vdso-ilp32.so: $(obj)/vdso-ilp32.so.dbg
+	@mkdir -p $(MODLIB)/vdso
+	$(call cmd,vdso_install)
+
+vdso_install: vdso-ilp32.so
diff --git a/arch/arm64/kernel/vdso-ilp32/vdso-ilp32.S b/arch/arm64/kernel/vdso-ilp32/vdso-ilp32.S
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Copyright (C) 2012 ARM Limited
+ * Author: Will Deacon <[email protected]>
+ */
+
+#include <linux/init.h>
+#include <linux/linkage.h>
+#include <linux/const.h>
+#include <asm/page.h>
+
+	__PAGE_ALIGNED_DATA
+
+	.globl vdso_ilp32_start, vdso_ilp32_end
+	.balign PAGE_SIZE
+vdso_ilp32_start:
+	.incbin "arch/arm64/kernel/vdso-ilp32/vdso-ilp32.so"
+	.balign PAGE_SIZE
+vdso_ilp32_end:
+
+	.previous
diff --git a/arch/arm64/kernel/vdso-ilp32/vdso-ilp32.lds.S b/arch/arm64/kernel/vdso-ilp32/vdso-ilp32.lds.S
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * GNU linker script for the VDSO library.
+ *
+ * Copyright (C) 2012 ARM Limited
+ * Author: Will Deacon <[email protected]>
+ * Heavily based on the vDSO linker scripts for other archs.
+ */
+
+#include <linux/const.h>
+#include <asm/page.h>
+#include <asm/vdso.h>
+
+SECTIONS
+{
+	PROVIDE(_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
+
+	. = ALIGN(16);
+
+	.text		: { *(.text*) }			:text	=0xd503201f
+	PROVIDE (__etext = .);
+	PROVIDE (_etext = .);
+	PROVIDE (etext = .);
+
+	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr
+	.eh_frame	: { KEEP (*(.eh_frame)) }	:text
+
+	.dynamic	: { *(.dynamic) }		:text	:dynamic
+
+	.rodata		: { *(.rodata*) }		:text
+
+	_end = .;
+	PROVIDE(end = .);
+
+	/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 */
+	eh_frame_hdr	PT_GNU_EH_FRAME;
+}
+
+/*
+ * This controls what symbols we export from the DSO.
+ */
+VERSION
+{
+	LINUX_4.12 {
+	global:
+		__kernel_rt_sigreturn;
+		__kernel_gettimeofday;
+		__kernel_clock_gettime;
+		__kernel_clock_getres;
+	local: *;
+	};
+}
+
+/*
+ * Make the sigreturn code visible to the kernel.
+ */
+VDSO_sigtramp_ilp32		= __kernel_rt_sigreturn;
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
@@ -26,8 +26,13 @@
 #include <asm/vdso.h>
 #include <asm/vdso_datapage.h>
 
-extern char vdso_start[], vdso_end[];
-static unsigned long vdso_pages __ro_after_init;
+extern char vdso_lp64_start[], vdso_lp64_end[];
+static unsigned long vdso_lp64_pages __ro_after_init;
+
+#ifdef CONFIG_ARM64_ILP32
+extern char vdso_ilp32_start[], vdso_ilp32_end[];
+static unsigned long vdso_ilp32_pages __ro_after_init;
+#endif
 
 /*
  * The vDSO data page.
@@ -171,7 +176,7 @@ static int vdso_mremap(const struct vm_special_mapping *sm,
 		struct vm_area_struct *new_vma)
 {
 	unsigned long new_size = new_vma->vm_end - new_vma->vm_start;
-	unsigned long vdso_size = vdso_end - vdso_start;
+	unsigned long vdso_size = vdso_lp64_end - vdso_lp64_start;
 
 	if (vdso_size != new_size)
 		return -EINVAL;
@@ -181,7 +186,7 @@ static int vdso_mremap(const struct vm_special_mapping *sm,
 	return 0;
 }
 
-static struct vm_special_mapping vdso_spec[2] __ro_after_init = {
+static struct vm_special_mapping vdso_lp64_spec[2] __ro_after_init = {
 	{
 		.name	= "[vvar]",
 	},
@@ -191,9 +196,23 @@ static struct vm_special_mapping vdso_spec[2] __ro_after_init = {
 	},
 };
 
-static int __init vdso_init(void)
+#ifdef CONFIG_ARM64_ILP32
+static struct vm_special_mapping vdso_ilp32_spec[2] __ro_after_init = {
+	{
+		.name	= "[vvar]",
+	},
+	{
+		.name	= "[vdso]",
+	},
+};
+#endif
+
+static int __init vdso_init(char *vdso_start, char *vdso_end,
+					  unsigned long *vdso_pagesp,
+					  struct vm_special_mapping *vdso_spec)
 {
 	int i;
+	unsigned long vdso_pages;
 	struct page **vdso_pagelist;
 	unsigned long pfn;
 
@@ -203,6 +222,7 @@ static int __init vdso_init(void)
 	}
 
 	vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
+	*vdso_pagesp = vdso_pages;
 
 	/* Allocate the vDSO pagelist, plus a page for the data. */
 	vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *),
@@ -225,16 +245,40 @@ static int __init vdso_init(void)
 
 	return 0;
 }
-arch_initcall(vdso_init);
+
+static int __init vdso_lp64_init(void)
+{
+	return vdso_init(vdso_lp64_start, vdso_lp64_end,
+				&vdso_lp64_pages, vdso_lp64_spec);
+}
+arch_initcall(vdso_lp64_init);
+
+#ifdef CONFIG_ARM64_ILP32
+static int __init vdso_ilp32_init(void)
+{
+	return vdso_init(vdso_ilp32_start, vdso_ilp32_end,
+				&vdso_ilp32_pages, vdso_ilp32_spec);
+}
+arch_initcall(vdso_ilp32_init);
+#endif
 
 int arch_setup_additional_pages(struct linux_binprm *bprm,
 				int uses_interp)
 {
 	struct mm_struct *mm = current->mm;
 	unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
 	void *ret;
+	unsigned long pages = vdso_lp64_pages;
+	struct vm_special_mapping *vdso_spec = vdso_lp64_spec;
+
+#ifdef CONFIG_ARM64_ILP32
+	if (is_ilp32_compat_task()) {
+		pages = vdso_ilp32_pages;
+		vdso_spec = vdso_ilp32_spec;
+	}
+#endif
 
-	vdso_text_len = vdso_pages << PAGE_SHIFT;
+	vdso_text_len = pages << PAGE_SHIFT;
 	/* Be sure to map the data page */
 	vdso_mapping_len = vdso_text_len + PAGE_SIZE;