[PATCH 7/8] Add 32 bit VDSO time support for 32 bit kernel
From: stefani
Date: Sun Feb 02 2014 - 06:27:39 EST
From: Stefani Seibold <stefani@xxxxxxxxxxx>
This patch add the time support for 32 bit a VDSO to a 32 bit kernel.
For 32 bit programs running on a 32 bit kernel, the same mechanism is
used as for 64 bit programs running on a 64 bit kernel.
Signed-off-by: Stefani Seibold <stefani@xxxxxxxxxxx>
---
arch/x86/include/asm/elf.h | 2 +-
arch/x86/include/asm/vdso.h | 3 ++
arch/x86/include/asm/vdso32.h | 10 ++++++
arch/x86/vdso/Makefile | 7 +++++
arch/x86/vdso/vclock_gettime.c | 59 +++++++++++++++++++++++++++++++++--
arch/x86/vdso/vdso-layout.lds.S | 25 +++++++++++++++
arch/x86/vdso/vdso32-setup.c | 47 ++++++++++++++++++++++------
arch/x86/vdso/vdso32/vclock_gettime.c | 16 ++++++++++
arch/x86/vdso/vdso32/vdso32.lds.S | 11 ++++++-
9 files changed, 167 insertions(+), 13 deletions(-)
create mode 100644 arch/x86/include/asm/vdso32.h
create mode 100644 arch/x86/vdso/vdso32/vclock_gettime.c
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 9c999c1..21bae90 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -289,7 +289,7 @@ do { \
#else /* CONFIG_X86_32 */
-#define VDSO_HIGH_BASE 0xffffe000U /* CONFIG_COMPAT_VDSO address */
+#define VDSO_HIGH_BASE 0xffffc000U /* CONFIG_COMPAT_VDSO address */
/* 1GB for 64bit, 8MB for 32bit */
#define STACK_RND_MASK (test_thread_flag(TIF_ADDR32) ? 0x7ff : 0x3fffff)
diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
index fddb53d..fe3cef9 100644
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -2,6 +2,9 @@
#define _ASM_X86_VDSO_H
#if defined CONFIG_X86_32 || defined CONFIG_COMPAT
+
+#include <asm/vdso32.h>
+
extern const char VDSO32_PRELINK[];
/*
diff --git a/arch/x86/include/asm/vdso32.h b/arch/x86/include/asm/vdso32.h
new file mode 100644
index 0000000..7dd2eb8
--- /dev/null
+++ b/arch/x86/include/asm/vdso32.h
@@ -0,0 +1,10 @@
+#ifndef _ASM_X86_VDSO32_H
+#define _ASM_X86_VDSO32_H
+
+#define VDSO_BASE_PAGE 0
+#define VDSO_VVAR_PAGE 1
+#define VDSO_HPET_PAGE 2
+#define VDSO_PAGES 3
+#define VDSO_OFFSET(x) ((x) * PAGE_SIZE)
+
+#endif
diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
index fd14be1..1ff5b0a 100644
--- a/arch/x86/vdso/Makefile
+++ b/arch/x86/vdso/Makefile
@@ -145,8 +145,15 @@ KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS))
$(vdso32-images:%=$(obj)/%.dbg): KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
$(vdso32-images:%=$(obj)/%.dbg): asflags-$(CONFIG_X86_64) += -m32
+KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
+KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=3 -freg-struct-return -fpic
+$(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
+
$(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \
$(obj)/vdso32/vdso32.lds \
+ $(obj)/vdso32/vclock_gettime.o \
$(obj)/vdso32/note.o \
$(obj)/vdso32/%.o
$(call if_changed,vdso)
diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index bf969a0..42f641c 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -4,6 +4,9 @@
*
* Fast user context implementation of clock_gettime, gettimeofday, and time.
*
+ * 32 Bit compat layer by Stefani Seibold <stefani@xxxxxxxxxxx>
+ * sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany
+ *
* The code should have no internal unresolved relocations.
* Check with readelf after changing.
*/
@@ -24,6 +27,8 @@
#include <asm/io.h>
#include <asm/pvclock.h>
+#ifndef BUILD_VDSO32
+
#define gtod (&VVAR(vsyscall_gtod_data))
static notrace cycle_t vread_hpet(void)
@@ -47,6 +52,54 @@ notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz)
"0" (__NR_gettimeofday), "D" (tv), "S" (tz) : "memory");
return ret;
}
+#else
+
+struct vsyscall_gtod_data vvar_vsyscall_gtod_data
+ __attribute__((visibility("hidden")));
+
+u8 hpet_page
+ __attribute__((visibility("hidden")));
+
+#define gtod (&vvar_vsyscall_gtod_data)
+
+#ifdef CONFIG_HPET_TIMER
+static notrace cycle_t vread_hpet(void)
+{
+ return readl(&hpet_page + HPET_COUNTER);
+}
+#endif
+
+notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
+{
+ long ret;
+
+ asm(
+ "push %%ebx \n"
+ "mov %2,%%ebx \n"
+ "call VDSO32_vsyscall \n"
+ "pop %%ebx \n"
+ : "=a" (ret)
+ : "0" (__NR_clock_gettime), "d" (clock), "c" (ts)
+ : "memory");
+ return ret;
+}
+
+notrace static long vdso_fallback_gtod(struct timeval *tv,
+ struct timezone *tz)
+{
+ long ret;
+
+ asm(
+ "push %%ebx \n"
+ "mov %2,%%ebx \n"
+ "call VDSO32_vsyscall \n"
+ "pop %%ebx \n"
+ : "=a" (ret)
+ : "0" (__NR_gettimeofday), "d" (tv), "c" (tz)
+ : "memory");
+ return ret;
+}
+#endif
#ifdef CONFIG_PARAVIRT_CLOCK
@@ -152,12 +205,14 @@ notrace static cycle_t vread_tsc(void)
notrace static inline u64 vgetsns(int *mode)
{
- long v;
+ u64 v;
cycles_t cycles;
if (gtod->clock.vclock_mode == VCLOCK_TSC)
cycles = vread_tsc();
+#ifdef CONFIG_HPET_TIMER
else if (gtod->clock.vclock_mode == VCLOCK_HPET)
cycles = vread_hpet();
+#endif
#ifdef CONFIG_PARAVIRT_CLOCK
else if (gtod->clock.vclock_mode == VCLOCK_PVCLOCK)
cycles = vread_pvclock(mode);
@@ -284,7 +339,7 @@ int gettimeofday(struct timeval *, struct timezone *)
*/
notrace time_t __vdso_time(time_t *t)
{
- /* This is atomic on x86_64 so we don't need any locks. */
+ /* This is atomic on x86 so we don't need any locks. */
time_t result = ACCESS_ONCE(gtod->wall_time_sec);
if (t)
diff --git a/arch/x86/vdso/vdso-layout.lds.S b/arch/x86/vdso/vdso-layout.lds.S
index 634a2cf..086567b 100644
--- a/arch/x86/vdso/vdso-layout.lds.S
+++ b/arch/x86/vdso/vdso-layout.lds.S
@@ -44,6 +44,27 @@ SECTIONS
. = ALIGN(0x100);
.text : { *(.text*) } :text =0x90909090
+
+#ifdef BUILD_VDSO32
+ . = ALIGN(PAGE_SIZE);
+
+ .vvar_sect : {
+ vvar = .;
+
+ /* Place all vvars at the offsets in asm/vvar.h. */
+#define EMIT_VVAR(name, offset) vvar_ ## name = vvar + offset;
+#define __VVAR_KERNEL_LDS
+#include <asm/vvar.h>
+#undef __VVAR_KERNEL_LDS
+#undef EMIT_VVAR
+ } :text :vvar_sect
+
+ . += PAGE_SIZE;
+
+ .hpet_sect : {
+ hpet_page = .;
+ } :text :hpet_sect
+#endif
}
/*
@@ -61,4 +82,8 @@ PHDRS
dynamic PT_DYNAMIC FLAGS(4); /* PF_R */
note PT_NOTE FLAGS(4); /* PF_R */
eh_frame_hdr PT_GNU_EH_FRAME;
+#ifdef BUILD_VDSO32
+ vvar_sect PT_NULL FLAGS(4); /* PF_R */
+ hpet_sect PT_NULL FLAGS(4); /* PF_R */
+#endif
}
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index d6bfb87..eb2050c 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -25,6 +25,7 @@
#include <asm/tlbflush.h>
#include <asm/vdso.h>
#include <asm/proto.h>
+#include <asm/fixmap.h>
enum {
VDSO_DISABLED = 0,
@@ -193,7 +194,7 @@ static __init void relocate_vdso(Elf32_Ehdr *ehdr)
}
}
-static struct page *vdso32_pages[1];
+static struct page *vdso32_pages[VDSO_PAGES];
#ifdef CONFIG_X86_64
@@ -310,6 +311,11 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
unsigned long addr;
int ret = 0;
bool compat;
+ struct vm_area_struct *vma;
+ extern char __vvar_page;
+#ifdef CONFIG_HPET_TIMER
+ extern unsigned long hpet_address;
+#endif
#ifdef CONFIG_X86_X32_ABI
if (test_thread_flag(TIF_X32))
@@ -330,7 +336,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
if (compat)
addr = VDSO_HIGH_BASE;
else {
- addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
+ addr = get_unmapped_area(NULL, 0, VDSO_OFFSET(VDSO_PAGES), 0, 0);
if (IS_ERR_VALUE(addr)) {
ret = addr;
goto up_fail;
@@ -340,16 +346,39 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
current->mm->context.vdso = (void *)addr;
if (compat_uses_vma || !compat) {
- /*
- * MAYWRITE to allow gdb to COW and set breakpoints
- */
- ret = install_special_mapping(mm, addr, PAGE_SIZE,
- VM_READ|VM_EXEC|
- VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
- vdso32_pages);
+
+ vma = _install_special_mapping(mm,
+ addr,
+ VDSO_OFFSET(VDSO_PAGES),
+ VM_READ|VM_EXEC,
+ vdso32_pages);
+
+ if (IS_ERR(vma)) {
+ ret = PTR_ERR(vma);
+ goto up_fail;
+ }
+
+ ret = remap_pfn_range(vma,
+ vma->vm_start + VDSO_OFFSET(VDSO_VVAR_PAGE),
+ __pa_symbol(&__vvar_page) >> PAGE_SHIFT,
+ PAGE_SIZE,
+ PAGE_READONLY);
if (ret)
goto up_fail;
+
+#ifdef CONFIG_HPET_TIMER
+ if (hpet_address) {
+ ret = io_remap_pfn_range(vma,
+ vma->vm_start + VDSO_OFFSET(VDSO_HPET_PAGE),
+ hpet_address >> PAGE_SHIFT,
+ PAGE_SIZE,
+ pgprot_noncached(PAGE_READONLY));
+
+ if (ret)
+ goto up_fail;
+ }
+#endif
}
current_thread_info()->sysenter_return =
diff --git a/arch/x86/vdso/vdso32/vclock_gettime.c b/arch/x86/vdso/vdso32/vclock_gettime.c
new file mode 100644
index 0000000..fab4ec6
--- /dev/null
+++ b/arch/x86/vdso/vdso32/vclock_gettime.c
@@ -0,0 +1,16 @@
+#define BUILD_VDSO32
+
+#ifdef CONFIG_X86_64
+
+#define _ASM_X86_PAGE_H
+
+#define __pa(x) 0
+#define __va(x) 0
+
+#undef CONFIG_ILLEGAL_POINTER_VALUE
+#define CONFIG_ILLEGAL_POINTER_VALUE 0
+
+#endif
+
+#include "../vclock_gettime.c"
+
diff --git a/arch/x86/vdso/vdso32/vdso32.lds.S b/arch/x86/vdso/vdso32/vdso32.lds.S
index 976124b..66e73b2 100644
--- a/arch/x86/vdso/vdso32/vdso32.lds.S
+++ b/arch/x86/vdso/vdso32/vdso32.lds.S
@@ -8,6 +8,9 @@
* values visible using the asm-x86/vdso.h macros from the kernel proper.
*/
+#include <asm/page.h>
+
+#define BUILD_VDSO32
#define VDSO_PRELINK 0
#include "../vdso-layout.lds.S"
@@ -19,11 +22,14 @@ ENTRY(__kernel_vsyscall);
*/
VERSION
{
- LINUX_2.5 {
+ LINUX_2.6 {
global:
__kernel_vsyscall;
__kernel_sigreturn;
__kernel_rt_sigreturn;
+ __vdso_clock_gettime;
+ __vdso_gettimeofday;
+ __vdso_time;
local: *;
};
}
@@ -35,3 +41,6 @@ VDSO32_PRELINK = VDSO_PRELINK;
VDSO32_vsyscall = __kernel_vsyscall;
VDSO32_sigreturn = __kernel_sigreturn;
VDSO32_rt_sigreturn = __kernel_rt_sigreturn;
+VDSO32_clock_gettime = clock_gettime;
+VDSO32_gettimeofday = gettimeofday;
+VDSO32_time = time;
--
1.8.5.3
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