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Date: Fri, 11 Jun 2021 19:02:36 +0100
From: Dmitry Safonov <dima@...sta.com>
To: linux-kernel@...r.kernel.org
Cc: Dmitry Safonov <0x7f454c46@...il.com>,
Dmitry Safonov <dima@...sta.com>,
Alexander Viro <viro@...iv.linux.org.uk>,
Andrew Morton <akpm@...ux-foundation.org>,
Andy Lutomirski <luto@...nel.org>,
Arnd Bergmann <arnd@...db.de>, Borislav Petkov <bp@...en8.de>,
Catalin Marinas <catalin.marinas@....com>,
Christophe Leroy <christophe.leroy@...roup.eu>,
Guo Ren <guoren@...nel.org>, "H. Peter Anvin" <hpa@...or.com>,
Ingo Molnar <mingo@...hat.com>,
Oleg Nesterov <oleg@...hat.com>,
Russell King <linux@...linux.org.uk>,
Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
Thomas Gleixner <tglx@...utronix.de>,
Vincenzo Frascino <vincenzo.frascino@....com>,
Will Deacon <will@...nel.org>, x86@...nel.org
Subject: [PATCH v3 17/23] x86/vdso: Migrate to generic vdso_base
Generic way to track the landing vma area.
As a bonus, after unmapping vdso, kernel won't try to land on its
previous position (due to UNMAPPED_VDSO_BASE check instead of
context.vdso != 0 check).
Signed-off-by: Dmitry Safonov <dima@...sta.com>
---
arch/x86/Kconfig | 1 +
arch/x86/entry/common.c | 2 +-
arch/x86/entry/vdso/extable.c | 4 ++--
arch/x86/entry/vdso/vma.c | 13 ++++++-------
arch/x86/ia32/ia32_signal.c | 4 ++--
arch/x86/include/asm/mmu.h | 1 -
arch/x86/include/asm/vdso.h | 2 +-
arch/x86/kernel/signal.c | 4 ++--
8 files changed, 15 insertions(+), 16 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index d30b952f4453..b1b6dab92fb6 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -93,6 +93,7 @@ config X86
select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
select ARCH_HAS_SYSCALL_WRAPPER
select ARCH_HAS_UBSAN_SANITIZE_ALL
+ select ARCH_HAS_VDSO_BASE
select ARCH_HAS_DEBUG_WX
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 385a1c4bf4c0..f5861f6e00a2 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -162,7 +162,7 @@ __visible noinstr long do_fast_syscall_32(struct pt_regs *regs)
* Called using the internal vDSO SYSENTER/SYSCALL32 calling
* convention. Adjust regs so it looks like we entered using int80.
*/
- landing_pad = (unsigned long)current->mm->context.vdso +
+ landing_pad = (unsigned long)current->mm->vdso_base +
vdso_image_32.sym_int80_landing_pad;
/*
diff --git a/arch/x86/entry/vdso/extable.c b/arch/x86/entry/vdso/extable.c
index afcf5b65beef..e5bfb35dafdb 100644
--- a/arch/x86/entry/vdso/extable.c
+++ b/arch/x86/entry/vdso/extable.c
@@ -25,10 +25,10 @@ bool fixup_vdso_exception(struct pt_regs *regs, int trapnr,
if (trapnr == X86_TRAP_DB || trapnr == X86_TRAP_BP)
return false;
- if (!current->mm->context.vdso)
+ if (current->mm->vdso_base == (void __user *)UNMAPPED_VDSO_BASE)
return false;
- base = (unsigned long)current->mm->context.vdso + image->extable_base;
+ base = (unsigned long)current->mm->vdso_base + image->extable_base;
nr_entries = image->extable_len / (sizeof(*extable));
extable = image->extable;
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index a286d44751be..f17e617c3b3e 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -77,7 +77,7 @@ static void vdso_fix_landing(const struct vdso_image *image,
struct pt_regs *regs = current_pt_regs();
unsigned long vdso_land = image->sym_int80_landing_pad;
unsigned long old_land_addr = vdso_land +
- (unsigned long)current->mm->context.vdso;
+ (unsigned long)current->mm->vdso_base;
/* Fixing userspace landing - look at do_fast_syscall_32 */
if (regs->ip == old_land_addr)
@@ -92,7 +92,6 @@ static void vdso_mremap(const struct vm_special_mapping *sm,
const struct vdso_image *image = current->mm->context.vdso_image;
vdso_fix_landing(image, new_vma);
- current->mm->context.vdso = (void __user *)new_vma->vm_start;
}
#ifdef CONFIG_TIME_NS
@@ -287,7 +286,7 @@ static int map_vdso(const struct vdso_image *image, unsigned long addr,
ret = PTR_ERR(vma);
do_munmap(mm, text_start, image->size, NULL);
} else {
- current->mm->context.vdso = (void __user *)text_start;
+ current->mm->vdso_base = (void __user *)text_start;
current->mm->context.vdso_image = image;
*sysinfo_ehdr = text_start;
}
@@ -362,8 +361,8 @@ int map_vdso_once(const struct vdso_image *image, unsigned long addr)
* Check if we have already mapped vdso blob - fail to prevent
* abusing from userspace install_special_mapping, which may
* not do accounting and rlimit right.
- * We could search vma near context.vdso, but it's a slowpath,
- * so let's explicitly check all VMAs to be completely sure.
+ * It's a slowpath, let's explicitly check all VMAs to be
+ * completely sure.
*/
for (vma = mm->mmap; vma; vma = vma->vm_next) {
if (vma_is_special_mapping(vma, &vdso_mapping) ||
@@ -415,9 +414,9 @@ bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
{
#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
const struct vdso_image *image = current->mm->context.vdso_image;
- unsigned long vdso = (unsigned long) current->mm->context.vdso;
+ unsigned long vdso = (unsigned long) current->mm->vdso_base;
- if (in_ia32_syscall() && image == &vdso_image_32) {
+ if (in_ia32_syscall() && current_has_vdso(&vdso_image_32)) {
if (regs->ip == vdso + image->sym_vdso32_sigreturn_landing_pad ||
regs->ip == vdso + image->sym_vdso32_rt_sigreturn_landing_pad)
return true;
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index 2af40ae53a0e..a98f4c7cdc38 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -256,7 +256,7 @@ int ia32_setup_frame(int sig, struct ksignal *ksig,
} else {
/* Return stub is in 32bit vsyscall page */
if (current_has_vdso(&vdso_image_32))
- restorer = current->mm->context.vdso +
+ restorer = current->mm->vdso_base +
vdso_image_32.sym___kernel_sigreturn;
else
restorer = &frame->retcode;
@@ -337,7 +337,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
if (ksig->ka.sa.sa_flags & SA_RESTORER)
restorer = ksig->ka.sa.sa_restorer;
else if (current_has_vdso(&vdso_image_32))
- restorer = current->mm->context.vdso +
+ restorer = current->mm->vdso_base +
vdso_image_32.sym___kernel_rt_sigreturn;
else
restorer = &frame->retcode;
diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h
index 5d7494631ea9..7bd10e6b8386 100644
--- a/arch/x86/include/asm/mmu.h
+++ b/arch/x86/include/asm/mmu.h
@@ -43,7 +43,6 @@ typedef struct {
#endif
struct mutex lock;
- void __user *vdso; /* vdso base address */
const struct vdso_image *vdso_image; /* vdso image in use */
atomic_t perf_rdpmc_allowed; /* nonzero if rdpmc is allowed */
diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
index 1ea7cb3f9b14..e4dcc189c30d 100644
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -46,7 +46,7 @@ extern const struct vdso_image vdso_image_32;
#endif
#define current_has_vdso(image) \
- (current->mm->context.vdso != 0 && \
+ (current->mm->vdso_base != (void __user *)UNMAPPED_VDSO_BASE && \
current->mm->context.vdso_image == image)
extern void __init init_vdso_image(const struct vdso_image *image);
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 77496ccb812d..c853d212e6cb 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -320,7 +320,7 @@ __setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
if (ksig->ka.sa.sa_flags & SA_RESTORER)
restorer = ksig->ka.sa.sa_restorer;
else if (current_has_vdso(&vdso_image_32))
- restorer = current->mm->context.vdso +
+ restorer = current->mm->vdso_base +
vdso_image_32.sym___kernel_sigreturn;
else
restorer = &frame->retcode;
@@ -382,7 +382,7 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
if (ksig->ka.sa.sa_flags & SA_RESTORER)
restorer = ksig->ka.sa.sa_restorer;
else if (current_has_vdso(&vdso_image_32))
- restorer = current->mm->context.vdso +
+ restorer = current->mm->vdso_base +
vdso_image_32.sym___kernel_rt_sigreturn;
else
restorer = &frame->retcode;
--
2.31.1
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