From c2ef45df3b98a027ec8f9081bd2a19dff520ef9d Mon Sep 17 00:00:00 2001 From: Stephen Wilson Date: Sun, 13 Mar 2011 15:49:13 -0400 Subject: x86: add context tag to mark mm when running a task in 32-bit compatibility mode This tag is intended to mirror the thread info TIF_IA32 flag. Will be used to identify mm's which support 32 bit tasks running in compatibility mode without requiring a reference to the task itself. Signed-off-by: Stephen Wilson Reviewed-by: Michel Lespinasse Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Signed-off-by: Al Viro --- arch/x86/include/asm/mmu.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'arch/x86') diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h index 80a1dee..aeff3e8 100644 --- a/arch/x86/include/asm/mmu.h +++ b/arch/x86/include/asm/mmu.h @@ -13,6 +13,12 @@ typedef struct { int size; struct mutex lock; void *vdso; + +#ifdef CONFIG_X86_64 + /* True if mm supports a task running in 32 bit compatibility mode. */ + unsigned short ia32_compat; +#endif + } mm_context_t; #ifdef CONFIG_SMP -- cgit v1.1 From 375906f8765e131a4a159b1ffebf78c15db7b3bf Mon Sep 17 00:00:00 2001 From: Stephen Wilson Date: Sun, 13 Mar 2011 15:49:14 -0400 Subject: x86: mark associated mm when running a task in 32 bit compatibility mode This patch simply follows the same practice as for setting the TIF_IA32 flag. In particular, an mm is marked as holding 32-bit tasks when a 32-bit binary is exec'ed. Both ELF and a.out formats are updated. Signed-off-by: Stephen Wilson Reviewed-by: Michel Lespinasse Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Signed-off-by: Al Viro --- arch/x86/ia32/ia32_aout.c | 1 + arch/x86/kernel/process_64.c | 8 ++++++++ 2 files changed, 9 insertions(+) (limited to 'arch/x86') diff --git a/arch/x86/ia32/ia32_aout.c b/arch/x86/ia32/ia32_aout.c index 2d93bdb..fd84387 100644 --- a/arch/x86/ia32/ia32_aout.c +++ b/arch/x86/ia32/ia32_aout.c @@ -298,6 +298,7 @@ static int load_aout_binary(struct linux_binprm *bprm, struct pt_regs *regs) /* OK, This is the point of no return */ set_personality(PER_LINUX); set_thread_flag(TIF_IA32); + current->mm->context.ia32_compat = 1; setup_new_exec(bprm); diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index bd387e8..6c9dd92 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -501,6 +501,10 @@ void set_personality_64bit(void) /* Make sure to be in 64bit mode */ clear_thread_flag(TIF_IA32); + /* Ensure the corresponding mm is not marked. */ + if (current->mm) + current->mm->context.ia32_compat = 0; + /* TBD: overwrites user setup. Should have two bits. But 64bit processes have always behaved this way, so it's not too bad. The main problem is just that @@ -516,6 +520,10 @@ void set_personality_ia32(void) set_thread_flag(TIF_IA32); current->personality |= force_personality32; + /* Mark the associated mm as containing 32-bit tasks. */ + if (current->mm) + current->mm->context.ia32_compat = 1; + /* Prepare the first "return" to user space */ current_thread_info()->status |= TS_COMPAT; } -- cgit v1.1 From 31db58b3ab432f72ea76be58b12e6ffaf627d5db Mon Sep 17 00:00:00 2001 From: Stephen Wilson Date: Sun, 13 Mar 2011 15:49:15 -0400 Subject: mm: arch: make get_gate_vma take an mm_struct instead of a task_struct Morally, the presence of a gate vma is more an attribute of a particular mm than a particular task. Moreover, dropping the dependency on task_struct will help make both existing and future operations on mm's more flexible and convenient. Signed-off-by: Stephen Wilson Reviewed-by: Michel Lespinasse Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Signed-off-by: Al Viro --- arch/x86/mm/init_64.c | 6 +++--- arch/x86/vdso/vdso32-setup.c | 11 ++++++----- 2 files changed, 9 insertions(+), 8 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 0aa3466..dd4809b 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -861,10 +861,10 @@ static struct vm_area_struct gate_vma = { .vm_flags = VM_READ | VM_EXEC }; -struct vm_area_struct *get_gate_vma(struct task_struct *tsk) +struct vm_area_struct *get_gate_vma(struct mm_struct *mm) { #ifdef CONFIG_IA32_EMULATION - if (test_tsk_thread_flag(tsk, TIF_IA32)) + if (!mm || mm->context.ia32_compat) return NULL; #endif return &gate_vma; @@ -872,7 +872,7 @@ struct vm_area_struct *get_gate_vma(struct task_struct *tsk) int in_gate_area(struct task_struct *task, unsigned long addr) { - struct vm_area_struct *vma = get_gate_vma(task); + struct vm_area_struct *vma = get_gate_vma(task->mm); if (!vma) return 0; diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c index 36df991..1f651f6 100644 --- a/arch/x86/vdso/vdso32-setup.c +++ b/arch/x86/vdso/vdso32-setup.c @@ -417,11 +417,12 @@ const char *arch_vma_name(struct vm_area_struct *vma) return NULL; } -struct vm_area_struct *get_gate_vma(struct task_struct *tsk) +struct vm_area_struct *get_gate_vma(struct mm_struct *mm) { - struct mm_struct *mm = tsk->mm; - - /* Check to see if this task was created in compat vdso mode */ + /* + * Check to see if the corresponding task was created in compat vdso + * mode. + */ if (mm && mm->context.vdso == (void *)VDSO_HIGH_BASE) return &gate_vma; return NULL; @@ -429,7 +430,7 @@ struct vm_area_struct *get_gate_vma(struct task_struct *tsk) int in_gate_area(struct task_struct *task, unsigned long addr) { - const struct vm_area_struct *vma = get_gate_vma(task); + const struct vm_area_struct *vma = get_gate_vma(task->mm); return vma && addr >= vma->vm_start && addr < vma->vm_end; } -- cgit v1.1 From 83b964bbf82eb13a8f31bb49ca420787fe01f7a6 Mon Sep 17 00:00:00 2001 From: Stephen Wilson Date: Sun, 13 Mar 2011 15:49:16 -0400 Subject: mm: arch: make in_gate_area take an mm_struct instead of a task_struct Morally, the question of whether an address lies in a gate vma should be asked with respect to an mm, not a particular task. Moreover, dropping the dependency on task_struct will help make existing and future operations on mm's more flexible and convenient. Signed-off-by: Stephen Wilson Reviewed-by: Michel Lespinasse Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Signed-off-by: Al Viro --- arch/x86/mm/init_64.c | 4 ++-- arch/x86/vdso/vdso32-setup.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index dd4809b..43c4416 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -870,9 +870,9 @@ struct vm_area_struct *get_gate_vma(struct mm_struct *mm) return &gate_vma; } -int in_gate_area(struct task_struct *task, unsigned long addr) +int in_gate_area(struct mm_struct *mm, unsigned long addr) { - struct vm_area_struct *vma = get_gate_vma(task->mm); + struct vm_area_struct *vma = get_gate_vma(mm); if (!vma) return 0; diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c index 1f651f6..f849bb2 100644 --- a/arch/x86/vdso/vdso32-setup.c +++ b/arch/x86/vdso/vdso32-setup.c @@ -428,9 +428,9 @@ struct vm_area_struct *get_gate_vma(struct mm_struct *mm) return NULL; } -int in_gate_area(struct task_struct *task, unsigned long addr) +int in_gate_area(struct mm_struct *mm, unsigned long addr) { - const struct vm_area_struct *vma = get_gate_vma(task->mm); + const struct vm_area_struct *vma = get_gate_vma(mm); return vma && addr >= vma->vm_start && addr < vma->vm_end; } -- cgit v1.1 From cae5d39032acf26c265f6b1dc73d7ce6ff4bc387 Mon Sep 17 00:00:00 2001 From: Stephen Wilson Date: Sun, 13 Mar 2011 15:49:17 -0400 Subject: mm: arch: rename in_gate_area_no_task to in_gate_area_no_mm Now that gate vma's are referenced with respect to a particular mm and not a particular task it only makes sense to propagate the change to this predicate as well. Signed-off-by: Stephen Wilson Reviewed-by: Michel Lespinasse Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Signed-off-by: Al Viro --- arch/x86/mm/init_64.c | 8 ++++---- arch/x86/vdso/vdso32-setup.c | 2 +- 2 files changed, 5 insertions(+), 5 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 43c4416..835393c 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -881,11 +881,11 @@ int in_gate_area(struct mm_struct *mm, unsigned long addr) } /* - * Use this when you have no reliable task/vma, typically from interrupt - * context. It is less reliable than using the task's vma and may give - * false positives: + * Use this when you have no reliable mm, typically from interrupt + * context. It is less reliable than using a task's mm and may give + * false positives. */ -int in_gate_area_no_task(unsigned long addr) +int in_gate_area_no_mm(unsigned long addr) { return (addr >= VSYSCALL_START) && (addr < VSYSCALL_END); } diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c index f849bb2..468d591 100644 --- a/arch/x86/vdso/vdso32-setup.c +++ b/arch/x86/vdso/vdso32-setup.c @@ -435,7 +435,7 @@ int in_gate_area(struct mm_struct *mm, unsigned long addr) return vma && addr >= vma->vm_start && addr < vma->vm_end; } -int in_gate_area_no_task(unsigned long addr) +int in_gate_area_no_mm(unsigned long addr) { return 0; } -- cgit v1.1