From 46a6e0cf1c6665a8e867d8f7798d7a3538633f03 Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Sun, 7 Jun 2015 11:37:02 -0700 Subject: x86/mpx: Clean up the code by not passing a task pointer around when unnecessary The MPX code can only work on the current task. You can not, for instance, enable MPX management in another process or thread. You can also not handle a fault for another process or thread. Despite this, we pass a task_struct around prolifically. This patch removes all of the task struct passing for code paths where the code can not deal with another task (which turns out to be all of them). This has no functional changes. It's just a cleanup. Signed-off-by: Dave Hansen Reviewed-by: Thomas Gleixner Cc: Andrew Morton Cc: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: bp@alien8.de Link: http://lkml.kernel.org/r/20150607183702.6A81DA2C@viggo.jf.intel.com Signed-off-by: Ingo Molnar --- arch/x86/mm/mpx.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) (limited to 'arch/x86/mm') diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c index 9d67e230b4fb..47e4a8564012 100644 --- a/arch/x86/mm/mpx.c +++ b/arch/x86/mm/mpx.c @@ -271,8 +271,7 @@ bad_opcode: * * The caller is expected to kfree() the returned siginfo_t. */ -siginfo_t *mpx_generate_siginfo(struct pt_regs *regs, - struct task_struct *tsk) +siginfo_t *mpx_generate_siginfo(struct pt_regs *regs) { const struct bndreg *bndregs, *bndreg; siginfo_t *info = NULL; @@ -340,7 +339,7 @@ err_out: return ERR_PTR(err); } -static __user void *task_get_bounds_dir(struct task_struct *tsk) +static __user void *mpx_get_bounds_dir(void) { const struct bndcsr *bndcsr; @@ -376,10 +375,10 @@ static __user void *task_get_bounds_dir(struct task_struct *tsk) (bndcsr->bndcfgu & MPX_BNDCFG_ADDR_MASK); } -int mpx_enable_management(struct task_struct *tsk) +int mpx_enable_management(void) { void __user *bd_base = MPX_INVALID_BOUNDS_DIR; - struct mm_struct *mm = tsk->mm; + struct mm_struct *mm = current->mm; int ret = 0; /* @@ -393,7 +392,7 @@ int mpx_enable_management(struct task_struct *tsk) * directory here means that we do not have to do xsave in the * unmap path; we can just use mm->bd_addr instead. */ - bd_base = task_get_bounds_dir(tsk); + bd_base = mpx_get_bounds_dir(); down_write(&mm->mmap_sem); mm->bd_addr = bd_base; if (mm->bd_addr == MPX_INVALID_BOUNDS_DIR) @@ -403,7 +402,7 @@ int mpx_enable_management(struct task_struct *tsk) return ret; } -int mpx_disable_management(struct task_struct *tsk) +int mpx_disable_management(void) { struct mm_struct *mm = current->mm; @@ -497,7 +496,7 @@ out_unmap: * bound table is 16KB. With 64-bit mode, the size of BD is 2GB, * and the size of each bound table is 4MB. */ -static int do_mpx_bt_fault(struct task_struct *tsk) +static int do_mpx_bt_fault(void) { unsigned long bd_entry, bd_base; const struct bndcsr *bndcsr; @@ -525,7 +524,7 @@ static int do_mpx_bt_fault(struct task_struct *tsk) return allocate_bt((long __user *)bd_entry); } -int mpx_handle_bd_fault(struct task_struct *tsk) +int mpx_handle_bd_fault(void) { /* * Userspace never asked us to manage the bounds tables, @@ -534,7 +533,7 @@ int mpx_handle_bd_fault(struct task_struct *tsk) if (!kernel_managing_mpx_tables(current->mm)) return -EINVAL; - if (do_mpx_bt_fault(tsk)) { + if (do_mpx_bt_fault()) { force_sig(SIGSEGV, current); /* * The force_sig() is essentially "handling" this -- cgit v1.2.3