From: Dave Hansen <dave.hansen@linux.intel.com> Date: Fri, 28 Sep 2018 16:02:25 +0000 (-0700) Subject: x86/mm: Add clarifying comments for user addr space X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=5b0c2cac54d44ea40d5c5aec7cbf14353b2a903e;p=openwrt%2Fstaging%2Fblogic.git x86/mm: Add clarifying comments for user addr space The SMAP and Reserved checking do not have nice comments. Add some to clarify and make it match everything else. Cc: x86@kernel.org Cc: Jann Horn <jannh@google.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: http://lkml.kernel.org/r/20180928160225.FFD44B8D@viggo.jf.intel.com --- diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 0d1f5d39fc63..1d838701a5f7 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1276,9 +1276,17 @@ void do_user_addr_fault(struct pt_regs *regs, if (unlikely(kprobes_fault(regs))) return; + /* + * Reserved bits are never expected to be set on + * entries in the user portion of the page tables. + */ if (unlikely(hw_error_code & X86_PF_RSVD)) pgtable_bad(regs, hw_error_code, address); + /* + * Check for invalid kernel (supervisor) access to user + * pages in the user address space. + */ if (unlikely(smap_violation(hw_error_code, regs))) { bad_area_nosemaphore(regs, hw_error_code, address, NULL); return;