From: Wei Yang <richardw.yang@linux.intel.com>
To: dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
Wei Yang <richardw.yang@linux.intel.com>
Subject: [PATCH 1/2] x86/mm: consolidate bad_area handling to the end
Date: Thu, 19 Sep 2019 10:08:43 +0800 [thread overview]
Message-ID: <20190919020844.27461-1-richardw.yang@linux.intel.com> (raw)
There are totally 7 bad_area[_nosemaphore] error branch in
do_user_addr_fault().
Consolidate all these handling to the end to make the code a little
neat.
BTW, after doing so, function bad_area is not used any more. Remove it.
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
---
arch/x86/mm/fault.c | 44 ++++++++++++++++----------------------------
1 file changed, 16 insertions(+), 28 deletions(-)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 9ceacd1156db..9d18b73b5f77 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -933,12 +933,6 @@ __bad_area(struct pt_regs *regs, unsigned long error_code,
__bad_area_nosemaphore(regs, error_code, address, pkey, si_code);
}
-static noinline void
-bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
-{
- __bad_area(regs, error_code, address, 0, SEGV_MAPERR);
-}
-
static inline bool bad_area_access_from_pkeys(unsigned long error_code,
struct vm_area_struct *vma)
{
@@ -1313,19 +1307,14 @@ void do_user_addr_fault(struct pt_regs *regs,
if (unlikely(cpu_feature_enabled(X86_FEATURE_SMAP) &&
!(hw_error_code & X86_PF_USER) &&
!(regs->flags & X86_EFLAGS_AC)))
- {
- bad_area_nosemaphore(regs, hw_error_code, address);
- return;
- }
+ goto bad_area_nosem;
/*
* If we're in an interrupt, have no user context or are running
* in a region with pagefaults disabled then we must not take the fault
*/
- if (unlikely(faulthandler_disabled() || !mm)) {
- bad_area_nosemaphore(regs, hw_error_code, address);
- return;
- }
+ if (unlikely(faulthandler_disabled() || !mm))
+ goto bad_area_nosem;
/*
* It's safe to allow irq's after cr2 has been saved and the
@@ -1385,8 +1374,7 @@ void do_user_addr_fault(struct pt_regs *regs,
* Fault from code in kernel from
* which we do not expect faults.
*/
- bad_area_nosemaphore(regs, hw_error_code, address);
- return;
+ goto bad_area_nosem;
}
retry:
down_read(&mm->mmap_sem);
@@ -1400,20 +1388,14 @@ void do_user_addr_fault(struct pt_regs *regs,
}
vma = find_vma(mm, address);
- if (unlikely(!vma)) {
- bad_area(regs, hw_error_code, address);
- return;
- }
+ if (unlikely(!vma))
+ goto bad_area;
if (likely(vma->vm_start <= address))
goto good_area;
- if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
- bad_area(regs, hw_error_code, address);
- return;
- }
- if (unlikely(expand_stack(vma, address))) {
- bad_area(regs, hw_error_code, address);
- return;
- }
+ if (unlikely(!(vma->vm_flags & VM_GROWSDOWN)))
+ goto bad_area;
+ if (unlikely(expand_stack(vma, address)))
+ goto bad_area;
/*
* Ok, we have a good vm_area for this memory access, so
@@ -1483,6 +1465,12 @@ void do_user_addr_fault(struct pt_regs *regs,
}
check_v8086_mode(regs, address, tsk);
+ return;
+
+bad_area:
+ up_read(&mm->mmap_sem);
+bad_area_nosem:
+ bad_area_nosemaphore(regs, hw_error_code, address);
}
NOKPROBE_SYMBOL(do_user_addr_fault);
--
2.17.1
next reply other threads:[~2019-09-19 2:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-19 2:08 Wei Yang [this message]
2019-09-19 2:08 ` [PATCH 2/2] x86/mm: replace a goto by merging two if clause Wei Yang
2019-09-23 9:22 ` Peter Zijlstra
2019-09-24 0:29 ` Wei Yang
2019-10-01 11:47 ` Wei Yang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190919020844.27461-1-richardw.yang@linux.intel.com \
--to=richardw.yang@linux.intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=peterz@infradead.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).