From: Anshuman Khandual <anshuman.khandual@arm.com>
To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc: Anshuman Khandual <anshuman.khandual@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
James Morse <james.morse@arm.com>,
Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH V3 1/2] arm64/mm: Consolidate page fault information capture
Date: Fri, 7 Jun 2019 14:43:05 +0530 [thread overview]
Message-ID: <1559898786-28530-2-git-send-email-anshuman.khandual@arm.com> (raw)
In-Reply-To: <1559898786-28530-1-git-send-email-anshuman.khandual@arm.com>
This consolidates page fault information capture and move them bit earlier.
While here it also adds an wrapper is_write_abort(). It also saves some
cycles by replacing multiple user_mode() calls into a single one earlier
during the fault.
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
---
arch/arm64/mm/fault.c | 26 +++++++++++++++++++-------
1 file changed, 19 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 7c1c8f4..95cac4a 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -435,6 +435,15 @@ static bool is_el0_instruction_abort(unsigned int esr)
return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW;
}
+/*
+ * Note: not valid for EL1 DC IVAC, but we never use that such that it
+ * should fault. EL0 cannot issue DC IVAC (undef).
+ */
+static bool is_write_abort(unsigned int esr)
+{
+ return (esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM);
+}
+
static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
@@ -443,6 +452,9 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
vm_fault_t fault, major = 0;
unsigned long vm_flags = VM_READ | VM_WRITE;
unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+ bool is_user = user_mode(regs);
+ bool is_el0_exec = is_el0_instruction_abort(esr);
+ bool is_write = is_write_abort(esr);
if (notify_page_fault(regs, esr))
return 0;
@@ -454,13 +466,13 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
if (faulthandler_disabled() || !mm)
goto no_context;
- if (user_mode(regs))
+ if (is_user)
mm_flags |= FAULT_FLAG_USER;
- if (is_el0_instruction_abort(esr)) {
+ if (is_el0_exec) {
vm_flags = VM_EXEC;
mm_flags |= FAULT_FLAG_INSTRUCTION;
- } else if ((esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM)) {
+ } else if (is_write) {
vm_flags = VM_WRITE;
mm_flags |= FAULT_FLAG_WRITE;
}
@@ -488,7 +500,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
* we can bug out early if this is from code which shouldn't.
*/
if (!down_read_trylock(&mm->mmap_sem)) {
- if (!user_mode(regs) && !search_exception_tables(regs->pc))
+ if (!is_user && !search_exception_tables(regs->pc))
goto no_context;
retry:
down_read(&mm->mmap_sem);
@@ -499,7 +511,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
*/
might_sleep();
#ifdef CONFIG_DEBUG_VM
- if (!user_mode(regs) && !search_exception_tables(regs->pc)) {
+ if (!is_user && !search_exception_tables(regs->pc)) {
up_read(&mm->mmap_sem);
goto no_context;
}
@@ -517,7 +529,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
* in __lock_page_or_retry in mm/filemap.c.
*/
if (fatal_signal_pending(current)) {
- if (!user_mode(regs))
+ if (!is_user)
goto no_context;
return 0;
}
@@ -562,7 +574,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
* If we are in kernel mode at this point, we have no context to
* handle this fault with.
*/
- if (!user_mode(regs))
+ if (!is_user)
goto no_context;
if (fault & VM_FAULT_OOM) {
--
2.7.4
next prev parent reply other threads:[~2019-06-07 9:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-07 9:13 [PATCH V3 0/2] arm64/mm: Clean ups for do_page_fault() Anshuman Khandual
2019-06-07 9:13 ` Anshuman Khandual [this message]
2019-06-07 10:30 ` [PATCH V3 1/2] arm64/mm: Consolidate page fault information capture Mark Rutland
2019-06-07 13:34 ` Catalin Marinas
2019-06-07 9:13 ` [PATCH V3 2/2] arm64/mm: Refactor __do_page_fault() Anshuman Khandual
2019-06-07 10:23 ` Mark Rutland
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