From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: linuxppc-dev@lists.ozlabs.org
Cc: aneesh.kumar@linux.vnet.ibm.com,
Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: [PATCH 14/24] powerpc/mm: Rework mm_fault_error()
Date: Wed, 19 Jul 2017 14:49:36 +1000 [thread overview]
Message-ID: <20170719044946.22030-14-benh@kernel.crashing.org> (raw)
In-Reply-To: <20170719044946.22030-1-benh@kernel.crashing.org>
First, handle the normal retry failure in do_page_fault itself,
since it's a simple return statement. That allows us to remove
the "continue" special return code from mm_fault_error().
Once that's done, we can have an implementation much closer to
x86 where we only call mm_fault_error() if VM_FAULT_ERROR is set
and directly return.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
arch/powerpc/mm/fault.c | 66 +++++++++++++++++++++----------------------------
1 file changed, 28 insertions(+), 38 deletions(-)
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 3903b55fccf8..0b217947d34f 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -147,10 +147,6 @@ static noinline int bad_area(struct pt_regs *regs, unsigned long address)
return __bad_area(regs, address, SEGV_MAPERR);
}
-#define MM_FAULT_RETURN 0
-#define MM_FAULT_CONTINUE -1
-#define MM_FAULT_ERR(sig) (sig)
-
static int do_sigbus(struct pt_regs *regs, unsigned long address,
unsigned int fault)
{
@@ -158,7 +154,7 @@ static int do_sigbus(struct pt_regs *regs, unsigned long address,
unsigned int lsb = 0;
if (!user_mode(regs))
- return MM_FAULT_ERR(SIGBUS);
+ return SIGBUS;
current->thread.trap_nr = BUS_ADRERR;
info.si_signo = SIGBUS;
@@ -179,25 +175,17 @@ static int do_sigbus(struct pt_regs *regs, unsigned long address,
#endif
info.si_addr_lsb = lsb;
force_sig_info(SIGBUS, &info, current);
- return MM_FAULT_RETURN;
+ return 0;
}
static int mm_fault_error(struct pt_regs *regs, unsigned long addr, int fault)
{
/*
- * Pagefault was interrupted by SIGKILL. We have no reason to
- * continue the pagefault.
+ * Kernel page fault interrupted by SIGKILL. We have no reason to
+ * continue processing.
*/
- if (fatal_signal_pending(current)) {
- /* Coming from kernel, we need to deal with uaccess fixups */
- if (user_mode(regs))
- return MM_FAULT_RETURN;
- return MM_FAULT_ERR(SIGKILL);
- }
-
- /* No fault: be happy */
- if (!(fault & VM_FAULT_ERROR))
- return MM_FAULT_CONTINUE;
+ if (fatal_signal_pending(current) && !user_mode(regs))
+ return SIGKILL;
/* Out of memory */
if (fault & VM_FAULT_OOM) {
@@ -206,17 +194,18 @@ static int mm_fault_error(struct pt_regs *regs, unsigned long addr, int fault)
* made us unable to handle the page fault gracefully.
*/
if (!user_mode(regs))
- return MM_FAULT_ERR(SIGKILL);
+ return SIGSEGV;
pagefault_out_of_memory();
- return MM_FAULT_RETURN;
+ } else {
+ if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|
+ VM_FAULT_HWPOISON_LARGE))
+ return do_sigbus(regs, addr, fault);
+ else if (fault & VM_FAULT_SIGSEGV)
+ return bad_area_nosemaphore(regs, addr);
+ else
+ BUG();
}
-
- if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE))
- return do_sigbus(regs, addr, fault);
-
- /* We don't understand the fault code, this is fatal */
- BUG();
- return MM_FAULT_CONTINUE;
+ return 0;
}
/* Is this a bad kernel fault ? */
@@ -274,7 +263,7 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
int is_user = user_mode(regs);
int is_write = page_fault_is_write(error_code);
int fault;
- int rc = 0, store_update_sp = 0;
+ int store_update_sp = 0;
#ifdef CONFIG_PPC_ICSWX
/*
@@ -283,7 +272,7 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
* look at it
*/
if (error_code & ICSWX_DSI_UCT) {
- rc = acop_handle_fault(regs, address, error_code);
+ int rc = acop_handle_fault(regs, address, error_code);
if (rc)
return rc;
}
@@ -492,18 +481,19 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
if (!fatal_signal_pending(current))
goto retry;
}
- /* We will enter mm_fault_error() below */
- } else
- up_read(¤t->mm->mmap_sem);
- if (unlikely(fault & (VM_FAULT_RETRY|VM_FAULT_ERROR))) {
- if (fault & VM_FAULT_SIGSEGV)
- return bad_area_nosemaphore(regs, address);
- rc = mm_fault_error(regs, address, fault);
- if (rc >= MM_FAULT_RETURN)
- return rc;
+ /*
+ * User mode? Just return to handle the fatal exception otherwise
+ * return to bad_page_fault
+ */
+ return is_user ? 0 : SIGBUS;
}
+ up_read(¤t->mm->mmap_sem);
+
+ if (unlikely(fault & VM_FAULT_ERROR))
+ return mm_fault_error(regs, address, fault);
+
/*
* Major/minor page fault accounting.
*/
--
2.13.3
next prev parent reply other threads:[~2017-07-19 4:57 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-19 4:49 [PATCH 01/24] powerpc/mm: Move exception_enter/exit to a do_page_fault wrapper Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 02/24] powerpc/mm: Pre-filter SRR1 bits before do_page_fault() Benjamin Herrenschmidt
2017-07-22 16:43 ` LEROY Christophe
2017-07-23 1:10 ` Benjamin Herrenschmidt
2017-07-24 13:48 ` Michael Ellerman
2017-07-19 4:49 ` [PATCH 03/24] powerpc/6xx: Handle DABR match before calling do_page_fault Benjamin Herrenschmidt
2017-08-03 0:19 ` Michael Ellerman
2017-08-03 1:00 ` Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 04/24] powerpc/mm: Update definitions of DSISR bits Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 05/24] powerpc/mm: Update bits used to skip hash_page Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 06/24] powerpc/mm: Use symbolic constants for filtering SRR1 bits on ISIs Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 07/24] powerpc/mm: Move out definition of CPU specific is_write bits Benjamin Herrenschmidt
2017-07-22 16:40 ` LEROY Christophe
2017-07-23 1:06 ` Benjamin Herrenschmidt
2017-07-24 11:58 ` Michael Ellerman
2017-07-19 4:49 ` [PATCH 08/24] powerpc/mm: Move error_code checks for bad faults earlier Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 09/24] powerpc/mm: Overhaul handling of bad page faults Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 10/24] powerpc/mm: Move debugger check to notify_page_fault() Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 11/24] powerpc/mm: Simplify returns from __do_page_fault Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 12/24] powerpc/mm: Fix reporting of kernel execute faults Benjamin Herrenschmidt
2018-11-07 8:35 ` Christophe LEROY
2018-11-07 10:39 ` Benjamin Herrenschmidt
[not found] ` <87zhtr5d1v.fsf@linux.ibm.com>
2018-11-30 6:08 ` Christophe LEROY
2017-07-19 4:49 ` [PATCH 13/24] powerpc/mm: Make bad_area* helper functions Benjamin Herrenschmidt
2017-07-19 4:49 ` Benjamin Herrenschmidt [this message]
2017-07-19 4:49 ` [PATCH 15/24] powerpc/mm: Move CMO accounting out of do_page_fault into a helper Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 16/24] powerpc/mm: Cosmetic fix to page fault accounting Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 17/24] powerpc/mm: Move the DSISR_PROTFAULT sanity check Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 18/24] powerpc/mm: Move/simplify faulthandler_disabled() and !mm check Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 19/24] powerpc/mm: Add a bunch of (un)likely annotations to do_page_fault Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 20/24] powerpc/mm: Set fault flags earlier Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 21/24] powerpc/mm: Move page fault VMA access checks to a helper Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 22/24] powerpc/mm: Don't lose "major" fault indication on retry Benjamin Herrenschmidt
2017-07-19 4:49 ` [PATCH 23/24] powerpc/mm: Cleanup check for stack expansion Benjamin Herrenschmidt
2017-07-21 16:59 ` LEROY Christophe
2017-07-24 10:47 ` Michael Ellerman
2017-07-24 17:34 ` LEROY Christophe
2017-07-25 11:19 ` Michael Ellerman
2017-07-31 11:37 ` Christophe LEROY
2017-07-19 4:49 ` [PATCH 24/24] powerpc: Remove old unused icswx based coprocessor support Benjamin Herrenschmidt
2017-08-07 10:41 ` [01/24] powerpc/mm: Move exception_enter/exit to a do_page_fault wrapper Michael Ellerman
2017-08-07 16:37 ` Christophe LEROY
2017-08-08 2:16 ` Michael Ellerman
2017-08-08 6:45 ` Christophe LEROY
2017-08-08 10:00 ` Michael Ellerman
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