From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:57438 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755390AbbISR2C (ORCPT ); Sat, 19 Sep 2015 13:28:02 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Max Filippov Subject: [PATCH 3.14 21/29] xtensa: fix kernel register spilling Date: Sat, 19 Sep 2015 10:27:43 -0700 Message-Id: <20150919171919.075514214@linuxfoundation.org> In-Reply-To: <20150919171918.169368855@linuxfoundation.org> References: <20150919171918.169368855@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: stable-owner@vger.kernel.org List-ID: 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Max Filippov commit 77d6273e79e3a86552fcf10cdd31a69b46ed2ce6 upstream. call12 can't be safely used as the first call in the inline function, because the compiler does not extend the stack frame of the bounding function accordingly, which may result in corruption of local variables. If a call needs to be done, do call8 first followed by call12. For pure assembly code in _switch_to increase stack frame size of the bounding function. Signed-off-by: Max Filippov Signed-off-by: Greg Kroah-Hartman --- arch/xtensa/include/asm/traps.h | 29 +++++++++++++++++++---------- arch/xtensa/kernel/entry.S | 4 ++-- 2 files changed, 21 insertions(+), 12 deletions(-) --- a/arch/xtensa/include/asm/traps.h +++ b/arch/xtensa/include/asm/traps.h @@ -25,30 +25,39 @@ static inline void spill_registers(void) { #if XCHAL_NUM_AREGS > 16 __asm__ __volatile__ ( - " call12 1f\n" + " call8 1f\n" " _j 2f\n" " retw\n" " .align 4\n" "1:\n" +#if XCHAL_NUM_AREGS == 32 + " _entry a1, 32\n" + " addi a8, a0, 3\n" + " _entry a1, 16\n" + " mov a12, a12\n" + " retw\n" +#else " _entry a1, 48\n" - " addi a12, a0, 3\n" -#if XCHAL_NUM_AREGS > 32 - " .rept (" __stringify(XCHAL_NUM_AREGS) " - 32) / 12\n" + " call12 1f\n" + " retw\n" + " .align 4\n" + "1:\n" + " .rept (" __stringify(XCHAL_NUM_AREGS) " - 16) / 12\n" " _entry a1, 48\n" " mov a12, a0\n" " .endr\n" -#endif - " _entry a1, 48\n" + " _entry a1, 16\n" #if XCHAL_NUM_AREGS % 12 == 0 - " mov a8, a8\n" -#elif XCHAL_NUM_AREGS % 12 == 4 " mov a12, a12\n" -#elif XCHAL_NUM_AREGS % 12 == 8 +#elif XCHAL_NUM_AREGS % 12 == 4 " mov a4, a4\n" +#elif XCHAL_NUM_AREGS % 12 == 8 + " mov a8, a8\n" #endif " retw\n" +#endif "2:\n" - : : : "a12", "a13", "memory"); + : : : "a8", "a9", "memory"); #else __asm__ __volatile__ ( " mov a12, a12\n" --- a/arch/xtensa/kernel/entry.S +++ b/arch/xtensa/kernel/entry.S @@ -1793,7 +1793,7 @@ ENDPROC(system_call) mov a12, a0 .endr #endif - _entry a1, 48 + _entry a1, 16 #if XCHAL_NUM_AREGS % 12 == 0 mov a8, a8 #elif XCHAL_NUM_AREGS % 12 == 4 @@ -1817,7 +1817,7 @@ ENDPROC(system_call) ENTRY(_switch_to) - entry a1, 16 + entry a1, 48 mov a11, a3 # and 'next' (a3)