From: Max Filippov <jcmvbkbc@gmail.com>
Date: Thu, 15 Nov 2012 02:25:48 +0000 (+0400)
Subject: xtensa: save and restore scompare1 SR on kernel entry
X-Git-Tag: v3.8-rc1~44^2~21
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=733536b865441d9bad02c4711a4372d48ce21e54;p=platform%2Fkernel%2Flinux-3.10.git

xtensa: save and restore scompare1 SR on kernel entry

Although scompare1 may be saved/restored by xchal_ncp_{load,store}
macros, explicit save/restore of registers manipulated by the kernel
itself is considered more correct.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
---

diff --git a/arch/xtensa/include/asm/ptrace.h b/arch/xtensa/include/asm/ptrace.h
index da21c17..9fe249c 100644
--- a/arch/xtensa/include/asm/ptrace.h
+++ b/arch/xtensa/include/asm/ptrace.h
@@ -37,7 +37,7 @@ struct pt_regs {
 	unsigned long windowstart;	/*  52 */
 	unsigned long syscall;		/*  56 */
 	unsigned long icountlevel;	/*  60 */
-	int reserved[1];		/*  64 */
+	unsigned long scompare1;	/*  64 */
 
 	/* Additional configurable registers that are used by the compiler. */
 	xtregs_opt_t xtregs_opt;
diff --git a/arch/xtensa/kernel/asm-offsets.c b/arch/xtensa/kernel/asm-offsets.c
index 7dc3f91..845475a 100644
--- a/arch/xtensa/kernel/asm-offsets.c
+++ b/arch/xtensa/kernel/asm-offsets.c
@@ -41,6 +41,7 @@ int main(void)
 	DEFINE(PT_SAR, offsetof (struct pt_regs, sar));
 	DEFINE(PT_ICOUNTLEVEL, offsetof (struct pt_regs, icountlevel));
 	DEFINE(PT_SYSCALL, offsetof (struct pt_regs, syscall));
+	DEFINE(PT_SCOMPARE1, offsetof(struct pt_regs, scompare1));
 	DEFINE(PT_AREG, offsetof (struct pt_regs, areg[0]));
 	DEFINE(PT_AREG0, offsetof (struct pt_regs, areg[0]));
 	DEFINE(PT_AREG1, offsetof (struct pt_regs, areg[1]));
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index 41ad9cf..4c2f270 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -372,6 +372,13 @@ common_exception:
 	s32i	a2, a1, PT_LBEG
 	s32i	a3, a1, PT_LEND
 
+	/* Save SCOMPARE1 */
+
+#if XCHAL_HAVE_S32C1I
+	rsr     a2, scompare1
+	s32i    a2, a1, PT_SCOMPARE1
+#endif
+
 	/* Save optional registers. */
 
 	save_xtregs_opt a1 a2 a4 a5 a6 a7 PT_XTREGS_OPT
@@ -433,6 +440,12 @@ common_exception_return:
 
 	load_xtregs_opt a1 a2 a4 a5 a6 a7 PT_XTREGS_OPT
 
+	/* Restore SCOMPARE1 */
+
+#if XCHAL_HAVE_S32C1I
+	l32i    a2, a1, PT_SCOMPARE1
+	wsr     a2, scompare1
+#endif
 	wsr	a3, ps		/* disable interrupts */
 
 	_bbci.l	a3, PS_UM_BIT, kernel_exception_exit