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 @@
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 @@
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 @@
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 @@
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