sh: Support thread fault code encoding.
This provides a simple interface modelled after sparc64/m32r to encode
the error code in the upper byte of thread_info for finer-grained
handling in the page fault path.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/include/asm/thread_info.h b/arch/sh/include/asm/thread_info.h
index 20ee40a..25a13e5 100644
--- a/arch/sh/include/asm/thread_info.h
+++ b/arch/sh/include/asm/thread_info.h
@@ -10,8 +10,18 @@
* - Incorporating suggestions made by Linus Torvalds and Dave Miller
*/
#ifdef __KERNEL__
+
#include <asm/page.h>
+/*
+ * Page fault error code bits
+ */
+#define FAULT_CODE_WRITE (1 << 0) /* write access */
+#define FAULT_CODE_INITIAL (1 << 1) /* initial page write */
+#define FAULT_CODE_ITLB (1 << 2) /* ITLB miss */
+#define FAULT_CODE_PROT (1 << 3) /* protection fault */
+#define FAULT_CODE_USER (1 << 4) /* user-mode access */
+
#ifndef __ASSEMBLY__
#include <asm/processor.h>
@@ -107,10 +117,13 @@
#endif /* __ASSEMBLY__ */
/*
- * thread information flags
- * - these are process state flags that various assembly files may need to access
- * - pending work-to-be-done flags are in LSW
- * - other flags in MSW
+ * Thread information flags
+ *
+ * - Limited to 24 bits, upper byte used for fault code encoding.
+ *
+ * - _TIF_ALLWORK_MASK and _TIF_WORK_MASK need to fit within 2 bytes, or
+ * we blow the tst immediate size constraints and need to fix up
+ * arch/sh/kernel/entry-common.S.
*/
#define TIF_SYSCALL_TRACE 0 /* syscall trace active */
#define TIF_SIGPENDING 1 /* signal pending */
@@ -133,12 +146,6 @@
#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
-/*
- * _TIF_ALLWORK_MASK and _TIF_WORK_MASK need to fit within 2 bytes, or we
- * blow the tst immediate size constraints and need to fix up
- * arch/sh/kernel/entry-common.S.
- */
-
/* work to do in syscall trace */
#define _TIF_WORK_SYSCALL_MASK (_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP | \
_TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
@@ -165,6 +172,7 @@
#define TS_USEDFPU 0x0002 /* FPU used by this task this quantum */
#ifndef __ASSEMBLY__
+
#define HAVE_SET_RESTORE_SIGMASK 1
static inline void set_restore_sigmask(void)
{
@@ -172,6 +180,24 @@
ti->status |= TS_RESTORE_SIGMASK;
set_bit(TIF_SIGPENDING, (unsigned long *)&ti->flags);
}
+
+#define TI_FLAG_FAULT_CODE_SHIFT 24
+
+/*
+ * Additional thread flag encoding
+ */
+static inline void set_thread_fault_code(unsigned int val)
+{
+ struct thread_info *ti = current_thread_info();
+ ti->flags = (ti->flags & (~0 >> (32 - TI_FLAG_FAULT_CODE_SHIFT)))
+ | (val << TI_FLAG_FAULT_CODE_SHIFT);
+}
+
+static inline unsigned int get_thread_fault_code(void)
+{
+ struct thread_info *ti = current_thread_info();
+ return ti->flags >> TI_FLAG_FAULT_CODE_SHIFT;
+}
#endif /* !__ASSEMBLY__ */
#endif /* __KERNEL__ */