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sh: Support thread fault code encoding.

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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>
This commit is contained in:
Paul Mundt
2012-05-14 14:57:28 +09:00
parent f007688a50
commit 5a1dc78a38
3 changed files with 78 additions and 47 deletions
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46
arch/sh/include/asm/thread_info.h
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@@ -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 @@ extern void init_thread_xstate(void);
#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 @@ extern void init_thread_xstate(void);
#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 @@ extern void init_thread_xstate(void);
#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 @@ static inline void set_restore_sigmask(void)
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__ */