[PATCH] powerpc: Merge thread_info.h

Merge ppc32 and ppc64 versions of thread_info.h.  They were pretty
similar already, the chief changes are:

	- Instead of inline asm to implement current_thread_info(),
which needs to be different for ppc32 and ppc64, we use C with an
asm("r1") register variable.  gcc turns it into the same asm as we
used to have for both platforms.
	- We replace ppc32's 'local_flags' with the ppc64
'syscall_noerror' field.  The noerror flag was in fact the only thing
in the local_flags field anyway, so the ppc64 approach is simpler, and
means we only need a load-immediate/store instead of load/mask/store
when clearing the flag.
	- In readiness for 64k pages, when THREAD_SIZE will be less
than a page, ppc64 used kmalloc() rather than get_free_pages() to
allocate the kernel stack.  With this patch we do the same for ppc32,
since there's no strong reason not to.
	- For ppc64, we no longer export THREAD_SHIFT and THREAD_SIZE
via asm-offsets, thread_info.h can now be safely included in asm, as
on ppc32.

Built and booted on G4 Powerbook (ARCH=ppc and ARCH=powerpc) and
Power5 (ARCH=ppc64 and ARCH=powerpc).

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 135 insertions, 0 deletions

diff --git a/include/asm-powerpc/thread_info.h b/include/asm-powerpc/thread_info.h
new file mode 100644
index 000000000000..0b4c24551c21
--- /dev/null
+++ b/include/asm-powerpc/thread_info.h
@@ -0,0 +1,135 @@
+/* thread_info.h: PowerPC low-level thread information
+ * adapted from the i386 version by Paul Mackerras
+ *
+ * Copyright (C) 2002  David Howells (dhowells@redhat.com)
+ * - Incorporating suggestions made by Linus Torvalds and Dave Miller
+ */
+
+#ifndef _ASM_POWERPC_THREAD_INFO_H
+#define _ASM_POWERPC_THREAD_INFO_H
+
+#ifdef __KERNEL__
+
+/* We have 8k stacks on ppc32 and 16k on ppc64 */
+
+#ifdef CONFIG_PPC64
+#define THREAD_SHIFT            14
+#else
+#define THREAD_SHIFT            13
+#endif
+
+#define THREAD_SIZE             (1 << THREAD_SHIFT)
+
+#ifndef __ASSEMBLY__
+#include <linux/config.h>
+#include <linux/cache.h>
+#include <asm/processor.h>
+#include <asm/page.h>
+#include <linux/stringify.h>
+
+/*
+ * low level task data.
+ */
+struct thread_info {
+        struct task_struct *task;               /* main task structure */
+        struct exec_domain *exec_domain;        /* execution domain */
+        int             cpu;                    /* cpu we're on */
+        int             preempt_count;          /* 0 => preemptable,
+                                                   <0 => BUG */
+        struct restart_block restart_block;
+        /* set by force_successful_syscall_return */
+        unsigned char   syscall_noerror;
+        /* low level flags - has atomic operations done on it */
+        unsigned long   flags ____cacheline_aligned_in_smp;
+};
+
+/*
+ * macros/functions for gaining access to the thread information structure
+ *
+ * preempt_count needs to be 1 initially, until the scheduler is functional.
+ */
+#define INIT_THREAD_INFO(tsk)                   \
+{                                               \
+        .task =         &tsk,                   \
+        .exec_domain =  &default_exec_domain,   \
+        .cpu =          0,                      \
+        .preempt_count = 1,                     \
+        .restart_block = {                      \
+                .fn = do_no_restart_syscall,    \
+        },                                      \
+        .flags =        0,                      \
+}
+
+#define init_thread_info        (init_thread_union.thread_info)
+#define init_stack              (init_thread_union.stack)
+
+/* thread information allocation */
+
+#ifdef CONFIG_DEBUG_STACK_USAGE
+#define alloc_thread_info(tsk)                                  \
+        ({                                                      \
+                struct thread_info *ret;                        \
+                                                                \
+                ret = kmalloc(THREAD_SIZE, GFP_KERNEL);         \
+                if (ret)                                        \
+                        memset(ret, 0, THREAD_SIZE);            \
+                ret;                                            \
+        })
+#else
+#define alloc_thread_info(tsk)  kmalloc(THREAD_SIZE, GFP_KERNEL)
+#endif
+#define free_thread_info(ti)    kfree(ti)
+#define get_thread_info(ti)     get_task_struct((ti)->task)
+#define put_thread_info(ti)     put_task_struct((ti)->task)
+
+/* how to get the thread information struct from C */
+static inline struct thread_info *current_thread_info(void)
+{
+        register unsigned long sp asm("r1");
+
+        /* gcc4, at least, is smart enough to turn this into a single
+         * rlwinm for ppc32 and clrrdi for ppc64 */
+        return (struct thread_info *)(sp & ~(THREAD_SIZE-1));
+}
+
+#endif /* __ASSEMBLY__ */
+
+#define PREEMPT_ACTIVE          0x10000000
+
+/*
+ * thread information flag bit numbers
+ */
+#define TIF_SYSCALL_TRACE       0       /* syscall trace active */
+#define TIF_NOTIFY_RESUME       1       /* resumption notification requested */
+#define TIF_SIGPENDING          2       /* signal pending */
+#define TIF_NEED_RESCHED        3       /* rescheduling necessary */
+#define TIF_POLLING_NRFLAG      4       /* true if poll_idle() is polling
+                                           TIF_NEED_RESCHED */
+#define TIF_32BIT               5       /* 32 bit binary */
+/* #define SPARE                6 */
+#define TIF_ABI_PENDING         7       /* 32/64 bit switch needed */
+#define TIF_SYSCALL_AUDIT       8       /* syscall auditing active */
+#define TIF_SINGLESTEP          9       /* singlestepping active */
+#define TIF_MEMDIE              10
+#define TIF_SECCOMP             11      /* secure computing */
+
+/* as above, but as bit values */
+#define _TIF_SYSCALL_TRACE      (1<<TIF_SYSCALL_TRACE)
+#define _TIF_NOTIFY_RESUME      (1<<TIF_NOTIFY_RESUME)
+#define _TIF_SIGPENDING         (1<<TIF_SIGPENDING)
+#define _TIF_NEED_RESCHED       (1<<TIF_NEED_RESCHED)
+#define _TIF_POLLING_NRFLAG     (1<<TIF_POLLING_NRFLAG)
+#define _TIF_32BIT              (1<<TIF_32BIT)
+/* #define _SPARE               (1<<SPARE) */
+#define _TIF_ABI_PENDING        (1<<TIF_ABI_PENDING)
+#define _TIF_SYSCALL_AUDIT      (1<<TIF_SYSCALL_AUDIT)
+#define _TIF_SINGLESTEP         (1<<TIF_SINGLESTEP)
+#define _TIF_SECCOMP            (1<<TIF_SECCOMP)
+#define _TIF_SYSCALL_T_OR_A     (_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP)
+
+#define _TIF_USER_WORK_MASK     (_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | \
+                                 _TIF_NEED_RESCHED)
+
+#endif /* __KERNEL__ */
+
+#endif /* _ASM_POWERPC_THREAD_INFO_H */