[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>

12 files changed, 45 insertions, 146 deletions

diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index b0d6a7cd85e9..1c83abd9f37c 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -56,8 +56,6 @@ int main(void)
         DEFINE(THREAD, offsetof(struct task_struct, thread));
         DEFINE(MM, offsetof(struct task_struct, mm));
 #ifdef CONFIG_PPC64
-        DEFINE(THREAD_SHIFT, THREAD_SHIFT);
-        DEFINE(THREAD_SIZE, THREAD_SIZE);
         DEFINE(AUDITCONTEXT, offsetof(struct task_struct, audit_context));
 #else
         DEFINE(THREAD_INFO, offsetof(struct task_struct, thread_info));
@@ -94,12 +92,10 @@ int main(void)
 
         DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
         DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count));
-#ifdef CONFIG_PPC64
         DEFINE(TI_SC_NOERR, offsetof(struct thread_info, syscall_noerror));
-#else
+#ifdef CONFIG_PPC32
         DEFINE(TI_TASK, offsetof(struct thread_info, task));
         DEFINE(TI_EXECDOMAIN, offsetof(struct thread_info, exec_domain));
-        DEFINE(TI_LOCAL_FLAGS, offsetof(struct thread_info, local_flags));
         DEFINE(TI_CPU, offsetof(struct thread_info, cpu));
 #endif /* CONFIG_PPC64 */
 
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index fc9dded9ac04..37b4396ca978 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -199,10 +199,9 @@ _GLOBAL(DoSyscall)
 #ifdef SHOW_SYSCALLS
         bl      do_show_syscall
 #endif /* SHOW_SYSCALLS */
-        rlwinm  r10,r1,0,0,18   /* current_thread_info() */
-        lwz     r11,TI_LOCAL_FLAGS(r10)
-        rlwinm  r11,r11,0,~_TIFL_FORCE_NOERROR
-        stw     r11,TI_LOCAL_FLAGS(r10)
+        rlwinm  r10,r1,0,0,(31-THREAD_SHIFT)    /* current_thread_info() */
+        li      r11,0
+        stb     r11,TI_SC_NOERR(r10)
         lwz     r11,TI_FLAGS(r10)
         andi.   r11,r11,_TIF_SYSCALL_T_OR_A
         bne-    syscall_dotrace
@@ -225,10 +224,10 @@ ret_from_syscall:
         mr      r6,r3
         li      r11,-_LAST_ERRNO
         cmplw   0,r3,r11
-        rlwinm  r12,r1,0,0,18   /* current_thread_info() */
+        rlwinm  r12,r1,0,0,(31-THREAD_SHIFT)    /* current_thread_info() */
         blt+    30f
-        lwz     r11,TI_LOCAL_FLAGS(r12)
-        andi.   r11,r11,_TIFL_FORCE_NOERROR
+        lbz     r11,TI_SC_NOERR(r12)
+        cmpwi   r11,0
         bne     30f
         neg     r3,r3
         lwz     r10,_CCR(r1)    /* Set SO bit in CR */
@@ -315,7 +314,7 @@ syscall_exit_work:
         LOAD_MSR_KERNEL(r10,MSR_KERNEL) /* doesn't include MSR_EE */
         SYNC
         MTMSRD(r10)             /* disable interrupts again */
-        rlwinm  r12,r1,0,0,18   /* current_thread_info() */
+        rlwinm  r12,r1,0,0,(31-THREAD_SHIFT)    /* current_thread_info() */
         lwz     r9,TI_FLAGS(r12)
 5:
         andi.   r0,r9,_TIF_NEED_RESCHED
@@ -630,7 +629,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_601)
         .globl  sigreturn_exit
 sigreturn_exit:
         subi    r1,r3,STACK_FRAME_OVERHEAD
-        rlwinm  r12,r1,0,0,18   /* current_thread_info() */
+        rlwinm  r12,r1,0,0,(31-THREAD_SHIFT)    /* current_thread_info() */
         lwz     r9,TI_FLAGS(r12)
         andi.   r0,r9,_TIF_SYSCALL_T_OR_A
         beq+    ret_from_except_full
@@ -657,7 +656,7 @@ ret_from_except:
 
 user_exc_return:                /* r10 contains MSR_KERNEL here */
         /* Check current_thread_info()->flags */
-        rlwinm  r9,r1,0,0,18
+        rlwinm  r9,r1,0,0,(31-THREAD_SHIFT)
         lwz     r9,TI_FLAGS(r9)
         andi.   r0,r9,(_TIF_SIGPENDING|_TIF_NEED_RESCHED)
         bne     do_work
@@ -677,7 +676,7 @@ restore_user:
 /* N.B. the only way to get here is from the beq following ret_from_except. */
 resume_kernel:
         /* check current_thread_info->preempt_count */
-        rlwinm  r9,r1,0,0,18
+        rlwinm  r9,r1,0,0,(31-THREAD_SHIFT)
         lwz     r0,TI_PREEMPT(r9)
         cmpwi   0,r0,0          /* if non-zero, just restore regs and return */
         bne     restore
@@ -687,7 +686,7 @@ resume_kernel:
         andi.   r0,r3,MSR_EE    /* interrupts off? */
         beq     restore         /* don't schedule if so */
 1:      bl      preempt_schedule_irq
-        rlwinm  r9,r1,0,0,18
+        rlwinm  r9,r1,0,0,(31-THREAD_SHIFT)
         lwz     r3,TI_FLAGS(r9)
         andi.   r0,r3,_TIF_NEED_RESCHED
         bne-    1b
@@ -889,7 +888,7 @@ recheck:
         LOAD_MSR_KERNEL(r10,MSR_KERNEL)
         SYNC
         MTMSRD(r10)             /* disable interrupts */
-        rlwinm  r9,r1,0,0,18
+        rlwinm  r9,r1,0,0,(31-THREAD_SHIFT)
         lwz     r9,TI_FLAGS(r9)
         andi.   r0,r9,_TIF_NEED_RESCHED
         bne-    do_resched
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index a4ceb9ae20fc..72b0d26e41d4 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -36,6 +36,7 @@
 #include <asm/setup.h>
 #include <asm/hvcall.h>
 #include <asm/iSeries/LparMap.h>
+#include <asm/thread_info.h>
 
 #ifdef CONFIG_PPC_ISERIES
 #define DO_SOFT_DISABLE
diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
index 8fe295693c09..4775bed42cac 100644
--- a/arch/powerpc/kernel/misc_64.S
+++ b/arch/powerpc/kernel/misc_64.S
@@ -26,6 +26,7 @@
 #include <asm/ppc_asm.h>
 #include <asm/asm-offsets.h>
 #include <asm/cputable.h>
+#include <asm/thread_info.h>
 
         .text
 
diff --git a/arch/ppc/kernel/asm-offsets.c b/arch/ppc/kernel/asm-offsets.c
index 7972db1f6570..968261d69572 100644
--- a/arch/ppc/kernel/asm-offsets.c
+++ b/arch/ppc/kernel/asm-offsets.c
@@ -130,10 +130,10 @@ main(void)
         DEFINE(CPU_SPEC_FEATURES, offsetof(struct cpu_spec, cpu_features));
         DEFINE(CPU_SPEC_SETUP, offsetof(struct cpu_spec, cpu_setup));
 
+        DEFINE(TI_SC_NOERR, offsetof(struct thread_info, syscall_noerror));
         DEFINE(TI_TASK, offsetof(struct thread_info, task));
         DEFINE(TI_EXECDOMAIN, offsetof(struct thread_info, exec_domain));
         DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
-        DEFINE(TI_LOCAL_FLAGS, offsetof(struct thread_info, local_flags));
         DEFINE(TI_CPU, offsetof(struct thread_info, cpu));
         DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count));
 
diff --git a/arch/ppc/kernel/entry.S b/arch/ppc/kernel/entry.S
index 68fc61221776..f044edbb454f 100644
--- a/arch/ppc/kernel/entry.S
+++ b/arch/ppc/kernel/entry.S
@@ -200,9 +200,8 @@ _GLOBAL(DoSyscall)
         bl      do_show_syscall
 #endif /* SHOW_SYSCALLS */
         rlwinm  r10,r1,0,0,18   /* current_thread_info() */
-        lwz     r11,TI_LOCAL_FLAGS(r10)
-        rlwinm  r11,r11,0,~_TIFL_FORCE_NOERROR
-        stw     r11,TI_LOCAL_FLAGS(r10)
+        li      r11,0
+        stb     r11,TI_SC_NOERR(r10)
         lwz     r11,TI_FLAGS(r10)
         andi.   r11,r11,_TIF_SYSCALL_T_OR_A
         bne-    syscall_dotrace
@@ -227,8 +226,8 @@ ret_from_syscall:
         cmplw   0,r3,r11
         rlwinm  r12,r1,0,0,18   /* current_thread_info() */
         blt+    30f
-        lwz     r11,TI_LOCAL_FLAGS(r12)
-        andi.   r11,r11,_TIFL_FORCE_NOERROR
+        lbz     r11,TI_SC_NOERR(r12)
+        cmpwi   r11,0
         bne     30f
         neg     r3,r3
         lwz     r10,_CCR(r1)    /* Set SO bit in CR */
diff --git a/arch/ppc64/kernel/asm-offsets.c b/arch/ppc64/kernel/asm-offsets.c
index 1378fbbe1e57..5e6046cb414e 100644
--- a/arch/ppc64/kernel/asm-offsets.c
+++ b/arch/ppc64/kernel/asm-offsets.c
@@ -46,8 +46,6 @@
 int main(void)
 {
         /* thread struct on stack */
-        DEFINE(THREAD_SHIFT, THREAD_SHIFT);
-        DEFINE(THREAD_SIZE, THREAD_SIZE);
         DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
         DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count));
         DEFINE(TI_SC_NOERR, offsetof(struct thread_info, syscall_noerror));
diff --git a/arch/ppc64/kernel/head.S b/arch/ppc64/kernel/head.S
index d5e6be200764..15c5f0c48043 100644
--- a/arch/ppc64/kernel/head.S
+++ b/arch/ppc64/kernel/head.S
@@ -36,6 +36,7 @@
 #include <asm/setup.h>
 #include <asm/hvcall.h>
 #include <asm/iSeries/LparMap.h>
+#include <asm/thread_info.h>
 
 #ifdef CONFIG_PPC_ISERIES
 #define DO_SOFT_DISABLE
diff --git a/arch/ppc64/kernel/misc.S b/arch/ppc64/kernel/misc.S
index ad73aad8dbb6..a33448c2bd91 100644
--- a/arch/ppc64/kernel/misc.S
+++ b/arch/ppc64/kernel/misc.S
@@ -28,6 +28,7 @@
 #include <asm/ppc_asm.h>
 #include <asm/asm-offsets.h>
 #include <asm/cputable.h>
+#include <asm/thread_info.h>
 
         .text
 
diff --git a/include/asm-ppc64/thread_info.h b/include/asm-powerpc/thread_info.h
index 71244d8a427d..0b4c24551c21 100644
--- a/include/asm-ppc64/thread_info.h
+++ b/include/asm-powerpc/thread_info.h
@@ -1,15 +1,25 @@
-/* thread_info.h: PPC low-level thread information
+/* 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_THREAD_INFO_H
-#define _ASM_THREAD_INFO_H
+#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>
@@ -24,7 +34,8 @@ 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 */
+        int             preempt_count;          /* 0 => preemptable,
+                                                   <0 => BUG */
         struct restart_block restart_block;
         /* set by force_successful_syscall_return */
         unsigned char   syscall_noerror;
@@ -54,9 +65,6 @@ struct thread_info {
 
 /* thread information allocation */
 
-#define THREAD_SHIFT            14
-#define THREAD_ORDER            (THREAD_SHIFT - PAGE_SHIFT)
-#define THREAD_SIZE             (1 << THREAD_SHIFT)
 #ifdef CONFIG_DEBUG_STACK_USAGE
 #define alloc_thread_info(tsk)                                  \
         ({                                                      \
@@ -68,7 +76,7 @@ struct thread_info {
                 ret;                                            \
         })
 #else
-#define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
+#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)
@@ -77,9 +85,11 @@ struct thread_info {
 /* how to get the thread information struct from C */
 static inline struct thread_info *current_thread_info(void)
 {
-        struct thread_info *ti;
-        __asm__("clrrdi %0,1,%1" : "=r"(ti) : "i" (THREAD_SHIFT));
-        return ti;
+        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__ */
@@ -122,4 +132,4 @@ static inline struct thread_info *current_thread_info(void)
 
 #endif /* __KERNEL__ */
 
-#endif /* _ASM_THREAD_INFO_H */
+#endif /* _ASM_POWERPC_THREAD_INFO_H */
diff --git a/include/asm-ppc/ptrace.h b/include/asm-ppc/ptrace.h
index 7043c164b537..c34fb4e37a97 100644
--- a/include/asm-ppc/ptrace.h
+++ b/include/asm-ppc/ptrace.h
@@ -57,7 +57,7 @@ extern unsigned long profile_pc(struct pt_regs *regs);
 
 #define force_successful_syscall_return()   \
         do { \
-                current_thread_info()->local_flags |= _TIFL_FORCE_NOERROR; \
+                current_thread_info()->syscall_noerror = 1; \
         } while(0)
 
 /*
diff --git a/include/asm-ppc/thread_info.h b/include/asm-ppc/thread_info.h
deleted file mode 100644
index 27903db42efc..000000000000
--- a/include/asm-ppc/thread_info.h
+++ /dev/null
@@ -1,107 +0,0 @@
-/* thread_info.h: PPC 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_THREAD_INFO_H
-#define _ASM_THREAD_INFO_H
-
-#ifdef __KERNEL__
-#ifndef __ASSEMBLY__
-/*
- * low level task data.
- * If you change this, change the TI_* offsets below to match.
- */
-struct thread_info {
-        struct task_struct      *task;          /* main task structure */
-        struct exec_domain      *exec_domain;   /* execution domain */
-        unsigned long           flags;          /* low level flags */
-        unsigned long           local_flags;    /* non-racy flags */
-        int                     cpu;            /* cpu we're on */
-        int                     preempt_count;  /* 0 => preemptable,
-                                                   <0 => BUG */
-        struct restart_block    restart_block;
-};
-
-#define INIT_THREAD_INFO(tsk)                   \
-{                                               \
-        .task =         &tsk,                   \
-        .exec_domain =  &default_exec_domain,   \
-        .flags =        0,                      \
-        .local_flags =  0,                      \
-        .cpu =          0,                      \
-        .preempt_count = 1,                     \
-        .restart_block = {                      \
-                .fn = do_no_restart_syscall,    \
-        },                                      \
-}
-
-#define init_thread_info        (init_thread_union.thread_info)
-#define init_stack              (init_thread_union.stack)
-
-/*
- * macros/functions for gaining access to the thread information structure
- */
-
-/* how to get the thread information struct from C */
-static inline struct thread_info *current_thread_info(void)
-{
-        struct thread_info *ti;
-        __asm__("rlwinm %0,1,0,0,18" : "=r"(ti));
-        return ti;
-}
-
-/* thread information allocation */
-#define alloc_thread_info(tsk) ((struct thread_info *) \
-                                __get_free_pages(GFP_KERNEL, 1))
-#define free_thread_info(ti)    free_pages((unsigned long) (ti), 1)
-#define get_thread_info(ti)     get_task_struct((ti)->task)
-#define put_thread_info(ti)     put_task_struct((ti)->task)
-#endif /* __ASSEMBLY__ */
-
-/*
- * Size of kernel stack for each process.
- */
-#define THREAD_SIZE             8192    /* 2 pages */
-
-#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_MEMDIE              5
-#define TIF_SYSCALL_AUDIT       6       /* syscall auditing active */
-#define TIF_SECCOMP             7      /* 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_SYSCALL_AUDIT      (1<<TIF_SYSCALL_AUDIT)
-#define _TIF_SECCOMP            (1<<TIF_SECCOMP)
-
-#define _TIF_SYSCALL_T_OR_A     (_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP)
-
-/*
- * Non racy (local) flags bit numbers
- */
-#define TIFL_FORCE_NOERROR      0       /* don't return error from current
-                                           syscall even if result < 0 */
-
-/* as above, but as bit values */
-#define _TIFL_FORCE_NOERROR     (1<<TIFL_FORCE_NOERROR)
-
-
-#endif /* __KERNEL__ */
-
-#endif /* _ASM_THREAD_INFO_H */