[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>

4 files changed, 15 insertions, 18 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