[PATCH] ppc: Make ARCH=ppc build again with new syscall path

This makes ARCH=ppc build in your powerpc tree again, with the new
syscall entry/exit path.

Still doesn't actually boot on my Pegasos; the last thing I see is
'MMU:exit'. But at least it builds -- I'll look at why it doesn't boot
later, so that I can see if the mv643xx_eth actually works with ARCH=ppc
(it doesn't with ARCH=powerpc; two in every three packets I receive are
offset by 4 bytes).

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 96 insertions, 71 deletions

diff --git a/arch/ppc/kernel/entry.S b/arch/ppc/kernel/entry.S
index f044edbb454..a48b950722a 100644
--- a/arch/ppc/kernel/entry.S
+++ b/arch/ppc/kernel/entry.S
@@ -200,8 +200,6 @@ _GLOBAL(DoSyscall)
         bl      do_show_syscall
 #endif /* SHOW_SYSCALLS */
         rlwinm  r10,r1,0,0,18   /* 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
@@ -222,25 +220,21 @@ ret_from_syscall:
         bl      do_show_syscall_exit
 #endif
         mr      r6,r3
-        li      r11,-_LAST_ERRNO
-        cmplw   0,r3,r11
         rlwinm  r12,r1,0,0,18   /* current_thread_info() */
-        blt+    30f
-        lbz     r11,TI_SC_NOERR(r12)
-        cmpwi   r11,0
-        bne     30f
-        neg     r3,r3
-        lwz     r10,_CCR(r1)    /* Set SO bit in CR */
-        oris    r10,r10,0x1000
-        stw     r10,_CCR(r1)
-
         /* disable interrupts so current_thread_info()->flags can't change */
-30:     LOAD_MSR_KERNEL(r10,MSR_KERNEL) /* doesn't include MSR_EE */
+        LOAD_MSR_KERNEL(r10,MSR_KERNEL) /* doesn't include MSR_EE */
         SYNC
         MTMSRD(r10)
         lwz     r9,TI_FLAGS(r12)
-        andi.   r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SIGPENDING|_TIF_NEED_RESCHED)
+        li      r8,-_LAST_ERRNO
+        andi.   r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SIGPENDING|_TIF_NEED_RESCHED|_TIF_RESTOREALL)
         bne-    syscall_exit_work
+        cmplw   0,r3,r8
+        blt+    syscall_exit_cont
+        lwz     r11,_CCR(r1)                    /* Load CR */
+        neg     r3,r3
+        oris    r11,r11,0x1000  /* Set SO bit in CR */
+        stw     r11,_CCR(r1)
 syscall_exit_cont:
 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
         /* If the process has its own DBCR0 value, load it up.  The single
@@ -292,46 +286,113 @@ syscall_dotrace:
         b       syscall_dotrace_cont
 
 syscall_exit_work:
-        stw     r6,RESULT(r1)   /* Save result */
+        andi.   r0,r9,_TIF_RESTOREALL
+        bne-    2f
+        cmplw   0,r3,r8
+        blt+    1f
+        andi.   r0,r9,_TIF_NOERROR
+        bne-    1f
+        lwz     r11,_CCR(r1)                    /* Load CR */
+        neg     r3,r3
+        oris    r11,r11,0x1000  /* Set SO bit in CR */
+        stw     r11,_CCR(r1)
+
+1:      stw     r6,RESULT(r1)   /* Save result */
         stw     r3,GPR3(r1)     /* Update return value */
-        andi.   r0,r9,_TIF_SYSCALL_T_OR_A
-        beq     5f
-        ori     r10,r10,MSR_EE
-        SYNC
-        MTMSRD(r10)             /* re-enable interrupts */
+2:      andi.   r0,r9,(_TIF_PERSYSCALL_MASK)
+        beq     4f
+
+        /* Clear per-syscall TIF flags if any are set, but _leave_
+        _TIF_SAVE_NVGPRS set in r9 since we haven't dealt with that
+        yet.  */
+
+        li      r11,_TIF_PERSYSCALL_MASK
+        addi    r12,r12,TI_FLAGS
+3:      lwarx   r8,0,r12
+        andc    r8,r8,r11
+#ifdef CONFIG_IBM405_ERR77
+        dcbt    0,r12
+#endif
+        stwcx.  r8,0,r12
+        bne-    3b
+        subi    r12,r12,TI_FLAGS
+        
+4:      /* Anything which requires enabling interrupts? */
+        andi.   r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SINGLESTEP|_TIF_SAVE_NVGPRS)
+        beq     7f
+
+        /* Save NVGPRS if they're not saved already */
         lwz     r4,TRAP(r1)
         andi.   r4,r4,1
-        beq     4f
+        beq     5f
         SAVE_NVGPRS(r1)
         li      r4,0xc00
         stw     r4,TRAP(r1)
-4:
+
+        /* Re-enable interrupts */
+5:      ori     r10,r10,MSR_EE
+        SYNC
+        MTMSRD(r10)
+
+        andi.   r0,r9,_TIF_SAVE_NVGPRS
+        bne     save_user_nvgprs
+
+save_user_nvgprs_cont:
+        andi.   r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SINGLESTEP)
+        beq     7f
+
         addi    r3,r1,STACK_FRAME_OVERHEAD
         bl      do_syscall_trace_leave
         REST_NVGPRS(r1)
-2:
-        lwz     r3,GPR3(r1)
+
+6:      lwz     r3,GPR3(r1)
         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() */
         lwz     r9,TI_FLAGS(r12)
-5:
+7:
         andi.   r0,r9,_TIF_NEED_RESCHED
-        bne     1f
+        bne     8f
         lwz     r5,_MSR(r1)
         andi.   r5,r5,MSR_PR
-        beq     syscall_exit_cont
+        beq     ret_from_except
         andi.   r0,r9,_TIF_SIGPENDING
-        beq     syscall_exit_cont
+        beq     ret_from_except
         b       do_user_signal
-1:
+8:
         ori     r10,r10,MSR_EE
         SYNC
         MTMSRD(r10)             /* re-enable interrupts */
         bl      schedule
-        b       2b
+        b       6b
+
+save_user_nvgprs:
+        lwz     r8,TI_SIGFRAME(r12)
+
+.macro savewords start, end
+  1:    stw \start,4*(\start)(r8)
+        .section __ex_table,"a"
+        .align  2
+        .long   1b,save_user_nvgprs_fault
+        .previous
+        .if \end - \start
+        savewords "(\start+1)",\end
+        .endif
+.endm   
+        savewords 14,31
+        b       save_user_nvgprs_cont
+
+        
+save_user_nvgprs_fault:
+        li      r3,11           /* SIGSEGV */
+        lwz     r4,TI_TASK(r12)
+        bl      force_sigsegv
 
+        rlwinm  r12,r1,0,0,18   /* current_thread_info() */
+        lwz     r9,TI_FLAGS(r12)
+        b       save_user_nvgprs_cont
+        
 #ifdef SHOW_SYSCALLS
 do_show_syscall:
 #ifdef SHOW_SYSCALLS_TASK
@@ -401,28 +462,10 @@ show_syscalls_task:
 #endif /* SHOW_SYSCALLS */
 
 /*
- * The sigsuspend and rt_sigsuspend system calls can call do_signal
- * and thus put the process into the stopped state where we might
- * want to examine its user state with ptrace.  Therefore we need
- * to save all the nonvolatile registers (r13 - r31) before calling
- * the C code.
+ * The fork/clone functions need to copy the full register set into
+ * the child process. Therefore we need to save all the nonvolatile
+ * registers (r13 - r31) before calling the C code.
  */
-        .globl  ppc_sigsuspend
-ppc_sigsuspend:
-        SAVE_NVGPRS(r1)
-        lwz     r0,TRAP(r1)
-        rlwinm  r0,r0,0,0,30            /* clear LSB to indicate full */
-        stw     r0,TRAP(r1)             /* register set saved */
-        b       sys_sigsuspend
-
-        .globl  ppc_rt_sigsuspend
-ppc_rt_sigsuspend:
-        SAVE_NVGPRS(r1)
-        lwz     r0,TRAP(r1)
-        rlwinm  r0,r0,0,0,30
-        stw     r0,TRAP(r1)
-        b       sys_rt_sigsuspend
-
         .globl  ppc_fork
 ppc_fork:
         SAVE_NVGPRS(r1)
@@ -447,14 +490,6 @@ ppc_clone:
         stw     r0,TRAP(r1)             /* register set saved */
         b       sys_clone
 
-        .globl  ppc_swapcontext
-ppc_swapcontext:
-        SAVE_NVGPRS(r1)
-        lwz     r0,TRAP(r1)
-        rlwinm  r0,r0,0,0,30            /* clear LSB to indicate full */
-        stw     r0,TRAP(r1)             /* register set saved */
-        b       sys_swapcontext
-
 /*
  * Top-level page fault handling.
  * This is in assembler because if do_page_fault tells us that
@@ -626,16 +661,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_601)
         .long   ret_from_except
 #endif
 
-        .globl  sigreturn_exit
-sigreturn_exit:
-        subi    r1,r3,STACK_FRAME_OVERHEAD
-        rlwinm  r12,r1,0,0,18   /* current_thread_info() */
-        lwz     r9,TI_FLAGS(r12)
-        andi.   r0,r9,_TIF_SYSCALL_T_OR_A
-        beq+    ret_from_except_full
-        bl      do_syscall_trace_leave
-        /* fall through */
-
         .globl  ret_from_except_full
 ret_from_except_full:
         REST_NVGPRS(r1)
@@ -658,7 +683,7 @@ user_exc_return:		/* r10 contains MSR_KERNEL here */
         /* Check current_thread_info()->flags */
         rlwinm  r9,r1,0,0,18
         lwz     r9,TI_FLAGS(r9)
-        andi.   r0,r9,(_TIF_SIGPENDING|_TIF_NEED_RESCHED)
+        andi.   r0,r9,(_TIF_SIGPENDING|_TIF_NEED_RESCHED|_TIF_RESTOREALL)
         bne     do_work
 
 restore_user: