microblaze: Save and restore r3/r4 in SAVE/RESTORE_REGS macros

Save and restore R3/R4 registers in macros. This change
help to cleanup entry.S.

In ret_from_trap function we are saving returning value from
syscall to pt_regs on stack that's why we don't need to save and
restore these values before kernel functions (schedule, do_signal).

Signed-off-by: Michal Simek <monstr@monstr.eu>

diff --git a/arch/microblaze/kernel/entry.S b/arch/microblaze/kernel/entry.S
index d40a59f..8f90ce7 100644 (file)
--- a/arch/microblaze/kernel/entry.S
+++ b/arch/microblaze/kernel/entry.S
@@ -194,6 +194,8 @@
 
 #define SAVE_REGS \
        swi     r2, r1, PTO+PT_R2;      /* Save SDA */                  \
+       swi     r3, r1, PTO+PT_R3;                                      \
+       swi     r4, r1, PTO+PT_R4;                                      \
        swi     r5, r1, PTO+PT_R5;                                      \
        swi     r6, r1, PTO+PT_R6;                                      \
        swi     r7, r1, PTO+PT_R7;                                      \
@@ -228,6 +230,8 @@
        mts     rmsr , r11;                                             \
        nop;                                                            \
        lwi     r2, r1, PTO+PT_R2;      /* restore SDA */               \
+       lwi     r3, r1, PTO+PT_R3;                                      \
+       lwi     r4, r1, PTO+PT_R4;                                      \
        lwi     r5, r1, PTO+PT_R5;                                      \
        lwi     r6, r1, PTO+PT_R6;                                      \
        lwi     r7, r1, PTO+PT_R7;                                      \
@@ -379,13 +383,12 @@ C_ENTRY(_user_exception):
 /* We re-enable BIP bit before state restore */
 C_ENTRY(ret_from_trap):
        set_bip;                        /*  Ints masked for state restore*/
-       lwi     r11, r1, PTO+PT_MODE;
-/* See if returning to kernel mode, if so, skip resched &c.  */
-       bnei    r11, 2f;
-
        swi     r3, r1, PTO + PT_R3
        swi     r4, r1, PTO + PT_R4
 
+       lwi     r11, r1, PTO+PT_MODE;
+/* See if returning to kernel mode, if so, skip resched &c.  */
+       bnei    r11, 2f;
        /* We're returning to user mode, so check for various conditions that
         * trigger rescheduling. */
        /* FIXME: Restructure all these flag checks. */
@@ -422,9 +425,6 @@ C_ENTRY(ret_from_trap):
 
 /* Finally, return to user state.  */
 1:
-       lwi     r3, r1, PTO + PT_R3; /* restore syscall result */
-       lwi     r4, r1, PTO + PT_R4;
-
        swi     r0, r0, PER_CPU(KM);    /* Now officially in user state. */
        swi     CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
        VM_OFF;
@@ -522,10 +522,6 @@ C_ENTRY(sys_rt_sigreturn_wrapper):
        swi     r11, r1, (PT_R1-PT_SIZE); /* Save original SP. */       \
        lwi     r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* restore r11 */\
        addik   r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack.  */\
-       /* store return registers separately because                    \
-        * this macros is use for others exceptions */                  \
-       swi     r3, r1, PTO + PT_R3;                                    \
-       swi     r4, r1, PTO + PT_R4;                                    \
        SAVE_REGS                                                       \
        /* PC, before IRQ/trap - this is one instruction above */       \
        swi     r17, r1, PTO+PT_PC;                                     \
@@ -543,10 +539,6 @@ C_ENTRY(sys_rt_sigreturn_wrapper):
        tophys(r1,r1);                                                  \
                                                                        \
        addik   r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack.  */\
-       /* store return registers separately because this macros        \
-        * is use for others exceptions */                              \
-       swi     r3, r1, PTO + PT_R3;                                    \
-       swi     r4, r1, PTO + PT_R4;                                    \
        SAVE_REGS                                                       \
        /* PC, before IRQ/trap - this is one instruction above FIXME*/  \
        swi     r17, r1, PTO+PT_PC;                                     \
@@ -689,9 +681,7 @@ C_ENTRY(ret_from_exc):
         * traps), but signal handlers may want to examine or change the
         * complete register state.  Here we save anything not saved by
         * the normal entry sequence, so that it may be safely restored
-        * (in a possibly modified form) after do_signal returns.
-        * store return registers separately because this macros is use
-        * for others exceptions */
+        * (in a possibly modified form) after do_signal returns. */
        la      r5, r1, PTO;            /* Arg 1: struct pt_regs *regs */
        addi    r7, r0, 0;              /* Arg 3: int in_syscall */
        bralid  r15, do_signal; /* Handle any signals */
@@ -703,8 +693,6 @@ C_ENTRY(ret_from_exc):
        VM_OFF;
        tophys(r1,r1);
 
-       lwi     r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
-       lwi     r4, r1, PTO+PT_R4;
        RESTORE_REGS;
        addik   r1, r1, STATE_SAVE_SIZE         /* Clean up stack space.  */
 
@@ -713,8 +701,6 @@ C_ENTRY(ret_from_exc):
 /* Return to kernel state.  */
 2:     VM_OFF;
        tophys(r1,r1);
-       lwi     r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
-       lwi     r4, r1, PTO+PT_R4;
        RESTORE_REGS;
        addik   r1, r1, STATE_SAVE_SIZE         /* Clean up stack space.  */
 
@@ -753,10 +739,6 @@ C_ENTRY(_interrupt):
        /* save registers */
 /* MS: Make room on the stack -> activation record */
        addik   r1, r1, -STATE_SAVE_SIZE;
-/* MS: store return registers separately because
- * this macros is use for others exceptions */
-       swi     r3, r1, PTO + PT_R3;
-       swi     r4, r1, PTO + PT_R4;
        SAVE_REGS
        /* MS: store mode */
        addi    r11, r0, 1; /* MS: Was in kernel-mode. */
@@ -776,8 +758,6 @@ C_ENTRY(_interrupt):
        tophys(r1,r1);
        /* save registers */
        addik   r1, r1, -STATE_SAVE_SIZE;
-       swi     r3, r1, PTO+PT_R3;
-       swi     r4, r1, PTO+PT_R4;
        SAVE_REGS
        /* calculate mode */
        swi     r0, r1, PTO + PT_MODE;
@@ -829,8 +809,6 @@ no_intr_resched:
        swi     CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE);
        VM_OFF;
        tophys(r1,r1);
-       lwi     r3, r1, PTO + PT_R3; /* MS: restore saved r3, r4 registers */
-       lwi     r4, r1, PTO + PT_R4;
        RESTORE_REGS
        addik   r1, r1, STATE_SAVE_SIZE /* MS: Clean up stack space. */
        lwi     r1, r1, PT_R1 - PT_SIZE;
@@ -859,8 +837,6 @@ restore:
 #endif
        VM_OFF /* MS: turn off MMU */
        tophys(r1,r1)
-       lwi     r3, r1, PTO + PT_R3; /* MS: restore saved r3, r4 registers */
-       lwi     r4, r1, PTO + PT_R4;
        RESTORE_REGS
        addik   r1, r1, STATE_SAVE_SIZE /* MS: Clean up stack space. */
        tovirt(r1,r1);
@@ -893,8 +869,6 @@ C_ENTRY(_debug_exception):
        lwi     r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* restore r11 */
 
        addik   r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack.  */
-       swi     r3, r1, PTO + PT_R3;
-       swi     r4, r1, PTO + PT_R4;
        SAVE_REGS;
 
        addi    r11, r0, 1;             /* Was in kernel-mode.  */
@@ -910,8 +884,6 @@ C_ENTRY(_debug_exception):
        tophys(r1,r1);
 
        addik   r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack.  */
-       swi     r3, r1, PTO + PT_R3;
-       swi     r4, r1, PTO + PT_R4;
        SAVE_REGS;
 
        swi     r0, r1, PTO+PT_MODE; /* Was in user-mode.  */
@@ -979,8 +951,6 @@ dbtrap_call:        rtbd    r11, 0;
        VM_OFF;
        tophys(r1,r1);
 
-       lwi     r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
-       lwi     r4, r1, PTO+PT_R4;
        RESTORE_REGS
        addik   r1, r1, STATE_SAVE_SIZE         /* Clean up stack space.  */
 
@@ -992,8 +962,6 @@ dbtrap_call:        rtbd    r11, 0;
 /* Return to kernel state.  */
 2:     VM_OFF;
        tophys(r1,r1);
-       lwi     r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
-       lwi     r4, r1, PTO+PT_R4;
        RESTORE_REGS
        addik   r1, r1, STATE_SAVE_SIZE         /* Clean up stack space.  */