powerpc/32: Perform normal function call in exception entry

Now that the MMU is re-enabled before calling the transfer function,
we don't need anymore that hack with the address of the handler and
the return function sitting just after the 'bl' to the transfer
fonction, that function is retrieving via a read relative to 'lr'.

Do a regular call to the transfer function, then to the handler,
then branch to the return function.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/73c00f3361ca280ef8fd7814c291bd1f5b6e2081.1615552867.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index ad1fd33..fb849ef 100644 (file)
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -104,7 +104,7 @@ transfer_to_handler:
 #ifdef CONFIG_PPC_BOOK3S_32
        kuep_lock r11, r12
 #endif
-       b       3f
+       blr
 
        /* if from kernel, check interrupted DOZE/NAP mode */
 2:
@@ -118,13 +118,7 @@ transfer_to_handler:
 #endif /* CONFIG_PPC_BOOK3S_32 || CONFIG_E500 */
        .globl transfer_to_handler_cont
 transfer_to_handler_cont:
-3:
-       mflr    r9
-       lwz     r11,0(r9)               /* virtual address of handler */
-       lwz     r9,4(r9)                /* where to go when done */
-       mtctr   r11
-       mtlr    r9
-       bctr                            /* jump to handler */
+       blr
 
 #if defined (CONFIG_PPC_BOOK3S_32) || defined(CONFIG_E500)
 4:     rlwinm  r12,r12,0,~_TLF_NAPPING
@@ -404,8 +398,8 @@ fee_restarts:
        stw     r10,_TRAP(r11)
        addi    r3,r1,STACK_FRAME_OVERHEAD
        bl      transfer_to_handler_full
-       .long   unrecoverable_exception
-       .long   ret_from_except
+       bl      unrecoverable_exception
+       b       ret_from_except
 #endif
 
        .globl  ret_from_except_full

diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h
index 160ebd5..e09585b 100644 (file)
--- a/arch/powerpc/kernel/head_32.h
+++ b/arch/powerpc/kernel/head_32.h
@@ -190,8 +190,8 @@ label:
        li      r10,trap;                                       \
        stw     r10,_TRAP(r11);                                 \
        bl      tfer;                                           \
-       .long   hdlr;                                           \
-       .long   ret
+       bl      hdlr;                                           \
+       b       ret
 
 #define EXC_XFER_STD(n, hdlr)          \
        EXC_XFER_TEMPLATE(hdlr, n, MSR_KERNEL, transfer_to_handler_full,        \

diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
index a127d5e..3707f49 100644 (file)
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h
@@ -322,9 +322,9 @@ label:
 #define EXC_XFER_TEMPLATE(hdlr, trap, msr, tfer, ret)  \
        li      r10,trap;                                       \
        stw     r10,_TRAP(r11);                                 \
-       bl      tfer;                                           \
-       .long   hdlr;                                           \
-       .long   ret
+       bl      tfer;                                           \
+       bl      hdlr;                                           \
+       b       ret;                                            \
 
 #define EXC_XFER_STD(n, hdlr)          \
        EXC_XFER_TEMPLATE(hdlr, n, MSR_KERNEL, transfer_to_handler_full, \