powerpc/32: Move exception prolog code into .text once MMU is back on

The space in the head section is rather constrained by the fact that
exception vectors are spread every 0x100 bytes and sometimes we
need to have "out of line" code because it doesn't fit.

Now that we are enabling MMU early in the prolog, take that opportunity
to jump somewhere else in the .text section where we don't have any
space constraint.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/38b31ca4bc782a4985bc7952a675404d7ff27c24.1615552867.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h
index d97ec94b34dab92d4ebc7aa28343785582e56885..3c0aa453851421948fbffc429d42d03d21bb3e70 100644 (file)
--- a/arch/powerpc/kernel/head_32.h
+++ b/arch/powerpc/kernel/head_32.h
@@ -70,6 +70,8 @@
        mtspr   SPRN_SRR0, r11
        mfspr   r11, SPRN_SPRG_SCRATCH2
        rfi
+
+       .text
 1:
        stw     r11,GPR1(r1)
        stw     r11,0(r1)
@@ -163,12 +165,14 @@
  */
 #ifdef CONFIG_PPC_BOOK3S
 #define        START_EXCEPTION(n, label)               \
+       __HEAD;                                 \
        . = n;                                  \
        DO_KVM n;                               \
 label:
 
 #else
 #define        START_EXCEPTION(n, label)               \
+       __HEAD;                                 \
        . = n;                                  \
 label:
 
@@ -196,6 +200,7 @@ label:
                          ret_from_except)
 
 .macro vmap_stack_overflow_exception
+       __HEAD
 vmap_stack_overflow:
 #ifdef CONFIG_SMP
        mfspr   r1, SPRN_SPRG_THREAD

diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S
index c14a71e0d6d37cc4ae7c52eae99f45feed689eda..e7d8856714d3aca0d8062e9cd796e6926bca1aa5 100644 (file)
--- a/arch/powerpc/kernel/head_40x.S
+++ b/arch/powerpc/kernel/head_40x.S
@@ -132,6 +132,8 @@ _ENTRY(crit_esr)
        ori     r11, r11, 1f@l
        mtspr   SPRN_SRR0, r11
        rfi
+
+       .text
 1:
        lwz     r11,crit_r1@l(0)
        stw     r11,GPR1(r1)
@@ -496,6 +498,7 @@ _ENTRY(crit_esr)
                crit_transfer_to_handler, ret_from_crit_exc)
 
        /* Programmable Interval Timer (PIT) Exception. (from 0x1000) */
+       __HEAD
 Decrementer:
        EXCEPTION_PROLOG
        lis     r0,TSR_PIS@h
@@ -504,12 +507,14 @@ Decrementer:
        EXC_XFER_LITE(0x1000, timer_interrupt)
 
        /* Fixed Interval Timer (FIT) Exception. (from 0x1010) */
+       __HEAD
 FITException:
        EXCEPTION_PROLOG
        addi    r3,r1,STACK_FRAME_OVERHEAD;
        EXC_XFER_STD(0x1010, unknown_exception)
 
        /* Watchdog Timer (WDT) Exception. (from 0x1020) */
+       __HEAD
 WDTException:
        CRITICAL_EXCEPTION_PROLOG;
        addi    r3,r1,STACK_FRAME_OVERHEAD;
@@ -523,6 +528,7 @@ WDTException:
  * reserved.
  */
 
+       __HEAD
        /* Damn, I came up one instruction too many to fit into the
         * exception space :-).  Both the instruction and data TLB
         * miss get to this point to load the TLB.

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 11789a077d769fc70be4110bb85a3b45130f624a..d16d0ec71bb2bd0de4a467756f5ca7a3467bb027 100644 (file)
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -133,7 +133,7 @@ instruction_counter:
        START_EXCEPTION(0x600, Alignment)
        EXCEPTION_PROLOG handle_dar_dsisr=1
        addi    r3,r1,STACK_FRAME_OVERHEAD
-       b       .Lalignment_exception_ool
+       EXC_XFER_STD(0x600, alignment_exception)
 
 /* Program check exception */
        EXCEPTION(0x700, ProgramCheck, program_check_exception, EXC_XFER_STD)
@@ -141,11 +141,6 @@ instruction_counter:
 /* Decrementer */
        EXCEPTION(0x900, Decrementer, timer_interrupt, EXC_XFER_LITE)
 
-       /* With VMAP_STACK there's not enough room for this at 0x600 */
-       . = 0xa00
-.Lalignment_exception_ool:
-       EXC_XFER_STD(0x600, alignment_exception)
-
 /* System call */
        START_EXCEPTION(0xc00, SystemCall)
        SYSCALL_ENTRY   0xc00
@@ -339,26 +334,25 @@ DARFixed:/* Return from dcbx instruction bug workaround */
  * support of breakpoints and such.  Someday I will get around to
  * using them.
  */
-do_databreakpoint:
-       EXCEPTION_PROLOG_1
-       EXCEPTION_PROLOG_2 handle_dar_dsisr=1
-       addi    r3,r1,STACK_FRAME_OVERHEAD
-       mfspr   r4,SPRN_BAR
-       stw     r4,_DAR(r11)
-       EXC_XFER_STD(0x1c00, do_break)
-
        START_EXCEPTION(0x1c00, DataBreakpoint)
        EXCEPTION_PROLOG_0 handle_dar_dsisr=1
        mfspr   r11, SPRN_SRR0
        cmplwi  cr1, r11, (.Ldtlbie - PAGE_OFFSET)@l
        cmplwi  cr7, r11, (.Litlbie - PAGE_OFFSET)@l
        cror    4*cr1+eq, 4*cr1+eq, 4*cr7+eq
-       bne     cr1, do_databreakpoint
+       bne     cr1, 1f
        mtcr    r10
        mfspr   r10, SPRN_SPRG_SCRATCH0
        mfspr   r11, SPRN_SPRG_SCRATCH1
        rfi
 
+1:     EXCEPTION_PROLOG_1
+       EXCEPTION_PROLOG_2 handle_dar_dsisr=1
+       addi    r3,r1,STACK_FRAME_OVERHEAD
+       mfspr   r4,SPRN_BAR
+       stw     r4,_DAR(r11)
+       EXC_XFER_STD(0x1c00, do_break)
+
 #ifdef CONFIG_PERF_EVENTS
        START_EXCEPTION(0x1d00, InstructionBreakpoint)
        mtspr   SPRN_SPRG_SCRATCH0, r10
@@ -376,6 +370,7 @@ do_databreakpoint:
        EXCEPTION(0x1e00, Trap_1e, unknown_exception, EXC_XFER_STD)
        EXCEPTION(0x1f00, Trap_1f, unknown_exception, EXC_XFER_STD)
 
+       __HEAD
        . = 0x2000
 
 /* This is the procedure to calculate the data EA for buggy dcbx,dcbi instructions

diff --git a/arch/powerpc/kernel/head_book3s_32.S b/arch/powerpc/kernel/head_book3s_32.S
index 17510c99802d7df00609a4a9bd5ca3bc471df0c5..4a74bbe7462b9bb33ebe25265b423f784e7dc91c 100644 (file)
--- a/arch/powerpc/kernel/head_book3s_32.S
+++ b/arch/powerpc/kernel/head_book3s_32.S
@@ -269,11 +269,10 @@ __secondary_hold_acknowledge:
 7:     EXCEPTION_PROLOG_2
        addi    r3,r1,STACK_FRAME_OVERHEAD
 #ifdef CONFIG_PPC_CHRP
-       beq     cr1, machine_check_tramp
+       beq     cr1, 1f
        twi     31, 0, 0
-#else
-       b       machine_check_tramp
 #endif
+1:     EXC_XFER_STD(0x200, machine_check_exception)
 
 /* Data access exception. */
        START_EXCEPTION(0x300, DataAccess)
@@ -297,7 +296,13 @@ ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_HPTE_TABLE)
 #endif
 1:     EXCEPTION_PROLOG_0 handle_dar_dsisr=1
        EXCEPTION_PROLOG_1
-       b       handle_page_fault_tramp_1
+       EXCEPTION_PROLOG_2 handle_dar_dsisr=1
+       lwz     r5, _DSISR(r11)
+       andis.  r0, r5, DSISR_DABRMATCH@h
+       bne-    1f
+       EXC_XFER_LITE(0x300, handle_page_fault)
+1:     EXC_XFER_STD(0x300, do_break)
+
 
 /* Instruction access exception. */
        START_EXCEPTION(0x400, InstructionAccess)
@@ -333,7 +338,7 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_HPTE_TABLE)
        START_EXCEPTION(0x600, Alignment)
        EXCEPTION_PROLOG handle_dar_dsisr=1
        addi    r3,r1,STACK_FRAME_OVERHEAD
-       b       alignment_exception_tramp
+       EXC_XFER_STD(0x600, alignment_exception)
 
 /* Program check exception */
        EXCEPTION(0x700, ProgramCheck, program_check_exception, EXC_XFER_STD)
@@ -385,6 +390,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_FPU_UNAVAILABLE)
        START_EXCEPTION(0xf20, AltiVecUnavailableTrap)
        b       AltiVecUnavailable
 
+       __HEAD
 /*
  * Handle TLB miss for instruction on 603/603e.
  * Note: we get an alternate set of r0 - r3 to use automatically.
@@ -627,22 +633,9 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_NEED_DTLB_SW_LRU)
        EXCEPTION(0x2e00, Trap_2e, unknown_exception, EXC_XFER_STD)
        EXCEPTION(0x2f00, Trap_2f, unknown_exception, EXC_XFER_STD)
 
+       __HEAD
        . = 0x3000
 
-machine_check_tramp:
-       EXC_XFER_STD(0x200, machine_check_exception)
-
-alignment_exception_tramp:
-       EXC_XFER_STD(0x600, alignment_exception)
-
-handle_page_fault_tramp_1:
-       EXCEPTION_PROLOG_2 handle_dar_dsisr=1
-       lwz     r5, _DSISR(r11)
-       andis.  r0, r5, DSISR_DABRMATCH@h
-       bne-    1f
-       EXC_XFER_LITE(0x300, handle_page_fault)
-1:     EXC_XFER_STD(0x300, do_break)
-
 #ifdef CONFIG_PPC_BOOK3S_604
 .macro save_regs_thread                thread
        stw     r0, THR0(\thread)
@@ -721,6 +714,7 @@ fast_hash_page_return:
        vmap_stack_overflow_exception
 #endif
 
+       __HEAD
 AltiVecUnavailable:
        EXCEPTION_PROLOG
 #ifdef CONFIG_ALTIVEC
@@ -731,12 +725,14 @@ AltiVecUnavailable:
 1:     addi    r3,r1,STACK_FRAME_OVERHEAD
        EXC_XFER_LITE(0xf20, altivec_unavailable_exception)
 
+       __HEAD
 PerformanceMonitor:
        EXCEPTION_PROLOG
        addi    r3,r1,STACK_FRAME_OVERHEAD
        EXC_XFER_STD(0xf00, performance_monitor_exception)
 
 
+       __HEAD
 /*
  * This code is jumped to from the startup code to copy
  * the kernel image to physical address PHYSICAL_START.