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Subject[RFC PATCH v1 19/41] powerpc/32: Move exception prolog code into .text once MMU is back on
Date
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>
---
arch/powerpc/kernel/head_32.h | 5 ++++
arch/powerpc/kernel/head_40x.S | 6 +++++
arch/powerpc/kernel/head_8xx.S | 25 ++++++++------------
arch/powerpc/kernel/head_book3s_32.S | 34 ++++++++++++----------------
4 files changed, 36 insertions(+), 34 deletions(-)

diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h
index d97ec94b34da..3c0aa4538514 100644
--- 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 @@
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 c14a71e0d6d3..e7d8856714d3 100644
--- 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 11789a077d76..d16d0ec71bb2 100644
--- 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 8f5c8c8da63d..56d7bc212866 100644
--- 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.
@@ -624,22 +630,9 @@ 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)
@@ -718,6 +711,7 @@ fast_hash_page_return:
vmap_stack_overflow_exception
#endif

+ __HEAD
AltiVecUnavailable:
EXCEPTION_PROLOG
#ifdef CONFIG_ALTIVEC
@@ -728,12 +722,14 @@ 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.
--
2.25.0
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