[PATCH v2] powerpc/32s: Only build hash code when CONFIG_PPC_BOOK3S_604 is selected

From: Christophe Leroy
Date: Fri Dec 18 2020 - 01:57:16 EST


It is now possible to only build book3s/32 kernel for
CPUs without hash table.

Opt out hash related code when CONFIG_PPC_BOOK3S_604 is not selected.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
v2: Rebased
---
arch/powerpc/kernel/head_book3s_32.S | 12 ++++++++++++
arch/powerpc/mm/book3s32/Makefile | 4 +++-
2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/head_book3s_32.S b/arch/powerpc/kernel/head_book3s_32.S
index 349bf3f0c3af..c02024bce544 100644
--- a/arch/powerpc/kernel/head_book3s_32.S
+++ b/arch/powerpc/kernel/head_book3s_32.S
@@ -286,6 +286,7 @@ MachineCheck:
DO_KVM 0x300
DataAccess:
#ifdef CONFIG_VMAP_STACK
+#ifdef CONFIG_PPC_BOOK3S_604
BEGIN_MMU_FTR_SECTION
mtspr SPRN_SPRG_SCRATCH2,r10
mfspr r10, SPRN_SPRG_THREAD
@@ -302,12 +303,14 @@ BEGIN_MMU_FTR_SECTION
MMU_FTR_SECTION_ELSE
b 1f
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
#else /* CONFIG_VMAP_STACK */
EXCEPTION_PROLOG handle_dar_dsisr=1
get_and_save_dar_dsisr_on_stack r4, r5, r11
+#ifdef CONFIG_PPC_BOOK3S_604
BEGIN_MMU_FTR_SECTION
andis. r0, r5, (DSISR_BAD_FAULT_32S | DSISR_DABRMATCH)@h
bne handle_page_fault_tramp_2 /* if not, try to put a PTE */
@@ -315,8 +318,11 @@ BEGIN_MMU_FTR_SECTION
bl hash_page
b handle_page_fault_tramp_1
MMU_FTR_SECTION_ELSE
+#endif
b handle_page_fault_tramp_2
+#ifdef CONFIG_PPC_BOOK3S_604
ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_HPTE_TABLE)
+#endif
#endif /* CONFIG_VMAP_STACK */

/* Instruction access exception. */
@@ -332,12 +338,14 @@ InstructionAccess:
mfspr r11, SPRN_SRR1 /* check whether user or kernel */
stw r11, SRR1(r10)
mfcr r10
+#ifdef CONFIG_PPC_BOOK3S_604
BEGIN_MMU_FTR_SECTION
andis. r11, r11, SRR1_ISI_NOPT@h /* no pte found? */
bne hash_page_isi
.Lhash_page_isi_cont:
mfspr r11, SPRN_SRR1 /* check whether user or kernel */
END_MMU_FTR_SECTION_IFSET(MMU_FTR_HPTE_TABLE)
+#endif
andi. r11, r11, MSR_PR

EXCEPTION_PROLOG_1
@@ -348,9 +356,11 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_HPTE_TABLE)
beq 1f /* if so, try to put a PTE */
li r3,0 /* into the hash table */
mr r4,r12 /* SRR0 is fault address */
+#ifdef CONFIG_PPC_BOOK3S_604
BEGIN_MMU_FTR_SECTION
bl hash_page
END_MMU_FTR_SECTION_IFSET(MMU_FTR_HPTE_TABLE)
+#endif
#endif /* CONFIG_VMAP_STACK */
1: mr r4,r12
andis. r5,r9,DSISR_SRR1_MATCH_32S@h /* Filter relevant SRR1 bits */
@@ -683,6 +693,7 @@ handle_page_fault_tramp_2:
EXC_XFER_LITE(0x300, handle_page_fault)

#ifdef CONFIG_VMAP_STACK
+#ifdef CONFIG_PPC_BOOK3S_604
.macro save_regs_thread thread
stw r0, THR0(\thread)
stw r3, THR3(\thread)
@@ -754,6 +765,7 @@ fast_hash_page_return:
mfspr r11, SPRN_SPRG_SCRATCH1
mfspr r10, SPRN_SPRG_SCRATCH0
rfi
+#endif /* CONFIG_PPC_BOOK3S_604 */

stack_overflow:
vmap_stack_overflow_exception
diff --git a/arch/powerpc/mm/book3s32/Makefile b/arch/powerpc/mm/book3s32/Makefile
index 3f972db17761..446d9de88ce4 100644
--- a/arch/powerpc/mm/book3s32/Makefile
+++ b/arch/powerpc/mm/book3s32/Makefile
@@ -6,4 +6,6 @@ ifdef CONFIG_KASAN
CFLAGS_mmu.o += -DDISABLE_BRANCH_PROFILING
endif

-obj-y += mmu.o hash_low.o mmu_context.o tlb.o nohash_low.o
+obj-y += mmu.o mmu_context.o
+obj-$(CONFIG_PPC_BOOK3S_603) += nohash_low.o
+obj-$(CONFIG_PPC_BOOK3S_604) += hash_low.o tlb.o
--
2.25.0