[PATCH] powerpc/64s: Remove EXSLB interrupt save area
From: Nicholas Piggin <npiggin@gmail.com>
Date: 2021-02-08 06:37:34
SLB faults should not be taken while the PACA save areas are live, all memory accesses should be fetches from the kernel text, and access to PACA and the current stack, before C code is called or any other accesses are made. All of these have pinned SLBs so will not take a SLB fault. Therefore EXSLB is not be required. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- arch/powerpc/include/asm/paca.h | 3 +-- arch/powerpc/kernel/asm-offsets.c | 1 - arch/powerpc/kernel/exceptions-64s.S | 5 ----- 3 files changed, 1 insertion(+), 8 deletions(-)
diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
index 9454d29ff4b4..be0b00cb9fbb 100644
--- a/arch/powerpc/include/asm/paca.h
+++ b/arch/powerpc/include/asm/paca.h@@ -108,8 +108,7 @@ struct paca_struct { */ /* used for most interrupts/exceptions */ u64 exgen[EX_SIZE] __attribute__((aligned(0x80))); - u64 exslb[EX_SIZE]; /* used for SLB/segment table misses - * on the linear mapping */ + /* SLB related definitions */ u16 vmalloc_sllp; u8 slb_cache_ptr;
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index b12d7c049bfe..31edd9bbce75 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c@@ -255,7 +255,6 @@ int main(void) #endif /* CONFIG_PPC_MM_SLICES */ OFFSET(PACA_EXGEN, paca_struct, exgen); OFFSET(PACA_EXMC, paca_struct, exmc); - OFFSET(PACA_EXSLB, paca_struct, exslb); OFFSET(PACA_EXNMI, paca_struct, exnmi); #ifdef CONFIG_PPC_PSERIES OFFSET(PACALPPACAPTR, paca_struct, lppaca_ptr);
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index dad35b59bcfb..27fa80248406 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S@@ -1392,13 +1392,9 @@ ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX) * on user-handler data structures. * * KVM: Same as 0x300, DSLB must test for KVM guest. - * - * A dedicated save area EXSLB is used (XXX: but it actually need not be - * these days, we could use EXGEN). */ INT_DEFINE_BEGIN(data_access_slb) IVEC=0x380 - IAREA=PACA_EXSLB IDAR=1 IKVM_SKIP=1 IKVM_REAL=1
@@ -1481,7 +1477,6 @@ ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX) */ INT_DEFINE_BEGIN(instruction_access_slb) IVEC=0x480 - IAREA=PACA_EXSLB IISIDE=1 IDAR=1 #ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
--
2.23.0