Remove the vmalloc segment from bolted SLBEs. This is not required to
be bolted, and seems like it was added to help pre-load the SLB on
context switch. However there are now other segments like the vmemmap
segment and non-zero node memory that often take misses after a context
switch, so it is better to solve this in a more general way.
A subsequent change will track free SLB entries and uses those rather
than round-robin overwrite valid entries, which makes it far less
likely for kernel SLBEs to be evicted after they are installed.
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
arch/powerpc/include/asm/book3s/64/mmu-hash.h | 2 +-
arch/powerpc/mm/slb.c | 23 ++++---------------
2 files changed, 6 insertions(+), 19 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
index b3520b549cba..20d9ca736bbd 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
@@ -30,7 +30,7 @@
* SLB
*/
-#define SLB_NUM_BOLTED 3
+#define SLB_NUM_BOLTED 2
#define SLB_CACHE_ENTRIES 8
#define SLB_MIN_SIZE 32
diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
index d952ece3abf7..a5e58f11d676 100644
--- a/arch/powerpc/mm/slb.c
+++ b/arch/powerpc/mm/slb.c
@@ -30,8 +30,7 @@
enum slb_index {
LINEAR_INDEX = 0, /* Kernel linear map (0xc000000000000000) */
- VMALLOC_INDEX = 1, /* Kernel virtual map (0xd000000000000000) */
- KSTACK_INDEX = 2, /* Kernel stack map */
+ KSTACK_INDEX = 1, /* Kernel stack map */
};
extern void slb_allocate(unsigned long ea);
@@ -133,13 +132,11 @@ static void __slb_flush_and_rebolt(void)
{
/* If you change this make sure you change SLB_NUM_BOLTED
* and PR KVM appropriately too. */
- unsigned long linear_llp, vmalloc_llp, lflags, vflags;
+ unsigned long linear_llp, lflags;
unsigned long ksp_esid_data, ksp_vsid_data;
linear_llp = mmu_psize_defs[mmu_linear_psize].sllp;
- vmalloc_llp = mmu_psize_defs[mmu_vmalloc_psize].sllp;
lflags = SLB_VSID_KERNEL | linear_llp;
- vflags = SLB_VSID_KERNEL | vmalloc_llp;
ksp_esid_data = mk_esid_data(get_paca()->kstack, mmu_kernel_ssize,
KSTACK_INDEX);
if ((ksp_esid_data & ~0xfffffffUL) <= PAGE_OFFSET) {
@@ -157,14 +154,10 @@ static void __slb_flush_and_rebolt(void)
* the stack between the slbia and rebolting it. */
asm volatile("isync\n"
"slbia\n"
- /* Slot 1 - first VMALLOC segment */
+ /* Slot 1 - kernel stack */
"slbmte %0,%1\n"
- /* Slot 2 - kernel stack */
- "slbmte %2,%3\n"
"isync"
- :: "r"(mk_vsid_data(VMALLOC_START, mmu_kernel_ssize,
vflags)),
- "r"(mk_esid_data(VMALLOC_START, mmu_kernel_ssize,
VMALLOC_INDEX)),
- "r"(ksp_vsid_data),
+ :: "r"(ksp_vsid_data),
"r"(ksp_esid_data)
: "memory");
}
@@ -186,10 +179,6 @@ void slb_flush_and_rebolt(void)
void slb_vmalloc_update(void)
{
- unsigned long vflags;
-
- vflags = SLB_VSID_KERNEL | mmu_psize_defs[mmu_vmalloc_psize].sllp;
- slb_shadow_update(VMALLOC_START, mmu_kernel_ssize, vflags,
VMALLOC_INDEX);
slb_flush_and_rebolt();
}
@@ -324,7 +313,7 @@ void slb_set_size(u16 size)
void slb_initialize(void)
{
unsigned long linear_llp, vmalloc_llp, io_llp;
- unsigned long lflags, vflags;
+ unsigned long lflags;
static int slb_encoding_inited;
#ifdef CONFIG_SPARSEMEM_VMEMMAP
unsigned long vmemmap_llp;
@@ -360,14 +349,12 @@ void slb_initialize(void)
get_paca()->stab_rr = SLB_NUM_BOLTED - 1;
lflags = SLB_VSID_KERNEL | linear_llp;
- vflags = SLB_VSID_KERNEL | vmalloc_llp;
/* Invalidate the entire SLB (even entry 0) & all the ERATS */
asm volatile("isync":::"memory");
asm volatile("slbmte %0,%0"::"r" (0) : "memory");
asm volatile("isync; slbia; isync":::"memory");
create_shadowed_slbe(PAGE_OFFSET, mmu_kernel_ssize, lflags,
LINEAR_INDEX);
- create_shadowed_slbe(VMALLOC_START, mmu_kernel_ssize, vflags,
VMALLOC_INDEX);
/* For the boot cpu, we're running on the stack in init_thread_union,
* which is in the first segment of the linear mapping, and also
--
2.18.0
