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Subject[PATCH] powerpc/8xx: Simplify flush_tlb_kernel_range()
Date
In the same spirit as commit 63f501e07a85 ("powerpc/8xx: Simplify TLB
handling"), simplify flush_tlb_kernel_range() for 8xx.

8xx cannot be SMP, and has 'tlbie' and 'tlbia' instructions, so
an inline version of flush_tlb_kernel_range() for 8xx is worth it.

With this page, first leg of change_page_attr() is:

2c: 55 29 00 3c rlwinm r9,r9,0,0,30
30: 91 23 00 00 stw r9,0(r3)
34: 7c 00 22 64 tlbie r4,r0
38: 7c 00 04 ac hwsync
3c: 38 60 00 00 li r3,0
40: 4e 80 00 20 blr

Before the patch it was:

30: 55 29 00 3c rlwinm r9,r9,0,0,30
34: 91 2a 00 00 stw r9,0(r10)
38: 94 21 ff f0 stwu r1,-16(r1)
3c: 7c 08 02 a6 mflr r0
40: 38 83 10 00 addi r4,r3,4096
44: 90 01 00 14 stw r0,20(r1)
48: 48 00 00 01 bl 48 <change_page_attr+0x48>
48: R_PPC_REL24 flush_tlb_kernel_range
4c: 80 01 00 14 lwz r0,20(r1)
50: 38 60 00 00 li r3,0
54: 7c 08 03 a6 mtlr r0
58: 38 21 00 10 addi r1,r1,16
5c: 4e 80 00 20 blr

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/include/asm/nohash/tlbflush.h | 12 +++++++++++-
arch/powerpc/mm/nohash/tlb.c | 2 ++
2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/nohash/tlbflush.h b/arch/powerpc/include/asm/nohash/tlbflush.h
index c08d25e3e626..698935d4f72d 100644
--- a/arch/powerpc/include/asm/nohash/tlbflush.h
+++ b/arch/powerpc/include/asm/nohash/tlbflush.h
@@ -30,7 +30,6 @@ struct mm_struct;

extern void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end);
-extern void flush_tlb_kernel_range(unsigned long start, unsigned long end);

#ifdef CONFIG_PPC_8xx
static inline void local_flush_tlb_mm(struct mm_struct *mm)
@@ -45,7 +44,18 @@ static inline void local_flush_tlb_page(struct vm_area_struct *vma, unsigned lon
{
asm volatile ("tlbie %0; sync" : : "r" (vmaddr) : "memory");
}
+
+static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end)
+{
+ start &= PAGE_MASK;
+
+ if (end - start <= PAGE_SIZE)
+ asm volatile ("tlbie %0; sync" : : "r" (start) : "memory");
+ else
+ asm volatile ("sync; tlbia; isync" : : : "memory");
+}
#else
+extern void flush_tlb_kernel_range(unsigned long start, unsigned long end);
extern void local_flush_tlb_mm(struct mm_struct *mm);
extern void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr);

diff --git a/arch/powerpc/mm/nohash/tlb.c b/arch/powerpc/mm/nohash/tlb.c
index fd2c77af5c55..47f81d1c35dc 100644
--- a/arch/powerpc/mm/nohash/tlb.c
+++ b/arch/powerpc/mm/nohash/tlb.c
@@ -358,6 +358,7 @@ void __init early_init_mmu_47x(void)
/*
* Flush kernel TLB entries in the given range
*/
+#ifndef CONFIG_PPC_8xx
void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
#ifdef CONFIG_SMP
@@ -370,6 +371,7 @@ void flush_tlb_kernel_range(unsigned long start, unsigned long end)
#endif
}
EXPORT_SYMBOL(flush_tlb_kernel_range);
+#endif

/*
* Currently, for range flushing, we just do a full mm flush. This should
--
2.35.1
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