[PATCH 3/3] x86: Support local_flush_tlb_kernel_range

[Minchan Kim <minchan@kernel.org>]

The zsmalloc [un]maps non-physical contiguos pages to contiguous
virual address frequently so it needs frequent tlb-flush.
Now x86 doesn't support common utility function for flushing just
a few tlb entries so zsmalloc have been used set_pte and __flush_tlb_one
which are x86 specific functions. It means zsmalloc have a dependency
with x86.

This patch adds new function, local_flush_tlb_kernel_range which
are good candidate for being common utility function because other
architecture(ex, MIPS, sh, unicore32, arm, score) already have
supportd it.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Cc: x86@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 arch/x86/include/asm/tlbflush.h  |   12 ++++++++++++
 drivers/staging/zsmalloc/Kconfig |    2 +-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index 4ece077..6e1253a 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -172,4 +172,16 @@ static inline void flush_tlb_kernel_range(unsigned long start,
 	flush_tlb_all();
 }
 
+static inline void local_flush_tlb_kernel_range(unsigned long start,
+		unsigned long end)
+{
+	if (cpu_has_invlpg) {
+		while (start < end) {
+			__flush_tlb_single(start);
+			start += PAGE_SIZE;
+		}
+	} else
+		local_flush_tlb();
+}
+
 #endif /* _ASM_X86_TLBFLUSH_H */
diff --git a/drivers/staging/zsmalloc/Kconfig b/drivers/staging/zsmalloc/Kconfig
index def2483..29819b8 100644
--- a/drivers/staging/zsmalloc/Kconfig
+++ b/drivers/staging/zsmalloc/Kconfig
@@ -3,7 +3,7 @@ config ZSMALLOC
 	# arch dependency is because of the use of local_unmap_kernel_range
 	# in zsmalloc-main.c.
 	# TODO: implement local_unmap_kernel_range in all architecture.
-	depends on (ARM || MIPS || SUPERH)
+	depends on (ARM || MIPS || SUPERH || X86)
 	default n
 	help
 	  zsmalloc is a slab-based memory allocator designed to store
-- 
1.7.9.5

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