[PATCH] x86: Quark: Add comment on TLB flush to setup_arch

[Bryan O'Donoghue]

Quark X1000 requires CR3 to be rewritten to flush TLB entries
irrespective of the PGE bits in CR4 or PTE.PGE

Add a comment to setup_arch to indicate that the code

load_cr3(swapper_pg_dir);
__flush_tlb_all();

Will already have flushed the TLB @ the CR3 reload allowing us
to skip over a potential if/else for Quark

Signed-off-by: Bryan O'Donoghue <pure.logic@xxxxxxxxxxxxxxxxx>
---
 arch/x86/kernel/setup.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 41ead8d..e7d7f6e 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -878,6 +878,11 @@ void __init setup_arch(char **cmdline_p)
 			initial_page_table + KERNEL_PGD_BOUNDARY,
 			KERNEL_PGD_PTRS);
 
+	/*
+	 * Locate the page directory and flush the TLB.
+	 * On Quark X1000 rewriting CR3 flushes the TLB no if/else is required
+	 * to choose between __flush_tlb() and __flush_tlb_all()
+	 */
 	load_cr3(swapper_pg_dir);
 	__flush_tlb_all();
 #else
-- 
1.9.1

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