MIPS: uprobes: Flush icache via kernel address

Update arch_uprobe_copy_ixol() to use the kmap_atomic() based kernel
address to flush the icache with flush_icache_range(), rather than the
user mapping. We have the kernel mapping available anyway and this
avoids having to switch to using the new __flush_icache_user_range() for
the sake of Enhanced Virtual Addressing (EVA) where flush_icache_range()
will become ineffective on user addresses.

Signed-off-by: James Hogan <[email protected]>
Cc: Leonid Yegoshin <[email protected]>
Cc: [email protected]
Patchwork: https://patchwork.linux-mips.org/patch/14154/
Patchwork: https://patchwork.linux-mips.org/patch/14308/
Signed-off-by: Ralf Baechle <[email protected]>

Author: James Hogan

arch/mips/kernel/uprobes.c

@@ -282,19 +282,14 @@ int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm,
 void __weak arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
 				  void *src, unsigned long len)
 {
-	void *kaddr;
+	unsigned long kaddr, kstart;
 
 	/* Initialize the slot */
-	kaddr = kmap_atomic(page);
-	memcpy(kaddr + (vaddr & ~PAGE_MASK), src, len);
-	kunmap_atomic(kaddr);
-
-	/*
-	 * The MIPS version of flush_icache_range will operate safely on
-	 * user space addresses and more importantly, it doesn't require a
-	 * VMA argument.
-	 */
-	flush_icache_range(vaddr, vaddr + len);
+	kaddr = (unsigned long)kmap_atomic(page);
+	kstart = kaddr + (vaddr & ~PAGE_MASK);
+	memcpy((void *)kstart, src, len);
+	flush_icache_range(kstart, kstart + len);
+	kunmap_atomic((void *)kaddr);
 }
 
 /**