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 <james.hogan@imgtec.com>
Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14154/
Patchwork: https://patchwork.linux-mips.org/patch/14308/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 6 insertions, 11 deletions

diff --git a/arch/mips/kernel/uprobes.c b/arch/mips/kernel/uprobes.c
index 4c7c1558944a..15ad17cb2b6e 100644
--- a/arch/mips/kernel/uprobes.c
+++ b/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);
 }
 
 /**