Merge branch 'iov_iter' into for-next

1 files changed, 21 insertions, 6 deletions

diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S
index 619b1dd7bcde..d18a44940968 100644
--- a/arch/arm64/kernel/efi-entry.S
+++ b/arch/arm64/kernel/efi-entry.S
@@ -54,18 +54,17 @@ ENTRY(efi_stub_entry)
 	b.eq	efi_load_fail
 
 	/*
-	 * efi_entry() will have relocated the kernel image if necessary
-	 * and we return here with device tree address in x0 and the kernel
-	 * entry point stored at *image_addr. Save those values in registers
-	 * which are callee preserved.
+	 * efi_entry() will have copied the kernel image if necessary and we
+	 * return here with device tree address in x0 and the kernel entry
+	 * point stored at *image_addr. Save those values in registers which
+	 * are callee preserved.
 	 */
 	mov	x20, x0		// DTB address
 	ldr	x0, [sp, #16]	// relocated _text address
 	mov	x21, x0
 
 	/*
-	 * Flush dcache covering current runtime addresses
-	 * of kernel text/data. Then flush all of icache.
+	 * Calculate size of the kernel Image (same for original and copy).
 	 */
 	adrp	x1, _text
 	add	x1, x1, #:lo12:_text
@@ -73,9 +72,24 @@ ENTRY(efi_stub_entry)
 	add	x2, x2, #:lo12:_edata
 	sub	x1, x2, x1
 
+	/*
+	 * Flush the copied Image to the PoC, and ensure it is not shadowed by
+	 * stale icache entries from before relocation.
+	 */
 	bl	__flush_dcache_area
 	ic	ialluis
 
+	/*
+	 * Ensure that the rest of this function (in the original Image) is
+	 * visible when the caches are disabled. The I-cache can't have stale
+	 * entries for the VA range of the current image, so no maintenance is
+	 * necessary.
+	 */
+	adr	x0, efi_stub_entry
+	adr	x1, efi_stub_entry_end
+	sub	x1, x1, x0
+	bl	__flush_dcache_area
+
 	/* Turn off Dcache and MMU */
 	mrs	x0, CurrentEL
 	cmp	x0, #CurrentEL_EL2
@@ -105,4 +119,5 @@ efi_load_fail:
 	ldp	x29, x30, [sp], #32
 	ret
 
+efi_stub_entry_end:
 ENDPROC(efi_stub_entry)