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Patch "MIPS: BPF: Fix multiple problems in JIT skb access helpers." has been added to the 4.9-stable tree

PATCH [email protected] 1 participant 1 message Mar 18, 2018

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This is a note to let you know that I've just added the patch titled

MIPS: BPF: Fix multiple problems in JIT skb access helpers.

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mips-bpf-fix-multiple-problems-in-jit-skb-access-helpers.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From foo@baz Sun Mar 18 16:55:33 CET 2018

From: David Daney <[email protected]>
Date: Tue, 14 Mar 2017 14:21:44 -0700
Subject: MIPS: BPF: Fix multiple problems in JIT skb access helpers.

From: David Daney <[email protected]>

[ Upstream commit a81507c79f4ae9a0f9fb1054b59b62a090620dd9 ]

o Socket data is unsigned, so use unsigned accessors instructions.

o Fix path result pointer generation arithmetic.

o Fix half-word byte swapping code for unsigned semantics.

Patchwork: https://patchwork.linux-mips.org/patch/15747/

---
 arch/mips/net/bpf_jit_asm.S |   23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)
arch/mips/net/bpf_jit_asm.S +12 -11
@@ -90,18 +90,14 @@ FEXPORT(sk_load_half_positive)
 	is_offset_in_header(2, half)
 	/* Offset within header boundaries */
 	PTR_ADDU t1, $r_skb_data, offset
-	.set	reorder
-	lh	$r_A, 0(t1)
-	.set	noreorder
+	lhu	$r_A, 0(t1)
 #ifdef CONFIG_CPU_LITTLE_ENDIAN
 # if defined(__mips_isa_rev) && (__mips_isa_rev >= 2)
-	wsbh	t0, $r_A
-	seh	$r_A, t0
+	wsbh	$r_A, $r_A
 # else
-	sll	t0, $r_A, 24
-	andi	t1, $r_A, 0xff00
-	sra	t0, t0, 16
-	srl	t1, t1, 8
+	sll	t0, $r_A, 8
+	srl	t1, $r_A, 8
+	andi	t0, t0, 0xff00
 	or	$r_A, t0, t1
 # endif
 #endif
@@ -115,7 +111,7 @@ FEXPORT(sk_load_byte_positive)
 	is_offset_in_header(1, byte)
 	/* Offset within header boundaries */
 	PTR_ADDU t1, $r_skb_data, offset
-	lb	$r_A, 0(t1)
+	lbu	$r_A, 0(t1)
 	jr	$r_ra
 	 move	$r_ret, zero
 	END(sk_load_byte)
@@ -139,6 +135,11 @@ FEXPORT(sk_load_byte_positive)
  * (void *to) is returned in r_s0
  *
  */
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+#define DS_OFFSET(SIZE) (4 * SZREG)
+#else
+#define DS_OFFSET(SIZE) ((4 * SZREG) + (4 - SIZE))
+#endif
 #define bpf_slow_path_common(SIZE)				\
 	/* Quick check. Are we within reasonable boundaries? */ \
 	LONG_ADDIU	$r_s1, $r_skb_len, -SIZE;		\
@@ -150,7 +151,7 @@ FEXPORT(sk_load_byte_positive)
 	PTR_LA		t0, skb_copy_bits;			\
 	PTR_S		$r_ra, (5 * SZREG)($r_sp);		\
 	/* Assign low slot to a2 */				\
-	move		a2, $r_sp;				\
+	PTR_ADDIU	a2, $r_sp, DS_OFFSET(SIZE);		\
 	jalr		t0;					\
 	/* Reset our destination slot (DS but it's ok) */	\
 	 INT_S		zero, (4 * SZREG)($r_sp);		\

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/mips-bpf-quit-clobbering-callee-saved-registers-in-jit-code.patch queue-4.9/pci-apply-cavium-acs-quirk-only-to-cn81xx-cn83xx-cn88xx-devices.patch queue-4.9/mips-bpf-fix-multiple-problems-in-jit-skb-access-helpers.patch