linux-omap4 3.4: Fix random segfaults and boot issues seen with gcc 4.8

Based on work
https://github.com/koenkooi/meta-beagleboard/commit/87efc663c4f76d3051cecf1e2c3e2bbd461d200b

Signed-off-by: Baptiste DURAND <baptiste.durand@gmail.com>
Signed-off-by: Denys Dmytriyenko <denys@ti.com>

3 files changed, 341 insertions, 0 deletions

diff --git a/recipes-kernel/linux/linux-omap4-3.4/pandaboard/0003-ARM-7668-1-fix-memset-related-crashes-caused-by-rece.patch b/recipes-kernel/linux/linux-omap4-3.4/pandaboard/0003-ARM-7668-1-fix-memset-related-crashes-caused-by-rece.patch
new file mode 100644
index 00000000..7b4e6528
--- /dev/null
+++ b/recipes-kernel/linux/linux-omap4-3.4/pandaboard/0003-ARM-7668-1-fix-memset-related-crashes-caused-by-rece.patch
@@ -0,0 +1,256 @@
+From b9ebe46e251c5c8becd02f92893ef514e834bf67 Mon Sep 17 00:00:00 2001
+From: Ivan Djelic <ivan.djelic@parrot.com>
+Date: Wed, 6 Mar 2013 20:09:27 +0100
+Subject: [PATCH 3/4] ARM: 7668/1: fix memset-related crashes caused by recent
+ GCC (4.7.2) optimizations
+
+Recent GCC versions (e.g. GCC-4.7.2) perform optimizations based on
+assumptions about the implementation of memset and similar functions.
+The current ARM optimized memset code does not return the value of
+its first argument, as is usually expected from standard implementations.
+
+For instance in the following function:
+
+void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
+{
+        memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
+        waiter->magic = waiter;
+        INIT_LIST_HEAD(&waiter->list);
+}
+
+compiled as:
+
+800554d0 <debug_mutex_lock_common>:
+800554d0:       e92d4008        push    {r3, lr}
+800554d4:       e1a00001        mov     r0, r1
+800554d8:       e3a02010        mov     r2, #16 ; 0x10
+800554dc:       e3a01011        mov     r1, #17 ; 0x11
+800554e0:       eb04426e        bl      80165ea0 <memset>
+800554e4:       e1a03000        mov     r3, r0
+800554e8:       e583000c        str     r0, [r3, #12]
+800554ec:       e5830000        str     r0, [r3]
+800554f0:       e5830004        str     r0, [r3, #4]
+800554f4:       e8bd8008        pop     {r3, pc}
+
+GCC assumes memset returns the value of pointer 'waiter' in register r0; causing
+register/memory corruptions.
+
+This patch fixes the return value of the assembly version of memset.
+It adds a 'mov' instruction and merges an additional load+store into
+existing load/store instructions.
+For ease of review, here is a breakdown of the patch into 4 simple steps:
+
+Step 1
+======
+Perform the following substitutions:
+ip -> r8, then
+r0 -> ip,
+and insert 'mov ip, r0' as the first statement of the function.
+At this point, we have a memset() implementation returning the proper result,
+but corrupting r8 on some paths (the ones that were using ip).
+
+Step 2
+======
+Make sure r8 is saved and restored when (! CALGN(1)+0) == 1:
+
+save r8:
+-       str     lr, [sp, #-4]!
++       stmfd   sp!, {r8, lr}
+
+and restore r8 on both exit paths:
+-       ldmeqfd sp!, {pc}               @ Now <64 bytes to go.
++       ldmeqfd sp!, {r8, pc}           @ Now <64 bytes to go.
+(...)
+        tst     r2, #16
+        stmneia ip!, {r1, r3, r8, lr}
+-       ldr     lr, [sp], #4
++       ldmfd   sp!, {r8, lr}
+
+Step 3
+======
+Make sure r8 is saved and restored when (! CALGN(1)+0) == 0:
+
+save r8:
+-       stmfd   sp!, {r4-r7, lr}
++       stmfd   sp!, {r4-r8, lr}
+
+and restore r8 on both exit paths:
+        bgt     3b
+-       ldmeqfd sp!, {r4-r7, pc}
++       ldmeqfd sp!, {r4-r8, pc}
+(...)
+        tst     r2, #16
+        stmneia ip!, {r4-r7}
+-       ldmfd   sp!, {r4-r7, lr}
++       ldmfd   sp!, {r4-r8, lr}
+
+Step 4
+======
+Rewrite register list "r4-r7, r8" as "r4-r8".
+
+Signed-off-by: Ivan Djelic <ivan.djelic@parrot.com>
+Reviewed-by: Nicolas Pitre <nico@linaro.org>
+Signed-off-by: Dirk Behme <dirk.behme@gmail.com>
+Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
+Signed-off-by: Khem Raj <raj.khem@gmail.com>
+---
+ arch/arm/lib/memset.S | 85 ++++++++++++++++++++++++++-------------------------
+ 1 file changed, 44 insertions(+), 41 deletions(-)
+
+diff --git a/arch/arm/lib/memset.S b/arch/arm/lib/memset.S
+index 650d592..d912e73 100644
+--- a/arch/arm/lib/memset.S
++++ b/arch/arm/lib/memset.S
+@@ -19,9 +19,9 @@
+ 1:     subs    r2, r2, #4              @ 1 do we have enough
+        blt     5f                      @ 1 bytes to align with?
+        cmp     r3, #2                  @ 1
+-       strltb  r1, [r0], #1            @ 1
+-       strleb  r1, [r0], #1            @ 1
+-       strb    r1, [r0], #1            @ 1
++       strltb  r1, [ip], #1            @ 1
++       strleb  r1, [ip], #1            @ 1
++       strb    r1, [ip], #1            @ 1
+        add     r2, r2, r3              @ 1 (r2 = r2 - (4 - r3))
+ /*
+  * The pointer is now aligned and the length is adjusted.  Try doing the
+@@ -29,10 +29,14 @@
+  */
+ 
+ ENTRY(memset)
+-       ands    r3, r0, #3              @ 1 unaligned?
++/*
++ * Preserve the contents of r0 for the return value.
++ */
++       mov     ip, r0
++       ands    r3, ip, #3              @ 1 unaligned?
+        bne     1b                      @ 1
+ /*
+- * we know that the pointer in r0 is aligned to a word boundary.
++ * we know that the pointer in ip is aligned to a word boundary.
+  */
+        orr     r1, r1, r1, lsl #8
+        orr     r1, r1, r1, lsl #16
+@@ -43,29 +47,28 @@ ENTRY(memset)
+ #if ! CALGN(1)+0
+ 
+ /*
+- * We need an extra register for this loop - save the return address and
+- * use the LR
++ * We need 2 extra registers for this loop - use r8 and the LR
+  */
+-       str     lr, [sp, #-4]!
+-       mov     ip, r1
++       stmfd   sp!, {r8, lr}
++       mov     r8, r1
+        mov     lr, r1
+ 
+ 2:     subs    r2, r2, #64
+-       stmgeia r0!, {r1, r3, ip, lr}   @ 64 bytes at a time.
+-       stmgeia r0!, {r1, r3, ip, lr}
+-       stmgeia r0!, {r1, r3, ip, lr}
+-       stmgeia r0!, {r1, r3, ip, lr}
++       stmgeia ip!, {r1, r3, r8, lr}   @ 64 bytes at a time.
++       stmgeia ip!, {r1, r3, r8, lr}
++       stmgeia ip!, {r1, r3, r8, lr}
++       stmgeia ip!, {r1, r3, r8, lr}
+        bgt     2b
+-       ldmeqfd sp!, {pc}               @ Now <64 bytes to go.
++       ldmeqfd sp!, {r8, pc}           @ Now <64 bytes to go.
+ /*
+  * No need to correct the count; we're only testing bits from now on
+  */
+        tst     r2, #32
+-       stmneia r0!, {r1, r3, ip, lr}
+-       stmneia r0!, {r1, r3, ip, lr}
++       stmneia ip!, {r1, r3, r8, lr}
++       stmneia ip!, {r1, r3, r8, lr}
+        tst     r2, #16
+-       stmneia r0!, {r1, r3, ip, lr}
+-       ldr     lr, [sp], #4
++       stmneia ip!, {r1, r3, r8, lr}
++       ldmfd   sp!, {r8, lr}
+ 
+ #else
+ 
+@@ -74,54 +77,54 @@ ENTRY(memset)
+  * whole cache lines at once.
+  */
+ 
+-       stmfd   sp!, {r4-r7, lr}
++       stmfd   sp!, {r4-r8, lr}
+        mov     r4, r1
+        mov     r5, r1
+        mov     r6, r1
+        mov     r7, r1
+-       mov     ip, r1
++       mov     r8, r1
+        mov     lr, r1
+ 
+        cmp     r2, #96
+-       tstgt   r0, #31
++       tstgt   ip, #31
+        ble     3f
+ 
+-       and     ip, r0, #31
+-       rsb     ip, ip, #32
+-       sub     r2, r2, ip
+-       movs    ip, ip, lsl #(32 - 4)
+-       stmcsia r0!, {r4, r5, r6, r7}
+-       stmmiia r0!, {r4, r5}
+-       tst     ip, #(1 << 30)
+-       mov     ip, r1
+-       strne   r1, [r0], #4
++       and     r8, ip, #31
++       rsb     r8, r8, #32
++       sub     r2, r2, r8
++       movs    r8, r8, lsl #(32 - 4)
++       stmcsia ip!, {r4, r5, r6, r7}
++       stmmiia ip!, {r4, r5}
++       tst     r8, #(1 << 30)
++       mov     r8, r1
++       strne   r1, [ip], #4
+ 
+ 3:     subs    r2, r2, #64
+-       stmgeia r0!, {r1, r3-r7, ip, lr}
+-       stmgeia r0!, {r1, r3-r7, ip, lr}
++       stmgeia ip!, {r1, r3-r8, lr}
++       stmgeia ip!, {r1, r3-r8, lr}
+        bgt     3b
+-       ldmeqfd sp!, {r4-r7, pc}
++       ldmeqfd sp!, {r4-r8, pc}
+ 
+        tst     r2, #32
+-       stmneia r0!, {r1, r3-r7, ip, lr}
++       stmneia ip!, {r1, r3-r8, lr}
+        tst     r2, #16
+-       stmneia r0!, {r4-r7}
+-       ldmfd   sp!, {r4-r7, lr}
++       stmneia ip!, {r4-r7}
++       ldmfd   sp!, {r4-r8, lr}
+ 
+ #endif
+ 
+ 4:     tst     r2, #8
+-       stmneia r0!, {r1, r3}
++       stmneia ip!, {r1, r3}
+        tst     r2, #4
+-       strne   r1, [r0], #4
++       strne   r1, [ip], #4
+ /*
+  * When we get here, we've got less than 4 bytes to zero.  We
+  * may have an unaligned pointer as well.
+  */
+ 5:     tst     r2, #2
+-       strneb  r1, [r0], #1
+-       strneb  r1, [r0], #1
++       strneb  r1, [ip], #1
++       strneb  r1, [ip], #1
+        tst     r2, #1
+-       strneb  r1, [r0], #1
++       strneb  r1, [ip], #1
+        mov     pc, lr
+ ENDPROC(memset)
+-- 
+1.8.2.1
+
diff --git a/recipes-kernel/linux/linux-omap4-3.4/pandaboard/0004-ARM-7670-1-fix-the-memset-fix.patch b/recipes-kernel/linux/linux-omap4-3.4/pandaboard/0004-ARM-7670-1-fix-the-memset-fix.patch
new file mode 100644
index 00000000..06584135
--- /dev/null
+++ b/recipes-kernel/linux/linux-omap4-3.4/pandaboard/0004-ARM-7670-1-fix-the-memset-fix.patch
@@ -0,0 +1,83 @@
+From 78429023fbec3428238e8dbdd81fa67e4619d04c Mon Sep 17 00:00:00 2001
+From: Nicolas Pitre <nicolas.pitre@linaro.org>
+Date: Tue, 12 Mar 2013 13:00:42 +0100
+Subject: [PATCH 4/4] ARM: 7670/1: fix the memset fix
+
+Commit 455bd4c430b0 ("ARM: 7668/1: fix memset-related crashes caused by
+recent GCC (4.7.2) optimizations") attempted to fix a compliance issue
+with the memset return value.  However the memset itself became broken
+by that patch for misaligned pointers.
+
+This fixes the above by branching over the entry code from the
+misaligned fixup code to avoid reloading the original pointer.
+
+Also, because the function entry alignment is wrong in the Thumb mode
+compilation, that fixup code is moved to the end.
+
+While at it, the entry instructions are slightly reworked to help dual
+issue pipelines.
+
+Signed-off-by: Nicolas Pitre <nico@linaro.org>
+Tested-by: Alexander Holler <holler@ahsoftware.de>
+Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
+---
+ arch/arm/lib/memset.S | 33 +++++++++++++--------------------
+ 1 file changed, 13 insertions(+), 20 deletions(-)
+
+diff --git a/arch/arm/lib/memset.S b/arch/arm/lib/memset.S
+index d912e73..94b0650 100644
+--- a/arch/arm/lib/memset.S
++++ b/arch/arm/lib/memset.S
+@@ -14,31 +14,15 @@
+ 
+        .text
+        .align  5
+-       .word   0
+-
+-1:     subs    r2, r2, #4              @ 1 do we have enough
+-       blt     5f                      @ 1 bytes to align with?
+-       cmp     r3, #2                  @ 1
+-       strltb  r1, [ip], #1            @ 1
+-       strleb  r1, [ip], #1            @ 1
+-       strb    r1, [ip], #1            @ 1
+-       add     r2, r2, r3              @ 1 (r2 = r2 - (4 - r3))
+-/*
+- * The pointer is now aligned and the length is adjusted.  Try doing the
+- * memset again.
+- */
+ 
+ ENTRY(memset)
+-/*
+- * Preserve the contents of r0 for the return value.
+- */
+-       mov     ip, r0
+-       ands    r3, ip, #3              @ 1 unaligned?
+-       bne     1b                      @ 1
++       ands    r3, r0, #3              @ 1 unaligned?
++       mov     ip, r0                  @ preserve r0 as return value
++       bne     6f                      @ 1
+ /*
+  * we know that the pointer in ip is aligned to a word boundary.
+  */
+-       orr     r1, r1, r1, lsl #8
++1:     orr     r1, r1, r1, lsl #8
+        orr     r1, r1, r1, lsl #16
+        mov     r3, r1
+        cmp     r2, #16
+@@ -127,4 +111,13 @@ ENTRY(memset)
+        tst     r2, #1
+        strneb  r1, [ip], #1
+        mov     pc, lr
++
++6:     subs    r2, r2, #4              @ 1 do we have enough
++       blt     5b                      @ 1 bytes to align with?
++       cmp     r3, #2                  @ 1
++       strltb  r1, [ip], #1            @ 1
++       strleb  r1, [ip], #1            @ 1
++       strb    r1, [ip], #1            @ 1
++       add     r2, r2, r3              @ 1 (r2 = r2 - (4 - r3))
++       b       1b
+ ENDPROC(memset)
+-- 
+1.8.2.1
+
diff --git a/recipes-kernel/linux/linux-omap4_3.4.bb b/recipes-kernel/linux/linux-omap4_3.4.bb
index 449e4eb8..52629de2 100644
--- a/recipes-kernel/linux/linux-omap4_3.4.bb
+++ b/recipes-kernel/linux/linux-omap4_3.4.bb
@@ -13,6 +13,8 @@ SRCREV = "c34a43ec74168b892a948b45695486f1a3d700af"
 
 SRC_URI = "git://dev.omapzoom.org/pub/scm/integration/kernel-ubuntu.git;protocol=git;branch=ti-ubuntu-3.4-1487 \
            file://defconfig \
+           file://0003-ARM-7668-1-fix-memset-related-crashes-caused-by-rece.patch \
+           file://0004-ARM-7670-1-fix-the-memset-fix.patch \
            "
 
 S = "${WORKDIR}/git"